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 A2DAE4BFE68; Thu, 10 Sep 2026 00:34:26 +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=1789000467; cv=none; b=O+zId+TXFAgXZV7QMGq9aQe3dXKuQzCZ/FQx1KCdw44a1YbqpcyayqnNaufM9R3QXL4qXD3WS6ULfRAiI9PLkHbE2ruNjKh5qv+1BnzKuBcp/BZTXswI8tlSuLB5cvvy1m3FD1LZfX9HDfSsWtnVTSR4hZdNHFjhZ3RK3ZW1dt8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789000467; c=relaxed/simple; bh=nfI70XfbB8Tg08XHW1UBeBZaszVmOJvGajs6CmBmAVM=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=PUMxIE3w02AEQtLOtlGon98TQ0W9pe70k84KgjU9fzON4nH8o6E9/3TmrBEPfENTAIPFK+r9rbDEJj2QnyxVT0vPN5h1WRdWHgeaMOwmrCPMgNIQk0HrplzubhdV8uK67ybrcxvJ1+RMdrkyT3dWprywmZNHAlKAYNZSJDF9gmo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bAEoLplI; 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="bAEoLplI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 989391F000FF; Thu, 10 Sep 2026 00:34:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789000466; bh=QD05iClpjTuKrQBi/AfupCRZI4bkgKtjfdTZMjzNS6E=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=bAEoLplI6y5a5YG488KxlFSq8y3bnNNaWrNO+UktuWu85Zm8O8EIf2kDMpR+mzoyS FBzVw2YCkYh8LNWKoG/i4OikOXrEooIAZCjdwfSJ7Oi8juik+n/WdpXEs37nsuJYYq jp6UASYnabRrCOgOGgxFjEh0PVMkarAKBNdLRWkjc6hZQtqcp4h0xwLHFkbENvllyV MBWattOSdZhBCr1EmBbBMIzW6aJ1Fws4nZ2ZiDLbCSOrHsEXHjYNeuC7nRMJjSFNO7 mFP+30rhKB40Gbdy8vrppitnchfBspDkNB61bWdj+/40PaMQaQ/MYHUG3b835Px4vv 4kKYa/fxkc9Fw== Date: Thu, 10 Sep 2026 09:34:22 +0900 From: Masami Hiramatsu (Google) To: "Masami Hiramatsu (Google)" Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Sang-Heon Jeon , stable@vger.kernel.org Subject: Re: [PATCH] tools/bootconfig: Fix integer overflow in size check Message-Id: <20260910093422.e24e680b0506c16af51b2bbd@kernel.org> In-Reply-To: <178900024679.183840.10345859264677533824.stgit@devnote2> References: <178900024679.183840.10345859264677533824.stgit@devnote2> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 10 Sep 2026 09:30:46 +0900 "Masami Hiramatsu (Google)" wrote: > From: Masami Hiramatsu (Google) > > Sashiko reported that on 32-bit systems, if the size in the bootconfig > footer is corrupted 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; > } > > This would lead to load_xbc_fd() being called with a negative size, > resulting in an undersized allocation, heap overflow on read, and > out-of-bounds write on the terminating null byte. > > Avoid the integer overflow by checking whether size is greater than > stat.st_size - BOOTCONFIG_FOOTER_SIZE. Since stat.st_size is already > verified to be at least BOOTCONFIG_FOOTER_SIZE earlier in the function, > this subtraction will never underflow. > > Fixes: 950313ebf79c ("tools: bootconfig: Add bootconfig command") > Reported-by: Sashiko > Closes: https://lore.kernel.org/all/20260909161113.16C691F00A3A@smtp.kernel.org/ > Assisted-by: Antigravity:gemini-3.8-flash OOps, I forgot to add: Cc: stable@vger.kernel.org Thanks, > Signed-off-by: Masami Hiramatsu (Google) > --- > tools/bootconfig/main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/bootconfig/main.c b/tools/bootconfig/main.c > index 7dc9fff9b637..b380ad6777fa 100644 > --- a/tools/bootconfig/main.c > +++ b/tools/bootconfig/main.c > @@ -218,7 +218,7 @@ 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 > stat.st_size - BOOTCONFIG_FOOTER_SIZE) { > pr_err("bootconfig size is too big\n"); > return -E2BIG; > } > -- Masami Hiramatsu (Google)