From e9a4aa3ba386c8a368baaadde6f9e5c3d5f17cfe Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Thu, 31 Jan 2013 11:16:46 +0300 Subject: [PATCH] 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 Signed-off-by: John W. Linville --- net/nfc/llcp/llcp.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) 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; -- 2.7.4