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| author | Xiongwei Song <sxwjean@gmail.com> | 2021-11-16 14:10:33 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-12-03 14:32:40 +0100 |
| commit | 545a32498c536ee152331cd2e7d2416aa0f20e01 (patch) | |
| tree | 99a3fac5f034cdcdbc4a8909cac0aa2bf624ad63 /drivers/block/floppy.c | |
| parent | floppy: Fix hang in watchdog when disk is ejected (diff) | |
| download | linux-545a32498c536ee152331cd2e7d2416aa0f20e01.tar.xz linux-545a32498c536ee152331cd2e7d2416aa0f20e01.zip | |
floppy: Add max size check for user space request
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>
Diffstat (limited to 'drivers/block/floppy.c')
| -rw-r--r-- | drivers/block/floppy.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index f0e36c18f349..e611411a934c 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -3081,6 +3081,8 @@ 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) { @@ -3108,7 +3110,7 @@ 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); |