xfs: kill suid/sgid through the truncate path.

XFS has failed to kill suid/sgid bits correctly when truncating
files of non-zero size since commit c4ed4243 ("xfs: split
xfs_setattr") introduced in the 3.1 kernel. Fix it.

Fix it.

cc: stable kernel <stable@vger.kernel.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

(cherry picked from commit 56c19e89b38618390addfc743d822f99519055c6)

1 files changed, 32 insertions, 15 deletions

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index d82efaa2ac73..ca9ecaa81112 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -455,6 +455,28 @@ xfs_vn_getattr(
         return 0;
 }
 
+static void
+xfs_setattr_mode(
+        struct xfs_trans        *tp,
+        struct xfs_inode        *ip,
+        struct iattr            *iattr)
+{
+        struct inode    *inode = VFS_I(ip);
+        umode_t         mode = iattr->ia_mode;
+
+        ASSERT(tp);
+        ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+
+        if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
+                mode &= ~S_ISGID;
+
+        ip->i_d.di_mode &= S_IFMT;
+        ip->i_d.di_mode |= mode & ~S_IFMT;
+
+        inode->i_mode &= S_IFMT;
+        inode->i_mode |= mode & ~S_IFMT;
+}
+
 int
 xfs_setattr_nonsize(
         struct xfs_inode        *ip,
@@ -606,18 +628,8 @@ xfs_setattr_nonsize(
         /*
          * Change file access modes.
          */
-        if (mask & ATTR_MODE) {
-                umode_t mode = iattr->ia_mode;
-
-                if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
-                        mode &= ~S_ISGID;
-
-                ip->i_d.di_mode &= S_IFMT;
-                ip->i_d.di_mode |= mode & ~S_IFMT;
-
-                inode->i_mode &= S_IFMT;
-                inode->i_mode |= mode & ~S_IFMT;
-        }
+        if (mask & ATTR_MODE)
+                xfs_setattr_mode(tp, ip, iattr);
 
         /*
          * Change file access or modified times.
@@ -714,9 +726,8 @@ xfs_setattr_size(
                 return XFS_ERROR(error);
 
         ASSERT(S_ISREG(ip->i_d.di_mode));
-        ASSERT((mask & (ATTR_MODE|ATTR_UID|ATTR_GID|ATTR_ATIME|ATTR_ATIME_SET|
-                        ATTR_MTIME_SET|ATTR_KILL_SUID|ATTR_KILL_SGID|
-                        ATTR_KILL_PRIV|ATTR_TIMES_SET)) == 0);
+        ASSERT((mask & (ATTR_UID|ATTR_GID|ATTR_ATIME|ATTR_ATIME_SET|
+                        ATTR_MTIME_SET|ATTR_KILL_PRIV|ATTR_TIMES_SET)) == 0);
 
         if (!(flags & XFS_ATTR_NOLOCK)) {
                 lock_flags |= XFS_IOLOCK_EXCL;
@@ -860,6 +871,12 @@ xfs_setattr_size(
                 xfs_inode_clear_eofblocks_tag(ip);
         }
 
+        /*
+         * Change file access modes.
+         */
+        if (mask & ATTR_MODE)
+                xfs_setattr_mode(tp, ip, iattr);
+
         if (mask & ATTR_CTIME) {
                 inode->i_ctime = iattr->ia_ctime;
                 ip->i_d.di_ctime.t_sec = iattr->ia_ctime.tv_sec;