From 073931017b49d9458aa351605b43a7e34598caef Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 19 Sep 2016 17:39:09 +0200 Subject: posix_acl: Clear SGID bit when setting file permissions 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 Reviewed-by: Jeff Layton Signed-off-by: Jan Kara Signed-off-by: Andreas Gruenbacher --- fs/orangefs/acl.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) (limited to 'fs/orangefs') diff --git a/fs/orangefs/acl.c b/fs/orangefs/acl.c index 28f2195..7a37544 100644 --- a/fs/orangefs/acl.c +++ b/fs/orangefs/acl.c @@ -73,14 +73,11 @@ int orangefs_set_acl(struct inode *inode, struct posix_acl *acl, int type) case ACL_TYPE_ACCESS: name = XATTR_NAME_POSIX_ACL_ACCESS; if (acl) { - umode_t mode = inode->i_mode; - /* - * can we represent this with the traditional file - * mode permission bits? - */ - error = posix_acl_equiv_mode(acl, &mode); - if (error < 0) { - gossip_err("%s: posix_acl_equiv_mode err: %d\n", + umode_t mode; + + error = posix_acl_update_mode(inode, &mode, &acl); + if (error) { + gossip_err("%s: posix_acl_update_mode err: %d\n", __func__, error); return error; @@ -90,8 +87,6 @@ int orangefs_set_acl(struct inode *inode, struct posix_acl *acl, int type) SetModeFlag(orangefs_inode); inode->i_mode = mode; mark_inode_dirty_sync(inode); - if (error == 0) - acl = NULL; } break; case ACL_TYPE_DEFAULT: -- cgit v1.1