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 3B4AC3F8891; Mon, 17 Aug 2026 13:55:28 +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=1786974932; cv=none; b=ajtkdBtnAxyhY5KuNcohQY+UU/IbK2ksZ9woNP8w2Lcg8GGcZsdHLvXkFgPr/ajwvc9KVrRocMBaTsy9PLzu/zIDQZrwq7P/bwHQlEBref8PNCOW7NWxG+99AQo0yMFi76FIsyuqidOlcA6fhuEIR8o8kh+UVBS9X4kMvRfH72k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786974932; c=relaxed/simple; bh=7y6DDt0AdppeyxwkSlGI3OiOglhCdbG6hODvZNmqXjc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FPm+snWHj/tw5oECak+UTv4lTKuk7lc38LaT2pe5ec8fTRPcloEOWB3ybRHxaWnSvpBh1cB6z+p85aroqpryHr8KXCTNwL6U57A5ZQonDuO3OAnUYm/0gYvpfVZYD67VEkjjru9iBr43A1tKe4beWpGke/KbyqYpD4+RkpvihUI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xBo1wxOU; 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="xBo1wxOU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2061B1F00A3A; Mon, 17 Aug 2026 13:55:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786974926; bh=S+/HZPwpCaxZ3R7T7TWHbLuovF3+ORHSmzJsIZBRzRI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=xBo1wxOUbT9hI2KXqjZlkJXjwog10jDKeDQoKVFw1p9fvF/H/NEZroMTxnOfQaHPX +WC9ghW6F2KucrhdbZ5bBjmSnct2Ie0kdGXFNsNnss4715qnQljaTFGhtity5Wk2QE LTm+fyfD57qPlXGjtOw5AMHsPqlgo6wxf+VgCiP8= 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 6.18 101/250] net/atm: fix slab-out-of-bounds read in vcc_setsockopt() Date: Mon, 17 Aug 2026 15:31:02 +0200 Message-ID: <20260817132540.649844933@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132536.466235697@linuxfoundation.org> References: <20260817132536.466235697@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 6.18-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 f4c6e0131c921..f4be6cb220861 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