From cc658db47d6897a8571fb6227f59d1d18151b0b2 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 21 Jun 2017 09:53:06 -0700 Subject: [PATCH] fs: Reorder inode_owner_or_capable() to avoid needless Checking for capabilities should be the last operation when performing access control tests so that PF_SUPERPRIV is set only when it was required for success (implying that the capability was needed for the operation). Reported-by: Solar Designer Signed-off-by: Kees Cook Acked-by: Serge Hallyn Reviewed-by: Andy Lutomirski Signed-off-by: Al Viro --- fs/inode.c | 2 +- fs/namei.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index db5914783a71..7092debe90cc 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -2023,7 +2023,7 @@ bool inode_owner_or_capable(const struct inode *inode) return true; ns = current_user_ns(); - if (ns_capable(ns, CAP_FOWNER) && kuid_has_mapping(ns, inode->i_uid)) + if (kuid_has_mapping(ns, inode->i_uid) && ns_capable(ns, CAP_FOWNER)) return true; return false; } diff --git a/fs/namei.c b/fs/namei.c index 6571a5f5112e..efe53a5d0737 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1008,7 +1008,7 @@ static int may_linkat(struct path *link) /* Source inode owner (or CAP_FOWNER) can hardlink all they like, * otherwise, it must be a safe source. */ - if (inode_owner_or_capable(inode) || safe_hardlink_source(inode)) + if (safe_hardlink_source(inode) || inode_owner_or_capable(inode)) return 0; audit_log_link_denied("linkat", link); -- 2.20.1