lkml.org 
[lkml]   [2022]   [Aug]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.10 526/545] dm raid: fix address sanitizer warning in raid_status
    Date
    From: Mikulas Patocka <mpatocka@redhat.com>

    commit 1fbeea217d8f297fe0e0956a1516d14ba97d0396 upstream.

    There is this warning when using a kernel with the address sanitizer
    and running this testsuite:
    https://gitlab.com/cki-project/kernel-tests/-/tree/main/storage/swraid/scsi_raid

    ==================================================================
    BUG: KASAN: slab-out-of-bounds in raid_status+0x1747/0x2820 [dm_raid]
    Read of size 4 at addr ffff888079d2c7e8 by task lvcreate/13319
    CPU: 0 PID: 13319 Comm: lvcreate Not tainted 5.18.0-0.rc3.<snip> #1
    Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
    Call Trace:
    <TASK>
    dump_stack_lvl+0x6a/0x9c
    print_address_description.constprop.0+0x1f/0x1e0
    print_report.cold+0x55/0x244
    kasan_report+0xc9/0x100
    raid_status+0x1747/0x2820 [dm_raid]
    dm_ima_measure_on_table_load+0x4b8/0xca0 [dm_mod]
    table_load+0x35c/0x630 [dm_mod]
    ctl_ioctl+0x411/0x630 [dm_mod]
    dm_ctl_ioctl+0xa/0x10 [dm_mod]
    __x64_sys_ioctl+0x12a/0x1a0
    do_syscall_64+0x5b/0x80

    The warning is caused by reading conf->max_nr_stripes in raid_status. The
    code in raid_status reads mddev->private, casts it to struct r5conf and
    reads the entry max_nr_stripes.

    However, if we have different raid type than 4/5/6, mddev->private
    doesn't point to struct r5conf; it may point to struct r0conf, struct
    r1conf, struct r10conf or struct mpconf. If we cast a pointer to one
    of these structs to struct r5conf, we will be reading invalid memory
    and KASAN warns about it.

    Fix this bug by reading struct r5conf only if raid type is 4, 5 or 6.

    Cc: stable@vger.kernel.org
    Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
    Signed-off-by: Mike Snitzer <snitzer@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    drivers/md/dm-raid.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    --- a/drivers/md/dm-raid.c
    +++ b/drivers/md/dm-raid.c
    @@ -3514,7 +3514,7 @@ static void raid_status(struct dm_target
    {
    struct raid_set *rs = ti->private;
    struct mddev *mddev = &rs->md;
    - struct r5conf *conf = mddev->private;
    + struct r5conf *conf = rs_is_raid456(rs) ? mddev->private : NULL;
    int i, max_nr_stripes = conf ? conf->max_nr_stripes : 0;
    unsigned long recovery;
    unsigned int raid_param_cnt = 1; /* at least 1 for chunksize */

    \
     
     \ /
      Last update: 2022-08-19 18:50    [W:2.154 / U:0.412 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site