From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELsk1O65hWPBa2svqaR662BiXwniMIe5k05Jm/HEe3/8kXjl4UUJZWOxSQkVhsXhcx/KwFUc ARC-Seal: i=1; a=rsa-sha256; t=1520451956; cv=none; d=google.com; s=arc-20160816; b=LNqsMP8l6JpwInawdwlQVWjmmlf+u351iNLWmIe8qdmE98uhqdZVT7h/ZzralC7a7p ZGA+Ejt1rOlqgoPAy+h86cTZ3UimukarRMWgKLo28KIjcS4GEMPDjqihiG0iqQUViuEd eRYS8wD/mdnWk9L0pu5anJseAdadGAkVnlke5rhEvnH1p2aliEHOuBXIKs0R6D6upNNB ZaP5BafuMcqKyHVUUi7nMAybWfjmIUIeSGVK92ixIq/CtnwzNiAj+Ra3Sc6pZAOyTN26 qZLJ8F6iNpYYJm+V9aiEc0lABlnfgjKvMYXc5fJYKsrzUGURdCM5kcux+Sjy4CsmFmtF GPYg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=GiFFDV7QNa41+gl7xa0IGZ+O7oeym7XJrF0aUPAM1MI=; b=aWGM5yxju5r+oJKI7NK2+Lx4CY7OA3gLf0uPEE9L8WoE7iR6swkz+tJf0CazhfXjTb i3I3sKuePj5ZAo7d8dDrRRAplLsG1vlx8GzyYJZYl3pT5qxgE6YQxTBGxpvHCTiVC8CA CqXtyf+m/jdv5/+KQTN1j9/CxYx9klhGs1dTJ9yjM5uo21z8LbmOVsdvK3dfTZ4tzHi7 dEieCphwW6TA1PjZeFLTZp8qZVUeQ9R2YergmAmax0sBZsGkZchSiAa2DC/qr75tzwb6 6KgkWDomjiX/tK+PhVHSZopp4cdvEZVyUZUi5NBnbOGSQDbj+vDrL7+zHqj+EPl6M7eX toUA== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 185.236.200.248 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 185.236.200.248 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexey Kodanev , Marcelo Ricardo Leitner , Neil Horman , "David S. Miller" Subject: [PATCH 4.14 045/110] sctp: verify size of a new chunk in _sctp_make_chunk() Date: Wed, 7 Mar 2018 11:38:28 -0800 Message-Id: <20180307191045.465399638@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180307191039.748351103@linuxfoundation.org> References: <20180307191039.748351103@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1594309139344235247?= X-GMAIL-MSGID: =?utf-8?q?1594309430735636196?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexey Kodanev [ Upstream commit 07f2c7ab6f8d0a7e7c5764c4e6cc9c52951b9d9c ] When SCTP makes INIT or INIT_ACK packet the total chunk length can exceed SCTP_MAX_CHUNK_LEN which leads to kernel panic when transmitting these packets, e.g. the crash on sending INIT_ACK: [ 597.804948] skbuff: skb_over_panic: text:00000000ffae06e4 len:120168 put:120156 head:000000007aa47635 data:00000000d991c2de tail:0x1d640 end:0xfec0 dev: ... [ 597.976970] ------------[ cut here ]------------ [ 598.033408] kernel BUG at net/core/skbuff.c:104! [ 600.314841] Call Trace: [ 600.345829] [ 600.371639] ? sctp_packet_transmit+0x2095/0x26d0 [sctp] [ 600.436934] skb_put+0x16c/0x200 [ 600.477295] sctp_packet_transmit+0x2095/0x26d0 [sctp] [ 600.540630] ? sctp_packet_config+0x890/0x890 [sctp] [ 600.601781] ? __sctp_packet_append_chunk+0x3b4/0xd00 [sctp] [ 600.671356] ? sctp_cmp_addr_exact+0x3f/0x90 [sctp] [ 600.731482] sctp_outq_flush+0x663/0x30d0 [sctp] [ 600.788565] ? sctp_make_init+0xbf0/0xbf0 [sctp] [ 600.845555] ? sctp_check_transmitted+0x18f0/0x18f0 [sctp] [ 600.912945] ? sctp_outq_tail+0x631/0x9d0 [sctp] [ 600.969936] sctp_cmd_interpreter.isra.22+0x3be1/0x5cb0 [sctp] [ 601.041593] ? sctp_sf_do_5_1B_init+0x85f/0xc30 [sctp] [ 601.104837] ? sctp_generate_t1_cookie_event+0x20/0x20 [sctp] [ 601.175436] ? sctp_eat_data+0x1710/0x1710 [sctp] [ 601.233575] sctp_do_sm+0x182/0x560 [sctp] [ 601.284328] ? sctp_has_association+0x70/0x70 [sctp] [ 601.345586] ? sctp_rcv+0xef4/0x32f0 [sctp] [ 601.397478] ? sctp6_rcv+0xa/0x20 [sctp] ... Here the chunk size for INIT_ACK packet becomes too big, mostly because of the state cookie (INIT packet has large size with many address parameters), plus additional server parameters. Later this chunk causes the panic in skb_put_data(): skb_packet_transmit() sctp_packet_pack() skb_put_data(nskb, chunk->skb->data, chunk->skb->len); 'nskb' (head skb) was previously allocated with packet->size from u16 'chunk->chunk_hdr->length'. As suggested by Marcelo we should check the chunk's length in _sctp_make_chunk() before trying to allocate skb for it and discard a chunk if its size bigger than SCTP_MAX_CHUNK_LEN. Signed-off-by: Alexey Kodanev Acked-by: Marcelo Ricardo Leitner Acked-by: Neil Horman Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sctp/sm_make_chunk.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/net/sctp/sm_make_chunk.c +++ b/net/sctp/sm_make_chunk.c @@ -1378,9 +1378,14 @@ static struct sctp_chunk *_sctp_make_chu struct sctp_chunk *retval; struct sk_buff *skb; struct sock *sk; + int chunklen; + + chunklen = SCTP_PAD4(sizeof(*chunk_hdr) + paylen); + if (chunklen > SCTP_MAX_CHUNK_LEN) + goto nodata; /* No need to allocate LL here, as this is only a chunk. */ - skb = alloc_skb(SCTP_PAD4(sizeof(*chunk_hdr) + paylen), gfp); + skb = alloc_skb(chunklen, gfp); if (!skb) goto nodata;