Go to file
Chao Yu 42bf546c1f f2fs: fix to do sanity check with secs_per_zone
As Wen Xu reported in below link:

https://bugzilla.kernel.org/show_bug.cgi?id=200183

- Overview
Divide zero in reset_curseg() when mounting a crafted f2fs image

- Reproduce

- Kernel message
[  588.281510] divide error: 0000 [#1] SMP KASAN PTI
[  588.282701] CPU: 0 PID: 1293 Comm: mount Not tainted 4.18.0-rc1+ #4
[  588.284000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
[  588.286178] RIP: 0010:reset_curseg+0x94/0x1a0
[  588.298166] RSP: 0018:ffff8801e88d7940 EFLAGS: 00010246
[  588.299360] RAX: 0000000000000014 RBX: ffff8801e1d46d00 RCX: ffffffffb88bf60b
[  588.300809] RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffff8801e1d46d64
[  588.305272] R13: 0000000000000000 R14: 0000000000000014 R15: 0000000000000000
[  588.306822] FS:  00007fad85008840(0000) GS:ffff8801f6e00000(0000) knlGS:0000000000000000
[  588.308456] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  588.309623] CR2: 0000000001705078 CR3: 00000001f30f8000 CR4: 00000000000006f0
[  588.311085] Call Trace:
[  588.311637]  f2fs_build_segment_manager+0x103f/0x3410
[  588.316136]  ? f2fs_commit_super+0x1b0/0x1b0
[  588.317031]  ? set_blocksize+0x90/0x140
[  588.319473]  f2fs_mount+0x15/0x20
[  588.320166]  mount_fs+0x60/0x1a0
[  588.320847]  ? alloc_vfsmnt+0x309/0x360
[  588.321647]  vfs_kern_mount+0x6b/0x1a0
[  588.322432]  do_mount+0x34a/0x18c0
[  588.323175]  ? strndup_user+0x46/0x70
[  588.323937]  ? copy_mount_string+0x20/0x20
[  588.324793]  ? memcg_kmem_put_cache+0x1b/0xa0
[  588.325702]  ? kasan_check_write+0x14/0x20
[  588.326562]  ? _copy_from_user+0x6a/0x90
[  588.327375]  ? memdup_user+0x42/0x60
[  588.328118]  ksys_mount+0x83/0xd0
[  588.328808]  __x64_sys_mount+0x67/0x80
[  588.329607]  do_syscall_64+0x78/0x170
[  588.330400]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  588.331461] RIP: 0033:0x7fad848e8b9a
[  588.336022] RSP: 002b:00007ffd7c5b6be8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
[  588.337547] RAX: ffffffffffffffda RBX: 00000000016f8030 RCX: 00007fad848e8b9a
[  588.338999] RDX: 00000000016f8210 RSI: 00000000016f9f30 RDI: 0000000001700ec0
[  588.340442] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000013
[  588.341887] R10: 00000000c0ed0000 R11: 0000000000000206 R12: 0000000001700ec0
[  588.343341] R13: 00000000016f8210 R14: 0000000000000000 R15: 0000000000000003
[  588.354891] ---[ end trace 4ce02f25ff7d3df5 ]---
[  588.355862] RIP: 0010:reset_curseg+0x94/0x1a0
[  588.360742] RSP: 0018:ffff8801e88d7940 EFLAGS: 00010246
[  588.361812] RAX: 0000000000000014 RBX: ffff8801e1d46d00 RCX: ffffffffb88bf60b
[  588.363485] RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffff8801e1d46d64
[  588.365213] RBP: ffff8801e88d7968 R08: ffffed003c32266f R09: ffffed003c32266f
[  588.366661] R10: 0000000000000001 R11: ffffed003c32266e R12: ffff8801f0337700
[  588.368110] R13: 0000000000000000 R14: 0000000000000014 R15: 0000000000000000
[  588.370057] FS:  00007fad85008840(0000) GS:ffff8801f6e00000(0000) knlGS:0000000000000000
[  588.372099] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  588.373291] CR2: 0000000001705078 CR3: 00000001f30f8000 CR4: 00000000000006f0

- Location
https://elixir.bootlin.com/linux/latest/source/fs/f2fs/segment.c#L2147
        curseg->zone = GET_ZONE_FROM_SEG(sbi, curseg->segno);

If secs_per_zone is corrupted due to fuzzing test, it will cause divide
zero operation when using GET_ZONE_FROM_SEG macro, so we should do more
sanity check with secs_per_zone during mount to avoid this issue.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2018-07-27 18:03:59 +09:00
arch Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2018-07-06 09:14:34 -07:00
block for-linus-20180629 2018-06-30 10:47:46 -07:00
certs certs/blacklist: fix const confusion 2018-06-26 09:43:03 -07:00
crypto Revert changes to convert to ->poll_mask() and aio IOCB_CMD_POLL 2018-06-28 10:40:47 -07:00
Documentation USB fixes for 4.18-rc3 2018-07-01 11:50:16 -07:00
drivers Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2018-07-06 09:14:34 -07:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs f2fs: fix to do sanity check with secs_per_zone 2018-07-27 18:03:59 +09:00
include While cleaning out my INBOX, I found a few patches that were lost 2018-07-05 19:29:07 -07:00
init Kbuild fixes for v4.18 2018-06-30 13:05:30 -07:00
ipc ipc: use new return type vm_fault_t 2018-06-15 07:55:25 +09:00
kernel While cleaning out my INBOX, I found a few patches that were lost 2018-07-05 19:29:07 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-07-02 11:18:28 -07:00
LICENSES LICENSES: Add Linux-OpenIB license text 2018-04-27 16:41:53 -06:00
mm mm: teach dump_page() to correctly output poisoned struct pages 2018-07-03 17:32:19 -07:00
net net/smc: fix up merge error with poll changes 2018-07-03 09:53:43 -07:00
samples bpf: Change bpf_fib_lookup to return lookup status 2018-06-29 00:02:02 +02:00
scripts Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-07-02 11:18:28 -07:00
security selinux/stable-4.18 PR 20180629 2018-06-30 11:15:12 -07:00
sound ALSA: seq: Fix UBSAN warning at SNDRV_SEQ_IOCTL_QUERY_NEXT_CLIENT ioctl 2018-06-25 11:18:04 +02:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-07-02 11:18:28 -07:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt KVM: arm64: Prevent KVM_COMPAT from being selected 2018-06-21 17:17:50 +01:00
.clang-format clang-format: add configuration file 2018-04-11 10:28:35 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap Merge branch 'asoc-4.17' into asoc-4.18 for compress dependencies 2018-04-26 12:24:28 +01:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS/CREDITS: Drop METAG ARCHITECTURE 2018-03-05 16:34:24 +00:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: add basic helper macros to scripts/Kconfig.include 2018-05-29 03:31:19 +09:00
MAINTAINERS proc: add Alexey to MAINTAINERS 2018-06-28 11:16:44 -07:00
Makefile Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-07-02 11:18:28 -07:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.