--- /dev/null
+From a0541334a6394f8237a4393b7372693cd7e96f15 Mon Sep 17 00:00:00 2001
+From: Jouni Malinen <j@w1.fi>
+Date: Sat, 13 Mar 2021 18:19:31 +0200
+Subject: [PATCH] ASN.1: Validate DigestAlgorithmIdentifier parameters
+
+The supported hash algorithms do not use AlgorithmIdentifier parameters.
+However, there are implementations that include NULL parameters in
+addition to ones that omit the parameters. Previous implementation did
+not check the parameters value at all which supported both these cases,
+but did not reject any other unexpected information.
+
+Use strict validation of digest algorithm parameters and reject any
+unexpected value when validating a signature. This is needed to prevent
+potential forging attacks.
+
+Signed-off-by: Jouni Malinen <j@w1.fi>
+
+Upstream-Status: Backport
+CVE: CVE-2021-30004
+
+Reference to upstream patch:
+[https://w1.fi/cgit/hostap/commit/?id=a0541334a6394f8237a4393b7372693cd7e96f15]
+
+Signed-off-by: Stefan Ghinea <stefan.ghinea@windriver.com>
+---
+ src/tls/pkcs1.c | 21 +++++++++++++++++++++
+ src/tls/x509v3.c | 20 ++++++++++++++++++++
+ 2 files changed, 41 insertions(+)
+
+diff --git a/src/tls/pkcs1.c b/src/tls/pkcs1.c
+index 141ac50..e09db07 100644
+--- a/src/tls/pkcs1.c
++++ b/src/tls/pkcs1.c
+@@ -240,6 +240,8 @@ int pkcs1_v15_sig_ver(struct crypto_public_key *pk,
+ os_free(decrypted);
+ return -1;
+ }
++ wpa_hexdump(MSG_MSGDUMP, "PKCS #1: DigestInfo",
++ hdr.payload, hdr.length);
+
+ pos = hdr.payload;
+ end = pos + hdr.length;
+@@ -261,6 +263,8 @@ int pkcs1_v15_sig_ver(struct crypto_public_key *pk,
+ os_free(decrypted);
+ return -1;
+ }
++ wpa_hexdump(MSG_MSGDUMP, "PKCS #1: DigestAlgorithmIdentifier",
++ hdr.payload, hdr.length);
+ da_end = hdr.payload + hdr.length;
+
+ if (asn1_get_oid(hdr.payload, hdr.length, &oid, &next)) {
+@@ -269,6 +273,23 @@ int pkcs1_v15_sig_ver(struct crypto_public_key *pk,
+ os_free(decrypted);
+ return -1;
+ }
++ wpa_hexdump(MSG_MSGDUMP, "PKCS #1: Digest algorithm parameters",
++ next, da_end - next);
++
++ /*
++ * RFC 5754: The correct encoding for the SHA2 algorithms would be to
++ * omit the parameters, but there are implementation that encode these
++ * as a NULL element. Allow these two cases and reject anything else.
++ */
++ if (da_end > next &&
++ (asn1_get_next(next, da_end - next, &hdr) < 0 ||
++ !asn1_is_null(&hdr) ||
++ hdr.payload + hdr.length != da_end)) {
++ wpa_printf(MSG_DEBUG,
++ "PKCS #1: Unexpected digest algorithm parameters");
++ os_free(decrypted);
++ return -1;
++ }
+
+ if (!asn1_oid_equal(&oid, hash_alg)) {
+ char txt[100], txt2[100];
+diff --git a/src/tls/x509v3.c b/src/tls/x509v3.c
+index 1bd5aa0..bf2289f 100644
+--- a/src/tls/x509v3.c
++++ b/src/tls/x509v3.c
+@@ -1834,6 +1834,7 @@ int x509_check_signature(struct x509_certificate *issuer,
+ os_free(data);
+ return -1;
+ }
++ wpa_hexdump(MSG_MSGDUMP, "X509: DigestInfo", hdr.payload, hdr.length);
+
+ pos = hdr.payload;
+ end = pos + hdr.length;
+@@ -1855,6 +1856,8 @@ int x509_check_signature(struct x509_certificate *issuer,
+ os_free(data);
+ return -1;
+ }
++ wpa_hexdump(MSG_MSGDUMP, "X509: DigestAlgorithmIdentifier",
++ hdr.payload, hdr.length);
+ da_end = hdr.payload + hdr.length;
+
+ if (asn1_get_oid(hdr.payload, hdr.length, &oid, &next)) {
+@@ -1862,6 +1865,23 @@ int x509_check_signature(struct x509_certificate *issuer,
+ os_free(data);
+ return -1;
+ }
++ wpa_hexdump(MSG_MSGDUMP, "X509: Digest algorithm parameters",
++ next, da_end - next);
++
++ /*
++ * RFC 5754: The correct encoding for the SHA2 algorithms would be to
++ * omit the parameters, but there are implementation that encode these
++ * as a NULL element. Allow these two cases and reject anything else.
++ */
++ if (da_end > next &&
++ (asn1_get_next(next, da_end - next, &hdr) < 0 ||
++ !asn1_is_null(&hdr) ||
++ hdr.payload + hdr.length != da_end)) {
++ wpa_printf(MSG_DEBUG,
++ "X509: Unexpected digest algorithm parameters");
++ os_free(data);
++ return -1;
++ }
+
+ if (x509_sha1_oid(&oid)) {
+ if (signature->oid.oid[6] != 5 /* sha-1WithRSAEncryption */) {
+--
+2.17.1
+
