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 93B013DDB0A for ; Wed, 16 Sep 2026 19:07:56 +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=1789585692; cv=none; b=nokeZ8zzLcEueF6uqPyzuD5qv4PuJdaGaB2KjI8/UpIDpEfz8X92Vylx8JkwylnLLM9OdXHANQaiQ8NkEUZ4wHyRw9QBlgJK7Wl8ZdcjL5Fyljhp0QNtlEaonbbda2/6JOuy7VZjy/Z1HaDUKCBxJ6ZqbqhnNf8IGDNYLSINBa8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789585692; c=relaxed/simple; bh=q2u1uHJd5fMnJda0vzPS6tLJB+Rmi7g//dFh5yOFCSA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Pvr20lDLCkuQCKEiWMKyZaterdbPoKAPKqLx6birUaB3A9Bey1DGemKWjX9vgI8nyq6c60MK+CPhYnStsUHb8y89wlkkyxAi36rZJwDCbveUMTzVj7KkHd6HXWLluxMaJ/kPQjK3YX6TRJlD+MhwdcAANEMpuyZv6BzECDmeOzs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gRukdulS; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gRukdulS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AEF121F008A1; Wed, 16 Sep 2026 19:07:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789585662; bh=CKfa7h1V8LbAEt5fftwgWFc5Y5eEEIMkNjni/pppzsY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gRukdulS9qe81+7CD31IpE0F+fvvXHjKPKPD5tWQN65P0yLr0vYW/fWKFYtMVvmmk uhL4DidaVUcSjvhn93KKMOlripMFUf9HEy3n31SqObsSKHtLHECtKgEQqzN5Bn6z/S FSKmgvHOyMu+935SPDCmFuDh4wvONJtBJ4KMDeVkRdMptqSPOoeEZuCsYtytTR7moD 9coioOICMvtqc3htKqZbm7+SnSvoCNTQBuw4e/VcFWRhFQoVOrn0c1JlBbwrATNND6 nFhHtvCNO7wzgEFAvIKKUgdCvqCTfQ/lWArQs55WOhOtVrTYpk+9VbaHwV8Z1vdsIE 3iSZ9wixA8UOA== From: Sasha Levin To: stable@vger.kernel.org Cc: "Masami Hiramatsu (Google)" , Sashiko , Sang-Heon Jeon , Sasha Levin Subject: [PATCH 5.10.y 7/7] tools/bootconfig: Fix integer overflow and truncation in size checks Date: Wed, 16 Sep 2026 15:07:35 -0400 Message-ID: <20260916190735.1968203-7-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260916190735.1968203-1-sashal@kernel.org> References: <2026091617-cackle-deeply-2ea2@gregkh> <20260916190735.1968203-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: "Masami Hiramatsu (Google)" [ Upstream commit 462d0b066b613103f579793031429db2ca23abc0 ] 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/all/178905332413.213925.3179977110281463499.stgit@devnote2/ Fixes: 950313ebf79c ("tools: bootconfig: Add bootconfig command") Cc: stable@vger.kernel.org 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 Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Sang-Heon Jeon Signed-off-by: Sasha Levin --- tools/bootconfig/main.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/tools/bootconfig/main.c b/tools/bootconfig/main.c index 717aa69473a60..f35ee15c19167 100644 --- a/tools/bootconfig/main.c +++ b/tools/bootconfig/main.c @@ -109,6 +109,9 @@ static int load_xbc_fd(int fd, char **buf, int size) { int ret; + if (size < 0 || size > XBC_DATA_MAX) + return -EINVAL; + *buf = malloc(size + 1); if (!*buf) return -ENOMEM; @@ -137,6 +140,13 @@ static int load_xbc_file(const char *path, char **buf) 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); @@ -187,7 +197,8 @@ static int load_xbc_from_initrd(int fd, char **buf) 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; } -- 2.53.0