Patch "USB: gadgetfs: fix unbounded memory allocation bug" has been added to the 4.4-stable tree
Subsystems (2)
This is a note to let you know that I've just added the patch titled
USB: gadgetfs: fix unbounded memory allocation bug
to the 4.4-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-gadgetfs-fix-unbounded-memory-allocation-bug.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.
Quoted 1 line
From
faab50984fe6636e616c7cc3d30308ba391d36fdMon Sep 17 00:00:00 2001
From: Alan Stern <[email protected]>
Date: Fri, 9 Dec 2016 15:17:46 -0500
Subject: USB: gadgetfs: fix unbounded memory allocation bug
From: Alan Stern <[email protected]>
commit faab50984fe6636e616c7cc3d30308ba391d36fd upstream.
Andrey Konovalov reports that fuzz testing with syzkaller causes a KASAN warning in gadgetfs:
BUG: KASAN: slab-out-of-bounds in dev_config+0x86f/0x1190 at addr ffff88003c47e160 Write of size 65537 by task syz-executor0/6356 CPU: 3 PID: 6356 Comm: syz-executor0 Not tainted 4.9.0-rc7+ #19 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 ffff88003c107ad8 ffffffff81f96aba ffffffff3dc11ef0 1ffff10007820eee ffffed0007820ee6 ffff88003dc11f00 0000000041b58ab3 ffffffff8598b4c8 ffffffff81f96828 ffffffff813fb4a0 ffff88003b6eadc0 ffff88003c107738 Call Trace: [< inline >] __dump_stack lib/dump_stack.c:15 [<ffffffff81f96aba>] dump_stack+0x292/0x398 lib/dump_stack.c:51 [<ffffffff817e4dec>] kasan_object_err+0x1c/0x70 mm/kasan/report.c:159 [< inline >] print_address_description mm/kasan/report.c:197 [<ffffffff817e5080>] kasan_report_error+0x1f0/0x4e0 mm/kasan/report.c:286 [<ffffffff817e5705>] kasan_report+0x35/0x40 mm/kasan/report.c:306 [< inline >] check_memory_region_inline mm/kasan/kasan.c:308 [<ffffffff817e3fb9>] check_memory_region+0x139/0x190 mm/kasan/kasan.c:315 [<ffffffff817e4044>] kasan_check_write+0x14/0x20 mm/kasan/kasan.c:326 [< inline >] copy_from_user arch/x86/include/asm/uaccess.h:689 [< inline >] ep0_write drivers/usb/gadget/legacy/inode.c:1135 [<ffffffff83228caf>] dev_config+0x86f/0x1190 drivers/usb/gadget/legacy/inode.c:1759 [<ffffffff817fdd55>] __vfs_write+0x5d5/0x760 fs/read_write.c:510 [<ffffffff817ff650>] vfs_write+0x170/0x4e0 fs/read_write.c:560 [< inline >] SYSC_write fs/read_write.c:607 [<ffffffff81803a5b>] SyS_write+0xfb/0x230 fs/read_write.c:599 [<ffffffff84f47ec1>] entry_SYSCALL_64_fastpath+0x1f/0xc2
Indeed, there is a comment saying that the value of len is restricted to a 16-bit integer, but the code doesn't actually do this.
This patch fixes the warning. It replaces the comment with a computation that forces the amount of data copied from the user in ep0_write() to be no larger than the wLength size for the control transfer, which is a 16-bit quantity.
--- drivers/usb/gadget/legacy/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/usb/gadget/legacy/inode.c +1 -1
@@ -1125,7 +1125,7 @@ ep0_write (struct file *fd, const char _/* data and/or status stage for control request */ }else if (dev->state ==STATE_DEV_SETUP ) { -/* IN DATA+STATUS caller makes len <= wLength */ + len =min_t (size_t, len, dev->setup_wLength);if (dev->setup_in) { retval =setup_req (dev->gadget->ep0, dev->req, len);if (retval ==0 ) {
Patches currently in stable-queue which might be from [email protected] are
queue-4.4/usb-dummy-hcd-fix-bug-in-stop_activity-handle-ep0.patch queue-4.4/usb-gadgetfs-fix-use-after-free-bug.patch queue-4.4/usb-gadgetfs-fix-checks-of-wtotallength-in-config-descriptors.patch queue-4.4/usb-fix-problems-with-duplicate-endpoint-addresses.patch queue-4.4/usb-gadgetfs-fix-unbounded-memory-allocation-bug.patch