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| author | Stanislav Kholmanskikh <stanislav.kholmanskikh@oracle.com> | 2013-12-11 14:16:36 +0400 |
|---|---|---|
| committer | J. Bruce Fields <bfields@redhat.com> | 2013-12-12 20:37:18 +0400 |
| commit | c4fa6d7c5971baa45eca4f81b8f100299848486a (patch) | |
| tree | 1186bdfec8025717f1bdaf3ed37c52dd28d637cb /fs/nfsd/vfs.c | |
| parent | 056785ea51a657f55953f6b0195baac2cceb1f16 (diff) | |
| download | linux-c4fa6d7c5971baa45eca4f81b8f100299848486a.tar.xz | |
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>
Diffstat (limited to 'fs/nfsd/vfs.c')
| -rw-r--r-- | fs/nfsd/vfs.c | 3 |
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 */ |