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authorStanislav Kholmanskikh <stanislav.kholmanskikh@oracle.com>2013-12-11 14:16:36 +0400
committerJ. Bruce Fields <bfields@redhat.com>2013-12-12 11:37:18 -0500
commitc4fa6d7c5971baa45eca4f81b8f100299848486a (patch)
tree1186bdfec8025717f1bdaf3ed37c52dd28d637cb
parent056785ea51a657f55953f6b0195baac2cceb1f16 (diff)
nfsd: revoking of suid/sgid bits after chown() in a consistent way
There is an inconsistency in the handling of SUID/SGID file bits after chown() between NFS and other local file systems. Local file systems (for example, ext3, ext4, xfs, btrfs) revoke SUID/SGID bits after chown() on a regular file even if the owner/group of the file has not been changed: ~# touch file; chmod ug+s file; chmod u+x file ~# ls -l file -rwsr-Sr-- 1 root root 0 Dec 6 04:49 file ~# chown root file; ls -l file -rwxr-Sr-- 1 root root 0 Dec 6 04:49 file but NFS doesn't do that: ~# touch file; chmod ug+s file; chmod u+x file ~# ls -l file -rwsr-Sr-- 1 root root 0 Dec 6 04:49 file ~# chown root file; ls -l file -rwsr-Sr-- 1 root root 0 Dec 6 04:49 file NFS does that only if the owner/group has been changed: ~# touch file; chmod ug+s file; chmod u+x file ~# ls -l file -rwsr-Sr-- 1 root root 0 Dec 6 05:02 file ~# chown bin file; ls -l file -rwxr-Sr-- 1 bin root 0 Dec 6 05:02 file See: http://pubs.opengroup.org/onlinepubs/9699919799/functions/chown.html "If the specified file is a regular file, one or more of the S_IXUSR, S_IXGRP, or S_IXOTH bits of the file mode are set, and the process has appropriate privileges, it is implementation-defined whether the set-user-ID and set-group-ID bits are altered." So both variants are acceptable by POSIX. This patch makes NFS to behave like local file systems. Signed-off-by: Stanislav Kholmanskikh <stanislav.kholmanskikh@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
-rw-r--r--fs/nfsd/vfs.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 7eea63cada1d..c8aa6ff99259 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -348,8 +348,7 @@ nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap)
/* Revoke setuid/setgid on chown */
if (!S_ISDIR(inode->i_mode) &&
- (((iap->ia_valid & ATTR_UID) && !uid_eq(iap->ia_uid, inode->i_uid)) ||
- ((iap->ia_valid & ATTR_GID) && !gid_eq(iap->ia_gid, inode->i_gid)))) {
+ ((iap->ia_valid & ATTR_UID) || (iap->ia_valid & ATTR_GID))) {
iap->ia_valid |= ATTR_KILL_PRIV;
if (iap->ia_valid & ATTR_MODE) {
/* we're setting mode too, just clear the s*id bits */