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 80DE33EDAB3 for ; Tue, 19 May 2026 22:30:02 +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=1779229803; cv=none; b=AOW3RTVZ+H3dbC+vqFOrM9Hy4PPnRGjOoRZMwXdfi1hbHTY3adBPGyyppd7MfnxxxOCecgLaDbLUzk+zd6HnNny/xtFI44V1RYxoP9em+i0inf5NQDHQa2RmjoawuUcHDtHTyg7yODaNdfLyRNR30gEzoa4fzlzBetpavwaPjVw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779229803; c=relaxed/simple; bh=KYY7YF581t9FoakHguW5K5u4vb4KwOhwVigS0T14oyY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=PnfGSldubYvlm7UQgbIrT9bQ329GRswVd7PLFjJm8dFJ9QZJcNbZNnR1MzFxG0Sle5z0QXaF+HhvuYASFOn/xEJ6rmOzGH4hT/Xxex8+UNpQAUgixQ5MloQqA2r/tdB6DITqJVH7MZBqzIVeyWxj3OazfoztKhgdmdsOoiimwf0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=E+3crCXI; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="E+3crCXI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D138C1F000E9; Tue, 19 May 2026 22:30:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779229802; bh=javdDT8NW6bNhiHy15NtSQhRTq4gh7HAPyiyb3k997M=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=E+3crCXIimZTQ+KJXZ6JO1vYLCD5dvKsJ4+CdLqHH0mdCp4RsG6WylNDGpqq64QuL iLXYjCkX6CeyAZ8oK3TQgU5EEK7emPo1lFFO6xHWL5Ki0idHX4HYHG7mBPL9axldxY hWYttJcEnDsFZ04KZgXvwA63MPJ341oYYT9uNCorQdey49igsRn0dYGuWS5fWjFFBr h/NrwhVB4rfYRq8+Pr232RKdQtWYMFcKkzwJPk6G6KgtIOCoApOpVQN2m7toWj6e8b r6ns9OfLGi5HLekKk4vubb+sUc/HtxrzlHJaMt+JAWDH/QGdRJYDdKwgs8xWCs4z+F helBkB9JluA3Q== Message-ID: <1b2e20b0-63b4-403b-841b-d261bbf358d5@kernel.org> Date: Tue, 19 May 2026 16:30:00 -0600 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net] ipv4: icmp: reject broadcast/multicast routes Content-Language: en-US To: Eric Dumazet , "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Ido Schimmel , netdev@vger.kernel.org, eric.dumazet@gmail.com, syzbot+c13a57c2639c2c0d03a6@syzkaller.appspotmail.com References: <20260519200836.4141061-1-edumazet@google.com> From: David Ahern In-Reply-To: <20260519200836.4141061-1-edumazet@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/19/26 2:08 PM, Eric Dumazet wrote: > syzbot was able to trigger ip_rt_bug() in a loop, using an IPv4 packet > with a crafted IPOPT_SSRR option: > > options: ipv4_options { > options: array[ipv4_option] { > union ipv4_option { > ssrr: ipv4_option_route[IPOPT_SSRR] { > type: const = 0x89 (1 bytes) > length: len = 0x7 (1 bytes) > pointer: int8 = 0xa2 (1 bytes) > data: array[ipv4_addr] { > union ipv4_addr { > broadcast: const = 0xffffffff (4 bytes) > } > } > } > } > > Change __icmp_send() to not send ICMP to broadcast/multicast destinations. > > Fixes: c378a9c019cf ("ipv4: Give backtrace in ip_rt_bug().") > Reported-by: syzbot+c13a57c2639c2c0d03a6@syzkaller.appspotmail.com > Closes: https://lore.kernel.org/netdev/6a0cc169.170a0220.1f6c2d.0004.GAE@google.com/T/#u > Signed-off-by: Eric Dumazet > --- > net/ipv4/icmp.c | 3 +++ > 1 file changed, 3 insertions(+) > Reviewed-by: David Ahern