This is a note to let you know that I've just added the patch titled
usb: usbfs: Enforce page requirements for mmap
to the 6.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-usbfs-enforce-page-requirements-for-mmap.patch
and it can be found in the queue-6.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 0143d148d1e882fb1538dc9974c94d63961719b9 Mon Sep 17 00:00:00 2001
From: Ruihan Li <lrh2000@xxxxxxxxxx>
Date: Mon, 15 May 2023 21:09:55 +0800
Subject: usb: usbfs: Enforce page requirements for mmap
From: Ruihan Li <lrh2000@xxxxxxxxxx>
commit 0143d148d1e882fb1538dc9974c94d63961719b9 upstream.
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@xxxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://lore.kernel.org/lkml/000000000000258e5e05fae79fc1@xxxxxxxxxx/ [1]
Fixes: f7d34b445abc ("USB: Add support for usbfs zerocopy.")
Fixes: ff2437befd8f ("usb: host: Fix excessive alignment restriction for local memory allocations")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Ruihan Li <lrh2000@xxxxxxxxxx>
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230515130958.32471-2-lrh2000@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/core/buffer.c | 41 +++++++++++++++++++++++++++++++++++++++++
drivers/usb/core/devio.c | 9 +++++----
include/linux/usb/hcd.h | 5 +++++
3 files changed, 51 insertions(+), 4 deletions(-)
--- a/drivers/usb/core/buffer.c
+++ b/drivers/usb/core/buffer.c
@@ -172,3 +172,44 @@ void hcd_buffer_free(
}
dma_free_coherent(hcd->self.sysdev, size, addr, dma);
}
+
+void *hcd_buffer_alloc_pages(struct usb_hcd *hcd,
+ size_t size, gfp_t mem_flags, dma_addr_t *dma)
+{
+ if (size == 0)
+ return NULL;
+
+ if (hcd->localmem_pool)
+ return gen_pool_dma_alloc_align(hcd->localmem_pool,
+ size, dma, PAGE_SIZE);
+
+ /* some USB hosts just use PIO */
+ if (!hcd_uses_dma(hcd)) {
+ *dma = DMA_MAPPING_ERROR;
+ return (void *)__get_free_pages(mem_flags,
+ get_order(size));
+ }
+
+ return dma_alloc_coherent(hcd->self.sysdev,
+ size, dma, mem_flags);
+}
+
+void hcd_buffer_free_pages(struct usb_hcd *hcd,
+ size_t size, void *addr, dma_addr_t dma)
+{
+ if (!addr)
+ return;
+
+ if (hcd->localmem_pool) {
+ gen_pool_free(hcd->localmem_pool,
+ (unsigned long)addr, size);
+ return;
+ }
+
+ if (!hcd_uses_dma(hcd)) {
+ free_pages((unsigned long)addr, get_order(size));
+ return;
+ }
+
+ dma_free_coherent(hcd->self.sysdev, size, addr, dma);
+}
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -186,6 +186,7 @@ static int connected(struct usb_dev_stat
static void dec_usb_memory_use_count(struct usb_memory *usbm, int *count)
{
struct usb_dev_state *ps = usbm->ps;
+ struct usb_hcd *hcd = bus_to_hcd(ps->dev->bus);
unsigned long flags;
spin_lock_irqsave(&ps->lock, flags);
@@ -194,8 +195,8 @@ static void dec_usb_memory_use_count(str
list_del(&usbm->memlist);
spin_unlock_irqrestore(&ps->lock, flags);
- usb_free_coherent(ps->dev, usbm->size, usbm->mem,
- usbm->dma_handle);
+ hcd_buffer_free_pages(hcd, usbm->size,
+ usbm->mem, usbm->dma_handle);
usbfs_decrease_memory_usage(
usbm->size + sizeof(struct usb_memory));
kfree(usbm);
@@ -247,8 +248,8 @@ static int usbdev_mmap(struct file *file
goto error_decrease_mem;
}
- mem = usb_alloc_coherent(ps->dev, size, GFP_USER | __GFP_NOWARN,
- &dma_handle);
+ mem = hcd_buffer_alloc_pages(hcd,
+ size, GFP_USER | __GFP_NOWARN, &dma_handle);
if (!mem) {
ret = -ENOMEM;
goto error_free_usbm;
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -503,6 +503,11 @@ void *hcd_buffer_alloc(struct usb_bus *b
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);
Patches currently in stable-queue which might be from lrh2000@xxxxxxxxxx are
queue-6.3/usb-usbfs-enforce-page-requirements-for-mmap.patch
queue-6.3/mm-page_table_check-make-it-dependent-on-exclusive_system_ram.patch
queue-6.3/usb-usbfs-use-consistent-mmap-functions.patch
queue-6.3/mm-page_table_check-ensure-user-pages-are-not-slab-pages.patch
