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David Howells 8f868d68d3 pipe: Fix missing mask update after pipe_wait()
Fix pipe_write() to not cache the ring index mask and max_usage as their
values are invalidated by calling pipe_wait() because the latter
function drops the pipe lock, thereby allowing F_SETPIPE_SZ change them.
Without this, pipe_write() may subsequently miscalculate the array
indices and pipe fullness, leading to an oops like the following:

  BUG: KASAN: slab-out-of-bounds in pipe_write+0xc25/0xe10 fs/pipe.c:481
  Write of size 8 at addr ffff8880771167a8 by task syz-executor.3/7987
  ...
  CPU: 1 PID: 7987 Comm: syz-executor.3 Not tainted 5.4.0-rc2-syzkaller #0
  ...
  Call Trace:
    pipe_write+0xc25/0xe10 fs/pipe.c:481
    call_write_iter include/linux/fs.h:1895 [inline]
    new_sync_write+0x3fd/0x7e0 fs/read_write.c:483
    __vfs_write+0x94/0x110 fs/read_write.c:496
    vfs_write+0x18a/0x520 fs/read_write.c:558
    ksys_write+0x105/0x220 fs/read_write.c:611
    __do_sys_write fs/read_write.c:623 [inline]
    __se_sys_write fs/read_write.c:620 [inline]
    __x64_sys_write+0x6e/0xb0 fs/read_write.c:620
    do_syscall_64+0xca/0x5d0 arch/x86/entry/common.c:290
    entry_SYSCALL_64_after_hwframe+0x49/0xbe

This is not a problem for pipe_read() as the mask is recalculated on
each pass of the loop, after pipe_wait() has been called.

Fixes: 8cefc107ca ("pipe: Use head and tail pointers for the ring, not cursor and length")
Reported-by: syzbot+838eb0878ffd51f27c41@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Eric Biggers <ebiggers@kernel.org>
[ Changed it to use a temporary variable 'mask' to avoid long lines -Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-05 15:56:20 -08:00
arch ARM: SoC fixes 2019-10-05 17:18:43 -07:00
block block: sed-opal: fix sparse warning: convert __be64 data 2019-10-03 14:21:32 -06:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
Documentation Kbuild fixes for v5.4 2019-10-05 12:56:59 -07:00
drivers pipe: Use head and tail pointers for the ring, not cursor and length 2019-10-31 15:12:34 +00:00
fs pipe: Fix missing mask update after pipe_wait() 2019-12-05 15:56:20 -08:00
include pipe: Allow pipes to have kernel-reserved slots 2019-11-15 16:22:54 +00:00
init Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
ipc ipc/sem.c: convert to use built-in RCU list checking 2019-09-25 17:51:41 -07:00
kernel Add wake_up_interruptible_sync_poll_locked() 2019-10-31 15:12:23 +00:00
lib pipe: Allow pipes to have kernel-reserved slots 2019-11-15 16:22:54 +00:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge branch 'hugepage-fallbacks' (hugepatch patches from David Rientjes) 2019-09-28 14:26:47 -07:00
net nfc: fix memory leak in llcp_sock_bind() 2019-10-04 18:31:36 -07:00
samples rpmsg updates for v5.4 2019-09-22 10:58:15 -07:00
scripts scripts/setlocalversion: clear local variable to make it work for sh 2019-10-05 15:29:49 +09:00
security pipe: Reduce #inclusion of pipe_fs_i.h 2019-10-23 17:02:34 +01:00
sound sound fixes for 5.4-rc1 2019-09-24 16:46:16 -07:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-10-05 08:50:15 -07:00
usr kbuild: update compile-test header list for v5.4-rc2 2019-10-05 15:29:49 +09:00
virt KVM/arm fixes for 5.4, take #1 2019-10-03 12:08:50 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2019-09-18 12:34:53 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS CREDITS: Update email address 2019-09-13 17:21:38 +03:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS kgdb patches for 5.4-rc2 2019-10-03 11:17:57 -07:00
Makefile Linux 5.4-rc2 2019-10-06 14:27:30 -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.