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From ca4d4c34ae9aa5c3c0da76662c5e549d2fc0cc86 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Fri, 2 Apr 2021 14:44:42 +0300
Subject: [PATCH] nfc: pn533: prevent potential memory corruption
Git-commit: ca4d4c34ae9aa5c3c0da76662c5e549d2fc0cc86
Patch-mainline: v5.13-rc1
References: git-fixes

If the "type_a->nfcid_len" is too large then it would lead to memory
corruption in pn533_target_found_type_a() when we do:

	memcpy(nfc_tgt->nfcid1, tgt_type_a->nfcid_data, nfc_tgt->nfcid1_len);

Fixes: c3b1e1e8a76f ("NFC: Export NFCID1 from pn533")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/nfc/pn533/pn533.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/nfc/pn533/pn533.c b/drivers/nfc/pn533/pn533.c
index f1469ac8ff42..3fe5b81eda2d 100644
--- a/drivers/nfc/pn533/pn533.c
+++ b/drivers/nfc/pn533/pn533.c
@@ -706,6 +706,9 @@ static bool pn533_target_type_a_is_valid(struct pn533_target_type_a *type_a,
 	if (PN533_TYPE_A_SEL_CASCADE(type_a->sel_res) != 0)
 		return false;
 
+	if (type_a->nfcid_len > NFC_NFCID1_MAXSIZE)
+		return false;
+
 	return true;
 }
 
-- 
2.26.2