[patch] NFC: llcp: integer underflow in nfc_llcp_set_remote_gb()
DORMANTno replies
From: Dan Carpenter <hidden>
Date: 2013-01-31 08:17:32
Also in:
kernel-janitors, linux-wireless
Subsystem:
networking [general], nfc subsystem, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Heidelberg, Linus Torvalds
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 <redacted>
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;