From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7D24919539F; Sun, 15 Mar 2026 20:43:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773607418; cv=none; b=lJfJktyc8jz4HaGzzvDzOHbC1yVqdk3n4u5eT/jiXthaaKODFoHqOWJwAbtzi6eVbocRIu53i9JrdOEsdsfYy1qNyfG3EWC4bLBjL+rYPaJ1DFmeH5tWJ9e1cwq1r3n8ZR0XPPSAoYp8DR35xVepUjJiZh25wnXu6yze8eBm3iA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773607418; c=relaxed/simple; bh=m+AZNwVISlRtlPucyx9mZpMA7diB7VjTP/3aEWFd8cg=; h=Date:To:From:Subject:Message-Id; b=hPPun6HHhWdvD59IX9amTNa6r0RSVKoeYEy8DrMrKa2a8ZxhY2+Tvy1dfgPszsd4d6rpO/m0/LhsjX+WgPNuKnTjEpBOf9S5Pxl2nCdt2+sHrwH9/zzq7BG60//5X1V/UgojwVC+SdoxQ4c3OGZpnbC3CX5OP8Yk+OTLcaqRrtI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=d/mSeMrf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="d/mSeMrf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F0897C4CEF7; Sun, 15 Mar 2026 20:43:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1773607418; bh=m+AZNwVISlRtlPucyx9mZpMA7diB7VjTP/3aEWFd8cg=; h=Date:To:From:Subject:From; b=d/mSeMrfhm7pvCWdx44c4UJ4xCrqtzPvVl9w0pVLREdNdybFY33rhU0RxWXHQxfiI 3gKIT90dLfPa6G5ENBLRNAAs7YPPBh43a1uqB151wF6V6WodCPHkRSz8M842LWepYr vZz61hVEC2NHTzKIYobYGoW4qy7bofYFVpn0M1cc= Date: Sun, 15 Mar 2026 13:43:37 -0700 To: mm-commits@vger.kernel.org,vschneid@redhat.com,vincent.guittot@linaro.org,surenb@google.com,stable@vger.kernel.org,rppt@kernel.org,rostedt@goodmis.org,peterz@infradead.org,oleg@redhat.com,mingo@redhat.com,mhocko@suse.com,mgorman@suse.de,lorenzo.stoakes@oracle.com,liam.howlett@oracle.com,kees@kernel.org,Kartikey406@gmail.com,juri.lelli@redhat.com,dietmar.eggemann@arm.com,david@kernel.org,bsegall@google.com,brauner@kernel.org,kartikey406@gmail.com,akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] kernel-fork-validate-exit_signal-in-clone-syscall.patch removed from -mm tree Message-Id: <20260315204337.F0897C4CEF7@smtp.kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: kernel/fork: validate exit_signal in clone() syscall has been removed from the -mm tree. Its filename was kernel-fork-validate-exit_signal-in-clone-syscall.patch This patch was dropped because an updated version will be issued ------------------------------------------------------ From: Deepanshu Kartikey Subject: kernel/fork: validate exit_signal in clone() syscall Date: Sat, 7 Mar 2026 12:12:02 +0530 When a child process exits, it sends exit_signal to its parent via do_notify_parent(). The clone() syscall constructs exit_signal as: (lower_32_bits(clone_flags) & CSIGNAL) CSIGNAL is 0xff, so values in the range 65-255 are possible. However, valid_signal() only accepts signals up to _NSIG (64 on x86_64), causing a WARN_ON in do_notify_parent() when the process exits: WARNING: kernel/signal.c:2174 do_notify_parent+0xc7e/0xd70 The syzkaller reproducer triggers this by calling clone() with flags=0x80, resulting in exit_signal = (0x80 & CSIGNAL) = 128, which exceeds _NSIG and is not a valid signal. The comment above kernel_clone() states that callers are expected to validate exit_signal. clone3() correctly does this: if (unlikely((args.exit_signal & ~((u64)CSIGNAL)) || !valid_signal(args.exit_signal))) return -EINVAL; The clone() syscall has no such check. Add the missing valid_signal() check to clone(), consistent with the existing validation in clone3(). Link: https://lkml.kernel.org/r/20260307064202.353405-1-kartikey406@gmail.com Fixes: 3f2c788a1314 ("fork: prevent accidental access to clone3 features") Signed-off-by: Deepanshu Kartikey Reported-by: syzbot+bbe6b99feefc3a0842de@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=bbe6b99feefc3a0842de Tested-by: syzbot+bbe6b99feefc3a0842de@syzkaller.appspotmail.com Cc: Ben Segall Cc: Christian Brauner Cc: David Hildenbrand Cc: Dietmar Eggemann Cc: Ingo Molnar Cc: Juri Lelli Cc: Kees Cook Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Mel Gorman Cc: Michal Hocko Cc: Mike Rapoport Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Suren Baghdasaryan Cc: Valentin Schneider Cc: Vincent Guittot Cc: Oleg Nesterov Cc: Signed-off-by: Andrew Morton --- kernel/fork.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/kernel/fork.c~kernel-fork-validate-exit_signal-in-clone-syscall +++ a/kernel/fork.c @@ -2796,7 +2796,8 @@ SYSCALL_DEFINE5(clone, unsigned long, cl .stack = newsp, .tls = tls, }; - + if (!valid_signal(args.exit_signal)) + return -EINVAL; return kernel_clone(&args); } #endif _ Patches currently in -mm which might be from kartikey406@gmail.com are