* [PATCH] fs: Reorder inode_owner_or_capable() to avoid needless
@ 2017-06-20 21:40 Kees Cook
2017-06-20 22:02 ` Serge E. Hallyn
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Kees Cook @ 2017-06-20 21:40 UTC (permalink / raw)
To: Alexander Viro
Cc: Solar Designer, Serge E. Hallyn, Andy Lutomirski, linux-fsdevel,
linux-kernel
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 <solar@openwall.com>
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
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
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] fs: Reorder inode_owner_or_capable() to avoid needless
2017-06-20 21:40 [PATCH] fs: Reorder inode_owner_or_capable() to avoid needless Kees Cook
@ 2017-06-20 22:02 ` Serge E. Hallyn
2017-06-21 14:55 ` Andy Lutomirski
2017-06-30 0:06 ` Al Viro
2 siblings, 0 replies; 4+ messages in thread
From: Serge E. Hallyn @ 2017-06-20 22:02 UTC (permalink / raw)
To: Kees Cook
Cc: Alexander Viro, Solar Designer, Serge E. Hallyn, Andy Lutomirski,
linux-fsdevel, linux-kernel
Quoting Kees Cook (keescook@chromium.org):
> 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 <solar@openwall.com>
> Cc: Serge E. Hallyn <serge@hallyn.com>
Makes sense, thanks.
Acked-by: Serge Hallyn <serge@hallyn.com>
> Cc: Andy Lutomirski <luto@kernel.org>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> 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
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] fs: Reorder inode_owner_or_capable() to avoid needless
2017-06-20 21:40 [PATCH] fs: Reorder inode_owner_or_capable() to avoid needless Kees Cook
2017-06-20 22:02 ` Serge E. Hallyn
@ 2017-06-21 14:55 ` Andy Lutomirski
2017-06-30 0:06 ` Al Viro
2 siblings, 0 replies; 4+ messages in thread
From: Andy Lutomirski @ 2017-06-21 14:55 UTC (permalink / raw)
To: Kees Cook
Cc: Alexander Viro, Solar Designer, Serge E. Hallyn, Andy Lutomirski,
Linux FS Devel, linux-kernel@vger.kernel.org
On Tue, Jun 20, 2017 at 2:40 PM, Kees Cook <keescook@chromium.org> wrote:
> 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).
>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] fs: Reorder inode_owner_or_capable() to avoid needless
2017-06-20 21:40 [PATCH] fs: Reorder inode_owner_or_capable() to avoid needless Kees Cook
2017-06-20 22:02 ` Serge E. Hallyn
2017-06-21 14:55 ` Andy Lutomirski
@ 2017-06-30 0:06 ` Al Viro
2 siblings, 0 replies; 4+ messages in thread
From: Al Viro @ 2017-06-30 0:06 UTC (permalink / raw)
To: Kees Cook
Cc: Solar Designer, Serge E. Hallyn, Andy Lutomirski, linux-fsdevel,
linux-kernel
On Tue, Jun 20, 2017 at 02:40:24PM -0700, Kees Cook wrote:
> 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).
Applied
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-06-30 0:06 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-06-20 21:40 [PATCH] fs: Reorder inode_owner_or_capable() to avoid needless Kees Cook
2017-06-20 22:02 ` Serge E. Hallyn
2017-06-21 14:55 ` Andy Lutomirski
2017-06-30 0:06 ` Al Viro
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).