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2017-02-16selinux: fix off-by-one in setprocattrStephen Smalley
commit 0c461cb727d146c9ef2d3e86214f498b78b7d125 upstream. SELinux tries to support setting/clearing of /proc/pid/attr attributes from the shell by ignoring terminating newlines and treating an attribute value that begins with a NUL or newline as an attempt to clear the attribute. However, the test for clearing attributes has always been wrong; it has an off-by-one error, and this could further lead to reading past the end of the allocated buffer since commit bb646cdb12e75d82258c2f2e7746d5952d3e321a ("proc_pid_attr_write(): switch to memdup_user()"). Fix the off-by-one error. Even with this fix, setting and clearing /proc/pid/attr attributes from the shell is not straightforward since the interface does not support multiple write() calls (so shells that write the value and newline separately will set and then immediately clear the attribute, requiring use of echo -n to set the attribute), whereas trying to use echo -n "" to clear the attribute causes the shell to skip the write() call altogether since POSIX says that a zero-length write causes no side effects. Thus, one must use echo -n to set and echo without -n to clear, as in the following example: $ echo -n unconfined_u:object_r:user_home_t:s0 > /proc/$$/attr/fscreate $ cat /proc/$$/attr/fscreate unconfined_u:object_r:user_home_t:s0 $ echo "" > /proc/$$/attr/fscreate $ cat /proc/$$/attr/fscreate Note the use of /proc/$$ rather than /proc/self, as otherwise the cat command will read its own attribute value, not that of the shell. There are no users of this facility to my knowledge; possibly we should just get rid of it. UPDATE: Upon further investigation it appears that a local process with the process:setfscreate permission can cause a kernel panic as a result of this bug. This patch fixes CVE-2017-2618. Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> [PM: added the update about CVE-2017-2618 to the commit description] Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-01-27apparmor: do not expose kernel stackHeinrich Schuchardt
commit f4ee2def2d70692ccff0d55353df4ee594fd0017 upstream. Do not copy uninitalized fields th.td_hilen, th.td_data. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: fix module parameters can be changed after policy is lockedJohn Johansen
commit 58acf9d911c8831156634a44d0b022d683e1e50c upstream. the policy_lock parameter is a one way switch that prevents policy from being further modified. Unfortunately some of the module parameters can effectively modify policy by turning off enforcement. split policy_admin_capable into a view check and a full admin check, and update the admin check to test the policy_lock parameter. Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: fix oops in profile_unpack() when policy_db is not presentJohn Johansen
commit 5f20fdfed16bc599a325a145bf0123a8e1c9beea upstream. BugLink: http://bugs.launchpad.net/bugs/1592547 If unpack_dfa() returns NULL due to the dfa not being present, profile_unpack() is not checking if the dfa is not present (NULL). Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: don't check for vmalloc_addr if kvzalloc() failedJohn Johansen
commit 3197f5adf539a3ee6331f433a51483f8c842f890 upstream. Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: add missing id bounds check on dfa verificationJohn Johansen
commit 15756178c6a65b261a080e21af4766f59cafc112 upstream. Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: fix refcount race when finding a child profileJohn Johansen
commit de7c4cc947f9f56f61520ee7edaf380434a98c8d upstream. When finding a child profile via an rcu critical section, the profile may be put and scheduled for deletion after the child is found but before its refcount is incremented. Protect against this by repeating the lookup if the profiles refcount is 0 and is one its way to deletion. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: check that xindex is in trans_table boundsJohn Johansen
commit 23ca7b640b4a55f8747301b6bd984dd05545f6a7 upstream. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: ensure the target profile name is always auditedJohn Johansen
commit f7da2de01127b58d93cebeab165136d0998e7b1a upstream. The target profile name was not being correctly audited in a few cases because the target variable was not being set and gotos passed the code to set it at apply: Since it is always based on new_profile just drop the target var and conditionally report based on new_profile. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com> Acked-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: fix audit full profile hname on successful loadJohn Johansen
commit 7ee6da25dcce27b6023a8673fdf8be98dcf7cacf upstream. Currently logging of a successful profile load only logs the basename of the profile. This can result in confusion when a child profile has the same name as the another profile in the set. Logging the hname will ensure there is no confusion. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: fix log failures for all profiles in a setJohn Johansen
commit bf15cf0c641be8e57d45f110a9d91464f5bb461a upstream. currently only the profile that is causing the failure is logged. This makes it more confusing than necessary about which profiles loaded and which didn't. So make sure to log success and failure messages for all profiles in the set being loaded. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: fix put() parent ref after updating the active refJohn Johansen
commit f351841f8d41072e741e45299070d421a5833a4a upstream. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: internal paths should be treated as disconnectedJohn Johansen
commit bd35db8b8ca6e27fc17a9057ef78e1ddfc0de351 upstream. Internal mounts are not mounted anywhere and as such should be treated as disconnected paths. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: fix disconnected bind mnts reconnectionJohn Johansen
commit f2e561d190da7ff5ee265fa460e2d7f753dddfda upstream. Bind mounts can fail to be properly reconnected when PATH_CONNECT is specified. Ensure that when PATH_CONNECT is specified the path has a root. BugLink: http://bugs.launchpad.net/bugs/1319984 Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: fix update the mtime of the profile file on replacementJohn Johansen
commit d671e890205a663429da74e1972e652bea4d73ab upstream. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: exec should not be returning ENOENT when it deniesJohn Johansen
commit 9049a7922124d843a2cd26a02b1d00a17596ec0c upstream. The current behavior is confusing as it causes exec failures to report the executable is missing instead of identifying that apparmor caused the failure. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: fix uninitialized lsm_audit memberJohn Johansen
