Patch "usb: gadget: f_fs: Assorted buffer overflow checks." has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    usb: gadget: f_fs: Assorted buffer overflow checks.

to the 4.9-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-gadget-f_fs-assorted-buffer-overflow-checks.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 83e526f2a2fa4b2e82b6bd3ddbb26b70acfa8947 Mon Sep 17 00:00:00 2001
From: Vincent Pelletier <plr.vincent@gmail.com>
Date: Wed, 18 Jan 2017 00:57:44 +0000
Subject: usb: gadget: f_fs: Assorted buffer overflow checks.

From: Vincent Pelletier <plr.vincent@gmail.com>

commit 83e526f2a2fa4b2e82b6bd3ddbb26b70acfa8947 upstream.

OS descriptor head, when flagged as provided, is accessed without
checking if it fits in provided buffer. Verify length before access.
Also, there are other places where buffer length it checked
after accessing offsets which are potentially past the end. Check
buffer length before as well to fail cleanly.

Signed-off-by: Vincent Pelletier <plr.vincent@gmail.com>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/gadget/function/f_fs.c |   13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -2269,6 +2269,8 @@ static int __ffs_data_do_os_desc(enum ff
 		if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
 			return -EINVAL;
 		length = le32_to_cpu(d->dwSize);
+		if (len < length)
+			return -EINVAL;
 		type = le32_to_cpu(d->dwPropertyDataType);
 		if (type < USB_EXT_PROP_UNICODE ||
 		    type > USB_EXT_PROP_UNICODE_MULTI) {
@@ -2277,6 +2279,11 @@ static int __ffs_data_do_os_desc(enum ff
 			return -EINVAL;
 		}
 		pnl = le16_to_cpu(d->wPropertyNameLength);
+		if (length < 14 + pnl) {
+			pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
+				  length, pnl, type);
+			return -EINVAL;
+		}
 		pdl = le32_to_cpu(*(u32 *)((u8 *)data + 10 + pnl));
 		if (length != 14 + pnl + pdl) {
 			pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
@@ -2363,6 +2370,9 @@ static int __ffs_data_got_descs(struct f
 		}
 	}
 	if (flags & (1 << i)) {
+		if (len < 4) {
+			goto error;
+		}
 		os_descs_count = get_unaligned_le32(data);
 		data += 4;
 		len -= 4;
@@ -2435,7 +2445,8 @@ static int __ffs_data_got_strings(struct
 
 	ENTER();
 
-	if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
+	if (unlikely(len < 16 ||
+		     get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
 		     get_unaligned_le32(data + 4) != len))
 		goto error;
 	str_count  = get_unaligned_le32(data + 8);


Patches currently in stable-queue which might be from plr.vincent@gmail.com are

queue-4.9/usb-gadget-f_fs-assorted-buffer-overflow-checks.patch