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    Subject[PATCH 4.9 170/191] ata/libata: Fix usage of page address by page_address in ata_scsi_mode_select_xlat function
    Date
    From: Ye Bin <yebin10@huawei.com>

    [ Upstream commit f650ef61e040bcb175dd8762164b00a5d627f20e ]

    BUG: KASAN: use-after-free in ata_scsi_mode_select_xlat+0x10bd/0x10f0
    drivers/ata/libata-scsi.c:4045
    Read of size 1 at addr ffff88803b8cd003 by task syz-executor.6/12621

    CPU: 1 PID: 12621 Comm: syz-executor.6 Not tainted 4.19.95 #1
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
    1.10.2-1ubuntu1 04/01/2014
    Call Trace:
    __dump_stack lib/dump_stack.c:77 [inline]
    dump_stack+0xac/0xee lib/dump_stack.c:118
    print_address_description+0x60/0x223 mm/kasan/report.c:253
    kasan_report_error mm/kasan/report.c:351 [inline]
    kasan_report mm/kasan/report.c:409 [inline]
    kasan_report.cold+0xae/0x2d8 mm/kasan/report.c:393
    ata_scsi_mode_select_xlat+0x10bd/0x10f0 drivers/ata/libata-scsi.c:4045
    ata_scsi_translate+0x2da/0x680 drivers/ata/libata-scsi.c:2035
    __ata_scsi_queuecmd drivers/ata/libata-scsi.c:4360 [inline]
    ata_scsi_queuecmd+0x2e4/0x790 drivers/ata/libata-scsi.c:4409
    scsi_dispatch_cmd+0x2ee/0x6c0 drivers/scsi/scsi_lib.c:1867
    scsi_queue_rq+0xfd7/0x1990 drivers/scsi/scsi_lib.c:2170
    blk_mq_dispatch_rq_list+0x1e1/0x19a0 block/blk-mq.c:1186
    blk_mq_do_dispatch_sched+0x147/0x3d0 block/blk-mq-sched.c:108
    blk_mq_sched_dispatch_requests+0x427/0x680 block/blk-mq-sched.c:204
    __blk_mq_run_hw_queue+0xbc/0x200 block/blk-mq.c:1308
    __blk_mq_delay_run_hw_queue+0x3c0/0x460 block/blk-mq.c:1376
    blk_mq_run_hw_queue+0x152/0x310 block/blk-mq.c:1413
    blk_mq_sched_insert_request+0x337/0x6c0 block/blk-mq-sched.c:397
    blk_execute_rq_nowait+0x124/0x320 block/blk-exec.c:64
    blk_execute_rq+0xc5/0x112 block/blk-exec.c:101
    sg_scsi_ioctl+0x3b0/0x6a0 block/scsi_ioctl.c:507
    sg_ioctl+0xd37/0x23f0 drivers/scsi/sg.c:1106
    vfs_ioctl fs/ioctl.c:46 [inline]
    file_ioctl fs/ioctl.c:501 [inline]
    do_vfs_ioctl+0xae6/0x1030 fs/ioctl.c:688
    ksys_ioctl+0x76/0xa0 fs/ioctl.c:705
    __do_sys_ioctl fs/ioctl.c:712 [inline]
    __se_sys_ioctl fs/ioctl.c:710 [inline]
    __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
    do_syscall_64+0xa0/0x2e0 arch/x86/entry/common.c:293
    entry_SYSCALL_64_after_hwframe+0x44/0xa9
    RIP: 0033:0x45c479
    Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89
    f7 48
    89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
    ff 0f
    83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
    RSP: 002b:00007fb0e9602c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
    RAX: ffffffffffffffda RBX: 00007fb0e96036d4 RCX: 000000000045c479
    RDX: 0000000020000040 RSI: 0000000000000001 RDI: 0000000000000003
    RBP: 000000000076bfc0 R08: 0000000000000000 R09: 0000000000000000
    R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
    R13: 000000000000046d R14: 00000000004c6e1a R15: 000000000076bfcc

    Allocated by task 12577:
    set_track mm/kasan/kasan.c:460 [inline]
    kasan_kmalloc mm/kasan/kasan.c:553 [inline]
    kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:531
    __kmalloc+0xf3/0x1e0 mm/slub.c:3749
    kmalloc include/linux/slab.h:520 [inline]
    load_elf_phdrs+0x118/0x1b0 fs/binfmt_elf.c:441
    load_elf_binary+0x2de/0x4610 fs/binfmt_elf.c:737
    search_binary_handler fs/exec.c:1654 [inline]
    search_binary_handler+0x15c/0x4e0 fs/exec.c:1632
    exec_binprm fs/exec.c:1696 [inline]
    __do_execve_file.isra.0+0xf52/0x1a90 fs/exec.c:1820
    do_execveat_common fs/exec.c:1866 [inline]
    do_execve fs/exec.c:1883 [inline]
    __do_sys_execve fs/exec.c:1964 [inline]
    __se_sys_execve fs/exec.c:1959 [inline]
    __x64_sys_execve+0x8a/0xb0 fs/exec.c:1959
    do_syscall_64+0xa0/0x2e0 arch/x86/entry/common.c:293
    entry_SYSCALL_64_after_hwframe+0x44/0xa9