commit b6b1b81b3afba922505b57f4c812bba022f7c4a9 upstream. BugLink: http://bugs.launchpad.net/bugs/1268727 The task field in the lsm_audit struct needs to be initialized if a change_hat fails, otherwise the following oops will occur BUG: unable to handle kernel paging request at 0000002fbead7d08 IP: [<ffffffff8171153e>] _raw_spin_lock+0xe/0x50 PGD 1e3f35067 PUD 0 Oops: 0002 [#1] SMP Modules linked in: pppox crc_ccitt p8023 p8022 psnap llc ax25 btrfs raid6_pq xor xfs libcrc32c dm_multipath scsi_dh kvm_amd dcdbas kvm microcode amd64_edac_mod joydev edac_core psmouse edac_mce_amd serio_raw k10temp sp5100_tco i2c_piix4 ipmi_si ipmi_msghandler acpi_power_meter mac_hid lp parport hid_generic usbhid hid pata_acpi mpt2sas ahci raid_class pata_atiixp bnx2 libahci scsi_transport_sas [last unloaded: tipc] CPU: 2 PID: 699 Comm: changehat_twice Tainted: GF O 3.13.0-7-generic #25-Ubuntu Hardware name: Dell Inc. PowerEdge R415/08WNM9, BIOS 1.8.6 12/06/2011 task: ffff8802135c6000 ti: ffff880212986000 task.ti: ffff880212986000 RIP: 0010:[<ffffffff8171153e>] [<ffffffff8171153e>] _raw_spin_lock+0xe/0x50 RSP: 0018:ffff880212987b68 EFLAGS: 00010006 RAX: 0000000000020000 RBX: 0000002fbead7500 RCX: 0000000000000000 RDX: 0000000000000292 RSI: ffff880212987ba8 RDI: 0000002fbead7d08 RBP: ffff880212987b68 R08: 0000000000000246 R09: ffff880216e572a0 R10: ffffffff815fd677 R11: ffffea0008469580 R12: ffffffff8130966f R13: ffff880212987ba8 R14: 0000002fbead7d08 R15: ffff8800d8c6b830 FS: 00002b5e6c84e7c0(0000) GS:ffff880216e40000(0000) knlGS:0000000055731700 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000002fbead7d08 CR3: 000000021270f000 CR4: 00000000000006e0 Stack: ffff880212987b98 ffffffff81075f17 ffffffff8130966f 0000000000000009 0000000000000000 0000000000000000 ffff880212987bd0 ffffffff81075f7c 0000000000000292 ffff880212987c08 ffff8800d8c6b800 0000000000000026 Call Trace: [<ffffffff81075f17>] __lock_task_sighand+0x47/0x80 [<ffffffff8130966f>] ? apparmor_cred_prepare+0x2f/0x50 [<ffffffff81075f7c>] do_send_sig_info+0x2c/0x80 [<ffffffff81075fee>] send_sig_info+0x1e/0x30 [<ffffffff8130242d>] aa_audit+0x13d/0x190 [<ffffffff8130c1dc>] aa_audit_file+0xbc/0x130 [<ffffffff8130966f>] ? apparmor_cred_prepare+0x2f/0x50 [<ffffffff81304cc2>] aa_change_hat+0x202/0x530 [<ffffffff81308fc6>] aa_setprocattr_changehat+0x116/0x1d0 [<ffffffff8130a11d>] apparmor_setprocattr+0x25d/0x300 [<ffffffff812cee56>] security_setprocattr+0x16/0x20 [<ffffffff8121fc87>] proc_pid_attr_write+0x107/0x130 [<ffffffff811b7604>] vfs_write+0xb4/0x1f0 [<ffffffff811b8039>] SyS_write+0x49/0xa0 [<ffffffff8171a1bf>] tracesys+0xe1/0xe6 Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com> Acked-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: fix replacement bug that adds new child to old parentJohn Johansen
commit ec34fa24a934f4c8fd68f39b84abf34c42e5b06a upstream. When set atomic replacement is used and the parent is updated before the child, and the child did not exist in the old parent so there is no direct replacement then the new child is incorrectly added to the old parent. This results in the new parent not having the child(ren) that it should and the old parent when being destroyed asserting the following error. AppArmor: policy_destroy: internal error, policy '<profile/name>' still contains profiles Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2017-01-27apparmor: fix refcount bug in profile replacementJohn Johansen
commit dcda617a0c5160c73e0aa02813c871339ea08004 upstream. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2016-12-12apparmor: fix change_hat not finding hat after policy replacementJohn Johansen
commit 3d40658c977769ce2138f286cf131537bf68bdfe upstream. After a policy replacement, the task cred may be out of date and need to be updated. However change_hat is using the stale profiles from the out of date cred resulting in either: a stale profile being applied or, incorrect failure when searching for a hat profile as it has been migrated to the new parent profile. Fixes: 01e2b670aa898a39259bc85c78e3d74820f4d3b6 (failure to find hat) Fixes: 898127c34ec03291c86f4ff3856d79e9e18952bc (stale policy being applied) Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=1000287 Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2016-11-22KEYS: Fix short sprintf buffer in /proc/keys show functionDavid Howells
commit 03dab869b7b239c4e013ec82aea22e181e441cfc upstream. This fixes CVE-2016-7042. Fix a short sprintf buffer in proc_keys_show(). If the gcc stack protector is turned on, this can cause a panic due to stack corruption. The problem is that xbuf[] is not big enough to hold a 64-bit timeout rendered as weeks: (gdb) p 0xffffffffffffffffULL/(60*60*24*7) $2 = 30500568904943 That's 14 chars plus NUL, not 11 chars plus NUL. Expand the buffer to 16 chars. I think the unpatched code apparently works if the stack-protector is not enabled because on a 32-bit machine the buffer won't be overflowed and on a 64-bit machine there's a 64-bit aligned pointer at one side and an int that isn't checked again on the other side. The panic incurred looks something like: Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffff81352ebe CPU: 0 PID: 1692 Comm: reproducer Not tainted 4.7.2-201.fc24.x86_64 #1 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 0000000000000086 00000000fbbd2679 ffff8800a044bc00 ffffffff813d941f ffffffff81a28d58 ffff8800a044bc98 ffff8800a044bc88 ffffffff811b2cb6 ffff880000000010 ffff8800a044bc98 ffff8800a044bc30 00000000fbbd2679 Call Trace: [<ffffffff813d941f>] dump_stack+0x63/0x84 [<ffffffff811b2cb6>] panic+0xde/0x22a [<ffffffff81352ebe>] ? proc_keys_show+0x3ce/0x3d0 [<ffffffff8109f7f9>] __stack_chk_fail+0x19/0x30 [<ffffffff81352ebe>] proc_keys_show+0x3ce/0x3d0 [<ffffffff81350410>] ? key_validate+0x50/0x50 [<ffffffff8134db30>] ? key_default_cmp+0x20/0x20 [<ffffffff8126b31c>] seq_read+0x2cc/0x390 [<ffffffff812b6b12>] proc_reg_read+0x42/0x70 [<ffffffff81244fc7>] __vfs_read+0x37/0x150 [<ffffffff81357020>] ? security_file_permission+0xa0/0xc0 [<ffffffff81246156>] vfs_read+0x96/0x130 [<ffffffff81247635>] SyS_read+0x55/0xc0 [<ffffffff817eb872>] entry_SYSCALL_64_fastpath+0x1a/0xa4 Reported-by: Ondrej Kozina <okozina@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Ondrej Kozina <okozina@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2016-10-07security: let security modules use PTRACE_MODE_* with bitmasksJann Horn
commit 3dfb7d8cdbc7ea0c2970450e60818bb3eefbad69 upstream. It looks like smack and yama weren't aware that the ptrace mode can have flags ORed into it - PTRACE_MODE_NOAUDIT until now, but only for /proc/$pid/stat, and with the PTRACE_MODE_*CREDS patch, all modes have flags ORed into them. [js] no smack changes in 3.12 as the code is not there yet Signed-off-by: Jann Horn <jann@thejh.net> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Morris <james.l.morris@oracle.com> Cc: "Serge E. Hallyn" <serge.hallyn@ubuntu.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Willy Tarreau <w@1wt.eu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2016-08-19apparmor: fix ref count leak when profile sha1 hash is readJohn Johansen
commit 0b938a2e2cf0b0a2c8bac9769111545aff0fee97 upstream. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2016-07-21KEYS: potential uninitialized variableDan Carpenter
