kernel/linux.git/drivers/usb/usbip, branch linux-7.1.y

usbip: vudc: Fix use after free bug in vudc_remove due to race condition

2026-05-22T09:13:06+00:00

This patch follows up Zheng Wang's 2023 report of a use-after-free in vudc_remove(). The original thread stalled on Shuah Khan's request for runtime testing of the unplug/unbind path. This patch supplies that testing and keeps Zheng's original fix shape. In vudc_probe(), v_init_timer() binds udc->tr_timer.timer to v_timer(). usbip_sockfd_store() starts the timer via v_start_timer()/v_kick_timer(). vudc_remove() can then free the containing struct vudc while the timer is still pending or executing. KASAN confirms the race on an unpatched x86_64 QEMU guest with CONFIG_KASAN=y, CONFIG_USBIP_VUDC=y, CONFIG_USB_ZERO=y, and a tight loop that repeatedly writes a socket fd to usbip_sockfd, closes the socket pair, and unbinds/rebinds usbip-vudc.0: BUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x8ba/0x8e0 Write of size 8 at addr ffff888001b80740 by task trigger_and_unb/239 Allocated by task 239: vudc_probe+0x4d/0xaa0 Freed by task 239: kfree+0x18f/0x520 device_release_driver_internal+0x388/0x540 unbind_store+0xd9/0x100 This lands in the timer core rather than v_timer() itself because the embedded timer_list is being walked after its containing struct vudc has already been freed. The underlying lifetime bug is the same one Zheng reported. With v_stop_timer() called from vudc_remove() and the timer deleted synchronously, the same harness completed 5000 bind/unbind iterations with no KASAN report. Fixes: b6a0ca111867 ("usbip: vudc: Add UDC specific ops") Cc: stable Reported-by: Zheng Wang Closes: https://lore.kernel.org/linux-usb/20230317100954.2626573-1-zyytlz.wz@163.com/ Signed-off-by: Michael Bommarito Acked-by: Shuah Khan Link: https://patch.msgid.link/20260417163552.807548-1-michael.bommarito@gmail.com Signed-off-by: Greg Kroah-Hartman

usbip: validate number_of_packets in usbip_pack_ret_submit()

2026-04-07T11:48:44+00:00

When a USB/IP client receives a RET_SUBMIT response, usbip_pack_ret_submit() unconditionally overwrites urb->number_of_packets from the network PDU. This value is subsequently used as the loop bound in usbip_recv_iso() and usbip_pad_iso() to iterate over urb->iso_frame_desc[], a flexible array whose size was fixed at URB allocation time based on the *original* number_of_packets from the CMD_SUBMIT. A malicious USB/IP server can set number_of_packets in the response to a value larger than what was originally submitted, causing a heap out-of-bounds write when usbip_recv_iso() writes to urb->iso_frame_desc[i] beyond the allocated region. KASAN confirmed this with kernel 7.0.0-rc5: BUG: KASAN: slab-out-of-bounds in usbip_recv_iso+0x46a/0x640 Write of size 4 at addr ffff888106351d40 by task vhci_rx/69 The buggy address is located 0 bytes to the right of allocated 320-byte region [ffff888106351c00, ffff888106351d40) The server side (stub_rx.c) and gadget side (vudc_rx.c) already validate number_of_packets in the CMD_SUBMIT path since commits c6688ef9f297 ("usbip: fix stub_rx: harden CMD_SUBMIT path to handle malicious input") and b78d830f0049 ("usbip: fix vudc_rx: harden CMD_SUBMIT path to handle malicious input"). The server side validates against USBIP_MAX_ISO_PACKETS because no URB exists yet at that point. On the client side we have the original URB, so we can use the tighter bound: the response must not exceed the original number_of_packets. This mirrors the existing validation of actual_length against transfer_buffer_length in usbip_recv_xbuff(), which checks the response value against the original allocation size. Kelvin Mbogo's series ("usb: usbip: fix integer overflow in usbip_recv_iso()", v2) hardens the receive-side functions themselves; this patch complements that work by catching the bad value at its source -- in usbip_pack_ret_submit() before the overwrite -- and using the tighter per-URB allocation bound rather than the global USBIP_MAX_ISO_PACKETS limit. Fix this by checking rpdu->number_of_packets against urb->number_of_packets in usbip_pack_ret_submit() before the overwrite. On violation, clamp to zero so that usbip_recv_iso() and usbip_pad_iso() safely return early. Fixes: 1325f85fa49f ("staging: usbip: bugfix add number of packets for isochronous frames") Cc: stable Acked-by: Shuah Khan Signed-off-by: Nathan Rebello Link: https://patch.msgid.link/20260402085259.234-1-nathan.c.rebello@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: usbip: fix OOB read/write in usbip_pad_iso()

