mirror of
https://github.com/Divested-Mobile/DivestOS-Build.git
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65 lines
3.2 KiB
Diff
65 lines
3.2 KiB
Diff
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From faab50984fe6636e616c7cc3d30308ba391d36fd Mon Sep 17 00:00:00 2001
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From: Alan Stern <stern@rowland.harvard.edu>
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Date: Fri, 9 Dec 2016 15:17:46 -0500
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Subject: [PATCH] USB: gadgetfs: fix unbounded memory allocation bug
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Andrey Konovalov reports that fuzz testing with syzkaller causes a
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KASAN warning in gadgetfs:
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BUG: KASAN: slab-out-of-bounds in dev_config+0x86f/0x1190 at addr ffff88003c47e160
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Write of size 65537 by task syz-executor0/6356
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CPU: 3 PID: 6356 Comm: syz-executor0 Not tainted 4.9.0-rc7+ #19
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Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
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ffff88003c107ad8 ffffffff81f96aba ffffffff3dc11ef0 1ffff10007820eee
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ffffed0007820ee6 ffff88003dc11f00 0000000041b58ab3 ffffffff8598b4c8
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ffffffff81f96828 ffffffff813fb4a0 ffff88003b6eadc0 ffff88003c107738
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Call Trace:
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[< inline >] __dump_stack lib/dump_stack.c:15
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[<ffffffff81f96aba>] dump_stack+0x292/0x398 lib/dump_stack.c:51
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[<ffffffff817e4dec>] kasan_object_err+0x1c/0x70 mm/kasan/report.c:159
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[< inline >] print_address_description mm/kasan/report.c:197
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[<ffffffff817e5080>] kasan_report_error+0x1f0/0x4e0 mm/kasan/report.c:286
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[<ffffffff817e5705>] kasan_report+0x35/0x40 mm/kasan/report.c:306
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[< inline >] check_memory_region_inline mm/kasan/kasan.c:308
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[<ffffffff817e3fb9>] check_memory_region+0x139/0x190 mm/kasan/kasan.c:315
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[<ffffffff817e4044>] kasan_check_write+0x14/0x20 mm/kasan/kasan.c:326
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[< inline >] copy_from_user arch/x86/include/asm/uaccess.h:689
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[< inline >] ep0_write drivers/usb/gadget/legacy/inode.c:1135
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[<ffffffff83228caf>] dev_config+0x86f/0x1190 drivers/usb/gadget/legacy/inode.c:1759
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[<ffffffff817fdd55>] __vfs_write+0x5d5/0x760 fs/read_write.c:510
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[<ffffffff817ff650>] vfs_write+0x170/0x4e0 fs/read_write.c:560
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[< inline >] SYSC_write fs/read_write.c:607
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[<ffffffff81803a5b>] SyS_write+0xfb/0x230 fs/read_write.c:599
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[<ffffffff84f47ec1>] entry_SYSCALL_64_fastpath+0x1f/0xc2
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Indeed, there is a comment saying that the value of len is restricted
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to a 16-bit integer, but the code doesn't actually do this.
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This patch fixes the warning. It replaces the comment with a
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computation that forces the amount of data copied from the user in
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ep0_write() to be no larger than the wLength size for the control
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transfer, which is a 16-bit quantity.
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Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
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Reported-by: Andrey Konovalov <andreyknvl@google.com>
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Tested-by: Andrey Konovalov <andreyknvl@google.com>
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CC: <stable@vger.kernel.org>
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Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
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---
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drivers/usb/gadget/legacy/inode.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
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index 48f1409b438ad..01ed3bc0c3c8e 100644
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--- a/drivers/usb/gadget/legacy/inode.c
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+++ b/drivers/usb/gadget/legacy/inode.c
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@@ -1126,7 +1126,7 @@ ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
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/* data and/or status stage for control request */
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} else if (dev->state == STATE_DEV_SETUP) {
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- /* IN DATA+STATUS caller makes len <= wLength */
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+ len = min_t(size_t, len, dev->setup_wLength);
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if (dev->setup_in) {
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retval = setup_req (dev->gadget->ep0, dev->req, len);
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if (retval == 0) {
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