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@xxxxxxxxxx>
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;
--
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