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| author |   Miklos Szeredi <mszeredi@redhat.com> | 2016-12-06 16:18:45 +0100 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@redhat.com> | 2016-12-06 16:18:45 +0100 |
| commit | c01638f5d919728f565bf8b5e0a6a159642df0d9 (patch) | |
| tree | 3dc341c250252908c912ad167f49d00b2fc2c734 /fs | |
| parent | Linux 4.9-rc8 (diff) | |
| download | linux-dev-c01638f5d919728f565bf8b5e0a6a159642df0d9.tar.xz linux-dev-c01638f5d919728f565bf8b5e0a6a159642df0d9.zip | |
fuse: fix clearing suid, sgid for chown()
Basically, the pjdfstests set the ownership of a file to 06555, and then
chowns it (as root) to a new uid/gid. Prior to commit a09f99eddef4 ("fuse:
fix killing s[ug]id in setattr"), fuse would send down a setattr with both
the uid/gid change and a new mode. Now, it just sends down the uid/gid
change.
Technically this is NOTABUG, since POSIX doesn't _require_ that we clear
these bits for a privileged process, but Linux (wisely) has done that and I
think we don't want to change that behavior here.
This is caused by the use of should_remove_suid(), which will always return
0 when the process has CAP_FSETID.
In fact we really don't need to be calling should_remove_suid() at all,
since we've already been indicated that we should remove the suid, we just
don't want to use a (very) stale mode for that.
This patch should fix the above as well as simplify the logic.
Reported-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: a09f99eddef4 ("fuse: fix killing s[ug]id in setattr")
Cc: <stable@vger.kernel.org>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/fuse/dir.c | 7 |
1 files changed, 2 insertions, 5 deletions
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index b3ebe512d64c..096f79997f75 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -1739,8 +1739,6 @@ static int fuse_setattr(struct dentry *entry, struct iattr *attr) * This should be done on write(), truncate() and chown(). */ if (!fc->handle_killpriv) { - int kill; - /* * ia_mode calculation may have used stale i_mode. * Refresh and recalculate. @@ -1750,12 +1748,11 @@ static int fuse_setattr(struct dentry *entry, struct iattr *attr) return ret; attr->ia_mode = inode->i_mode; - kill = should_remove_suid(entry); - if (kill & ATTR_KILL_SUID) { + if (inode->i_mode & S_ISUID) { attr->ia_valid |= ATTR_MODE; attr->ia_mode &= ~S_ISUID; } - if (kill & ATTR_KILL_SGID) { + if ((inode->i_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { attr->ia_valid |= ATTR_MODE; attr->ia_mode &= ~S_ISGID; } |