linux-kernel - [PATCH RFC 3/8] openat2: explicitly return -E2BIG for (usize > PAGE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240902-extensible-structs-check_fields-v1-3-545e93ede2f2@cyphar.com>
Date: Mon, 02 Sep 2024 17:06:25 +1000
From: Aleksa Sarai <cyphar@...har.com>
To: Ingo Molnar <mingo@...hat.com>, Peter Zijlstra <peterz@...radead.org>, 
 Juri Lelli <juri.lelli@...hat.com>, 
 Vincent Guittot <vincent.guittot@...aro.org>, 
 Dietmar Eggemann <dietmar.eggemann@....com>, 
 Steven Rostedt <rostedt@...dmis.org>, Ben Segall <bsegall@...gle.com>, 
 Mel Gorman <mgorman@...e.de>, Valentin Schneider <vschneid@...hat.com>, 
 Alexander Viro <viro@...iv.linux.org.uk>, 
 Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>, 
 Arnd Bergmann <arnd@...db.de>, Shuah Khan <shuah@...nel.org>
Cc: Kees Cook <kees@...nel.org>, Florian Weimer <fweimer@...hat.com>, 
 Arnd Bergmann <arnd@...db.de>, Mark Rutland <mark.rutland@....com>, 
 linux-kernel@...r.kernel.org, linux-api@...r.kernel.org, 
 linux-fsdevel@...r.kernel.org, linux-arch@...r.kernel.org, 
 linux-kselftest@...r.kernel.org, Aleksa Sarai <cyphar@...har.com>, 
 stable@...r.kernel.org
Subject: [PATCH RFC 3/8] openat2: explicitly return -E2BIG for (usize >
 PAGE_SIZE)

While we do currently return -EFAULT in this case, it seems prudent to
follow the behaviour of other syscalls like clone3. It seems quite
unlikely that anyone depends on this error code being EFAULT, but we can
always revert this if it turns out to be an issue.

Cc: <stable@...r.kernel.org> # v5.6+
Fixes: fddb5d430ad9 ("open: introduce openat2(2) syscall")
Signed-off-by: Aleksa Sarai <cyphar@...har.com>
---
 fs/open.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/open.c b/fs/open.c
index 22adbef7ecc2..30bfcddd505d 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -1458,6 +1458,8 @@ SYSCALL_DEFINE4(openat2, int, dfd, const char __user *, filename,
 
 	if (unlikely(usize < OPEN_HOW_SIZE_VER0))
 		return -EINVAL;
+	if (unlikely(usize > PAGE_SIZE))
+		return -E2BIG;
 
 	err = copy_struct_from_user(&tmp, sizeof(tmp), how, usize);
 	if (err)

-- 
2.46.0