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NFC: llcp: integer underflow in nfc_llcp_set_remote_gb()

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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>
This commit is contained in:
Dan Carpenter 2013-01-31 11:16:46 +03:00 committed by John W. Linville
parent c6d3b2046e
commit e9a4aa3ba3
1 changed files with 2 additions and 3 deletions
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5
net/nfc/llcp/llcp.c
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@ -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"); pr_err("No LLCP device\n");
return -ENODEV; return -ENODEV;
} }
if (gb_len < 3)
return -EINVAL;
memset(local->remote_gb, 0, NFC_MAX_GT_LEN); memset(local->remote_gb, 0, NFC_MAX_GT_LEN);
memcpy(local->remote_gb, gb, gb_len); memcpy(local->remote_gb, gb, gb_len);
local->remote_gb_len = 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)) { if (memcmp(local->remote_gb, llcp_magic, 3)) {
pr_err("MAC does not support LLCP\n"); pr_err("MAC does not support LLCP\n");
return -EINVAL; return -EINVAL;