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 685AB471D03; Wed, 2 Sep 2026 11:06:32 +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=1788347193; cv=none; b=loFqwZ6qcNtpoooRhH5FUtMNBDe5Fc0IWeixh+LjrGWy2kyojYASR6ZPIm2TScvuI/+LXxOCjAoObU3Z3WhfEWQScer1DLULHSnZY7jJ9b0xb7E5nspCXMtSBbdz7PCWxJsYGurZxbki1eNPeS7rIqdxUZkXHeUC9RP8bvUYoFE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788347193; c=relaxed/simple; bh=gg4oaeObB+ZvkDbunSo+2Wv3qmDg2Ckasda83xkxFyo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=cvHJip52UvO5yyNLgzuDBtu9e2RPZQN3VBEUjC0ur6qUuUghySQW5fLI/15C/coRUYU7eTXF84Lnscd4urbSCMK5Zwiu4Yyb786xDqJE212zgamCKeXhoAiUqv8cv53fhB/piKaYqK5/tAIlkDz8g7/uyFhIvkT2LrHaMTdEXac= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=G521DKuj; 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="G521DKuj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95B081F000E9; Wed, 2 Sep 2026 11:06:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788347192; bh=2KejZkyIUl3Cw92CMKhHBilt7CFXtfyld/pR8L9PEQk=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=G521DKujJWRyJA+Xl0Q2x2JtSmwNopaAg2YObYd6S+0UASQAlplqL4x7Klc0EI8nm pr1OguEkQ2RI2NZIl95Optq7a5LiAVTxryK87q+QgPqZ5Nl5FOgUV17Ys34Y1UKiG2 1dPQTOipNhNu+t2REFVbMEMEEPwCYaCyCRWmOwyE= Date: Wed, 2 Sep 2026 13:06:27 +0200 From: Greg Kroah-Hartman To: Vasileios Almpanis Cc: Andrey Smirnov , David Woodhouse , "Gustavo A. R. Silva" , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] ihex: Fix 16 bit truncation in ihex_binrec_size() Message-ID: <2026090223-napped-nerd-790e@gregkh> References: <20260902-ihex-v1-1-67fdbf8d97ff@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260902-ihex-v1-1-67fdbf8d97ff@gmail.com> On Wed, Sep 02, 2026 at 12:21:19PM +0200, Vasileios Almpanis wrote: > ihex_binrec_size() returns uint16_t while computing be16_to_cpu(p->len) + > sizeof(struct ihex_binrec), so record lengths of 65530 and above wrap. > __ihex_next_binrec() uses the result as the offset to the next record. A > length of 65530 gives an advance of zero, so ihex_validate_fw() spins on > the same record forever. Lengths of 65531 to 65535 advance by 4 or 8 > instead of 65544, so a 14 byte image passes validation while its first > record claims 65535 bytes of payload. emi26_load_firmware() passes it to > emi26_writememory(), which kmemdup()s 65535 bytes out of a 14 byte buffer > producing the following splat: > > BUG: KASAN: vmalloc-out-of-bounds in kmemdup_noprof+0x3b/0x50 > Read of size 65535 at addr ffffc90000075006 by task kworker/11:1/174 > Workqueue: usb_hub_wq hub_event > Call Trace: > > kasan_check_range+0x10f/0x1e0 > __asan_memcpy+0x23/0x60 > kmemdup_noprof+0x3b/0x50 > emi26_writememory+0x29/0xd0 > emi26_probe+0x2d1/0xb64 Is this a real firmware image being sent? Or a fake one? And root triggers this, right? > > Return size_t so neither the addition nor the following ALIGN() can wrap. > > Fixes: 9fb4ab4d3dd6 ("ihex: Simplify next record offset calculation") > Cc: stable@vger.kernel.org > Signed-off-by: Vasileios Almpanis > --- > include/linux/ihex.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/ihex.h b/include/linux/ihex.h > index b824877e6d1b..0da1c4e3e693 100644 > --- a/include/linux/ihex.h > +++ b/include/linux/ihex.h > @@ -21,7 +21,7 @@ struct ihex_binrec { > uint8_t data[]; > } __attribute__((packed)); > > -static inline uint16_t ihex_binrec_size(const struct ihex_binrec *p) > +static inline size_t ihex_binrec_size(const struct ihex_binrec *p) but size_t changes depending on the platform, right? Why not make it u32 instead? And if this hasn't shown a problem yet, in the 8 years since that commit happened, is this really a bug? What changed to suddenly cause this to show up? thanks, greg k-h