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authorJan Kara2016-09-19 17:39:09 +0200
committerJan Kara2016-09-22 10:55:32 +0200
commit073931017b49d9458aa351605b43a7e34598caef (patch)
tree8c4374e82e5cad92bdb589e5be417f1a94870399 /fs/ceph
parent5d3ddd84eaefffd23c028bce5610dac8726f71c1 (diff)
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 <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>
Diffstat (limited to 'fs/ceph')
-rw-r--r--fs/ceph/acl.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/fs/ceph/acl.c b/fs/ceph/acl.c
index 4f67227f69a5..d0b6b342dff9 100644
--- a/fs/ceph/acl.c
+++ b/fs/ceph/acl.c
@@ -95,11 +95,9 @@ int ceph_set_acl(struct inode *inode, struct posix_acl *acl, int type)
case ACL_TYPE_ACCESS:
name = XATTR_NAME_POSIX_ACL_ACCESS;
if (acl) {
- ret = posix_acl_equiv_mode(acl, &new_mode);
- if (ret < 0)
+ ret = posix_acl_update_mode(inode, &new_mode, &acl);
+ if (ret)
goto out;
- if (ret == 0)
- acl = NULL;
}
break;
case ACL_TYPE_DEFAULT: