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Filename Latest commit message Latest commit date
Randy Dunlap 4e3b08cfe6 JFS: more checks for invalid superblock
commit 3bef198f1b17d1bb89260bad947ef084c0a2d1a6 upstream.

syzbot is feeding invalid superblock data to JFS for mount testing.
JFS does not check several of the fields -- just assumes that they
are good since the JFS_MAGIC and version fields are good.

In this case (syzbot reproducer), we have s_l2bsize == 0xda0c,
pad == 0xf045, and s_state == 0x50, all of which are invalid IMO.
Having s_l2bsize == 0xda0c causes this UBSAN warning:
  UBSAN: shift-out-of-bounds in fs/jfs/jfs_mount.c:373:25
  shift exponent -9716 is negative

s_l2bsize can be tested for correctness. pad can be tested for non-0
and punted. s_state can be tested for its valid values and punted.

Do those 3 tests and if any of them fails, report the superblock as
invalid/corrupt and let fsck handle it.

With this patch, chkSuper() says this when JFS_DEBUG is enabled:
  jfs_mount: Mount Failure: superblock is corrupt!
  Mount JFS Failure: -22
  jfs_mount failed w/return code = -22

The obvious problem with this method is that next week there could
be another syzbot test that uses different fields for invalid values,
this making this like a game of whack-a-mole.

syzkaller link: https://syzkaller.appspot.com/bug?extid=36315852ece4132ec193

Reported-by: syzbot+36315852ece4132ec193@syzkaller.appspotmail.com
Reported-by: kernel test robot <lkp@intel.com> # v2
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Cc: jfs-discussion@lists.sourceforge.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-07 12:20:41 +01:00
arch MIPS: VDSO: Use CLANG_FLAGS instead of filtering out '--target=' 2021-03-07 12:20:41 +01:00
block blk-settings: align max_sectors on "logical_block_size" boundary 2021-03-04 10:26:40 +01:00
certs certs: Fix blacklist flag type confusion 2021-03-04 10:26:29 +01:00
crypto crypto: ecdh_helper - Ensure 'len >= secret.len' in decode_key() 2021-03-04 10:26:25 +01:00
Documentation seq_file: document how per-entry resources are managed. 2021-03-04 10:26:48 +01:00
drivers nvme-pci: fix error unwind in nvme_map_data 2021-03-07 12:20:41 +01:00
fs JFS: more checks for invalid superblock 2021-03-07 12:20:41 +01:00
include net: sched: fix police ext initialization 2021-03-04 10:26:53 +01:00
init fgraph: Initialize tracing_graph_pause at task creation 2021-02-10 09:25:29 +01:00
ipc
kernel printk: fix deadlock when kernel panic 2021-03-04 10:26:50 +01:00
lib udp: fix skb_copy_and_csum_datagram with odd segment sizes 2021-02-17 10:35:19 +01:00
LICENSES
mm hugetlb: fix copy_huge_page_from_user contig page struct assumption 2021-03-04 10:26:49 +01:00
net net: qrtr: Fix memory leak in qrtr_tun_open 2021-03-04 10:26:53 +01:00
samples samples: bpf: Fix lwt_len_hist reusing previous BPF map 2020-12-30 11:51:12 +01:00
scripts scripts/recordmcount.pl: support big endian for ARCH sh 2021-02-26 10:10:28 +01:00
security KEYS: trusted: Fix migratable=1 failing 2021-03-04 10:26:44 +01:00
sound ALSA: hda/realtek: modify EAPD in the ALC886 2021-03-04 10:26:42 +01:00
tools perf test: Fix unaligned access in sample parsing test 2021-03-04 10:26:35 +01:00
usr
virt KVM: Use kvm_pfn_t for local PFN variable in hva_to_pfn_remapped() 2021-02-26 10:10:28 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
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.gitignore
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COPYING
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Kconfig
MAINTAINERS
Makefile Linux 5.4.102 2021-03-04 10:26:54 +01:00
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.