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authorVivek Goyal <vgoyal@redhat.com>2020-10-09 14:15:09 -0400
committerMiklos Szeredi <mszeredi@redhat.com>2020-11-11 17:22:33 +0100
commit3179216135ec09825d7c7875580951a6e69dc5df (patch)
treedd0b2cbe15cfddb6747a1078fbd434b3b58705fa /fs/fuse
parentb866739596ae3c3c60c43f1cf04a516c5aa20fd1 (diff)
fuse: setattr should set FATTR_KILL_SUIDGID
If fc->handle_killpriv_v2 is enabled, we expect file server to clear suid/sgid/security.capbility upon chown/truncate/write as appropriate. Upon truncate (ATTR_SIZE), suid/sgid are cleared only if caller does not have CAP_FSETID. File server does not know whether caller has CAP_FSETID or not. Hence set FATTR_KILL_SUIDGID upon truncate to let file server know that caller does not have CAP_FSETID and it should kill suid/sgid as appropriate. On chown (ATTR_UID/ATTR_GID) suid/sgid need to be cleared irrespective of capabilities of calling process, so set FATTR_KILL_SUIDGID unconditionally in that case. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/dir.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index c3e22a3dd323..28b07ae5e55f 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1648,10 +1648,20 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
inarg.valid |= FATTR_FH;
inarg.fh = ff->fh;
}
+
+ /* Kill suid/sgid for non-directory chown unconditionally */
+ if (fc->handle_killpriv_v2 && !S_ISDIR(inode->i_mode) &&
+ attr->ia_valid & (ATTR_UID | ATTR_GID))
+ inarg.valid |= FATTR_KILL_SUIDGID;
+
if (attr->ia_valid & ATTR_SIZE) {
/* For mandatory locking in truncate */
inarg.valid |= FATTR_LOCKOWNER;
inarg.lock_owner = fuse_lock_owner_id(fc, current->files);
+
+ /* Kill suid/sgid for truncate only if no CAP_FSETID */
+ if (fc->handle_killpriv_v2 && !capable(CAP_FSETID))
+ inarg.valid |= FATTR_KILL_SUIDGID;
}
fuse_setattr_fill(fc, &args, inode, &inarg, &outarg);
err = fuse_simple_request(fm, &args);