lkml.org 
[lkml]   [2022]   [Jan]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.4 174/320] floppy: Add max size check for user space request
    Date
    From: Xiongwei Song <sxwjean@gmail.com>

    [ Upstream commit 545a32498c536ee152331cd2e7d2416aa0f20e01 ]

    We need to check the max request size that is from user space before
    allocating pages. If the request size exceeds the limit, return -EINVAL.
    This check can avoid the warning below from page allocator.

    WARNING: CPU: 3 PID: 16525 at mm/page_alloc.c:5344 current_gfp_context include/linux/sched/mm.h:195 [inline]
    WARNING: CPU: 3 PID: 16525 at mm/page_alloc.c:5344 __alloc_pages+0x45d/0x500 mm/page_alloc.c:5356
    Modules linked in:
    CPU: 3 PID: 16525 Comm: syz-executor.3 Not tainted 5.15.0-syzkaller #0
    Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
    RIP: 0010:__alloc_pages+0x45d/0x500 mm/page_alloc.c:5344
    Code: be c9 00 00 00 48 c7 c7 20 4a 97 89 c6 05 62 32 a7 0b 01 e8 74 9a 42 07 e9 6a ff ff ff 0f 0b e9 a0 fd ff ff 40 80 e5 3f eb 88 <0f> 0b e9 18 ff ff ff 4c 89 ef 44 89 e6 45 31 ed e8 1e 76 ff ff e9
    RSP: 0018:ffffc90023b87850 EFLAGS: 00010246
    RAX: 0000000000000000 RBX: 1ffff92004770f0b RCX: dffffc0000000000
    RDX: 0000000000000000 RSI: 0000000000000033 RDI: 0000000000010cc1
    RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
    R10: ffffffff81bb4686 R11: 0000000000000001 R12: ffffffff902c1960
    R13: 0000000000000033 R14: 0000000000000000 R15: ffff88804cf64a30
    FS: 0000000000000000(0000) GS:ffff88802cd00000(0063) knlGS:00000000f44b4b40
    CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
    CR2: 000000002c921000 CR3: 000000004f507000 CR4: 0000000000150ee0
    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
    Call Trace:
    <TASK>
    alloc_pages+0x1a7/0x300 mm/mempolicy.c:2191
    __get_free_pages+0x8/0x40 mm/page_alloc.c:5418
    raw_cmd_copyin drivers/block/floppy.c:3113 [inline]
    raw_cmd_ioctl drivers/block/floppy.c:3160 [inline]
    fd_locked_ioctl+0x12e5/0x2820 drivers/block/floppy.c:3528
    fd_ioctl drivers/block/floppy.c:3555 [inline]
    fd_compat_ioctl+0x891/0x1b60 drivers/block/floppy.c:3869
    compat_blkdev_ioctl+0x3b8/0x810 block/ioctl.c:662
    __do_compat_sys_ioctl+0x1c7/0x290 fs/ioctl.c:972
    do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
    __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
    do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203
    entry_SYSENTER_compat_after_hwframe+0x4d/0x5c

    Reported-by: syzbot+23a02c7df2cf2bc93fa2@syzkaller.appspotmail.com
    Link: https://lore.kernel.org/r/20211116131033.27685-1-sxwjean@me.com
    Signed-off-by: Xiongwei Song <sxwjean@gmail.com>
    Signed-off-by: Denis Efremov <efremov@linux.com>
    Signed-off-by: Jens Axboe <axboe@kernel.dk>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/block/floppy.c | 4 +++-
    1 file changed, 3 insertions(+), 1 deletion(-)

    diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
    index 212a1e1ce0d9e..02af4f109e59f 100644
    --- a/drivers/block/floppy.c
    +++ b/drivers/block/floppy.c
    @@ -3112,6 +3112,8 @@ static void raw_cmd_free(struct floppy_raw_cmd **ptr)
    }
    }

    +#define MAX_LEN (1UL << MAX_ORDER << PAGE_SHIFT)
    +
    static int raw_cmd_copyin(int cmd, void __user *param,
    struct floppy_raw_cmd **rcmd)
    {
    @@ -3149,7 +3151,7 @@ loop:
    ptr->resultcode = 0;

    if (ptr->flags & (FD_RAW_READ | FD_RAW_WRITE)) {
    - if (ptr->length <= 0)
    + if (ptr->length <= 0 || ptr->length >= MAX_LEN)
    return -EINVAL;
    ptr->kernel_data = (char *)fd_dma_mem_alloc(ptr->length);
    fallback_on_nodma_alloc(&ptr->kernel_data, ptr->length);
    --
    2.34.1


    \
     
     \ /
      Last update: 2022-01-24 21:11    [W:5.523 / U:0.964 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site