From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 71CD83D522C; Wed, 8 Apr 2026 18:23:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775672618; cv=none; b=UH1SjpFusBgtSYsFny74CaFhT2pp0IspyOadPJOisoC0XUbps7l/5U3iYcWzzvChqoKXO3jZIcB2xNbJAIkiHVpQm3tzABJymRIAf7noI1YC3r2fDzWQJcWhZeINpuRGoPE7bh34SBThR0MFi0sxXjIkrDAIbMcfQozg4HHg4V4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775672618; c=relaxed/simple; bh=YITmQwIB4vSfdoxlZt0b3iTAVYCZ2ZXOqlJdsYwzfig=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oTnw+GRdCLANMzalSBZcubQD+uxVwGpbfGXtWx9EK9EIHdl+exchDnFypSI7quVkZcu8K1msKbR3LHVSlm7NPCAtgg1QNQbl+cdK9gllNRwPzbW/GoIzHwak4cDunKrml9+nLjpuMeJ6qNi6dNcLHLGSmLK3i3Mh23DHXkKbw+w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=RGwBAQXQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="RGwBAQXQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 07761C19421; Wed, 8 Apr 2026 18:23:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1775672618; bh=YITmQwIB4vSfdoxlZt0b3iTAVYCZ2ZXOqlJdsYwzfig=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RGwBAQXQ2JlRc5QIoe9swKzO2uYeLd1VAD7hPJo8sh0eUevpcfcVjz5hn+TcbrZHk sR0esFn2Id5GDF2C0/myqkgjlpSbI0pixM+5lIfhb0N4Iumlz73cY1j/jgu3kZ0pA4 z31i36RFcZU8GkWPmjx9CodkBUhZ7rJZIoo2hQXo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andrey Konovalov , Berk Cem Goksel , Takashi Iwai Subject: [PATCH 6.6 077/160] ALSA: caiaq: fix stack out-of-bounds read in init_card Date: Wed, 8 Apr 2026 20:02:44 +0200 Message-ID: <20260408175916.071717156@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260408175913.177092714@linuxfoundation.org> References: <20260408175913.177092714@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Berk Cem Goksel commit 45424e871abf2a152e247a9cff78359f18dd95c0 upstream. The loop creates a whitespace-stripped copy of the card shortname where `len < sizeof(card->id)` is used for the bounds check. Since sizeof(card->id) is 16 and the local id buffer is also 16 bytes, writing 16 non-space characters fills the entire buffer, overwriting the terminating nullbyte. When this non-null-terminated string is later passed to snd_card_set_id() -> copy_valid_id_string(), the function scans forward with `while (*nid && ...)` and reads past the end of the stack buffer, reading the contents of the stack. A USB device with a product name containing many non-ASCII, non-space characters (e.g. multibyte UTF-8) will reliably trigger this as follows: BUG: KASAN: stack-out-of-bounds in copy_valid_id_string sound/core/init.c:696 [inline] BUG: KASAN: stack-out-of-bounds in snd_card_set_id_no_lock+0x698/0x74c sound/core/init.c:718 The off-by-one has been present since commit bafeee5b1f8d ("ALSA: snd_usb_caiaq: give better shortname") from June 2009 (v2.6.31-rc1), which first introduced this whitespace-stripping loop. The original code never accounted for the null terminator when bounding the copy. Fix this by changing the loop bound to `sizeof(card->id) - 1`, ensuring at least one byte remains as the null terminator. Fixes: bafeee5b1f8d ("ALSA: snd_usb_caiaq: give better shortname") Cc: stable@vger.kernel.org Cc: Andrey Konovalov Reported-by: Berk Cem Goksel Signed-off-by: Berk Cem Goksel Link: https://patch.msgid.link/20260329133825.581585-1-berkcgoksel@gmail.com Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/usb/caiaq/device.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/sound/usb/caiaq/device.c +++ b/sound/usb/caiaq/device.c @@ -488,7 +488,7 @@ static int init_card(struct snd_usb_caia memset(id, 0, sizeof(id)); for (c = card->shortname, len = 0; - *c && len < sizeof(card->id); c++) + *c && len < sizeof(card->id) - 1; c++) if (*c != ' ') id[len++] = *c;