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 <so...@openwall.com>
Signed-off-by: Kees Cook <keesc...@chromium.org>
Acked-by: Serge Hallyn <se...@hallyn.com>
Reviewed-by: Andy Lutomirski <l...@kernel.org>
---
v2: add acks/reviews, actually include akpm in "To" :)
---
 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);
-- 
2.7.4


-- 
Kees Cook
Pixel Security

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