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 34C1E185924; Fri, 15 Nov 2024 06:44:05 +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=1731653045; cv=none; b=C3QO/vJYacvNR4NFLjIzzRo3GqfzzWMkhYCeFIiaeUp7zSToaV9agN4ScxYxQespmUUWxZugqSjCvjkCvBvXKEvEq+g2DCv2YiwjW3TLnf8a+VRdTxV5TlpG06mI2SFWexn2v7NkVa3pvz9ks1yynLCRKzN/wOeBlcFZSDvi34g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731653045; c=relaxed/simple; bh=V3ThoFeNBSkZhRiqkbpC3NjpkB52yGG53WIKhAW7u4o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rucKME01N+GPD0AV5SnBP7/7ZFSBepN4GtnIcAToSjwjcSb1v0iV0ZuGdmbD9riwgPQKpHpxilYn/xflcmQslP+ldFCmIe9WELCl6TWHKmAy6OxD1a8niqeVbl38irVR6UFeGflu0KPF6JPndBZ8SxWny+/UClaJM4Y+q+tDbfk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=cOdRT+kI; 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="cOdRT+kI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 99AF3C4CECF; Fri, 15 Nov 2024 06:44:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1731653045; bh=V3ThoFeNBSkZhRiqkbpC3NjpkB52yGG53WIKhAW7u4o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cOdRT+kI6FGbE1Yc9AJWemSfrZXgZJ6AeYprPXDY/FYl2emSkieRcYQ60iiP1iFD8 FylMhfBTpOgSGFLBI7YLN8XuE6Mcx7UedfKuvgUx38JsMCsvwTC49XXV6grcLOv3Lb NP751oUE4OypIvbeHdO/PE8STnG1ebwWxCPLuUD8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+a63a1f6a062033cf0f40@syzkaller.appspotmail.com, Nikolay Aleksandrov , "David S. Miller" , Randy MacLeod Subject: [PATCH 5.4 37/66] net: bridge: xmit: make sure we have at least eth header len bytes Date: Fri, 15 Nov 2024 07:37:46 +0100 Message-ID: <20241115063724.186159647@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241115063722.834793938@linuxfoundation.org> References: <20241115063722.834793938@linuxfoundation.org> User-Agent: quilt/0.67 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 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nikolay Aleksandrov commit 8bd67ebb50c0145fd2ca8681ab65eb7e8cde1afc upstream. syzbot triggered an uninit value[1] error in bridge device's xmit path by sending a short (less than ETH_HLEN bytes) skb. To fix it check if we can actually pull that amount instead of assuming. Tested with dropwatch: drop at: br_dev_xmit+0xb93/0x12d0 [bridge] (0xffffffffc06739b3) origin: software timestamp: Mon May 13 11:31:53 2024 778214037 nsec protocol: 0x88a8 length: 2 original length: 2 drop reason: PKT_TOO_SMALL [1] BUG: KMSAN: uninit-value in br_dev_xmit+0x61d/0x1cb0 net/bridge/br_device.c:65 br_dev_xmit+0x61d/0x1cb0 net/bridge/br_device.c:65 __netdev_start_xmit include/linux/netdevice.h:4903 [inline] netdev_start_xmit include/linux/netdevice.h:4917 [inline] xmit_one net/core/dev.c:3531 [inline] dev_hard_start_xmit+0x247/0xa20 net/core/dev.c:3547 __dev_queue_xmit+0x34db/0x5350 net/core/dev.c:4341 dev_queue_xmit include/linux/netdevice.h:3091 [inline] __bpf_tx_skb net/core/filter.c:2136 [inline] __bpf_redirect_common net/core/filter.c:2180 [inline] __bpf_redirect+0x14a6/0x1620 net/core/filter.c:2187 ____bpf_clone_redirect net/core/filter.c:2460 [inline] bpf_clone_redirect+0x328/0x470 net/core/filter.c:2432 ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997 __bpf_prog_run512+0xb5/0xe0 kernel/bpf/core.c:2238 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline] __bpf_prog_run include/linux/filter.h:657 [inline] bpf_prog_run include/linux/filter.h:664 [inline] bpf_test_run+0x499/0xc30 net/bpf/test_run.c:425 bpf_prog_test_run_skb+0x14ea/0x1f20 net/bpf/test_run.c:1058 bpf_prog_test_run+0x6b7/0xad0 kernel/bpf/syscall.c:4269 __sys_bpf+0x6aa/0xd90 kernel/bpf/syscall.c:5678 __do_sys_bpf kernel/bpf/syscall.c:5767 [inline] __se_sys_bpf kernel/bpf/syscall.c:5765 [inline] __x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5765 x64_sys_call+0x96b/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:322 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+a63a1f6a062033cf0f40@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=a63a1f6a062033cf0f40 Signed-off-by: Nikolay Aleksandrov Signed-off-by: David S. Miller Signed-off-by: Randy MacLeod Signed-off-by: Greg Kroah-Hartman --- net/bridge/br_device.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/net/bridge/br_device.c +++ b/net/bridge/br_device.c @@ -35,6 +35,11 @@ netdev_tx_t br_dev_xmit(struct sk_buff * const unsigned char *dest; u16 vid = 0; + if (unlikely(!pskb_may_pull(skb, ETH_HLEN))) { + kfree_skb(skb); + return NETDEV_TX_OK; + } + memset(skb->cb, 0, sizeof(struct br_input_skb_cb)); rcu_read_lock();