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linux/drivers/isdn/capi
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Eric Biggers fe163e534e isdn/capi: check message length in capi_write() 
syzbot reported:

    BUG: KMSAN: uninit-value in capi_write+0x791/0xa90 drivers/isdn/capi/capi.c:700
    CPU: 0 PID: 10025 Comm: syz-executor379 Not tainted 4.20.0-rc7+ #2
    Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
    Call Trace:
      __dump_stack lib/dump_stack.c:77 [inline]
      dump_stack+0x173/0x1d0 lib/dump_stack.c:113
      kmsan_report+0x12e/0x2a0 mm/kmsan/kmsan.c:613
      __msan_warning+0x82/0xf0 mm/kmsan/kmsan_instr.c:313
      capi_write+0x791/0xa90 drivers/isdn/capi/capi.c:700
      do_loop_readv_writev fs/read_write.c:703 [inline]
      do_iter_write+0x83e/0xd80 fs/read_write.c:961
      vfs_writev fs/read_write.c:1004 [inline]
      do_writev+0x397/0x840 fs/read_write.c:1039
      __do_sys_writev fs/read_write.c:1112 [inline]
      __se_sys_writev+0x9b/0xb0 fs/read_write.c:1109
      __x64_sys_writev+0x4a/0x70 fs/read_write.c:1109
      do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
      entry_SYSCALL_64_after_hwframe+0x63/0xe7
    [...]

The problem is that capi_write() is reading past the end of the message.
Fix it by checking the message's length in the needed places.

Reported-and-tested-by: syzbot+0849c524d9c634f5ae66@syzkaller.appspotmail.com
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-09-07 17:44:25 +02:00
..
capi.c isdn/capi: check message length in capi_write() 2019-09-07 17:44:25 +02:00
capilib.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
capiutil.c isdn/capi: correct argument types of command_2_index 2014-12-10 15:06:10 -05:00
kcapi_proc.c proc: introduce proc_create_seq{,_data} 2018-05-16 07:23:35 +02:00
kcapi.c isdn: fix kernel-infoleak in capi_unlocked_ioctl 2019-01-02 10:31:39 -08:00
kcapi.h
Kconfig isdn: move capi drivers to staging 2019-05-31 11:17:41 +02:00
Makefile isdn: move capi drivers to staging 2019-05-31 11:17:41 +02:00