commit 0dd68b5d01d022fc9c5e71c82a82b0a94d3d0671 upstream.

usbdev_release() drops its reference to the struct usb_device before
draining the list of completed async URBs, but that drain path reads back
through the same object: free_async() calls dec_usb_memory_use_count()
for any URB whose buffer came from the usbfs mmap() region, and its first
statement is bus_to_hcd(ps->dev->bus).

After a disconnect the usbfs reference can be the last one, in which case
usb_put_dev() frees the device and the subsequent loop reads offset 80 of
freed memory and uses the result as a struct usb_hcd *, which
hcd_buffer_free_pages() then dereferences.

This is reachable by an unprivileged process that has read/write access to
a /dev/bus/usb node: mmap() the fd, submit one URB with a buffer inside the
mapping, wait for the device to be unplugged, then munmap() and close().
It reproduces on every attempt rather than being a race, because a live
MAP_SHARED vma holds a reference on the struct file, so usbdev_release()
cannot run until the last vma is gone and the freeing branch of
dec_usb_memory_use_count() is always taken.

  BUG: KASAN: slab-use-after-free in dec_usb_memory_use_count+0x3ae/0x410
  Read of size 8 at addr ffff8880122ee050 by task poc/769
  CPU: 1 UID: 1000 PID: 769 Comm: poc Tainted: G    B    6.12.94 #3

  Call Trace:
   dec_usb_memory_use_count+0x3ae/0x410
   free_async+0x2aa/0x4f0
   usbdev_release+0x375/0x460
   __fput+0x3ea/0xb50
   __x64_sys_close+0x86/0x100

  Allocated by task 11:
   usb_alloc_dev+0x55/0xd90
   hub_event+0x2524/0x43d0

  Freed by task 769:
   kfree+0x121/0x360
   device_release+0xd2/0x280
   usb_put_dev+0x23/0x30
   usbdev_release+0x2d8/0x460

Release the device reference after the drain loop instead. Nothing between
the two points requires it to have been dropped.

Fixes: f7d34b445abc ("USB: Add support for usbfs zerocopy.")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-5
Signed-off-by: Miguel Peñaranda <mig.penaranda07@gmail.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://patch.msgid.link/20260810121209.795089-1-mig.penaranda07@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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 <kees@kernel.org>

Since len1 is unsigned int, len1 < 0 always false. Remove it keep code
simple.

Signed-off-by: Rex Nie <rex.nie@jaguarmicro.com>
Rule: add
Link: https://lore.kernel.org/stable/20241108094255.2133-1-rex.nie%40jaguarmicro.com
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20241112152021.2236-1-rex.nie@jaguarmicro.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbdev_mmap() creates VMAs which can only be used through
usbdev_do_ioctl(), which requires FMODE_WRITE; so usbdev_mmap() is only
useful with FMODE_WRITE.

On typical Linux systems, files at /dev/bus/usb/*/* are mode 0664, so
UIDs without any special privileges can't use usbdev_do_ioctl(), but
they can still execute the usbdev_mmap() codepath.

Check for FMODE_WRITE in usbdev_mmap() to reduce attack surface a little
bit.

Signed-off-by: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/r/20241016-usbdev-mmap-require-write-v1-1-6f8256414d5c@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Convert to using the new inode timestamp accessor functions.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20231004185347.80880-12-jlayton@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

In later patches, we're going to change how the inode's ctime field is
used. Switch to using accessor functions instead of raw accesses of
inode->i_ctime.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230705190309.579783-18-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

In general, POSIX requires that when the mtime is updated that the ctime
be updated as well. Add the missing timestamp updates to the usb ioctls.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-ID: <20230612104524.17058-3-jlayton@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

We need the USB fixes in here are well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When hcd->localmem_pool is non-null, localmem_pool is used to allocate
DMA memory. In this case, the dma address will be properly returned (in
dma_handle), and dma_mmap_coherent should be used to map this memory
into the user space. However, the current implementation uses
pfn_remap_range, which is supposed to map normal pages.

Instead of repeating the logic in the memory allocation function, this
patch introduces a more robust solution. Here, the type of allocated
memory is checked by testing whether dma_handle is properly set. If
dma_handle is properly returned, it means some DMA pages are allocated
and dma_mmap_coherent should be used to map them. Otherwise, normal
pages are allocated and pfn_remap_range should be called. This ensures
that the correct mmap functions are used consistently, independently
with logic details that determine which type of memory gets allocated.

Fixes: a0e710a7def4 ("USB: usbfs: fix mmap dma mismatch")
Cc: stable@vger.kernel.org
Signed-off-by: Ruihan Li <lrh2000@pku.edu.cn>
Link: https://lore.kernel.org/r/20230515130958.32471-3-lrh2000@pku.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>