commit 38327424b40bcebe2de92d07312c89360ac9229a upstream. If __key_link_begin() failed then "edit" would be uninitialized. I've added a check to fix that. This allows a random user to crash the kernel, though it's quite difficult to achieve. There are three ways it can be done as the user would have to cause an error to occur in __key_link(): (1) Cause the kernel to run out of memory. In practice, this is difficult to achieve without ENOMEM cropping up elsewhere and aborting the attempt. (2) Revoke the destination keyring between the keyring ID being looked up and it being tested for revocation. In practice, this is difficult to time correctly because the KEYCTL_REJECT function can only be used from the request-key upcall process. Further, users can only make use of what's in /sbin/request-key.conf, though this does including a rejection debugging test - which means that the destination keyring has to be the caller's session keyring in practice. (3) Have just enough key quota available to create a key, a new session keyring for the upcall and a link in the session keyring, but not then sufficient quota to create a link in the nominated destination keyring so that it fails with EDQUOT. The bug can be triggered using option (3) above using something like the following: echo 80 >/proc/sys/kernel/keys/root_maxbytes keyctl request2 user debug:fred negate @t The above sets the quota to something much lower (80) to make the bug easier to trigger, but this is dependent on the system. Note also that the name of the keyring created contains a random number that may be between 1 and 10 characters in size, so may throw the test off by changing the amount of quota used. Assuming the failure occurs, something like the following will be seen: kfree_debugcheck: out of range ptr 6b6b6b6b6b6b6b68h ------------[ cut here ]------------ kernel BUG at ../mm/slab.c:2821! ... RIP: 0010:[<ffffffff811600f9>] kfree_debugcheck+0x20/0x25 RSP: 0018:ffff8804014a7de8 EFLAGS: 00010092 RAX: 0000000000000034 RBX: 6b6b6b6b6b6b6b68 RCX: 0000000000000000 RDX: 0000000000040001 RSI: 00000000000000f6 RDI: 0000000000000300 RBP: ffff8804014a7df0 R08: 0000000000000001 R09: 0000000000000000 R10: ffff8804014a7e68 R11: 0000000000000054 R12: 0000000000000202 R13: ffffffff81318a66 R14: 0000000000000000 R15: 0000000000000001 ... Call Trace: kfree+0xde/0x1bc assoc_array_cancel_edit+0x1f/0x36 __key_link_end+0x55/0x63 key_reject_and_link+0x124/0x155 keyctl_reject_key+0xb6/0xe0 keyctl_negate_key+0x10/0x12 SyS_keyctl+0x9f/0xe7 do_syscall_64+0x63/0x13a entry_SYSCALL64_slow_path+0x25/0x25 Fixes: f70e2e06196a ('KEYS: Do preallocation for __key_link()') Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2016-04-23EVM: Use crypto_memneq() for digest comparisonsRyan Ware
commit 613317bd212c585c20796c10afe5daaa95d4b0a1 upstream. This patch fixes vulnerability CVE-2016-2085. The problem exists because the vm_verify_hmac() function includes a use of memcmp(). Unfortunately, this allows timing side channel attacks; specifically a MAC forgery complexity drop from 2^128 to 2^12. This patch changes the memcmp() to the cryptographically safe crypto_memneq(). Reported-by: Xiaofei Rex Guo <xiaofei.rex.guo@intel.com> Signed-off-by: Ryan Ware <ware@linux.intel.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2016-04-23KEYS: Fix handling of stored error in a negatively instantiated user keyDavid Howells
commit 096fe9eaea40a17e125569f9e657e34cdb6d73bd upstream. If a user key gets negatively instantiated, an error code is cached in the payload area. A negatively instantiated key may be then be positively instantiated by updating it with valid data. However, the ->update key type method must be aware that the error code may be there. The following may be used to trigger the bug in the user key type: keyctl request2 user user "" @u keyctl add user user "a" @u which manifests itself as: BUG: unable to handle kernel paging request at 00000000ffffff8a IP: [<ffffffff810a376f>] __call_rcu.constprop.76+0x1f/0x280 kernel/rcu/tree.c:3046 PGD 7cc30067 PUD 0 Oops: 0002 [#1] SMP Modules linked in: CPU: 3 PID: 2644 Comm: a.out Not tainted 4.3.0+ #49 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: ffff88003ddea700 ti: ffff88003dd88000 task.ti: ffff88003dd88000 RIP: 0010:[<ffffffff810a376f>] [<ffffffff810a376f>] __call_rcu.constprop.76+0x1f/0x280 [<ffffffff810a376f>] __call_rcu.constprop.76+0x1f/0x280 kernel/rcu/tree.c:3046 RSP: 0018:ffff88003dd8bdb0 EFLAGS: 00010246 RAX: 00000000ffffff82 RBX: 0000000000000000 RCX: 0000000000000001 RDX: ffffffff81e3fe40 RSI: 0000000000000000 RDI: 00000000ffffff82 RBP: ffff88003dd8bde0 R08: ffff88007d2d2da0 R09: 0000000000000000 R10: 0000000000000000 R11: ffff88003e8073c0 R12: 00000000ffffff82 R13: ffff88003dd8be68 R14: ffff88007d027600 R15: ffff88003ddea700 FS: 0000000000b92880(0063) GS:ffff88007fd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00000000ffffff8a CR3: 000000007cc5f000 CR4: 00000000000006e0 Stack: ffff88003dd8bdf0 ffffffff81160a8a 0000000000000000 00000000ffffff82 ffff88003dd8be68 ffff88007d027600 ffff88003dd8bdf0 ffffffff810a39e5 ffff88003dd8be20 ffffffff812a31ab ffff88007d027600 ffff88007d027620 Call Trace: [<ffffffff810a39e5>] kfree_call_rcu+0x15/0x20 kernel/rcu/tree.c:3136 [<ffffffff812a31ab>] user_update+0x8b/0xb0 security/keys/user_defined.c:129 [< inline >] __key_update security/keys/key.c:730 [<ffffffff8129e5c1>] key_create_or_update+0x291/0x440 security/keys/key.c:908 [< inline >] SYSC_add_key security/keys/keyctl.c:125 [<ffffffff8129fc21>] SyS_add_key+0x101/0x1e0 security/keys/keyctl.c:60 [<ffffffff8185f617>] entry_SYSCALL_64_fastpath+0x12/0x6a arch/x86/entry/entry_64.S:185 Note the error code (-ENOKEY) in EDX. A similar bug can be tripped by: keyctl request2 trusted user "" @u keyctl add trusted user "a" @u This should also affect encrypted keys - but that has to be correctly parameterised or it will fail with EINVAL before getting to the bit that will crashes. Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2016-02-24ptrace: use fsuid, fsgid, effective creds for fs access checksJann Horn
commit caaee6234d05a58c5b4d05e7bf766131b810a657 upstream. By checking the effective credentials instead of the real UID / permitted capabilities, ensure that the calling process actually intended to use its credentials. To ensure that all ptrace checks use the correct caller credentials (e.g. in case out-of-tree code or newly added code omits the PTRACE_MODE_*CREDS flag), use two new flags and require one of them to be set. The problem was that when a privileged task had temporarily dropped its privileges, e.g. by calling setreuid(0, user_uid), with the intent to perform following syscalls with the credentials of a user, it still passed ptrace access checks that the user would not be able to pass. While an attacker should not be able to convince the privileged task to perform a ptrace() syscall, this is a problem because the ptrace access check is reused for things in procfs. In particular, the following somewhat interesting procfs entries only rely on ptrace access checks: /proc/$pid/stat - uses the check for determining whether pointers should be visible, useful for bypassing ASLR /proc/$pid/maps - also useful for bypassing ASLR /proc/$pid/cwd - useful for gaining access to restricted directories that contain files with lax permissions, e.g. in this scenario: lrwxrwxrwx root root /proc/13020/cwd -> /root/foobar drwx------ root root /root drwxr-xr-x root root /root/foobar -rw-r--r-- root root /root/foobar/secret Therefore, on a system where a root-owned mode 6755 binary changes its effective credentials as described and then dumps a user-specified file, this could be used by an attacker to reveal the memory layout of root's processes or reveal the contents of files he is not allowed to access (through /proc/$pid/cwd). [akpm@linux-foundation.org: fix warning] Signed-off-by: Jann Horn <jann@thejh.net> Acked-by: Kees Cook <keescook@chromium.org> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Morris <james.l.morris@oracle.com> Cc: "Serge E. Hallyn" <serge.hallyn@ubuntu.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Willy Tarreau <w@1wt.eu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2016-01-25KEYS: Fix keyring ref leak in join_session_keyring()Yevgeny Pats
