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Minchan Kim 0bc9f5d14a drivers/block/zram/zram_drv.c: fix idle/writeback string compare
Makoto report a below KASAN error: zram does out-of-bounds read.  Because
strscpy copies from source up to count bytes unconditionally.  It could
cause out-of-bounds read on next object in slab.

To prevent it, use strlcpy which checks source's length automatically.

   BUG: KASAN: slab-out-of-bounds in strscpy+0x68/0x154
   Read of size 8 at addr ffffffc0c3495a00 by task system_server/1314
   ..
   Call trace:
     strscpy+0x68/0x154
     idle_store+0xc4/0x34c
     dev_attr_store+0x50/0x6c
     sysfs_kf_write+0x98/0xb4
     kernfs_fop_write+0x198/0x260
     __vfs_write+0x10c/0x338
     vfs_write+0x114/0x238
     SyS_write+0xc8/0x168
     __sys_trace_return+0x0/0x4

   Allocated by task 1314:
    __kmalloc+0x280/0x318
    kernfs_fop_write+0xac/0x260
    __vfs_write+0x10c/0x338
    vfs_write+0x114/0x238
    SyS_write+0xc8/0x168
    __sys_trace_return+0x0/0x4

   Freed by task 2855:
    kfree+0x138/0x630
    kernfs_put_open_node+0x10c/0x124
    kernfs_fop_release+0xd8/0x114
    __fput+0x130/0x2a4
    ____fput+0x1c/0x28
    task_work_run+0x16c/0x1c8
    do_notify_resume+0x2bc/0x107c
    work_pending+0x8/0x10

   The buggy address belongs to the object at ffffffc0c3495a00
    which belongs to the cache kmalloc-128 of size 128
   The buggy address is located 0 bytes inside of
    128-byte region [ffffffc0c3495a00, ffffffc0c3495a80)
   The buggy address belongs to the page:
   page:ffffffbf030d2500 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
   flags: 0x4000000000010200(slab|head)
   page dumped because: kasan: bad access detected

   Memory state around the buggy address:
    ffffffc0c3495900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    ffffffc0c3495980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
   >ffffffc0c3495a00: 04 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                      ^
    ffffffc0c3495a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
    ffffffc0c3495b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Link: http://lkml.kernel.org/r/20190319231911.145968-1-minchan@kernel.org
Cc: <stable@vger.kernel.org>	[5.0]
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reported-by: Makoto Wu <makotowu@google.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-29 10:01:37 -07:00
Documentation vfs: Update mount API docs 2019-03-28 08:54:20 -07:00
LICENSES LICENSES: Add GCC runtime library exception text 2019-01-16 14:54:15 -07:00
arch s390 update with improvements and bug fixes for 5.1-rc2 2019-03-28 08:35:32 -07:00
block io_uring-20190323 2019-03-23 10:25:12 -07:00
certs kexec, KEYS: Make use of platform keyring for signature verify 2019-02-04 17:34:07 -05:00
crypto lib/lzo: separate lzo-rle from lzo 2019-03-07 18:32:03 -08:00
drivers drivers/block/zram/zram_drv.c: fix idle/writeback string compare 2019-03-29 10:01:37 -07:00
fs fs/proc/kcore.c: make kcore_modules static 2019-03-29 10:01:37 -07:00
include ptrace: take into account saved_sigmask in PTRACE{GET,SET}SIGMASK 2019-03-29 10:01:37 -07:00
init init/main: add checks for the return value of memblock_alloc*() 2019-03-12 10:04:02 -07:00
ipc Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 14:08:19 -07:00
kernel ptrace: take into account saved_sigmask in PTRACE{GET,SET}SIGMASK 2019-03-29 10:01:37 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-03-27 12:22:57 -07:00
mm mm/page_isolation.c: fix a wrong flag in set_migratetype_isolate() 2019-03-29 10:01:37 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-03-27 12:22:57 -07:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-03-11 08:54:01 -07:00
scripts kconfig: remove stale lxdialog/.gitignore 2019-03-17 15:47:02 +09:00
security selinux: fix NULL dereference in policydb_destroy() 2019-03-18 12:19:48 -04:00
sound sound fixes for 5.1-rc2 2019-03-22 14:04:38 -07:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-03-27 12:22:57 -07:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt ARM: some cleanups, direct physical timer assignment, cache sanitization 2019-03-15 15:00:28 -07:00
.clang-format Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 13:43:42 -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: Add support for DT binding schema checks 2018-12-13 09:41:32 -06:00
.mailmap mailmap: add Changbin Du 2019-03-29 10:01:37 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS io_uring-20190323 2019-03-23 10:25:12 -07:00
Makefile Linux 5.1-rc2 2019-03-24 14:02:26 -07:00
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.