From f421a3b18aa78acb3f8433cc357853978f6940a1 Mon Sep 17 00:00:00 2001 From: Aleksa Sarai Date: Thu, 10 Oct 2024 07:40:36 +1100 Subject: [PATCH] openat2: explicitly return -E2BIG for (usize > PAGE_SIZE) commit f92f0a1b05698340836229d791b3ffecc71b265a upstream. 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@vger.kernel.org # v5.6+ Fixes: fddb5d430ad9 ("open: introduce openat2(2) syscall") Signed-off-by: Aleksa Sarai Link: https://lore.kernel.org/r/20241010-extensible-structs-check_fields-v3-3-d2833dfe6edd@cyphar.com Signed-off-by: Christian Brauner Signed-off-by: Greg Kroah-Hartman --- fs/open.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/open.c b/fs/open.c index 59db720693f9..f9ac703ec1b2 100644 --- a/fs/open.c +++ b/fs/open.c @@ -1461,6 +1461,8 @@ 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)