commit 81944d1529202bd28359bede57c0a15deb65ba8a
Author: fullwaywang <fullwaywang@tencent.com>
Date:   Mon May 29 10:38:48 2023 +0800
Subject: [PATCH] pkcs15init: correct left length calculation to fix buffer overrun bug.

    Fixes #2785

CVE: CVE-2023-2977

Upstream-Status: Backport [https://github.com/OpenSC/OpenSC/pull/2787/commits/3bf3ab2f9091f984cda6dd910654ccbbe3f06a40]

Signed-off-by: Soumya <soumya.sambu@windriver.com>
---

diff --git a/src/pkcs15init/pkcs15-cardos.c b/src/pkcs15init/pkcs15-cardos.c
index 9715cf39..f41f73c3 100644
--- a/src/pkcs15init/pkcs15-cardos.c
+++ b/src/pkcs15init/pkcs15-cardos.c
@@ -872,7 +872,7 @@ static int cardos_have_verifyrc_package(sc_card_t *card)
	sc_apdu_t apdu;
         u8        rbuf[SC_MAX_APDU_BUFFER_SIZE];
         int       r;
-	const u8  *p = rbuf, *q;
+	const u8  *p = rbuf, *q, *pp;
	size_t    len, tlen = 0, ilen = 0;

	sc_format_apdu(card, &apdu, SC_APDU_CASE_2_SHORT, 0xca, 0x01, 0x88);
@@ -888,13 +888,13 @@ static int cardos_have_verifyrc_package(sc_card_t *card)
		return 0;

	while (len != 0) {
-		p = sc_asn1_find_tag(card->ctx, p, len, 0xe1, &tlen);
-		if (p == NULL)
+		pp = sc_asn1_find_tag(card->ctx, p, len, 0xe1, &tlen);
+		if (pp == NULL)
			return 0;
		if (card->type == SC_CARD_TYPE_CARDOS_M4_3)	{
			/* the verifyRC package on CardOS 4.3B use Manufacturer ID 0x01	*/
			/* and Package Number 0x07					*/
-			q = sc_asn1_find_tag(card->ctx, p, tlen, 0x01, &ilen);
+			q = sc_asn1_find_tag(card->ctx, pp, tlen, 0x01, &ilen);
			if (q == NULL || ilen != 4)
				return 0;
			if (q[0] == 0x07)
@@ -902,7 +902,7 @@ static int cardos_have_verifyrc_package(sc_card_t *card)
		} else if (card->type == SC_CARD_TYPE_CARDOS_M4_4)	{
			/* the verifyRC package on CardOS 4.4 use Manufacturer ID 0x03	*/
			/* and Package Number 0x02					*/
-			q = sc_asn1_find_tag(card->ctx, p, tlen, 0x03, &ilen);
+			q = sc_asn1_find_tag(card->ctx, pp, tlen, 0x03, &ilen);
			if (q == NULL || ilen != 4)
				return 0;
			if (q[0] == 0x02)
