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 BE809345EC0; Thu, 17 Sep 2026 15:32:02 +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=1789659133; cv=none; b=gU5ioAeIw1LU2AbK93aLftY0Iio+OnpBiuXO3/WlIjhNgHE9YNf5i9My0D2FGBMI3gYOgIQMQRBp6RoFJL1m6E0pblDN4bVfSP8FNjAIYgddRthmxNMxcU21Keh4fzV3cq5dV/Rq6u1EvOdGhHa9M0z/TrAzRDhv8uZbRShC2tI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789659133; c=relaxed/simple; bh=cozsA1d5pqG1VpC/y83VQQEsRteST/L8pmBzcytGhlA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OZAPSYW1rNSESf47RutBkrh9UevjmZhiceFRC/aOaRzXyRHLa1gWlj8+ps8OCs2Md/Y3aDQXT0ND6lehZruV5RbxRKmWf3crBquGSeN3NnALCUgZ6oPOE1zD8pVDHfCfXTxH9soeLUdtIN3isapIv6291zJb8lVsTCqxrbyc3VY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=O62C1Hcf; 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="O62C1Hcf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B3B8D1F00899; Thu, 17 Sep 2026 15:31:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789659120; bh=BTdgU4LxAt8lDiFMp7aqqkUskWddrHbFxRgyiG235rI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=O62C1Hcft0ksmsAsU83Xk0HV9vXU0rsMqHpkFa9QvLIDCPOvH7AIclbAPPAzZRow2 RwvB0TaZNB2tHdzyfkGRXTJtkjg/OFK8l5mbKY0BSY+KOa0q78EYrmB0jFksNEvwcM GsXy9clwK99dsAFCgktndhUJulCNA/iiRjihDHjo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+73df3f89e1e13089e466@syzkaller.appspotmail.com, Kuniyuki Iwashima , Eric Dumazet , Willem de Bruijn , Paolo Abeni , Sasha Levin Subject: [PATCH 7.2 149/733] af_packet: Dont cast tpacket_hdr.tp_len to int in tpacket_parse_header(). Date: Thu, 17 Sep 2026 16:07:37 +0100 Message-ID: <20260917151354.766911420@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151350.597953846@linuxfoundation.org> References: <20260917151350.597953846@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 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kuniyuki Iwashima [ Upstream commit 73e594c19b4f815d8343461cec7074c4713bbde7 ] syzbot reported BUG() in sock_sendmsg_nosec(). [0] The problem is that tpacket_parse_header() casts user-provided tpacket_hdr.tp_len, which is u32, to int. If the length is larger than INT_MAX, the following condition in tpacket_parse_header() passes, if (unlikely(tp_len > size_max)) and any negative value can be returned to the caller, up to sock_sendmsg_nosec(). The repro set tpacket_hdr.tp_len to 0xfffffdef, which is cast to -EIOCBQUEUED (-529), triggering BUG() in sock_sendmsg_nosec(). *(uint64_t*)0x200000000008 = 0xfffffdef; ... syscall(__NR_write, /*fd=*/r[0], /*buf=*/0x200000000000ul, /*count=*/1ul); Let's define the local tp_len as u32 in tpacket_parse_header(). [0]: kernel BUG at net/socket.c:803! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 0 UID: 0 PID: 5628 Comm: syz-executor176 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:sock_sendmsg_nosec+0x145/0x180 net/socket.c:803 Code: 06 67 48 0f b9 3a eb 95 e8 e8 3a 22 f8 48 89 df 4c 89 f6 4c 89 e2 4d 89 fb 2e e8 32 a5 5c 16 e9 51 ff ff ff e8 cc 3a 22 f8 90 <0f> 0b e8 c4 3a 22 f8 48 83 c3 18 48 89 d8 48 c1 e8 03 42 80 3c 28 RSP: 0018:ffffc90003aefb48 EFLAGS: 00010293 RAX: ffffffff89a578d4 RBX: ffff8880764c67c0 RCX: ffff88807fb23e80 RDX: 0000000000000000 RSI: 00000000fffffdef RDI: 00000000fffffdef RBP: 00000000fffffdef R08: ffffc90003aef747 R09: 1ffff9200075dee8 R10: dffffc0000000000 R11: fffff5200075dee9 R12: 0000000000000001 R13: dffffc0000000000 R14: ffffc90003aefbc0 R15: ffffffff8aac4310 FS: 000055559101b400(0000) GS:ffff888124ce0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000210 CR3: 0000000073dca000 CR4: 00000000003526f0 Call Trace: __sock_sendmsg net/socket.c:815 [inline] sock_write_iter+0x2de/0x3e0 net/socket.c:1266 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x612/0xba0 fs/read_write.c:687 ksys_write+0x150/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f173130ecb9 Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 d8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd67e44248 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007f173130ecb9 RDX: 0000000000000001 RSI: 0000200000000000 RDI: 0000000000000003 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd67e44388 R13: 0000000000000002 R14: 00002000000000c0 R15: 0000000000000002 Fixes: 69e3c75f4d54 ("net: TX_RING and packet mmap") Reported-by: syzbot+73df3f89e1e13089e466@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/6a946ffa.1d9ded08.62e62.0123.GAE@google.com/ Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20260830180915.260225-1-kuniyu@google.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/packet/af_packet.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index b22cda3221363..76bde7906d494 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2675,7 +2675,8 @@ static int tpacket_parse_header(struct packet_sock *po, void *frame, int size_max, void **data) { union tpacket_uhdr ph; - int tp_len, off; + u32 tp_len; + int off; ph.raw = frame; @@ -2695,7 +2696,7 @@ static int tpacket_parse_header(struct packet_sock *po, void *frame, break; } if (unlikely(tp_len > size_max)) { - pr_err("packet size is too long (%d > %d)\n", tp_len, size_max); + pr_err("packet size is too long (%u > %d)\n", tp_len, size_max); return -EMSGSIZE; } -- 2.53.0