A mirror of the official Linux kernel repository just in case
Go to file
Davide Caratti 31fe34a011 net/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets
when 'act_mirred' tries to fragment IPv4 packets that had been previously
re-assembled using 'act_ct', splats like the following can be observed on
kernels built with KASAN:

 BUG: KASAN: stack-out-of-bounds in ip_do_fragment+0x1b03/0x1f60
 Read of size 1 at addr ffff888147009574 by task ping/947

 CPU: 0 PID: 947 Comm: ping Not tainted 5.12.0-rc6+ #418
 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014
 Call Trace:
  <IRQ>
  dump_stack+0x92/0xc1
  print_address_description.constprop.7+0x1a/0x150
  kasan_report.cold.13+0x7f/0x111
  ip_do_fragment+0x1b03/0x1f60
  sch_fragment+0x4bf/0xe40
  tcf_mirred_act+0xc3d/0x11a0 [act_mirred]
  tcf_action_exec+0x104/0x3e0
  fl_classify+0x49a/0x5e0 [cls_flower]
  tcf_classify_ingress+0x18a/0x820
  __netif_receive_skb_core+0xae7/0x3340
  __netif_receive_skb_one_core+0xb6/0x1b0
  process_backlog+0x1ef/0x6c0
  __napi_poll+0xaa/0x500
  net_rx_action+0x702/0xac0
  __do_softirq+0x1e4/0x97f
  do_softirq+0x71/0x90
  </IRQ>
  __local_bh_enable_ip+0xdb/0xf0
  ip_finish_output2+0x760/0x2120
  ip_do_fragment+0x15a5/0x1f60
  __ip_finish_output+0x4c2/0xea0
  ip_output+0x1ca/0x4d0
  ip_send_skb+0x37/0xa0
  raw_sendmsg+0x1c4b/0x2d00
  sock_sendmsg+0xdb/0x110
  __sys_sendto+0x1d7/0x2b0
  __x64_sys_sendto+0xdd/0x1b0
  do_syscall_64+0x33/0x40
  entry_SYSCALL_64_after_hwframe+0x44/0xae
 RIP: 0033:0x7f82e13853eb
 Code: 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 48 8d 05 75 42 2c 00 41 89 ca 8b 00 85 c0 75 14 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 75 c3 0f 1f 40 00 41 57 4d 89 c7 41 56 41 89
 RSP: 002b:00007ffe01fad888 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
 RAX: ffffffffffffffda RBX: 00005571aac13700 RCX: 00007f82e13853eb
 RDX: 0000000000002330 RSI: 00005571aac13700 RDI: 0000000000000003
 RBP: 0000000000002330 R08: 00005571aac10500 R09: 0000000000000010
 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe01faefb0
 R13: 00007ffe01fad890 R14: 00007ffe01fad980 R15: 00005571aac0f0a0

 The buggy address belongs to the page:
 page:000000001dff2e03 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x147009
 flags: 0x17ffffc0001000(reserved)
 raw: 0017ffffc0001000 ffffea00051c0248 ffffea00051c0248 0000000000000000
 raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
 page dumped because: kasan: bad access detected

 Memory state around the buggy address:
  ffff888147009400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ffff888147009480: f1 f1 f1 f1 04 f2 f2 f2 f2 f2 f2 f2 00 00 00 00
 >ffff888147009500: 00 00 00 00 00 00 00 00 00 00 f2 f2 f2 f2 f2 f2
                                                              ^
  ffff888147009580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ffff888147009600: 00 00 00 00 00 00 00 00 00 00 00 00 00 f2 f2 f2

for IPv4 packets, sch_fragment() uses a temporary struct dst_entry. Then,
in the following call graph:

  ip_do_fragment()
    ip_skb_dst_mtu()
      ip_dst_mtu_maybe_forward()
        ip_mtu_locked()

the pointer to struct dst_entry is used as pointer to struct rtable: this
turns the access to struct members like rt_mtu_locked into an OOB read in
the stack. Fix this changing the temporary variable used for IPv4 packets
in sch_fragment(), similarly to what is done for IPv6 few lines below.

Fixes: c129412f74 ("net/sched: sch_frag: add generic packet fragment support.")
Cc: <stable@vger.kernel.org> # 5.11
Reported-by: Shuang Li <shuali@redhat.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-04-29 15:31:53 -07:00
arch Networking changes for 5.13. 2021-04-29 11:57:23 -07:00
block SCSI misc on 20210428 2021-04-28 17:22:10 -07:00
certs certs: add 'x509_revocation_list' to gitignore 2021-04-26 10:48:07 -07:00
crypto for-5.13/drivers-2021-04-27 2021-04-28 14:39:37 -07:00
Documentation Networking changes for 5.13. 2021-04-29 11:57:23 -07:00
drivers Networking changes for 5.13. 2021-04-29 11:57:23 -07:00
fs Networking changes for 5.13. 2021-04-29 11:57:23 -07:00
include seg6: add counters support for SRv6 Behaviors 2021-04-29 15:26:57 -07:00
init Networking changes for 5.13. 2021-04-29 11:57:23 -07:00
ipc fs: make helpers idmap mount aware 2021-01-24 14:27:20 +01:00
kernel Networking changes for 5.13. 2021-04-29 11:57:23 -07:00
lib Networking changes for 5.13. 2021-04-29 11:57:23 -07:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm \n 2021-04-29 11:06:13 -07:00
net net/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets 2021-04-29 15:31:53 -07:00
samples Networking changes for 5.13. 2021-04-29 11:57:23 -07:00
scripts Networking changes for 5.13. 2021-04-29 11:57:23 -07:00
security Networking changes for 5.13. 2021-04-29 11:57:23 -07:00
sound - Core Frameworks 2021-04-28 15:59:13 -07:00
tools Networking changes for 5.13. 2021-04-29 11:57:23 -07:00
usr Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
virt KVM: x86/mmu: Consider the hva in mmu_notifier retry 2021-02-22 13:16:53 -05:00
.clang-format cxl for 5.12 2021-02-24 09:38:36 -08:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore clang-lto series for v5.12-rc1 2021-02-23 09:28:51 -08:00
.mailmap It's been a relatively busy cycle in docsland, though more than usually 2021-04-26 13:22:43 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS - Core Frameworks 2021-04-28 15:59:13 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Networking changes for 5.13. 2021-04-29 11:57:23 -07:00
Makefile CFI on arm64 series for v5.13-rc1 2021-04-27 10:16:46 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.