commit 23567fd052a9abb6d67fe8e7a9ccdd9800a540f2 upstream. This fixes CVE-2016-0728. If a thread is asked to join as a session keyring the keyring that's already set as its session, we leak a keyring reference. This can be tested with the following program: #include <stddef.h> #include <stdio.h> #include <sys/types.h> #include <keyutils.h> int main(int argc, const char *argv[]) { int i = 0; key_serial_t serial; serial = keyctl(KEYCTL_JOIN_SESSION_KEYRING, "leaked-keyring"); if (serial < 0) { perror("keyctl"); return -1; } if (keyctl(KEYCTL_SETPERM, serial, KEY_POS_ALL | KEY_USR_ALL) < 0) { perror("keyctl"); return -1; } for (i = 0; i < 100; i++) { serial = keyctl(KEYCTL_JOIN_SESSION_KEYRING, "leaked-keyring"); if (serial < 0) { perror("keyctl"); return -1; } } return 0; } If, after the program has run, there something like the following line in /proc/keys: 3f3d898f I--Q--- 100 perm 3f3f0000 0 0 keyring leaked-keyring: empty with a usage count of 100 * the number of times the program has been run, then the kernel is malfunctioning. If leaked-keyring has zero usages or has been garbage collected, then the problem is fixed. Reported-by: Yevgeny Pats <yevgeny@perception-point.io> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Don Zickus <dzickus@redhat.com> Acked-by: Prarit Bhargava <prarit@redhat.com> Acked-by: Jarod Wilson <jarod@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2016-01-25KEYS: Fix race between read and revokeDavid Howells
commit b4a1b4f5047e4f54e194681125c74c0aa64d637d upstream. This fixes CVE-2015-7550. There's a race between keyctl_read() and keyctl_revoke(). If the revoke happens between keyctl_read() checking the validity of a key and the key's semaphore being taken, then the key type read method will see a revoked key. This causes a problem for the user-defined key type because it assumes in its read method that there will always be a payload in a non-revoked key and doesn't check for a NULL pointer. Fix this by making keyctl_read() check the validity of a key after taking semaphore instead of before. I think the bug was introduced with the original keyrings code. This was discovered by a multithreaded test program generated by syzkaller (http://github.com/google/syzkaller). Here's a cleaned up version: #include <sys/types.h> #include <keyutils.h> #include <pthread.h> void *thr0(void *arg) { key_serial_t key = (unsigned long)arg; keyctl_revoke(key); return 0; } void *thr1(void *arg) { key_serial_t key = (unsigned long)arg; char buffer[16]; keyctl_read(key, buffer, 16); return 0; } int main() { key_serial_t key = add_key("user", "%", "foo", 3, KEY_SPEC_USER_KEYRING); pthread_t th[5]; pthread_create(&th[0], 0, thr0, (void *)(unsigned long)key); pthread_create(&th[1], 0, thr1, (void *)(unsigned long)key); pthread_create(&th[2], 0, thr0, (void *)(unsigned long)key); pthread_create(&th[3], 0, thr1, (void *)(unsigned long)key); pthread_join(th[0], 0); pthread_join(th[1], 0); pthread_join(th[2], 0); pthread_join(th[3], 0); return 0; } Build as: cc -o keyctl-race keyctl-race.c -lkeyutils -lpthread Run as: while keyctl-race; do :; done as it may need several iterations to crash the kernel. The crash can be summarised as: BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 IP: [<ffffffff81279b08>] user_read+0x56/0xa3 ... Call Trace: [<ffffffff81276aa9>] keyctl_read_key+0xb6/0xd7 [<ffffffff81277815>] SyS_keyctl+0x83/0xe0 [<ffffffff815dbb97>] entry_SYSCALL_64_fastpath+0x12/0x6f Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2015-11-18KEYS: Fix crash when attempt to garbage collect an uninstantiated keyringDavid Howells
commit f05819df10d7b09f6d1eb6f8534a8f68e5a4fe61 upstream. The following sequence of commands: i=`keyctl add user a a @s` keyctl request2 keyring foo bar @t keyctl unlink $i @s tries to invoke an upcall to instantiate a keyring if one doesn't already exist by that name within the user's keyring set. However, if the upcall fails, the code sets keyring->type_data.reject_error to -ENOKEY or some other error code. When the key is garbage collected, the key destroy function is called unconditionally and keyring_destroy() uses list_empty() on keyring->type_data.link - which is in a union with reject_error. Subsequently, the kernel tries to unlink the keyring from the keyring names list - which oopses like this: BUG: unable to handle kernel paging request at 00000000ffffff8a IP: [<ffffffff8126e051>] keyring_destroy+0x3d/0x88 ... Workqueue: events key_garbage_collector ... RIP: 0010:[<ffffffff8126e051>] keyring_destroy+0x3d/0x88 RSP: 0018:ffff88003e2f3d30 EFLAGS: 00010203 RAX: 00000000ffffff82 RBX: ffff88003bf1a900 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 000000003bfc6901 RDI: ffffffff81a73a40 RBP: ffff88003e2f3d38 R08: 0000000000000152 R09: 0000000000000000 R10: ffff88003e2f3c18 R11: 000000000000865b R12: ffff88003bf1a900 R13: 0000000000000000 R14: ffff88003bf1a908 R15: ffff88003e2f4000 ... CR2: 00000000ffffff8a CR3: 000000003e3ec000 CR4: 00000000000006f0 ... Call Trace: [<ffffffff8126c756>] key_gc_unused_keys.constprop.1+0x5d/0x10f [<ffffffff8126ca71>] key_garbage_collector+0x1fa/0x351 [<ffffffff8105ec9b>] process_one_work+0x28e/0x547 [<ffffffff8105fd17>] worker_thread+0x26e/0x361 [<ffffffff8105faa9>] ? rescuer_thread+0x2a8/0x2a8 [<ffffffff810648ad>] kthread+0xf3/0xfb [<ffffffff810647ba>] ? kthread_create_on_node+0x1c2/0x1c2 [<ffffffff815f2ccf>] ret_from_fork+0x3f/0x70 [<ffffffff810647ba>] ? kthread_create_on_node+0x1c2/0x1c2 Note the value in RAX. This is a 32-bit representation of -ENOKEY. The solution is to only call ->destroy() if the key was successfully instantiated. Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2015-11-18KEYS: Fix race between key destruction and finding a keyring by nameDavid Howells
commit 94c4554ba07adbdde396748ee7ae01e86cf2d8d7 upstream. There appears to be a race between: (1) key_gc_unused_keys() which frees key->security and then calls keyring_destroy() to unlink the name from the name list (2) find_keyring_by_name() which calls key_permission(), thus accessing key->security, on a key before checking to see whether the key usage is 0 (ie. the key is dead and might be cleaned up). Fix this by calling ->destroy() before cleaning up the core key data - including key->security. Reported-by: Petr Matousek <pmatouse@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2015-08-19ima: extend "mask" policy matching supportMimi Zohar
commit 4351c294b8c1028077280f761e158d167b592974 upstream. The current "mask" policy option matches files opened as MAY_READ, MAY_WRITE, MAY_APPEND or MAY_EXEC. This patch extends the "mask" option to match files opened containing one of these modes. For example, "mask=^MAY_READ" would match files opened read-write. Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Dr. Greg Wettstein <gw@idfusion.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2015-08-19ima: add support for new "euid" policy conditionMimi Zohar
commit 139069eff7388407f19794384c42a534d618ccd7 upstream. The new "euid" policy condition measures files with the specified effective uid (euid). In addition, for CAP_SETUID files it measures files with the specified uid or suid. Changelog: - fixed checkpatch.pl warnings - fixed avc denied {setuid} messages - based on Roberto's feedback Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Dr. Greg Wettstein <gw@idfusion.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2015-06-10lsm: copy comm before calling audit_log to avoid race in string printingRichard Guy Briggs
commit 5deeb5cece3f9b30c8129786726b9d02c412c8ca upstream. When task->comm is passed directly to audit_log_untrustedstring() without getting a copy or using the task_lock, there is a race that could happen that would output a NULL (\0) in the middle of the output string that would effectively truncate the rest of the report text after the comm= field in the audit log message, losing fields. Using get_task_comm() to get a copy while acquiring the task_lock to prevent this and to prevent the result from being a mixture of old and new values of comm would incur potentially unacceptable overhead, considering that the value can be influenced by userspace and therefore untrusted anyways. Copy the value before passing it to audit_log_untrustedstring() ensures that a local copy is used to calculate the length *and* subsequently printed. Even if this value contains a mix of old and new values, it will only calculate and copy up to the first NULL, preventing the rest of the audit log message being truncated. Use a second local copy of comm to avoid a race between the first and second calls to audit_log_untrustedstring() with comm. Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2015-04-27nick kvfree() from apparmorAl Viro
commit 39f1f78d53b9bcbca91967380c5f0f2305a5c55f upstream. too many places open-code it Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2015-04-22selinux: fix sel_write_enforce broken return valueJoe Perches
commit 6436a123a147db51a0b06024a8350f4c230e73ff upstream. Return a negative error value like the rest of the entries in this function. Signed-off-by: Joe Perches <joe@perches.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> [PM: tweaked subject line] Signed-off-by: Paul Moore <pmoore@redhat.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2015-04-09Don't leak a key reference if request_key() tries to use a revoked keyringDavid Jeffery
commit d0709f1e66e8066c4ac6a54620ec116aa41937c0 upstream. If a request_key() call to allocate and fill out a key attempts to insert the key structure into a revoked keyring, the key will leak, using memory and part of the user's key quota until the system reboots. This is from a failure of construct_alloc_key() to decrement the key's reference count after the attempt to insert into the requested keyring is rejected. key_put() needs to be called in the link_prealloc_failed callpath to ensure the unused key is released. Signed-off-by: David Jeffery <djeffery@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2015-02-16SELinux: fix selinuxfs policy file on big endian systemsEric Paris
commit b138004ea0382bdc6d02599c39392651b4f63889 upstream. The /sys/fs/selinux/policy file is not valid on big endian systems like ppc64 or s390. Let's see why: static int hashtab_cnt(void *key, void *data, void *ptr) { int *cnt = ptr; *cnt = *cnt + 1; return 0; } static int range_write(struct policydb *p, void *fp) { size_t nel; [...] /* count the number of entries in the hashtab */ nel = 0; rc = hashtab_map(p->range_tr, hashtab_cnt, &nel); if (rc) return rc; buf[0] = cpu_to_le32(nel); rc = put_entry(buf, sizeof(u32), 1, fp); So size_t is 64 bits. But then we pass a pointer to it as we do to hashtab_cnt. hashtab_cnt thinks it is a 32 bit int and only deals with the first 4 bytes. On x86_64 which is little endian, those first 4 bytes and the least significant, so this works out fine. On ppc64/s390 those first 4 bytes of memory are the high order bits. So at the end of the call to hashtab_map nel has a HUGE number. But the least significant 32 bits are all 0's. We then pass that 64 bit number to cpu_to_le32() which happily truncates it to a 32 bit number and does endian swapping. But the low 32 bits are all 0's. So no matter how many entries are in the hashtab, big endian systems always say there are 0 entries because I screwed up the counting. The fix is easy. Use a 32 bit int, as the hashtab_cnt expects, for nel. Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Paul Moore <pmoore@redhat.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2015-01-29move d_rcu from overlapping d_child to overlapping d_aliasAl Viro
commit 946e51f2bf37f1656916eb75bd0742ba33983c28 upstream. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2015-01-29KEYS: close race between key lookup and freeingSasha Levin
commit a3a8784454692dd72e5d5d34dcdab17b4420e74c upstream. When a key is being garbage collected, it's key->user would get put before the ->destroy() callback is called, where the key is removed from it's respective tracking structures. This leaves a key hanging in a semi-invalid state which leaves a window open for a different task to try an access key->user. An example is find_keyring_by_name() which would dereference key->user for a key that is in the process of being garbage collected (where key->user was freed but ->destroy() wasn't called yet - so it's still present in the linked list). This would cause either a panic, or corrupt memory. Fixes CVE-2014-9529. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2015-01-07KEYS: Fix stale key registration at error pathTakashi Iwai
commit b26bdde5bb27f3f900e25a95e33a0c476c8c2c48 upstream. When loading encrypted-keys module, if the last check of aes_get_sizes() in init_encrypted() fails, the driver just returns an error without unregistering its key type. This results in the stale entry in the list. In addition to memory leaks, this leads to a kernel crash when registering a new key type later. This patch fixes the problem by swapping the calls of aes_get_sizes() and register_key_type(), and releasing resources properly at the error paths. Bugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=908163 Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2014-11-13selinux: fix inode security list corruptionStephen Smalley
commit 923190d32de4428afbea5e5773be86bea60a9925 upstream. sb_finish_set_opts() can race with inode_free_security() when initializing inode security structures for inodes created prior to initial policy load or by the filesystem during ->mount(). This appears to have always been a possible race, but commit 3dc91d4 ("SELinux: Fix possible NULL pointer dereference in selinux_inode_permission()") made it more evident by immediately reusing the unioned list/rcu element of the inode security structure for call_rcu() upon an inode_free_security(). But the underlying issue was already present before that commit as a possible use-after-free of isec. Shivnandan Kumar reported the list corruption and proposed a patch to split the list and rcu elements out of the union as separate fields of the inode_security_struct so that setting the rcu element would not affect the list element. However, this would merely hide the issue and not truly fix the code. This patch instead moves up the deletion of the list entry prior to dropping the sbsec->isec_lock initially. Then, if the inode is dropped subsequently, there will be no further references to the isec. Reported-by: Shivnandan Kumar <shivnandan.k@samsung.com> Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <pmoore@redhat.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2014-11-13evm: check xattr value length and type in evm_inode_setxattr()Dmitry Kasatkin
