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 465372F2900 for ; Tue, 12 Aug 2025 16:20:44 +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=1755015644; cv=none; b=YXDham+BJBoTKc3muia3OlYxZH0mUvo9vkKGMydep8n9t9+UQG6cvFIS4hEAB8xKW7ea7smUnZ04SX3qU42rAaVgkPbGVSD7bxT0khxig0LdyECBfnspnBpP+mibSK/T+LiofB3DumyJpns9OTEX266Uo8PV8woLLQ5wwwI9o4U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755015644; c=relaxed/simple; bh=AWSZOr1YbPkR1PAkpSZU5+LPhZPdp+TLHr6GpDbOvXg=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=G3TkTW9q904QVi9Dk1OKaFPFrkkpGFQM87eysoYufjTOIvWlYYdCboN5lSlabfzDPR911McNpe6IaFSYsNDy0yRXZLVLVzjN89DE+ns1Wk8doyMdAfI9PlidomrotEX3anda51dPoKGZJIBnCflOOfk4PPn64OkCXTIFBOG0JrU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1Havzly7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="1Havzly7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9739DC4CEF1; Tue, 12 Aug 2025 16:20:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755015644; bh=AWSZOr1YbPkR1PAkpSZU5+LPhZPdp+TLHr6GpDbOvXg=; h=Subject:To:Cc:From:Date:From; b=1Havzly7/tltuzie/mEYoaQYNHOPpiRVl840fduPtvg06hNIiImMxX0VEovsLFZBR oKjPsCyqo/CZBX+SqcwrmbewqThPCB+JAZZk0dh40i8G0m/oVSOCXJ2ikJ+TwDDs/d RBujFR7b2eUyAtvAokBHGFW5afINeIwswc5zxju4= Subject: FAILED: patch "[PATCH] HID: core: Harden s32ton() against conversion to 0 bits" failed to apply to 6.6-stable tree To: stern@rowland.harvard.edu,bentiss@kernel.org Cc: From: Date: Tue, 12 Aug 2025 18:20:32 +0200 Message-ID: <2025081232-immovable-among-3b59@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x a6b87bfc2ab5bccb7ad953693c85d9062aef3fdd # git commit -s git send-email --to '' --in-reply-to '2025081232-immovable-among-3b59@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From a6b87bfc2ab5bccb7ad953693c85d9062aef3fdd Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Wed, 23 Jul 2025 10:37:04 -0400 Subject: [PATCH] HID: core: Harden s32ton() against conversion to 0 bits Testing by the syzbot fuzzer showed that the HID core gets a shift-out-of-bounds exception when it tries to convert a 32-bit quantity to a 0-bit quantity. Ideally this should never occur, but there are buggy devices and some might have a report field with size set to zero; we shouldn't reject the report or the device just because of that. Instead, harden the s32ton() routine so that it returns a reasonable result instead of crashing when it is called with the number of bits set to 0 -- the same as what snto32() does. Signed-off-by: Alan Stern Reported-by: syzbot+b63d677d63bcac06cf90@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-usb/68753a08.050a0220.33d347.0008.GAE@google.com/ Tested-by: syzbot+b63d677d63bcac06cf90@syzkaller.appspotmail.com Fixes: dde5845a529f ("[PATCH] Generic HID layer - code split") Cc: stable@vger.kernel.org Link: https://patch.msgid.link/613a66cd-4309-4bce-a4f7-2905f9bce0c9@rowland.harvard.edu Signed-off-by: Benjamin Tissoires diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index ef1f79951d9b..f7d4efcae603 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -66,8 +66,12 @@ static s32 snto32(__u32 value, unsigned int n) static u32 s32ton(__s32 value, unsigned int n) { - s32 a = value >> (n - 1); + s32 a; + if (!value || !n) + return 0; + + a = value >> (n - 1); if (a && a != -1) return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1; return value & ((1 << n) - 1);