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authorStefan Berger <stefanb@linux.ibm.com>2024-02-23 12:25:05 -0500
committerMimi Zohar <zohar@linux.ibm.com>2024-04-09 17:14:57 -0400
commit3253804773c0613a1bad5bfea2edf172b760d8b6 (patch)
treed3f6b1b665725dbf66221496577d3030b9a9692f
parentc21632b66895eb23c05e4eeedb68128fb243d168 (diff)
security: allow finer granularity in permitting copy-up of security xattrs
Copying up xattrs is solely based on the security xattr name. For finer granularity add a dentry parameter to the security_inode_copy_up_xattr hook definition, allowing decisions to be based on the xattr content as well. Co-developed-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com> Acked-by: Amir Goldstein <amir73il@gmail.com> Acked-by: Paul Moore <paul@paul-moore.com> (LSM,SELinux) Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
-rw-r--r--fs/overlayfs/copy_up.c2
-rw-r--r--include/linux/lsm_hook_defs.h3
-rw-r--r--include/linux/security.h4
-rw-r--r--security/integrity/evm/evm_main.c2
-rw-r--r--security/security.c5
-rw-r--r--security/selinux/hooks.c2
-rw-r--r--security/smack/smack_lsm.c2
7 files changed, 11 insertions, 9 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 0762575a1e70..a5ef2005a2cc 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -114,7 +114,7 @@ int ovl_copy_xattr(struct super_block *sb, const struct path *oldpath, struct de
if (ovl_is_private_xattr(sb, name))
continue;
- error = security_inode_copy_up_xattr(name);
+ error = security_inode_copy_up_xattr(old, name);
if (error < 0 && error != -EOPNOTSUPP)
break;
if (error == 1) {
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 334e00efbde4..f804b76cde44 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -176,7 +176,8 @@ LSM_HOOK(int, 0, inode_listsecurity, struct inode *inode, char *buffer,
size_t buffer_size)
LSM_HOOK(void, LSM_RET_VOID, inode_getsecid, struct inode *inode, u32 *secid)
LSM_HOOK(int, 0, inode_copy_up, struct dentry *src, struct cred **new)
-LSM_HOOK(int, -EOPNOTSUPP, inode_copy_up_xattr, const char *name)
+LSM_HOOK(int, -EOPNOTSUPP, inode_copy_up_xattr, struct dentry *src,
+ const char *name)
LSM_HOOK(int, 0, kernfs_init_security, struct kernfs_node *kn_dir,
struct kernfs_node *kn)
LSM_HOOK(int, 0, file_permission, struct file *file, int mask)
diff --git a/include/linux/security.h b/include/linux/security.h
index 41a8f667bdfa..21cf70346b33 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -398,7 +398,7 @@ int security_inode_setsecurity(struct inode *inode, const char *name, const void
int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size);
void security_inode_getsecid(struct inode *inode, u32 *secid);
int security_inode_copy_up(struct dentry *src, struct cred **new);
-int security_inode_copy_up_xattr(const char *name);
+int security_inode_copy_up_xattr(struct dentry *src, const char *name);
int security_kernfs_init_security(struct kernfs_node *kn_dir,
struct kernfs_node *kn);
int security_file_permission(struct file *file, int mask);
@@ -1016,7 +1016,7 @@ static inline int security_kernfs_init_security(struct kernfs_node *kn_dir,
return 0;
}
-static inline int security_inode_copy_up_xattr(const char *name)
+static inline int security_inode_copy_up_xattr(struct dentry *src, const char *name)
{
return -EOPNOTSUPP;
}
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index 81dbade5b9b3..b0a862bfd74a 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -946,7 +946,7 @@ static void evm_inode_post_setattr(struct mnt_idmap *idmap,
evm_update_evmxattr(dentry, NULL, NULL, 0);
}
-static int evm_inode_copy_up_xattr(const char *name)
+static int evm_inode_copy_up_xattr(struct dentry *src, const char *name)
{
if (strcmp(name, XATTR_NAME_EVM) == 0)
return 1; /* Discard */
diff --git a/security/security.c b/security/security.c
index 0a9a0ac3f266..e5da848c50b9 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2628,6 +2628,7 @@ EXPORT_SYMBOL(security_inode_copy_up);
/**
* security_inode_copy_up_xattr() - Filter xattrs in an overlayfs copy-up op
+ * @src: union dentry of copy-up file
* @name: xattr name
*
* Filter the xattrs being copied up when a unioned file is copied up from a
@@ -2638,7 +2639,7 @@ EXPORT_SYMBOL(security_inode_copy_up);
* if the security module does not know about attribute, or a negative
* error code to abort the copy up.
*/
-int security_inode_copy_up_xattr(const char *name)
+int security_inode_copy_up_xattr(struct dentry *src, const char *name)
{
int rc;
@@ -2647,7 +2648,7 @@ int security_inode_copy_up_xattr(const char *name)
* xattr), -EOPNOTSUPP if it does not know anything about the xattr or
* any other error code in case of an error.
*/
- rc = call_int_hook(inode_copy_up_xattr, name);
+ rc = call_int_hook(inode_copy_up_xattr, src, name);
if (rc != LSM_RET_DEFAULT(inode_copy_up_xattr))
return rc;
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 3448454c82d0..9f018f51e47a 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3530,7 +3530,7 @@ static int selinux_inode_copy_up(struct dentry *src, struct cred **new)
return 0;
}
-static int selinux_inode_copy_up_xattr(const char *name)
+static int selinux_inode_copy_up_xattr(struct dentry *dentry, const char *name)
{
/* The copy_up hook above sets the initial context on an inode, but we
* don't then want to overwrite it by blindly copying all the lower
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 146667937811..79d8dc633b9a 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -4885,7 +4885,7 @@ static int smack_inode_copy_up(struct dentry *dentry, struct cred **new)
return 0;
}
-static int smack_inode_copy_up_xattr(const char *name)
+static int smack_inode_copy_up_xattr(struct dentry *src, const char *name)
{
/*
* Return 1 if this is the smack access Smack attribute.