diff options
| author | Oliver Neukum <oneukum@suse.com> | 2022-02-15 11:35:47 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-02-15 15:56:10 +0100 |
| commit | 8d2b1a1ec9f559d30b724877da4ce592edc41fdc (patch) | |
| tree | 2b5bad2d091e5bf2cb4f403ffb9305250a394594 | |
| parent | mctp: fix use after free (diff) | |
| download | linux-8d2b1a1ec9f559d30b724877da4ce592edc41fdc.tar.xz linux-8d2b1a1ec9f559d30b724877da4ce592edc41fdc.zip | |
CDC-NCM: avoid overflow in sanity checking
A broken device may give an extreme offset like 0xFFF0
and a reasonable length for a fragment. In the sanity
check as formulated now, this will create an integer
overflow, defeating the sanity check. Both offset
and offset + len need to be checked in such a manner
that no overflow can occur.
And those quantities should be unsigned.
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/usb/cdc_ncm.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c index e303b522efb5..15f91d691bba 100644 --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -1715,10 +1715,10 @@ int cdc_ncm_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in) { struct sk_buff *skb; struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0]; - int len; + unsigned int len; int nframes; int x; - int offset; + unsigned int offset; union { struct usb_cdc_ncm_ndp16 *ndp16; struct usb_cdc_ncm_ndp32 *ndp32; @@ -1790,8 +1790,8 @@ next_ndp: break; } - /* sanity checking */ - if (((offset + len) > skb_in->len) || + /* sanity checking - watch out for integer wrap*/ + if ((offset > skb_in->len) || (len > skb_in->len - offset) || (len > ctx->rx_max) || (len < ETH_HLEN)) { netif_dbg(dev, rx_err, dev->net, "invalid frame detected (ignored) offset[%u]=%u, length=%u, skb=%p\n", |