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 32646457E72; Thu, 10 Sep 2026 21:27:42 +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=1789075664; cv=none; b=FG2+ugNobtF+XdcEIYVjS0RBGs6SebXIFX+HTOVyWRwgRT1t0pjLRqUkteZIN3Mlh73tieZQuRROlwBezPAP2dt7DdVVDn4UouliJB4WIxsC5Xfy10Q8/JId9Z3qjKhtFyfTgi3gnhI0s3SsJqln2XacrrUwX8VshzV09YNvrd0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789075664; c=relaxed/simple; bh=dFIzst35MERHABkuU+MLX0RKDi+7ulpeKwmPqelxdK0=; h=Date:To:From:Subject:Message-Id; b=vCPNXq50NAv8O8zBKdN17p83VYNhcFM6khcB6vw+ymND2IDMjjluwdbc5gr4ROye/2mpCjuLSYNtAQVDO5nkHU2hKavVMPVLElSHZuaz+raxJba10FGhu1a+I1jokWSomx+9wf9vGF3tyBvMq4ZZvKEY+pKWWpjVZvYFQi4xtww= 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=X19Ov3ud; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="X19Ov3ud" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B1D6A1F000FF; Thu, 10 Sep 2026 21:27:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1789075662; bh=SEBXreW/ftBwCyZs5fdXJFQvSLeiDtZf/AJR4XqKPAM=; h=Date:To:From:Subject; b=X19Ov3udny+3faMC2vhKIO+OPkJ2qwGtgz7cB2vcZMP49sORb+pC1u9Np2/9jiMn9 irFvTQxxSanZ+YqOW3frPkDCiDBSlshGPJmXGaKxVo5YzetHM1YB5gO4GID1hzv//r /teDxL+kHhFg+XNcTo49PVkUf7Ed9wf83ZVuv8hA= Date: Thu, 10 Sep 2026 14:27:42 -0700 To: mm-commits@vger.kernel.org,thomas.weissschuh@linutronix.de,stable@vger.kernel.org,sashiko-bot@kernel.org,ryan.roberts@arm.com,mark.rutland@arm.com,leitao@debian.org,ekffu200098@gmail.com,dianders@chromium.org,chenhuacai@kernel.org,brauner@kernel.org,mhiramat@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + tools-bootconfig-fix-integer-overflow-and-truncation-in-size-checks.patch added to mm-nonmm-unstable branch Message-Id: <20260910212742.B1D6A1F000FF@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: tools/bootconfig: fix integer overflow and truncation in size checks has been added to the -mm mm-nonmm-unstable branch. Its filename is tools-bootconfig-fix-integer-overflow-and-truncation-in-size-checks.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/tools-bootconfig-fix-integer-overflow-and-truncation-in-size-checks.patch This patch will later appear in the mm-nonmm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Masami Hiramatsu (Google) Subject: tools/bootconfig: fix integer overflow and truncation in size checks Date: Fri, 11 Sep 2026 00:15:24 +0900 Sashiko reported that on 32-bit systems, if an attacker crafts size in the bootconfig footer such that adding BOOTCONFIG_FOOTER_SIZE wraps around (for instance, if size is 0xFFFFFFFF), the size check in load_xbc_from_initrd() can be bypassed: if (stat.st_size < size + BOOTCONFIG_FOOTER_SIZE) { pr_err("bootconfig size is too big\n"); return -E2BIG; } Furthermore, on 64-bit systems with an initrd > 4.29 GB, comparing a corrupted 32-bit size (e.g. 0xFFFFFFFF) against stat.st_size - BOOTCONFIG_FOOTER_SIZE can also bypass the check if size is not bounded. Similarly, load_xbc_file() passes 64-bit stat.st_size directly into the 32-bit int size parameter of load_xbc_fd(), truncating large standalone files (>= 2GB). In both cases, passing 0xFFFFFFFF to load_xbc_fd() truncates to -1, resulting in malloc(0), an integer overflow in read(), and an out-of-bounds null-byte write. Fix this by: 1. Rejecting size > XBC_DATA_MAX or size > stat.st_size - BOOTCONFIG_FOOTER_SIZE in load_xbc_from_initrd(). 2. Rejecting stat.st_size > XBC_DATA_MAX in load_xbc_file() before passing it to load_xbc_fd(). 3. Checking size < 0 || size > XBC_DATA_MAX defensively in load_xbc_fd(). Link: https://lore.kernel.org/178905332413.213925.3179977110281463499.stgit@devnote2 Fixes: 950313ebf79c ("tools: bootconfig: Add bootconfig command") Signed-off-by: Masami Hiramatsu (Google) Reported-by: Sashiko Closes: https://lore.kernel.org/all/20260909161113.16C691F00A3A@smtp.kernel.org/ Closes: https://lore.kernel.org/all/20260910010137.EE0431F000FF@smtp.kernel.org/ Assisted-by: Antigravity:gemini-3.8-flash Reviewed-by: Sang-Heon Jeon Cc: Breno Leitao Cc: Christian Brauner Cc: Doug Anderson Cc: Huacai Chen Cc: Marc Rutland Cc: Ryan Roberts Cc: Thomas Weißschuh Cc: Signed-off-by: Andrew Morton --- tools/bootconfig/main.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) --- a/tools/bootconfig/main.c~tools-bootconfig-fix-integer-overflow-and-truncation-in-size-checks +++ a/tools/bootconfig/main.c @@ -181,6 +181,9 @@ static int load_xbc_fd(int fd, char **bu { int ret; + if (size < 0 || size > XBC_DATA_MAX) + return -EINVAL; + *buf = malloc(size + 1); if (!*buf) return -ENOMEM; @@ -209,6 +212,13 @@ static int load_xbc_file(const char *pat return ret; } + if (stat.st_size > XBC_DATA_MAX) { + pr_err("%s size is too big\n", path); + ret = -E2BIG; + close(fd); + return ret; + } + ret = load_xbc_fd(fd, buf, stat.st_size); close(fd); @@ -258,7 +268,8 @@ static int load_xbc_from_initrd(int fd, csum = le32toh(csum); /* Wrong size error */ - if (stat.st_size < size + BOOTCONFIG_FOOTER_SIZE) { + if (size > XBC_DATA_MAX || + size > stat.st_size - BOOTCONFIG_FOOTER_SIZE) { pr_err("bootconfig size is too big\n"); return -E2BIG; } _ Patches currently in -mm which might be from mhiramat@kernel.org are bootconfig-reject-unexpected-data-after-null-character.patch tools-bootconfig-consolidate-xbc_init-to-error-message-wrapper.patch bootconfig-skip-internal-tree-sanity-checks-in-kernel.patch tools-bootconfig-fix-integer-overflow-and-truncation-in-size-checks.patch bootconfig-fix-integer-overflow-in-initrd-size-check.patch