From nobody Tue Jun 16 01:26:12 2026 Received: from mail-qk1-f176.google.com (mail-qk1-f176.google.com [209.85.222.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D78FE2C3757 for ; Wed, 15 Apr 2026 06:37:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.176 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776235036; cv=none; b=bn1ptdPg2mNGr8pdEPnIMgCWS1gVSZFZXlRoIJEoG82cnr+bmiexL52JPDRXJhzQLT5zimvqn760kNoGQYwC8XghH1eV0g/+2NXTsuAIBkxTJV+oJX4xhde4IWa1GHQwTvW3AOyo1rv+fSZH6rSppvTm2Vq6O3/JF9DEF8rLFlE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776235036; c=relaxed/simple; bh=yJ9CzZdh0ITtrg/Qg4Whi7FTsOhB5NFwZmHZHk5gvDQ=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=XyRSVEiaG/I9UOVErPXWU9qw/ysYZhyRFvyGOfY5RnyNtwlNBx4UjNd5N1eiaeK9j60SxPrvzraW1sK/D9wTC9MV/6T/wAknTwCd0/Vlke3o+q/Xrf31FrlBt4i4pt6ZUvV+O5R4f3IDc/Bv7irZkeSBgB8mnV4xSKlb+CPQ5Sc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=LzME5p3c; arc=none smtp.client-ip=209.85.222.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="LzME5p3c" Received: by mail-qk1-f176.google.com with SMTP id af79cd13be357-8d6d5e45c43so777467585a.3 for ; Tue, 14 Apr 2026 23:37:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1776235034; x=1776839834; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=rrC9vNrM6E6rzZeBaqxVv48Wut0j5e/JM27h9uWS1lQ=; b=LzME5p3cZ//ZOSu7QCVtD6m3PnoYyPtXmpsibWdgflbxsNBCfy2GRVPZNtdXHqqI09 9wjUKpf+PObtTmjsiMfPiWuoVqIMwf/xCf3ghGfEYCmF5/4dUhH1ojyedtqPzaGptyU/ pyA3mkEhLMSfpIBlkbt7FGp3+Kejsix0vVXOKilLFDxmvBjbY46Ujf48/4d2XkoZo6fQ Fr2qiob10hzpVyUmkek0gYKDiMo/tVcEsKSlNeZYB1un9G+Rjb/g8id3kFkjZWWtP2Td z2Q1xN9aZtsTMMWHpVDYBnZ+uYfehu5FMFAyOpfEDUgPSJxBPfQTpJbFOcq19HFTI7jK o8KQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776235034; x=1776839834; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=rrC9vNrM6E6rzZeBaqxVv48Wut0j5e/JM27h9uWS1lQ=; b=hXYktj5o4qCISdwhxD0Tkxh9Zrn/rZV+idTc79CqYlCoQAWjoZ4XiEky8hFoiWQXFQ BZX5B/XMUajrugiraAfoa86TQ5mVr9eQRWiDBBGjTjqherp6Ws10J1ZzuiQfvU99Na4l NwLdPpAhLLdJgsRD5S+hl8Jn5JSFbmqdloLY9mFuIu21uC+R+XiRmS2S04Q2C7ei7JFZ e9fE1XDDC0KjYq80VIIoFzuvb6X4U+BUIRECRAc3ASVZ3wAJccnRN3EVbVsNdDmQmEcC ik5BW5KGHQFPJHr8dBZBopIIXsmOiA0zYO5MmmqmquqSHuAgeeUcfByhkLsq/IDX97ws QeOg== X-Forwarded-Encrypted: i=1; AFNElJ+0wfgmQYwFILiFql385mKl6tKGg9laqPjBE4eIK4ElexqoB1FBxY+ehZhGXeRGDpXzGV8vXwh2ahaivf4=@vger.kernel.org X-Gm-Message-State: AOJu0Yz2I5bve5JiT/cM4P8LZZRIEoH4hG1KQtCHPWBAfimIrsl3kX// FUsvNsp47vfbrrD8Fp7FY7APdw0BWkA9kg//i5+L6ACb1wSo8w3wyhGNYpORq8BhNoh1yg== X-Gm-Gg: AeBDies7V/QLHh4skYkwlNnRVp8ARgRXrTHIU4kpFk+cmyi/ERql+W8E7YPANPPHVdw eUSNGPL0fm+vRyqYCEuI67X0yyKUVVNBhU/+DcUFkSDB4dAIgk/Quw02dzLrN+OJZep+2X2TxOt fr5XPR0XxTjIaJxw1FYrpiG3xdaPkS2U/iuDFW7opEULO/yhwWLqvdf0nf/tfgj1rCzMAVvf+Sg