    Freed by task 12577:
    set_track mm/kasan/kasan.c:460 [inline]
    __kasan_slab_free+0x129/0x170 mm/kasan/kasan.c:521
    slab_free_hook mm/slub.c:1370 [inline]
    slab_free_freelist_hook mm/slub.c:1397 [inline]
    slab_free mm/slub.c:2952 [inline]
    kfree+0x8b/0x1a0 mm/slub.c:3904
    load_elf_binary+0x1be7/0x4610 fs/binfmt_elf.c:1118
    search_binary_handler fs/exec.c:1654 [inline]
    search_binary_handler+0x15c/0x4e0 fs/exec.c:1632
    exec_binprm fs/exec.c:1696 [inline]
    __do_execve_file.isra.0+0xf52/0x1a90 fs/exec.c:1820
    do_execveat_common fs/exec.c:1866 [inline]
    do_execve fs/exec.c:1883 [inline]
    __do_sys_execve fs/exec.c:1964 [inline]
    __se_sys_execve fs/exec.c:1959 [inline]
    __x64_sys_execve+0x8a/0xb0 fs/exec.c:1959
    do_syscall_64+0xa0/0x2e0 arch/x86/entry/common.c:293
    entry_SYSCALL_64_after_hwframe+0x44/0xa9

    The buggy address belongs to the object at ffff88803b8ccf00
    which belongs to the cache kmalloc-512 of size 512
    The buggy address is located 259 bytes inside of
    512-byte region [ffff88803b8ccf00, ffff88803b8cd100)
    The buggy address belongs to the page:
    page:ffffea0000ee3300 count:1 mapcount:0 mapping:ffff88806cc03080
    index:0xffff88803b8cc780 compound_mapcount: 0
    flags: 0x100000000008100(slab|head)
    raw: 0100000000008100 ffffea0001104080 0000000200000002 ffff88806cc03080
    raw: ffff88803b8cc780 00000000800c000b 00000001ffffffff 0000000000000000
    page dumped because: kasan: bad access detected

    Memory state around the buggy address:
    ffff88803b8ccf00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
    ffff88803b8ccf80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
    >ffff88803b8cd000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
    ^
    ffff88803b8cd080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
    ffff88803b8cd100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc

    You can refer to "https://www.lkml.org/lkml/2019/1/17/474" reproduce
    this error.

    The exception code is "bd_len = p[3];", "p" value is ffff88803b8cd000
    which belongs to the cache kmalloc-512 of size 512. The "page_address(sg_page(scsi_sglist(scmd)))"
    maybe from sg_scsi_ioctl function "buffer" which allocated by kzalloc, so "buffer"
    may not page aligned.
    This also looks completely buggy on highmem systems and really needs to use a
    kmap_atomic. --Christoph Hellwig
    To address above bugs, Paolo Bonzini advise to simpler to just make a char array
    of size CACHE_MPAGE_LEN+8+8+4-2(or just 64 to make it easy), use sg_copy_to_buffer
    to copy from the sglist into the buffer, and workthere.

    Signed-off-by: Ye Bin <yebin10@huawei.com>
    Signed-off-by: Jens Axboe <axboe@kernel.dk>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/ata/libata-scsi.c | 9 ++++++---
    1 file changed, 6 insertions(+), 3 deletions(-)

    diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
    index c4f2b563c9f03..f4b38adb9d8a7 100644
    --- a/drivers/ata/libata-scsi.c
    +++ b/drivers/ata/libata-scsi.c
    @@ -3967,12 +3967,13 @@ static unsigned int ata_scsi_mode_select_xlat(struct ata_queued_cmd *qc)
    {
    struct scsi_cmnd *scmd = qc->scsicmd;
    const u8 *cdb = scmd->cmnd;
    - const u8 *p;
    u8 pg, spg;
    unsigned six_byte, pg_len, hdr_len, bd_len;
    int len;
    u16 fp = (u16)-1;
    u8 bp = 0xff;
    + u8 buffer[64];
    + const u8 *p = buffer;

    VPRINTK("ENTER\n");

    @@ -4006,12 +4007,14 @@ static unsigned int ata_scsi_mode_select_xlat(struct ata_queued_cmd *qc)
    if (!scsi_sg_count(scmd) || scsi_sglist(scmd)->length < len)
    goto invalid_param_len;

    - p = page_address(sg_page(scsi_sglist(scmd)));
    -
    /* Move past header and block descriptors. */
    if (len < hdr_len)
    goto invalid_param_len;

    + if (!sg_copy_to_buffer(scsi_sglist(scmd), scsi_sg_count(scmd),
    + buffer, sizeof(buffer)))
    + goto invalid_param_len;
    +
    if (six_byte)
    bd_len = p[3];
    else
    --
    2.25.1
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