2026-04-02T07:52:51+00:00

usbip_pad_iso() repositions ISO frame data within the transfer buffer via memmove(). Neither the source offset (actualoffset, derived by subtracting wire-supplied actual_length values) nor the destination offset (iso_frame_desc[i].offset, taken directly from the wire) is bounds-checked. If a crafted actual_length wraps actualoffset negative through the subtraction (see patch 2/3 for the root cause), the memmove source points before the allocation - slab OOB read, data returned to userspace. Independently, iso_frame_desc[i].offset is never validated against transfer_buffer_length. Setting offset past the end of the buffer gives a fully controlled OOB write into whatever sits next in the slab - confirmed with offset=400 on a 392-byte buffer, 64-byte write. Add bounds checks for both the source and destination ranges before each memmove call. Use unsigned comparisons after the sign check on actualoffset to avoid signed/unsigned conversion surprises. Signed-off-by: Kelvin Mbogo Link: https://patch.msgid.link/20260325103640.8090-3-addcontent08@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: usbip: validate iso frame actual_length in usbip_recv_iso()

2026-04-02T07:52:51+00:00

usbip_recv_iso() sums each frame's actual_length into an int accumulator without checking the individual values first: total_length += urb->iso_frame_desc[i].actual_length; A malicious server can send actual_length = 0xFFFFFFFC for one frame and a small value for the other, making the signed sum wrap around to match urb->actual_length. The sanity check passes, and usbip_pad_iso() later computes a negative actualoffset, feeding it to memmove() as a source pointer - reads before the allocation, leaked to userspace via USBDEVFS_REAPURB. Reject any frame whose actual_length exceeds transfer_buffer_length (one frame can't carry more data than the whole buffer), and widen the accumulator to u32 so that many moderately-large frames can't wrap it either. Signed-off-by: Kelvin Mbogo Link: https://patch.msgid.link/20260325103640.8090-2-addcontent08@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: usbip: fix integer overflow in usbip_recv_iso()

2026-04-02T07:52:46+00:00

usbip_recv_iso() computes the iso descriptor buffer size as: int size = np * sizeof(*iso); where np comes straight from the wire (urb->number_of_packets, set by usbip_pack_ret_submit() before we get here). With np = 0x10000001 and sizeof(*iso) == 16 the product is 0x100000010 which truncates to 16 on a 32-bit int. kzalloc(16) succeeds but the following receive loop writes np * 16 bytes into it - game over. USBIP_MAX_ISO_PACKETS (1024) already exists in usbip_common.h for the submit path but was never enforced on the receive side. Clamp np to [1, USBIP_MAX_ISO_PACKETS] and switch to kcalloc() so the allocator itself can catch overflows in the future. Fold the existing np == 0 early return into the new bounds check. usbip_pack_ret_submit() already copied the bogus np into urb->number_of_packets before we run, so just returning -EPROTO is not enough - processcompl() in the HCD will still iterate that many iso_frame_desc entries when it completes the failed URB. Zero out urb->number_of_packets before bailing to prevent that secondary crash (confirmed on 6.12.0, processcompl+0x63 with CR2 in unmapped slab). Signed-off-by: Kelvin Mbogo Link: https://patch.msgid.link/20260325103640.8090-1-addcontent08@gmail.com Signed-off-by: Greg Kroah-Hartman

USB: usbip: drop redundant device reference

2026-03-18T14:51:44+00:00

Driver core holds a reference to the USB device while it is bound to a driver and there is no need to take additional references unless the structure is needed after disconnect. Drop the redundant device reference to reduce cargo culting, make it easier to spot drivers where an extra reference is needed, and reduce the risk of memory leaks when drivers fail to release it. Signed-off-by: Johan Hovold Link: https://patch.msgid.link/20260305133851.2952-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

usbip: vhci_sysfs: Use safer strscpy() instead of strcpy()

2026-03-11T14:39:04+00:00

Use a safer function strscpy() instead of strcpy() for copying to arrays. Only idiomatic code replacement, and no functional changes. Signed-off-by: Ai Chao Link: https://patch.msgid.link/20260310094434.3639602-7-aichao@kylinos.cn Signed-off-by: Greg Kroah-Hartman

Convert more 'alloc_obj' cases to default GFP_KERNEL arguments

2026-02-22T04:03:00+00:00

This converts some of the visually simpler cases that have been split over multiple lines. I only did the ones that are easy to verify the resulting diff by having just that final GFP_KERNEL argument on the next line. Somebody should probably do a proper coccinelle script for this, but for me the trivial script actually resulted in an assertion failure in the middle of the script. I probably had made it a bit _too_ trivial. So after fighting that far a while I decided to just do some of the syntactically simpler cases with variations of the previous 'sed' scripts. The more syntactically complex multi-line cases would mostly really want whitespace cleanup anyway. Signed-off-by: Linus Torvalds

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook