Commit e9a4aa3b authored Jan 31, 2013 by Dan Carpenter Committed by John W. Linville Feb 08, 2013

NFC: llcp: integer underflow in nfc_llcp_set_remote_gb()



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>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

parent c6d3b204

net/nfc/llcp/llcp.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -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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