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Davide Caratti a1478374b0 openvswitch: fix stack OOB read while fragmenting IPv4 packets 
commit 7c0ea5930c upstream.

running openvswitch on kernels built with KASAN, it's possible to see the
following splat while testing fragmentation of IPv4 packets:

 BUG: KASAN: stack-out-of-bounds in ip_do_fragment+0x1b03/0x1f60
 Read of size 1 at addr ffff888112fc713c by task handler2/1367

 CPU: 0 PID: 1367 Comm: handler2 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:
  dump_stack+0x92/0xc1
  print_address_description.constprop.7+0x1a/0x150
  kasan_report.cold.13+0x7f/0x111
  ip_do_fragment+0x1b03/0x1f60
  ovs_fragment+0x5bf/0x840 [openvswitch]
  do_execute_actions+0x1bd5/0x2400 [openvswitch]
  ovs_execute_actions+0xc8/0x3d0 [openvswitch]
  ovs_packet_cmd_execute+0xa39/0x1150 [openvswitch]
  genl_family_rcv_msg_doit.isra.15+0x227/0x2d0
  genl_rcv_msg+0x287/0x490
  netlink_rcv_skb+0x120/0x380
  genl_rcv+0x24/0x40
  netlink_unicast+0x439/0x630
  netlink_sendmsg+0x719/0xbf0
  sock_sendmsg+0xe2/0x110
  ____sys_sendmsg+0x5ba/0x890
  ___sys_sendmsg+0xe9/0x160
  __sys_sendmsg+0xd3/0x170
  do_syscall_64+0x33/0x40
  entry_SYSCALL_64_after_hwframe+0x44/0xae
 RIP: 0033:0x7f957079db07
 Code: c3 66 90 41 54 41 89 d4 55 48 89 f5 53 89 fb 48 83 ec 10 e8 eb ec ff ff 44 89 e2 48 89 ee 89 df 41 89 c0 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 48 89 44 24 08 e8 24 ed ff ff 48
 RSP: 002b:00007f956ce35a50 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
 RAX: ffffffffffffffda RBX: 0000000000000019 RCX: 00007f957079db07
 RDX: 0000000000000000 RSI: 00007f956ce35ae0 RDI: 0000000000000019
 RBP: 00007f956ce35ae0 R08: 0000000000000000 R09: 00007f9558006730
 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
 R13: 00007f956ce37308 R14: 00007f956ce35f80 R15: 00007f956ce35ae0

 The buggy address belongs to the page:
 page:00000000af2a1d93 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x112fc7
 flags: 0x17ffffc0000000()
 raw: 0017ffffc0000000 0000000000000000 dead000000000122 0000000000000000
 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
 page dumped because: kasan: bad access detected

 addr ffff888112fc713c is located in stack of task handler2/1367 at offset 180 in frame:
  ovs_fragment+0x0/0x840 [openvswitch]

 this frame has 2 objects:
  [32, 144) 'ovs_dst'
  [192, 424) 'ovs_rt'

 Memory state around the buggy address:
  ffff888112fc7000: f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ffff888112fc7080: 00 f1 f1 f1 f1 00 00 00 00 00 00 00 00 00 00 00
 >ffff888112fc7100: 00 00 00 f2 f2 f2 f2 f2 f2 00 00 00 00 00 00 00
                                         ^
  ffff888112fc7180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ffff888112fc7200: 00 00 00 00 00 00 f2 f2 f2 00 00 00 00 00 00 00

for IPv4 packets, ovs_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 ovs_fragment(), similarly to what is done for IPv6 few lines below.

Fixes: d52e5a7e7c ("ipv4: lock mtu in fnhe when received PMTU < net.ipv4.route.min_pmt")
Cc: <stable@vger.kernel.org>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-11 14:47:34 +02:00
arch arm64/vdso: Discard .note.gnu.property sections in vDSO 2021-05-11 14:47:33 +02:00
block block: return -EBUSY when there are open partitions in blkdev_reread_part 2021-04-28 13:39:59 +02:00
certs certs: Fix blacklist flag type confusion 2021-03-04 11:37:59 +01:00
crypto crypto: api - check for ERR pointers in crypto_destroy_tfm() 2021-05-11 14:47:16 +02:00
Documentation dt-bindings: net: ethernet-controller: fix typo in NVMEM 2021-04-14 08:42:12 +02:00
drivers mlxsw: spectrum_mr: Update egress RIF list before route's action 2021-05-11 14:47:34 +02:00
fs f2fs: fix to avoid out-of-bounds memory access 2021-05-11 14:47:34 +02:00
include perf: Rework perf_event_exit_event() 2021-05-11 14:47:31 +02:00
init init/Kconfig: make COMPILE_TEST depend on HAS_IOMEM 2021-04-10 13:36:11 +02:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel kcsan, debugfs: Move debugfs file creation out of early init 2021-05-11 14:47:33 +02:00
lib dyndbg: fix parsing file query without a line-range suffix 2021-05-11 14:47:11 +02:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm: ptdump: fix build failure 2021-04-21 13:00:57 +02:00
net openvswitch: fix stack OOB read while fragmenting IPv4 packets 2021-05-11 14:47:34 +02:00
samples samples, bpf: Add missing munmap in xdpsock 2021-03-17 17:06:12 +01:00
scripts kasan: fix hwasan build for gcc 2021-04-28 13:40:02 +02:00
security KEYS: trusted: Fix TPM reservation for seal/unseal 2021-04-28 13:39:59 +02:00
sound ALSA: hda/realtek: Add quirk for Intel Clevo PCx0Dx 2021-05-11 14:47:33 +02:00
tools tools/power/turbostat: Fix turbostat for AMD Zen CPUs 2021-05-11 14:47:33 +02:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: Use kvm_pfn_t for local PFN variable in hva_to_pfn_remapped() 2021-02-26 10:13:01 +01:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.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 .gitignore: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
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 MAINTAINERS: move the staging subsystem to lists.linux.dev 2021-03-25 09:04:18 +01:00
Makefile Makefile: Move -Wno-unused-but-set-variable out of GCC only block 2021-05-11 14:47:33 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

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.