CVE-2022-48857

In the Linux kernel, the following vulnerability has been resolved:

NFC: port100: fix use-after-free in port100_send_complete

Syzbot reported UAF in port100_send_complete(). The root case is in missing usb_kill_urb() calls on error handling path of ->probe function.

port100_send_complete() accesses devm allocated memory which will be freed on probe failure. We should kill this urbs before returning an error from probe function to prevent reported use-after-free

Fail log:

BUG: KASAN: use-after-free in port100_send_complete+0x16e/0x1a0 drivers/nfc/port100.c:935 Read of size 1 at addr ffff88801bb59540 by task ksoftirqd/2/26 … Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0x8d/0x303 mm/kasan/report.c:255 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459 port100_send_complete+0x16e/0x1a0 drivers/nfc/port100.c:935 __usb_hcd_giveback_urb+0x2b0/0x5c0 drivers/usb/core/hcd.c:1670

…

Allocated by task 1255: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:436 [inline] ____kasan_kmalloc mm/kasan/common.c:515 [inline] ____kasan_kmalloc mm/kasan/common.c:474 [inline] __kasan_kmalloc+0xa6/0xd0 mm/kasan/common.c:524 alloc_dr drivers/base/devres.c:116 [inline] devm_kmalloc+0x96/0x1d0 drivers/base/devres.c:823 devm_kzalloc include/linux/device.h:209 [inline] port100_probe+0x8a/0x1320 drivers/nfc/port100.c:1502

Freed by task 1255: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:45 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free+0xff/0x140 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:236 [inline] __cache_free mm/slab.c:3437 [inline] kfree+0xf8/0x2b0 mm/slab.c:3794 release_nodes+0x112/0x1a0 drivers/base/devres.c:501 devres_release_all+0x114/0x190 drivers/base/devres.c:530 really_probe+0x626/0xcc0 drivers/base/dd.c:670

Weakness

Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

Affected Software

Extended Description

The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system’s reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:

In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.

Potential Mitigations

References

• https://git.kernel.org/stable/c/0e721b8f2ee5e11376dd55363f9ccb539d754b8a
• https://git.kernel.org/stable/c/205c4ec78e71cbf561794e6043da80e7bae6790f
• https://git.kernel.org/stable/c/2b1c85f56512d49e43bc53741fce2f508cd90029
• https://git.kernel.org/stable/c/32e866ae5a7af590597ef4bcff8451bf96d5f980
• https://git.kernel.org/stable/c/7194737e1be8fdc89d2a9382bd2f371f7ee2eda8
• https://git.kernel.org/stable/c/b1db33d4e54bc35d8db96ce143ea0ef92e23d58e
• https://git.kernel.org/stable/c/cd2a5c0da0d1ddf11d1f84e9c9b1949f50f6e161
• https://git.kernel.org/stable/c/f80cfe2f26581f188429c12bd937eb905ad3ac7b