commit 3b1deef6b1289a99505858a3b212c5b50adf0c2f upstream. evm_inode_setxattr() can be called with no value. The function does not check the length so that following command can be used to produce the kernel oops: setfattr -n security.evm FOO. This patch fixes it. Changes in v3: * there is no reason to return different error codes for EVM_XATTR_HMAC and non EVM_XATTR_HMAC. Remove unnecessary test then. Changes in v2: * testing for validity of xattr type [ 1106.396921] BUG: unable to handle kernel NULL pointer dereference at (null) [ 1106.398192] IP: [<ffffffff812af7b8>] evm_inode_setxattr+0x2a/0x48 [ 1106.399244] PGD 29048067 PUD 290d7067 PMD 0 [ 1106.399953] Oops: 0000 [#1] SMP [ 1106.400020] Modules linked in: bridge stp llc evdev serio_raw i2c_piix4 button fuse [ 1106.400020] CPU: 0 PID: 3635 Comm: setxattr Not tainted 3.16.0-kds+ #2936 [ 1106.400020] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 1106.400020] task: ffff8800291a0000 ti: ffff88002917c000 task.ti: ffff88002917c000 [ 1106.400020] RIP: 0010:[<ffffffff812af7b8>] [<ffffffff812af7b8>] evm_inode_setxattr+0x2a/0x48 [ 1106.400020] RSP: 0018:ffff88002917fd50 EFLAGS: 00010246 [ 1106.400020] RAX: 0000000000000000 RBX: ffff88002917fdf8 RCX: 0000000000000000 [ 1106.400020] RDX: 0000000000000000 RSI: ffffffff818136d3 RDI: ffff88002917fdf8 [ 1106.400020] RBP: ffff88002917fd68 R08: 0000000000000000 R09: 00000000003ec1df [ 1106.400020] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800438a0a00 [ 1106.400020] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 1106.400020] FS: 00007f7dfa7d7740(0000) GS:ffff88005da00000(0000) knlGS:0000000000000000 [ 1106.400020] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1106.400020] CR2: 0000000000000000 CR3: 000000003763e000 CR4: 00000000000006f0 [ 1106.400020] Stack: [ 1106.400020] ffff8800438a0a00 ffff88002917fdf8 0000000000000000 ffff88002917fd98 [ 1106.400020] ffffffff812a1030 ffff8800438a0a00 ffff88002917fdf8 0000000000000000 [ 1106.400020] 0000000000000000 ffff88002917fde0 ffffffff8116d08a ffff88002917fdc8 [ 1106.400020] Call Trace: [ 1106.400020] [<ffffffff812a1030>] security_inode_setxattr+0x5d/0x6a [ 1106.400020] [<ffffffff8116d08a>] vfs_setxattr+0x6b/0x9f [ 1106.400020] [<ffffffff8116d1e0>] setxattr+0x122/0x16c [ 1106.400020] [<ffffffff811687e8>] ? mnt_want_write+0x21/0x45 [ 1106.400020] [<ffffffff8114d011>] ? __sb_start_write+0x10f/0x143 [ 1106.400020] [<ffffffff811687e8>] ? mnt_want_write+0x21/0x45 [ 1106.400020] [<ffffffff811687c0>] ? __mnt_want_write+0x48/0x4f [ 1106.400020] [<ffffffff8116d3e6>] SyS_setxattr+0x6e/0xb0 [ 1106.400020] [<ffffffff81529da9>] system_call_fastpath+0x16/0x1b [ 1106.400020] Code: c3 0f 1f 44 00 00 55 48 89 e5 41 55 49 89 d5 41 54 49 89 fc 53 48 89 f3 48 c7 c6 d3 36 81 81 48 89 df e8 18 22 04 00 85 c0 75 07 <41> 80 7d 00 02 74 0d 48 89 de 4c 89 e7 e8 5a fe ff ff eb 03 83 [ 1106.400020] RIP [<ffffffff812af7b8>] evm_inode_setxattr+0x2a/0x48 [ 1106.400020] RSP <ffff88002917fd50> [ 1106.400020] CR2: 0000000000000000 [ 1106.428061] ---[ end trace ae08331628ba3050 ]--- Reported-by: Jan Kara <jack@suse.cz> Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2014-09-17CAPABILITIES: remove undefined caps from all processesEric Paris
commit 7d8b6c63751cfbbe5eef81a48c22978b3407a3ad upstream. This is effectively a revert of 7b9a7ec565505699f503b4fcf61500dceb36e744 plus fixing it a different way... We found, when trying to run an application from an application which had dropped privs that the kernel does security checks on undefined capability bits. This was ESPECIALLY difficult to debug as those undefined bits are hidden from /proc/$PID/status. Consider a root application which drops all capabilities from ALL 4 capability sets. We assume, since the application is going to set eff/perm/inh from an array that it will clear not only the defined caps less than CAP_LAST_CAP, but also the higher 28ish bits which are undefined future capabilities. The BSET gets cleared differently. Instead it is cleared one bit at a time. The problem here is that in security/commoncap.c::cap_task_prctl() we actually check the validity of a capability being read. So any task which attempts to 'read all things set in bset' followed by 'unset all things set in bset' will not even attempt to unset the undefined bits higher than CAP_LAST_CAP. So the 'parent' will look something like: CapInh: 0000000000000000 CapPrm: 0000000000000000 CapEff: 0000000000000000 CapBnd: ffffffc000000000 All of this 'should' be fine. Given that these are undefined bits that aren't supposed to have anything to do with permissions. But they do... So lets now consider a task which cleared the eff/perm/inh completely and cleared all of the valid caps in the bset (but not the invalid caps it couldn't read out of the kernel). We know that this is exactly what the libcap-ng library does and what the go capabilities library does. They both leave you in that above situation if you try to clear all of you capapabilities from all 4 sets. If that root task calls execve() the child task will pick up all caps not blocked by the bset. The bset however does not block bits higher than CAP_LAST_CAP. So now the child task has bits in eff which are not in the parent. These are 'meaningless' undefined bits, but still bits which the parent doesn't have. The problem is now in cred_cap_issubset() (or any operation which does a subset test) as the child, while a subset for valid cap bits, is not a subset for invalid cap bits! So now we set durring commit creds that the child is not dumpable. Given it is 'more priv' than its parent. It also means the parent cannot ptrace the child and other stupidity. The solution here: 1) stop hiding capability bits in status This makes debugging easier! 2) stop giving any task undefined capability bits. it's simple, it you don't put those invalid bits in CAP_FULL_SET you won't get them in init and you won't get them in any other task either. This fixes the cap_issubset() tests and resulting fallout (which made the init task in a docker container untraceable among other things) 3) mask out undefined bits when sys_capset() is called as it might use ~0, ~0 to denote 'all capabilities' for backward/forward compatibility. This lets 'capsh --caps="all=eip" -- -c /bin/bash' run. 4) mask out undefined bit when we read a file capability off of disk as again likely all bits are set in the xattr for forward/backward compatibility. This lets 'setcap all+pe /bin/bash; /bin/bash' run Signed-off-by: Eric Paris <eparis@redhat.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Andrew Vagin <avagin@openvz.org> Cc: Andrew G. Morgan <morgan@kernel.org> Cc: Serge E. Hallyn <serge.hallyn@canonical.com> Cc: Kees Cook <keescook@chromium.org> Cc: Steve Grubb <sgrubb@redhat.com> Cc: Dan Walsh <dwalsh@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2014-06-23evm: prohibit userspace writing 'security.evm' HMAC valueMimi Zohar
commit 2fb1c9a4f2dbc2f0bd2431c7fa64d0b5483864e4 upstream. Calculating the 'security.evm' HMAC value requires access to the EVM encrypted key. Only the kernel should have access to it. This patch prevents userspace tools(eg. setfattr, cp --preserve=xattr) from setting/modifying the 'security.evm' HMAC value directly. Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2014-06-23ima: introduce ima_kernel_read()Dmitry Kasatkin
commit 0430e49b6e7c6b5e076be8fefdee089958c9adad upstream. Commit 8aac62706 "move exit_task_namespaces() outside of exit_notify" introduced the kernel opps since the kernel v3.10, which happens when Apparmor and IMA-appraisal are enabled at the same time. ---------------------------------------------------------------------- [ 106.750167] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 [ 106.750221] IP: [<ffffffff811ec7da>] our_mnt+0x1a/0x30 [ 106.750241] PGD 0 [ 106.750254] Oops: 0000 [#1] SMP [ 106.750272] Modules linked in: cuse parport_pc ppdev bnep rfcomm bluetooth rpcsec_gss_krb5 nfsd auth_rpcgss nfs_acl nfs lockd sunrpc fscache dm_crypt intel_rapl x86_pkg_temp_thermal intel_powerclamp kvm_intel snd_hda_codec_hdmi kvm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 glue_helper lrw gf128mul ablk_helper cryptd snd_hda_codec_realtek dcdbas snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_page_alloc snd_seq_midi snd_seq_midi_event snd_rawmidi psmouse snd_seq microcode serio_raw snd_timer snd_seq_device snd soundcore video lpc_ich coretemp mac_hid lp parport mei_me mei nbd hid_generic e1000e usbhid ahci ptp hid libahci pps_core [ 106.750658] CPU: 6 PID: 1394 Comm: mysqld Not tainted 3.13.0-rc7-kds+ #15 [ 106.750673] Hardware name: Dell Inc. OptiPlex 9010/0M9KCM, BIOS A08 09/19/2012 [ 106.750689] task: ffff8800de804920 ti: ffff880400fca000 task.ti: ffff880400fca000 [ 106.750704] RIP: 0010:[<ffffffff811ec7da>] [<ffffffff811ec7da>] our_mnt+0x1a/0x30 [ 106.750725] RSP: 0018:ffff880400fcba60 EFLAGS: 00010286 [ 106.750738] RAX: 0000000000000000 RBX: 0000000000000100 RCX: ffff8800d51523e7 [ 106.750764] RDX: ffffffffffffffea RSI: ffff880400fcba34 RDI: ffff880402d20020 [ 106.750791] RBP: ffff880400fcbae0 R08: 0000000000000000 R09: 0000000000000001 [ 106.750817] R10: 0000000000000000 R11: 0000000000000001 R12: ffff8800d5152300 [ 106.750844] R13: ffff8803eb8df510 R14: ffff880400fcbb28 R15: ffff8800d51523e7 [ 106.750871] FS: 0000000000000000(0000) GS:ffff88040d200000(0000) knlGS:0000000000000000 [ 106.750910] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 106.750935] CR2: 0000000000000018 CR3: 0000000001c0e000 CR4: 00000000001407e0 [ 106.750962] Stack: [ 106.750981] ffffffff813434eb ffff880400fcbb20 ffff880400fcbb18 0000000000000000 [ 106.751037] ffff8800de804920 ffffffff8101b9b9 0001800000000000 0000000000000100 [ 106.751093] 0000010000000000 0000000000000002 000000000000000e ffff8803eb8df500 [ 106.751149] Call Trace: [ 106.751172] [<ffffffff813434eb>] ? aa_path_name+0x2ab/0x430 [ 106.751199] [<ffffffff8101b9b9>] ? sched_clock+0x9/0x10 [ 106.751225] [<ffffffff8134a68d>] aa_path_perm+0x7d/0x170 [ 106.751250] [<ffffffff8101b945>] ? native_sched_clock+0x15/0x80 [ 106.751276] [<ffffffff8134aa73>] aa_file_perm+0x33/0x40 [ 106.751301] [<ffffffff81348c5e>] common_file_perm+0x8e/0xb0 [ 106.751327] [<ffffffff81348d78>] apparmor_file_permission+0x18/0x20 [ 106.751355] [<ffffffff8130c853>] security_file_permission+0x23/0xa0 [ 106.751382] [<ffffffff811c77a2>] rw_verify_area+0x52/0xe0 [ 106.751407] [<ffffffff811c789d>] vfs_read+0x6d/0x170 [ 106.751432] [<ffffffff811cda31>] kernel_read+0x41/0x60 [ 106.751457] [<ffffffff8134fd45>] ima_calc_file_hash+0x225/0x280 [ 106.751483] [<ffffffff8134fb52>] ? ima_calc_file_hash+0x32/0x280 [ 106.751509] [<ffffffff8135022d>] ima_collect_measurement+0x9d/0x160 [ 106.751536] [<ffffffff810b552d>] ? trace_hardirqs_on+0xd/0x10 [ 106.751562] [<ffffffff8134f07c>] ? ima_file_free+0x6c/0xd0 [ 106.751587] [<ffffffff81352824>] ima_update_xattr+0x34/0x60 [ 106.751612] [<ffffffff8134f0d0>] ima_file_free+0xc0/0xd0 [ 106.751637] [<ffffffff811c9635>] __fput+0xd5/0x300 [ 106.751662] [<ffffffff811c98ae>] ____fput+0xe/0x10 [ 106.751687] [<ffffffff81086774>] task_work_run+0xc4/0xe0 [ 106.751712] [<ffffffff81066fad>] do_exit+0x2bd/0xa90 [ 106.751738] [<ffffffff8173c958>] ? retint_swapgs+0x13/0x1b [ 106.751763] [<ffffffff8106780c>] do_group_exit+0x4c/0xc0 [ 106.751788] [<ffffffff81067894>] SyS_exit_group+0x14/0x20 [ 106.751814] [<ffffffff8174522d>] system_call_fastpath+0x1a/0x1f [ 106.751839] Code: c3 0f 1f 44 00 00 55 48 89 e5 e8 22 fe ff ff 5d c3 0f 1f 44 00 00 55 65 48 8b 04 25 c0 c9 00 00 48 8b 80 28 06 00 00 48 89 e5 5d <48> 8b 40 18 48 39 87 c0 00 00 00 0f 94 c0 c3 0f 1f 80 00 00 00 [ 106.752185] RIP [<ffffffff811ec7da>] our_mnt+0x1a/0x30 [ 106.752214] RSP <ffff880400fcba60> [ 106.752236] CR2: 0000000000000018 [ 106.752258] ---[ end trace 3c520748b4732721 ]--- ---------------------------------------------------------------------- The reason for the oops is that IMA-appraisal uses "kernel_read()" when file is closed. kernel_read() honors LSM security hook which calls Apparmor handler, which uses current->nsproxy->mnt_ns. The 'guilty' commit changed the order of cleanup code so that nsproxy->mnt_ns was not already available for Apparmor. Discussion about the issue with Al Viro and Eric W. Biederman suggested that kernel_read() is too high-level for IMA. Another issue, except security checking, that was identified is mandatory locking. kernel_read honors it as well and it might prevent IMA from calculating necessary hash. It was suggested to use simplified version of the function without security and locking checks. This patch introduces special version ima_kernel_read(), which skips security and mandatory locking checking. It prevents the kernel oops to happen. Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com> Suggested-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2014-06-20ima: audit log files opened with O_DIRECT flagMimi Zohar
commit f9b2a735bdddf836214b5dca74f6ca7712e5a08c upstream. Files are measured or appraised based on the IMA policy. When a file, in policy, is opened with the O_DIRECT flag, a deadlock occurs. The first attempt at resolving this lockdep temporarily removed the O_DIRECT flag and restored it, after calculating the hash. The second attempt introduced the O_DIRECT_HAVELOCK flag. Based on this flag, do_blockdev_direct_IO() would skip taking the i_mutex a second time. The third attempt, by Dmitry Kasatkin, resolves the i_mutex locking issue, by re-introducing the IMA mutex, but uncovered another problem. Reading a file with O_DIRECT flag set, writes directly to userspace pages. A second patch allocates a user-space like memory. This works for all IMA hooks, except ima_file_free(), which is called on __fput() to recalculate the file hash. Until this last issue is addressed, do not 'collect' the measurement for measuring, appraising, or auditing files opened with the O_DIRECT flag set. Based on policy, permit or deny file access. This patch defines a new IMA policy rule option named 'permit_directio'. Policy rules could be defined, based on LSM or other criteria, to permit specific applications to open files with the O_DIRECT flag set. Changelog v1: - permit or deny file access based IMA policy rules Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Acked-by: Dmitry Kasatkin <d.kasatkin@samsung.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2014-06-09device_cgroup: check if exception removal is allowedAristeu Rozanski
