From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 A33B63B9DA8; Wed, 26 Aug 2026 15:45:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787759137; cv=none; b=gAE9XUyiEf/c2V3Kq02yEhQj4W4CJDzyH8NdZUc86+1lhfxMoEUAj4c3Sl9zBWVB//hQj3FyBEMy8Hs45WBb+EfsAZl02l/nNC/w0Tx5F+VE3pLk6HASSHnJKSKxwO3BUtdnPwUF7bo4eH5aHSgcIOux7jaSJusltDZc6T1zDxE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787759137; c=relaxed/simple; bh=KXcUPHVoaQJfAjh0Xr6CYc3qr686V/ZOfBvoUG+IKCA=; h=Content-Type:Mime-Version:Subject:From:In-Reply-To:Date:Cc: Message-Id:References:To; b=aZqeqVB3kStSot76yvjB1y031R2LdV0LtzOtm1GXHfeeJNj9TI4NEPBP5LqOYNYkxnZa1yZTvJVFrUOZ6fymElsAIkvev25ncHR2ooJJA8yIMWYPuDbSvZ9fPutK/UVRbE8eqtIGFkigE7Cfn5F9McuEY7Gp/P0HVZ2P/DzBjzM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=jkTTR/rM; arc=none smtp.client-ip=148.163.158.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="jkTTR/rM" Received: from pps.filterd (m0356516.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 67QE1hka4099807; Wed, 26 Aug 2026 15:44:46 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=pp1; bh=QHF3Ke bkIZ+vGajKHXIlWCi+fcg+Ol06VbFwHvqxa1o=; b=jkTTR/rMq2EQrhbiRdeocp 957Pnj701hoAbAUxVDCdclrngvAWSxbFVoA61xcx3oiyk+by80JKBYh+TPI98JOl rQClrkDZVL934D0GrE4vOGjWR0qjpOZH65/wQR2mfkqLMSYc7hQXpDdbHGeLYWST WyP+Mtr8cbDaK2IlQWFVf7OEsho1JwsjjG6dExGQtU4o9iIGyNN/XXrT7FwPh5Dv jAomC0yG43n7MtSl4KJeQvW2HKQp53O4SU8lWT4vk+nLAeME7i3oiYQFpdDAoreK MGwYgzPpgD1C6KvYsuW8m420OyUkiJB9cqH8FSEeMaXJU3DlUtu1SDgoQosg77Kg == Received: from ppma12.dal12v.mail.ibm.com (dc.9e.1632.ip4.static.sl-reverse.com [50.22.158.220]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4g716hyr5p-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 26 Aug 2026 15:44:46 +0000 (GMT) Received: from pps.filterd (ppma12.dal12v.mail.ibm.com [127.0.0.1]) by ppma12.dal12v.mail.ibm.com (8.18.1.7/8.18.1.7) with ESMTP id 67QFfHXJ010818; Wed, 26 Aug 2026 15:44:44 GMT Received: from smtprelay05.fra02v.mail.ibm.com ([9.218.2.225]) by ppma12.dal12v.mail.ibm.com (PPS) with ESMTPS id 4g7p3qay9g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 26 Aug 2026 15:44:44 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (smtpav02.fra02v.mail.ibm.com [10.20.54.101]) by smtprelay05.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 67QFigVA50462990 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 26 Aug 2026 15:44:42 GMT Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B5B2F20040; Wed, 26 Aug 2026 15:44:42 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DF9F52004B; Wed, 26 Aug 2026 15:44:40 +0000 (GMT) Received: from smtpclient.apple (unknown [9.124.213.3]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTPS; Wed, 26 Aug 2026 15:44:40 +0000 (GMT) Content-Type: text/plain; charset=utf-8 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3864.700.51.1.1\)) Subject: Re: [PATCH 2/2] crypto: rsassa-pkcs1: reject undersized keys when verifying From: Sudhakar Kuppusamy In-Reply-To: <20260826103744.1554131-3-Jeremy.Jean@oss.cyber.gouv.fr> Date: Wed, 26 Aug 2026 21:14:30 +0530 Cc: Lukas Wunner , Ignat Korchagin , Herbert Xu , "David S. Miller" , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: References: <20260826103744.1554131-1-Jeremy.Jean@oss.cyber.gouv.fr> <20260826103744.1554131-3-Jeremy.Jean@oss.cyber.gouv.fr> To: =?utf-8?B?SsOpcsOpbXkgSmVhbg==?= X-Mailer: Apple Mail (2.3864.700.51.1.1) X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Info: AW1haW4tMjYwODI2MDEyOSBTYWx0ZWRfX7qTLye1e0wro zWYuWJr0yq7pg5k5tjXKeebFu7jPDxhLZZtEQvFCTqg3c3r3gRDXR9c0BTww7Wv2v0Yt8hVZueP JsJPLWpau8/s1XcTCnJPOlWB+TDj0s8= X-Proofpoint-GUID: De3-inlnaXpaCoihQWPci-xmyBuLLUIs X-Proofpoint-ORIG-GUID: De3-inlnaXpaCoihQWPci-xmyBuLLUIs X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODI2MDEyOSBTYWx0ZWRfX6Q0iUrMjShJO HoCqoAeYT4J0ddps+8gFTx9CAgbsYUkeyIiCgXi9OHOl9/jZ3qOGObEIbINBf3K8XEhu4hneA20 UhZRIHzRCqqodNiBqi14O+l9eGcT6wnEUbNgmXVnZN1UNH9Fl9+unVX6UO0iKBwHCEniJEXorSg nOX/VhjTozgZqFXa2mTv47S0Asm7C6XADFWrYR2RN1uSzyeO55ziftS9pCQY3GeFy08NfVdY0jx 7GIn1vqwiwmbAkt5I1BToTLu5QdKbQK+4PBbNoZQ9I1iUNbnRxD931YByzQD6UDfmjwA15dQ+cu b2YHpMWvF5mxWrTKaP5fxKFiPeVLFvvcfrAxZ13A7r1IQiQ65EYXH+lHYxNrg9D8vi409qI2S8i Bbs9vbey2J297dTPzW6cW/x5Gn/Xv3yxnfs5YthdTz3WD2PFe9BuzNaXTCyJUuNmgFINEeRbikt OZcG16FbApveM4r931A== X-Authority-Analysis: v=2.4 cv=H7brBeYi c=1 sm=1 tr=0 ts=6a8f09ee cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VnNF1IyMAAAA:8 a=Qxsn6e9zUWdzkDgwqbgA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-26_04,2026-08-26_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 malwarescore=0 lowpriorityscore=0 impostorscore=0 spamscore=0 bulkscore=0 adultscore=0 priorityscore=1501 clxscore=1015 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608260129 > On 26 Aug 2026, at 4:07=E2=80=AFPM, J=C3=A9r=C3=A9my Jean = wrote: >=20 > rsassa_pkcs1_verify() accepts any nonzero key size. >=20 > With a one-byte key and a zero RSA result, the leading-zero handling > decrements dst_len to zero and advances out_buf past the allocation. > The next out_buf[0] access reads out of bounds. >=20 > KASAN reports: >=20 > BUG: KASAN: slab-out-of-bounds in rsassa_pkcs1_verify+0x79d/0x900 > Read of size 1 at addr ... > The buggy address is located 0 bytes to the right of > allocated 73-byte region [...] >=20 > Reject keys shorter than the minimum PKCS#1 v1.5 encoded message size. >=20 > Fixes: 3d5b1ecdea6f ("crypto: rsa - RSA padding algorithm") > Assisted-by: Codex:gpt-5 > Signed-off-by: J=C3=A9r=C3=A9my Jean Reviewed-by: Sudhakar Kuppusamy Thanks, Sudhakar > --- > crypto/rsassa-pkcs1.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) >=20 > diff --git a/crypto/rsassa-pkcs1.c b/crypto/rsassa-pkcs1.c > index d0e4a885397f..39137476ce81 100644 > --- a/crypto/rsassa-pkcs1.c > +++ b/crypto/rsassa-pkcs1.c > @@ -231,7 +231,7 @@ static int rsassa_pkcs1_verify(struct crypto_sig = *tfm, > int err; >=20 > /* RFC 8017 sec 8.2.2 step 1 - length checking */ > - if (!ctx->key_size || > + if (ctx->key_size < 11 || > slen !=3D ctx->key_size || > rsassa_pkcs1_invalid_hash_len(dlen, hash_prefix)) > return -EINVAL; > --=20 > 2.47.3 >=20 >=20