diff options
| author | Oliver Neukum <oneukum@suse.com> | 2022-02-15 11:35:47 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-02 11:42:47 +0100 |
| commit | 69560efa001397ebb8dc1c3e6a3ce00302bb9f7f (patch) | |
| tree | 031aced186f8625d16d678998bd4b06a61c2f9a0 /drivers/net/usb | |
| parent | 2aeba1ea7ce8bf82b688cdffb844d26014e243b2 (diff) | |
CDC-NCM: avoid overflow in sanity checking
commit 8d2b1a1ec9f559d30b724877da4ce592edc41fdc upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/net/usb')
| -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 eaaa5aee5825..ab91fa5b0194 100644 --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -1702,10 +1702,10 @@ 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; @@ -1777,8 +1777,8 @@ 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", |