faab50984f
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. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-by: Andrey Konovalov <andreyknvl@google.com> Tested-by: Andrey Konovalov <andreyknvl@google.com> CC: <stable@vger.kernel.org> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.