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 6043B2E093A; Mon, 20 Apr 2026 16:02:47 +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=1776700967; cv=none; b=YNWdFu4ahb0PL91c+Dxmuykl9yQV4b+g1axtf2HdIdKp592aaUVICIGJ0ohfacBTlaNzAa5Ttz0MI5slst1EBoEftpNY7kQks8uEEofRquNUJAQbIuJPbENlO1AWJMCO9Pv4sr4//CZWIi9J8gXx08Eja1l0T1OyY3mZqjlzbZQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776700967; c=relaxed/simple; bh=rwiqXnk6vQc9FS8SSH55E3u0t/+xTbDPEciknjZCcnw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=J5WAU0dEw6P61cUlpz+so0fgdfTTxEvjfrC/SHS92V5UkhFZRw/BSNXcO+mBi6U+AbYh0wofOQW/JCUZ4XouXdVgOYxzqNLVYVh+pArTrDrtJERKaTVt0VeINNMk957fyMHUL3TPkbmoSzakIMaoe+MSdLRPmJRV7GbuEP7z/x0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=0J42BFOd; 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="0J42BFOd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E8A56C2BCB4; Mon, 20 Apr 2026 16:02:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776700967; bh=rwiqXnk6vQc9FS8SSH55E3u0t/+xTbDPEciknjZCcnw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0J42BFOdJaK24n+AFXxC0/XntZWtQiryGSGqqtwyEdWWiqw89gPKaiu3uCGR0HHHv XLB8s6NwqIGZ3MqmsNnl3T2hrWyZ/rvO7s7/5cphafqJ884m44mQHl33GZ9HVes9MH aay1LgDzI8XHH4d8FhV7gLY3Lq1t2G7DoGZfSs0U= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Simon Horman , Kees Cook , Thierry Escande , Samuel Ortiz , stable , Jakub Kicinski Subject: [PATCH 6.18 129/198] NFC: digital: Bounds check NFC-A cascade depth in SDD response handler Date: Mon, 20 Apr 2026 17:41:48 +0200 Message-ID: <20260420153940.253151918@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260420153935.605963767@linuxfoundation.org> References: <20260420153935.605963767@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Greg Kroah-Hartman commit 46ce8be2ced389bccd84bcc04a12cf2f4d0c22d1 upstream. The NFC-A anti-collision cascade in digital_in_recv_sdd_res() appends 3 or 4 bytes to target->nfcid1 on each round, but the number of cascade rounds is controlled entirely by the peer device. The peer sets the cascade tag in the SDD_RES (deciding 3 vs 4 bytes) and the cascade-incomplete bit in the SEL_RES (deciding whether another round follows). ISO 14443-3 limits NFC-A to three cascade levels and target->nfcid1 is sized accordingly (NFC_NFCID1_MAXSIZE = 10), but nothing in the driver actually enforces this. This means a malicious peer can keep the cascade running, writing past the heap-allocated nfc_target with each round. Fix this by rejecting the response when the accumulated UID would exceed the buffer. Commit e329e71013c9 ("NFC: nci: Bounds check struct nfc_target arrays") fixed similar missing checks against the same field on the NCI path. Cc: Simon Horman Cc: Kees Cook Cc: Thierry Escande Cc: Samuel Ortiz Fixes: 2c66daecc409 ("NFC Digital: Add NFC-A technology support") Cc: stable Assisted-by: gregkh_clanker_t1000 Signed-off-by: Greg Kroah-Hartman Link: https://patch.msgid.link/2026040913-figure-seducing-bd3f@gregkh Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/nfc/digital_technology.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/net/nfc/digital_technology.c +++ b/net/nfc/digital_technology.c @@ -424,6 +424,12 @@ static void digital_in_recv_sdd_res(stru size = 4; } + if (target->nfcid1_len + size > NFC_NFCID1_MAXSIZE) { + PROTOCOL_ERR("4.7.2.1"); + rc = -EPROTO; + goto exit; + } + memcpy(target->nfcid1 + target->nfcid1_len, sdd_res->nfcid1 + offset, size); target->nfcid1_len += size;