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| author | Christian Brauner <brauner@kernel.org> | 2023-05-02 16:36:02 +0300 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2023-06-05 16:01:41 +0300 |
| commit | 2d8ae8c417db284f598dffb178cc01e7db0f1821 (patch) | |
| tree | ca755bbff5219a5574ec4e8cad52ea4038f6c69e /fs/nfsd/vfs.c | |
| parent | 9561de3a55bed6bdd44a12820ba81ec416e705a7 (diff) | |
| download | linux-2d8ae8c417db284f598dffb178cc01e7db0f1821.tar.xz | |
nfsd: use vfs setgid helper
We've aligned setgid behavior over multiple kernel releases. The details
can be found in commit cf619f891971 ("Merge tag 'fs.ovl.setgid.v6.2' of
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping") and
commit 426b4ca2d6a5 ("Merge tag 'fs.setgid.v6.0' of
git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux").
Consistent setgid stripping behavior is now encapsulated in the
setattr_should_drop_sgid() helper which is used by all filesystems that
strip setgid bits outside of vfs proper. Usually ATTR_KILL_SGID is
raised in e.g., chown_common() and is subject to the
setattr_should_drop_sgid() check to determine whether the setgid bit can
be retained. Since nfsd is raising ATTR_KILL_SGID unconditionally it
will cause notify_change() to strip it even if the caller had the
necessary privileges to retain it. Ensure that nfsd only raises
ATR_KILL_SGID if the caller lacks the necessary privileges to retain the
setgid bit.
Without this patch the setgid stripping tests in LTP will fail:
> As you can see, the problem is S_ISGID (0002000) was dropped on a
> non-group-executable file while chown was invoked by super-user, while
[...]
> fchown02.c:66: TFAIL: testfile2: wrong mode permissions 0100700, expected 0102700
[...]
> chown02.c:57: TFAIL: testfile2: wrong mode permissions 0100700, expected 0102700
With this patch all tests pass.
Reported-by: Sherry Yang <sherry.yang@oracle.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'fs/nfsd/vfs.c')
| -rw-r--r-- | fs/nfsd/vfs.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index db67f8e19344..0016bcc04a59 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -388,7 +388,9 @@ nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap) iap->ia_mode &= ~S_ISGID; } else { /* set ATTR_KILL_* bits and let VFS handle it */ - iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID); + iap->ia_valid |= ATTR_KILL_SUID; + iap->ia_valid |= + setattr_should_drop_sgid(&nop_mnt_idmap, inode); } } } |