diff options
| author | Jan Kara <jack@suse.cz> | 2016-12-14 13:24:50 +0100 |
|---|---|---|
| committer | Sasha Levin <alexander.levin@verizon.com> | 2016-12-23 08:56:35 -0500 |
| commit | 62fa696b7b435e93ed114dd6a23aa0881d7f81b9 (patch) | |
| tree | b79fe7082c8370a323a83b947804d7340c823f35 /fs/ext2 | |
| parent | de42b9559d0c540152260d484dbc70b3e81f8738 (diff) | |
posix_acl: Clear SGID bit when setting file permissions
[ Upstream commit 073931017b49d9458aa351605b43a7e34598caef ]
When file permissions are modified via chmod(2) and the user is not in
the owning group or capable of CAP_FSETID, the setgid bit is cleared in
inode_change_ok(). Setting a POSIX ACL via setxattr(2) sets the file
permissions as well as the new ACL, but doesn't clear the setgid bit in
a similar way; this allows to bypass the check in chmod(2). Fix that.
References: CVE-2016-7097
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Philipp Hahn <hahn@univention.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Diffstat (limited to 'fs/ext2')
| -rw-r--r-- | fs/ext2/acl.c | 12 |
1 files changed, 4 insertions, 8 deletions
diff --git a/fs/ext2/acl.c b/fs/ext2/acl.c index 27695e6f4e46..d6aeb84e90b6 100644 --- a/fs/ext2/acl.c +++ b/fs/ext2/acl.c @@ -193,15 +193,11 @@ ext2_set_acl(struct inode *inode, struct posix_acl *acl, int type) case ACL_TYPE_ACCESS: name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS; if (acl) { - error = posix_acl_equiv_mode(acl, &inode->i_mode); - if (error < 0) + error = posix_acl_update_mode(inode, &inode->i_mode, &acl); + if (error) return error; - else { - inode->i_ctime = CURRENT_TIME_SEC; - mark_inode_dirty(inode); - if (error == 0) - acl = NULL; - } + inode->i_ctime = CURRENT_TIME_SEC; + mark_inode_dirty(inode); } break; |