commit d2c2b11cfa134f4fbdcc34088824da26a084d8de upstream. [PATCH v3 1/2] device_cgroup: check if exception removal is allowed When the device cgroup hierarchy was introduced in bd2953ebbb53 - devcg: propagate local changes down the hierarchy a specific case was overlooked. Consider the hierarchy bellow: A default policy: ALLOW, exceptions will deny access \ B default policy: ALLOW, exceptions will deny access There's no need to verify when an new exception is added to B because in this case exceptions will deny access to further devices, which is always fine. Hierarchy in device cgroup only makes sure B won't have more access than A. But when an exception is removed (by writing devices.allow), it isn't checked if the user is in fact removing an inherited exception from A, thus giving more access to B. Example: # echo 'a' >A/devices.allow # echo 'c 1:3 rw' >A/devices.deny # echo $$ >A/B/tasks # echo >/dev/null -bash: /dev/null: Operation not permitted # echo 'c 1:3 w' >A/B/devices.allow # echo >/dev/null # This shouldn't be allowed and this patch fixes it by making sure to never allow exceptions in this case to be removed if the exception is partially or fully present on the parent. v3: missing '*' in function description v2: improved log message and formatting fixes Cc: cgroups@vger.kernel.org Cc: Li Zefan <lizefan@huawei.com> Signed-off-by: Aristeu Rozanski <arozansk@redhat.com> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2014-06-09device_cgroup: rework device access check and exception checkingAristeu Rozanski
commit 79d719749d23234e9b725098aa49133f3ef7299d upstream. Whenever a device file is opened and checked against current device cgroup rules, it uses the same function (may_access()) as when a new exception rule is added by writing devices.{allow,deny}. And in both cases, the algorithm is the same, doesn't matter the behavior. First problem is having device access to be considered the same as rule checking. Consider the following structure: A (default behavior: allow, exceptions disallow access) \ B (default behavior: allow, exceptions disallow access) A new exception is added to B by writing devices.deny: c 12:34 rw When checking if that exception is allowed in may_access(): if (dev_cgroup->behavior == DEVCG_DEFAULT_ALLOW) { if (behavior == DEVCG_DEFAULT_ALLOW) { /* the exception will deny access to certain devices */ return true; Which is ok, since B is not getting more privileges than A, it doesn't matter and the rule is accepted Now, consider it's a device file open check and the process belongs to cgroup B. The access will be generated as: behavior: allow exception: c 12:34 rw The very same chunk of code will allow it, even if there's an explicit exception telling to do otherwise. A simple test case: # mkdir new_group # cd new_group # echo $$ >tasks # echo "c 1:3 w" >devices.deny # echo >/dev/null # echo $? 0 This is a serious bug and was introduced on c39a2a3018f8 devcg: prepare may_access() for hierarchy support To solve this problem, the device file open function was split from the new exception check. Second problem is how exceptions are processed by may_access(). The first part of the said function tries to match fully with an existing exception: list_for_each_entry_rcu(ex, &dev_cgroup->exceptions, list) { if ((refex->type & DEV_BLOCK) && !(ex->type & DEV_BLOCK)) continue; if ((refex->type & DEV_CHAR) && !(ex->type & DEV_CHAR)) continue; if (ex->major != ~0 && ex->major != refex->major) continue; if (ex->minor != ~0 && ex->minor != refex->minor) continue; if (refex->access & (~ex->access)) continue; match = true; break; } That means the new exception should be contained into an existing one to be considered a match: New exception Existing match? notes b 12:34 rwm b 12:34 rwm yes b 12:34 r b *:34 rw yes b 12:34 rw b 12:34 w no extra "r" b *:34 rw b 12:34 rw no too broad "*" b *:34 rw b *:34 rwm yes Which is fine in some cases. Consider: A (default behavior: deny, exceptions allow access) \ B (default behavior: deny, exceptions allow access) In this case the full match makes sense, the new exception cannot add more access than the parent allows But this doesn't always work, consider: A (default behavior: allow, exceptions disallow access) \ B (default behavior: deny, exceptions allow access) In this case, a new exception in B shouldn't match any of the exceptions in A, after all you can't allow something that was forbidden by A. But consider this scenario: New exception Existing in A match? outcome b 12:34 rw b 12:34 r no exception is accepted Because the new exception has "w" as extra, it doesn't match, so it'll be added to B's exception list. The same problem can happen during a file access check. Consider a cgroup with allow as default behavior: Access Exception match? b 12:34 rw b 12:34 r no In this case, the access didn't match any of the exceptions in the cgroup, which is required since exceptions will disallow access. To solve this problem, two new functions were created to match an exception either fully or partially. In the example above, a partial check will be performed and it'll produce a match since at least "b 12:34 r" from "b 12:34 rw" access matches. Cc: cgroups@vger.kernel.org Cc: Tejun Heo <tj@kernel.org> Cc: Serge Hallyn <serge.hallyn@canonical.com> Cc: Li Zefan <lizefan@huawei.com> Signed-off-by: Aristeu Rozanski <arozansk@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2014-04-13selinux: correctly label /proc inodes in use before the policy is loadedPaul Moore
commit f64410ec665479d7b4b77b7519e814253ed0f686 upstream. This patch is based on an earlier patch by Eric Paris, he describes the problem below: "If an inode is accessed before policy load it will get placed on a list of inodes to be initialized after policy load. After policy load we call inode_doinit() which calls inode_doinit_with_dentry() on all inodes accessed before policy load. In the case of inodes in procfs that means we'll end up at the bottom where it does: /* Default to the fs superblock SID. */ isec->sid = sbsec->sid; if ((sbsec->flags & SE_SBPROC) && !S_ISLNK(inode->i_mode)) { if (opt_dentry) { isec->sclass = inode_mode_to_security_class(...) rc = selinux_proc_get_sid(opt_dentry, isec->sclass, &sid); if (rc) goto out_unlock; isec->sid = sid; } } Since opt_dentry is null, we'll never call selinux_proc_get_sid() and will leave the inode labeled with the label on the superblock. I believe a fix would be to mimic the behavior of xattrs. Look for an alias of the inode. If it can't be found, just leave the inode uninitialized (and pick it up later) if it can be found, we should be able to call selinux_proc_get_sid() ..." On a system exhibiting this problem, you will notice a lot of files in /proc with the generic "proc_t" type (at least the ones that were accessed early in the boot), for example: # ls -Z /proc/sys/kernel/shmmax | awk '{ print $4 " " $5 }' system_u:object_r:proc_t:s0 /proc/sys/kernel/shmmax However, with this patch in place we see the expected result: # ls -Z /proc/sys/kernel/shmmax | awk '{ print $4 " " $5 }' system_u:object_r:sysctl_kernel_t:s0 /proc/sys/kernel/shmmax Cc: Eric Paris <eparis@redhat.com> Signed-off-by: Paul Moore <pmoore@redhat.com> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-03 15:09:14 +0000