linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	syzbot+7010af67ced6105e5ab6@syzkaller.appspotmail.com,
	Vasily Averin <vvs@virtuozzo.com>,
	Willem de Bruijn <willemb@google.com>,
	Jakub Kicinski <kuba@kernel.org>
Subject: [PATCH 4.9 25/25] net: drop bogus skb with CHECKSUM_PARTIAL and offset beyond end of trimmed packet
Date: Fri, 15 Jan 2021 13:27:56 +0100	[thread overview]
Message-ID: <20210115121957.929556660@linuxfoundation.org> (raw)
In-Reply-To: <20210115121956.679956165@linuxfoundation.org>

From: Vasily Averin <vvs@virtuozzo.com>

commit 54970a2fbb673f090b7f02d7f57b10b2e0707155 upstream.

syzbot reproduces BUG_ON in skb_checksum_help():
tun creates (bogus) skb with huge partial-checksummed area and
small ip packet inside. Then ip_rcv trims the skb based on size
of internal ip packet, after that csum offset points beyond of
trimmed skb. Then checksum_tg() called via netfilter hook
triggers BUG_ON:

        offset = skb_checksum_start_offset(skb);
        BUG_ON(offset >= skb_headlen(skb));

To work around the problem this patch forces pskb_trim_rcsum_slow()
to return -EINVAL in described scenario. It allows its callers to
drop such kind of packets.

Link: https://syzkaller.appspot.com/bug?id=b419a5ca95062664fe1a60b764621eb4526e2cd0
Reported-by: syzbot+7010af67ced6105e5ab6@syzkaller.appspotmail.com
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/1b2494af-2c56-8ee2-7bc0-923fcad1cdf8@virtuozzo.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/core/skbuff.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1592,6 +1592,12 @@ int pskb_trim_rcsum_slow(struct sk_buff
 		skb->csum = csum_block_sub(skb->csum,
 					   skb_checksum(skb, len, delta, 0),
 					   len);
+	} else if (skb->ip_summed == CHECKSUM_PARTIAL) {
+		int hdlen = (len > skb_headlen(skb)) ? skb_headlen(skb) : len;
+		int offset = skb_checksum_start_offset(skb) + skb->csum_offset;
+
+		if (offset + sizeof(__sum16) > hdlen)
+			return -EINVAL;
 	}
 	return __pskb_trim(skb, len);
 }



  parent reply	other threads:[~2021-01-15 12:31 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-15 12:27 [PATCH 4.9 00/25] 4.9.252-rc1 review Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 01/25] target: bounds check XCOPY segment descriptor list Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 02/25] target: simplify XCOPY wwn->se_dev lookup helper Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 03/25] target: use XCOPY segment descriptor CSCD IDs Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 04/25] xcopy: loop over devices using idr helper Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 05/25] scsi: target: Fix XCOPY NAA identifier lookup Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 06/25] target: add XCOPY target/segment desc sense codes Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 07/25] powerpc: Fix incorrect stw{, ux, u, x} instructions in __set_pte_at Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 08/25] net: ip: always refragment ip defragmented packets Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 09/25] net: fix pmtu check in nopmtudisc mode Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 10/25] vmlinux.lds.h: Add PGO and AutoFDO input sections Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 11/25] drm/i915: Fix mismatch between misplaced vma check and vma insert Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 12/25] ubifs: wbuf: Dont leak kernel memory to flash Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 13/25] spi: pxa2xx: Fix use-after-free on unbind Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 14/25] ARM: OMAP2+: omap_device: fix idling of devices during probe Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 15/25] cpufreq: powernow-k8: pass policy rather than use cpufreq_cpu_get() Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 16/25] dmaengine: xilinx_dma: check dma_async_device_register return value Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 17/25] dmaengine: xilinx_dma: fix mixed_enum_type coverity warning Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 18/25] wil6210: select CONFIG_CRC32 Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 19/25] block: rsxx: " Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 20/25] iommu/intel: Fix memleak in intel_irq_remapping_alloc Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 21/25] net/mlx5e: Fix memleak in mlx5e_create_l2_table_groups Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 22/25] wan: ds26522: select CONFIG_BITREVERSE Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 23/25] KVM: arm64: Dont access PMCR_EL0 when no PMU is available Greg Kroah-Hartman
2021-01-15 12:27 ` [PATCH 4.9 24/25] block: fix use-after-free in disk_part_iter_next Greg Kroah-Hartman
2021-01-15 12:27 ` Greg Kroah-Hartman [this message]
2021-01-15 21:14 ` [PATCH 4.9 00/25] 4.9.252-rc1 review Shuah Khan
2021-01-15 21:18 ` Guenter Roeck
2021-01-16  7:41 ` Naresh Kamboju

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210115121957.929556660@linuxfoundation.org \
    --to=gregkh@linuxfoundation.org \
    --cc=kuba@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=stable@vger.kernel.org \
    --cc=syzbot+7010af67ced6105e5ab6@syzkaller.appspotmail.com \
    --cc=vvs@virtuozzo.com \
    --cc=willemb@google.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).