diff options
author | Ruihan Li <lrh2000@pku.edu.cn> | 2023-05-15 21:09:55 +0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-05-29 16:14:28 +0100 |
commit | 0143d148d1e882fb1538dc9974c94d63961719b9 (patch) | |
tree | 81ec7174c2d10fd89b1f4176eceaa0757aa8a3d3 /include | |
parent | 7b32040f6d7f885ffc09a6df7c17992d56d2eab8 (diff) |
usb: usbfs: Enforce page requirements for mmap
The current implementation of usbdev_mmap uses usb_alloc_coherent to
allocate memory pages that will later be mapped into the user space.
Meanwhile, usb_alloc_coherent employs three different methods to
allocate memory, as outlined below:
* If hcd->localmem_pool is non-null, it uses gen_pool_dma_alloc to
allocate memory;
* If DMA is not available, it uses kmalloc to allocate memory;
* Otherwise, it uses dma_alloc_coherent.
However, it should be noted that gen_pool_dma_alloc does not guarantee
that the resulting memory will be page-aligned. Furthermore, trying to
map slab pages (i.e., memory allocated by kmalloc) into the user space
is not resonable and can lead to problems, such as a type confusion bug
when PAGE_TABLE_CHECK=y [1].
To address these issues, this patch introduces hcd_alloc_coherent_pages,
which addresses the above two problems. Specifically,
hcd_alloc_coherent_pages uses gen_pool_dma_alloc_align instead of
gen_pool_dma_alloc to ensure that the memory is page-aligned. To replace
kmalloc, hcd_alloc_coherent_pages directly allocates pages by calling
__get_free_pages.
Reported-by: syzbot+fcf1a817ceb50935ce99@syzkaller.appspotmail.comm
Closes: https://lore.kernel.org/lkml/000000000000258e5e05fae79fc1@google.com/ [1]
Fixes: f7d34b445abc ("USB: Add support for usbfs zerocopy.")
Fixes: ff2437befd8f ("usb: host: Fix excessive alignment restriction for local memory allocations")
Cc: stable@vger.kernel.org
Signed-off-by: Ruihan Li <lrh2000@pku.edu.cn>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20230515130958.32471-2-lrh2000@pku.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/usb/hcd.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h index 094c77eaf455..0c7eff91adf4 100644 --- a/include/linux/usb/hcd.h +++ b/include/linux/usb/hcd.h @@ -501,6 +501,11 @@ void *hcd_buffer_alloc(struct usb_bus *bus, size_t size, void hcd_buffer_free(struct usb_bus *bus, size_t size, void *addr, dma_addr_t dma); +void *hcd_buffer_alloc_pages(struct usb_hcd *hcd, + size_t size, gfp_t mem_flags, dma_addr_t *dma); +void hcd_buffer_free_pages(struct usb_hcd *hcd, + size_t size, void *addr, dma_addr_t dma); + /* generic bus glue, needed for host controllers that don't use PCI */ extern irqreturn_t usb_hcd_irq(int irq, void *__hcd); |