y0dgD5c00O2ArV86viF6Vkwtt55O2x3SCn+pwC3nXa/mNuXYbsoZCc0vgOQNmQZyypcn/dFjmUV 9MRGFTWQtUST8hiAczLB2xM32mUOsn6rNRXkANkGHZAb1baSl84F83fK9N3vgt/WBjcXX86wK1e yYmlhxK3gsYB4+pvZBXkS4JzylE981Ka2lT8dE7smeUNY/v+7AZo2MWcfhN30lfEfuUX5PxLaJH cqu941fSuJdVs9ubyRy3cu21fHJnpZIxSifvIo3Qk4xJx/o6EWRZVWSmuMgWzfY/vepC3TPw3Xv jDKRDMsAxxESTNir/Z+P0otXELbdBVpvONbDeE= X-Received: by 2002:a05:622a:134c:b0:50d:82ca:7c9c with SMTP id d75a77b69052e-50dd5adaf18mr314133561cf.14.1776235033794; Tue, 14 Apr 2026 23:37:13 -0700 (PDT) Received: from TDC4045031631.e0cglfehwr0e5gttmepj3hi3hf.ux.internal.cloudapp.net ([20.63.37.123]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-50e1afebd48sm6222121cf.26.2026.04.14.23.37.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Apr 2026 23:37:13 -0700 (PDT) From: Ashutosh Desai To: netdev@vger.kernel.org Cc: linux-hams@vger.kernel.org, jreuter@yaina.de, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, stable@vger.kernel.org, linux-kernel@vger.kernel.org, Ashutosh Desai Subject: [PATCH v3 net] ax25: fix OOB read after address header strip in ax25_rcv() Date: Wed, 15 Apr 2026 06:36:54 +0000 Message-Id: <20260415063654.3831353-1-ashutoshdesai993@gmail.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" A remote station can send a crafted KISS frame that is just long enough to pass ax25_addr_parse() (minimum 14 address bytes) but carries no control or PID bytes. After ax25_kiss_rcv() strips the KISS framing byte and ax25_rcv() strips the address header with skb_pull(), skb->len drops to zero. The subsequent reads of skb->data[0] (control byte) and skb->data[1] (PID byte) are then out of bounds, which can crash the kernel or leak heap memory to a remote attacker. Use pskb_may_pull(skb, 2) after the skb_pull() to ensure both bytes are in the linear area before reading them. Discard malformed frames that carry no control/PID pair. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Ashutosh Desai --- V2 -> V3: remove incorrect Suggested-by; add symptom, Fixes, Cc stable V1 -> V2: use pskb_may_pull(skb, 2) instead of skb->len < 2 v2: https://lore.kernel.org/netdev/20260409152400.2219716-1-ashutoshdesai99= 3@gmail.com/ v1: https://lore.kernel.org/netdev/20260409012235.2049389-1-ashutoshdesai99= 3@gmail.com/ net/ax25/ax25_in.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/ax25/ax25_in.c b/net/ax25/ax25_in.c index d75b3e9ed93d..6a71dea876a1 100644 --- a/net/ax25/ax25_in.c +++ b/net/ax25/ax25_in.c @@ -217,6 +217,11 @@ static int ax25_rcv(struct sk_buff *skb, struct net_de= vice *dev, */ skb_pull(skb, ax25_addr_size(&dp)); =20 + if (!pskb_may_pull(skb, 2)) { + kfree_skb(skb); + return 0; + } + /* For our port addresses ? */ if (ax25cmp(&dest, dev_addr) =3D=3D 0 && dp.lastrepeat + 1 =3D=3D dp.ndig= i) mine =3D 1; --=20 2.34.1