| Message ID | 20130131081645.GA14812@elgon.mountain (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
Hi Dan, On Thursday 31 of January 2013 10:16:46 Dan Carpenter wrote: > If gb_len is less than 3 it would cause an integer underflow and > possibly memory corruption in nfc_llcp_parse_gb_tlv(). > > I removed the old test for gb_len == 0. I also removed the test for > ->remote_gb == NULL. It's not possible for ->remote_gb to be NULL and > we have already dereferenced ->remote_gb_len so it's too late to test. > > The old test return -ENODEV but my test returns -EINVAL. > > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> > > diff --git a/net/nfc/llcp/llcp.c b/net/nfc/llcp/llcp.c > index 85bc75c..746f5a2 100644 > --- a/net/nfc/llcp/llcp.c > +++ b/net/nfc/llcp/llcp.c > @@ -549,14 +549,13 @@ int nfc_llcp_set_remote_gb(struct nfc_dev *dev, u8 *gb, u8 gb_len) > pr_err("No LLCP device\n"); > return -ENODEV; > } > + if (gb_len < 3) > + return -EINVAL; Maybe define NFC_MIN_GT_LEN and test it together with NFC_MAX_GT_LEN in nfc_set_remote_general_bytes() ? > > memset(local->remote_gb, 0, NFC_MAX_GT_LEN); > memcpy(local->remote_gb, gb, gb_len); > local->remote_gb_len = gb_len; > > - if (local->remote_gb == NULL || local->remote_gb_len == 0) > - return -ENODEV; > - > if (memcmp(local->remote_gb, llcp_magic, 3)) { > pr_err("MAC does not support LLCP\n"); > return -EINVAL;
diff --git a/net/nfc/llcp/llcp.c b/net/nfc/llcp/llcp.c index 85bc75c..746f5a2 100644 --- a/net/nfc/llcp/llcp.c +++ b/net/nfc/llcp/llcp.c @@ -549,14 +549,13 @@ int nfc_llcp_set_remote_gb(struct nfc_dev *dev, u8 *gb, u8 gb_len) pr_err("No LLCP device\n"); return -ENODEV; } + if (gb_len < 3) + return -EINVAL; memset(local->remote_gb, 0, NFC_MAX_GT_LEN); memcpy(local->remote_gb, gb, gb_len); local->remote_gb_len = gb_len; - if (local->remote_gb == NULL || local->remote_gb_len == 0) - return -ENODEV; - if (memcmp(local->remote_gb, llcp_magic, 3)) { pr_err("MAC does not support LLCP\n"); return -EINVAL;
If gb_len is less than 3 it would cause an integer underflow and possibly memory corruption in nfc_llcp_parse_gb_tlv(). I removed the old test for gb_len == 0. I also removed the test for ->remote_gb == NULL. It's not possible for ->remote_gb to be NULL and we have already dereferenced ->remote_gb_len so it's too late to test. The old test return -ENODEV but my test returns -EINVAL. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html