From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 95D3A3D5C07; Mon, 17 Aug 2026 15:26:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786980389; cv=none; b=JG5z23x+XAO6yB1z1lWJ+lUe0qUBXfVwf/8XCjB8It2/MCIbb5koL0V382SBp8p32lfPaSiRp+PvmUsDvt82i2BdMiHfjSoY2y2v/UVykL7YhF21YjYpqLZsTJHlOQDhvF3EpccVxpoSo95NgoPANFXNVm5DqpPb5Sy/YLlwM2k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786980389; c=relaxed/simple; bh=RqzIXxkjkVMircxgOHCE0aCXTlQKdHQC6iE7oxpEix4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cvZR/qMMr8zVU7fVthfidN0veOkAGLLQRmlzQS3PXAErgfnW0vp/T5+kXhDS7JMpR5IeyoTb+kp25QCm18K9NL9AX2T1j8tVFAbgT7SP9kKsgXxUfFsfDjcsVm96ciIGMrN2E0uZrXbkuBr74Ci7klnx7sCFdNz/myUYaDpjqyE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Vkatoe3w; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Vkatoe3w" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EDFC11F00A3A; Mon, 17 Aug 2026 15:26:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786980388; bh=phouA+ugPyEa6cH2Uac3aTvRrIrF7P3xDx08cvl7bus=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Vkatoe3wSVJgxIz5aJhjiZMVzH4VpK4V1+jwGfVYTAkVnez1UvTUhbZNboXaWNwR+ RmTiYrkPYVXgWMVSX/nsi5cm+jOxUbLbf636R9o6ap1OoSWz7bsU8F/DUmaOQxf1U+ /kOf3Vy/apEjSOB/6cj/lfIC9z/SUpB7VG5bQ66U= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+53ecc09fb81df10ef4de@syzkaller.appspotmail.com, Eric Dumazet , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.1 529/609] net/atm: fix slab-out-of-bounds read in vcc_setsockopt() Date: Mon, 17 Aug 2026 15:33:45 +0200 Message-ID: <20260817132601.496251375@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132543.039278408@linuxfoundation.org> References: <20260817132543.039278408@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit d0c80dbb970439bd2eeb0e5effff8c16a5f4e1e3 ] vcc_setsockopt() contained an ineffective optlen check: if (__SO_LEVEL_MATCH(optname, level) && optlen != __SO_SIZE(optname)) return -EINVAL; If __SO_LEVEL_MATCH(optname, level) evaluated to false (e.g. if the caller passed a mismatched level), the length check optlen != __SO_SIZE(optname) was short-circuited and bypassed. Execution then fell through to switch(optname), calling copy_from_sockptr() assuming optval contained sufficient space. Furthermore, even if level matched, a cgroup BPF setsockopt filter could shrink optlen after entry. Because copy_from_sockptr() on kernel pointers uses memcpy(), this leads to a KASAN slab-out-of-bounds read when optlen is smaller than the expected structure size. Fix this by using copy_safe_from_sockptr(), which unconditionally validates that optlen is at least the expected size before copying. Also change the local 'value' variable type from 'unsigned long' to 'int' so that SO_SETCLP matches its sizeof(int) ABI encoding on 64-bit systems. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+53ecc09fb81df10ef4de@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=53ecc09fb81df10ef4de Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260805131508.3227331-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/atm/common.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/net/atm/common.c b/net/atm/common.c index 96f680a45e306..f3f68c231935a 100644 --- a/net/atm/common.c +++ b/net/atm/common.c @@ -760,7 +760,7 @@ int vcc_setsockopt(struct socket *sock, int level, int optname, sockptr_t optval, unsigned int optlen) { struct atm_vcc *vcc; - unsigned long value; + int value; int error; if (__SO_LEVEL_MATCH(optname, level) && optlen != __SO_SIZE(optname)) @@ -772,8 +772,10 @@ int vcc_setsockopt(struct socket *sock, int level, int optname, { struct atm_qos qos; - if (copy_from_sockptr(&qos, optval, sizeof(qos))) - return -EFAULT; + error = copy_safe_from_sockptr(&qos, sizeof(qos), optval, + optlen); + if (error) + return error; error = check_qos(&qos); if (error) return error; @@ -786,8 +788,10 @@ int vcc_setsockopt(struct socket *sock, int level, int optname, return 0; } case SO_SETCLP: - if (copy_from_sockptr(&value, optval, sizeof(value))) - return -EFAULT; + error = copy_safe_from_sockptr(&value, sizeof(value), optval, + optlen); + if (error) + return error; if (value) vcc->atm_options |= ATM_ATMOPT_CLP; else -- 2.53.0