usb/gadget: warning in dev_config/memdup_user

[Andrey Konovalov]

Hi!

I've got the following error report while running the syzkaller fuzzer.

The length passed to memdup_user() directly without limitations.

On commit 2caceb3294a78c389b462e7e236a4e744a53a474 (Dec 1).

WARNING: CPU: 3 PID: 14477 at mm/page_alloc.c:3511
__alloc_pages_nodemask+0x159c/0x1e20
Kernel panic - not syncing: panic_on_warn set ...

CPU: 3 PID: 14477 Comm: syz-executor0 Not tainted 4.9.0-rc7+ #61
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 ffff880039b67298 ffffffff81f96bba ffffffff00000200 1ffff1000736cde6
 ffffed000736cdde 0000000000000a06 0000000041b58ab3 ffffffff8598af00
 ffffffff81f96928 0000000041b58ab3 ffffffff859423c8 ffffffff81432790
Call Trace:
 [<     inline     >] __dump_stack lib/dump_stack.c:15
 [<ffffffff81f96bba>] dump_stack+0x292/0x398 lib/dump_stack.c:51
 [<ffffffff8168c7ae>] panic+0x1cb/0x3a9 kernel/panic.c:179
 [<ffffffff812b80b4>] __warn+0x1c4/0x1e0 kernel/panic.c:542
 [<ffffffff812b831c>] warn_slowpath_null+0x2c/0x40 kernel/panic.c:585
 [<     inline     >] __alloc_pages_slowpath mm/page_alloc.c:3511
 [<ffffffff816c07cc>] __alloc_pages_nodemask+0x159c/0x1e20 mm/page_alloc.c:3781
 [<ffffffff817cdd27>] alloc_pages_current+0x1c7/0x6b0 mm/mempolicy.c:2072
 [<     inline     >] alloc_pages include/linux/gfp.h:469
 [<ffffffff8172fcdf>] kmalloc_order+0x1f/0x70 mm/slab_common.c:1015
 [<ffffffff8172fd4f>] kmalloc_order_trace+0x1f/0x160 mm/slab_common.c:1026
 [<     inline     >] kmalloc_large include/linux/slab.h:422
 [<ffffffff817e348f>] __kmalloc_track_caller+0x1df/0x290 mm/slub.c:4233
 [<ffffffff8171bb3c>] memdup_user+0x2c/0xa0 mm/util.c:137
 [<ffffffff83228ca2>] dev_config+0x2e2/0x1180
drivers/usb/gadget/legacy/inode.c:1776
 [<ffffffff817fde55>] __vfs_write+0x5d5/0x760 fs/read_write.c:510
 [<ffffffff817ff750>] vfs_write+0x170/0x4e0 fs/read_write.c:560
 [<     inline     >] SYSC_write fs/read_write.c:607
 [<ffffffff81803b5b>] SyS_write+0xfb/0x230 fs/read_write.c:599
 [<ffffffff84f44cc1>] entry_SYSCALL_64_fastpath+0x1f/0xc2
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled