From d2217c88df6e65c756013417e5ee4f470dd12470 Mon Sep 17 00:00:00 2001
From: Tomas Mraz <tomas@openssl.org>
Date: Tue, 30 Nov 2021 11:52:10 +0100
Subject: [PATCH] various kdfs: Always reset buflen after clearing the buffer

Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/17165)
---
 providers/implementations/kdfs/krb5kdf.c   | 1 +
 providers/implementations/kdfs/pbkdf1.c    | 4 +++-
 providers/implementations/kdfs/pbkdf2.c    | 4 +++-
 providers/implementations/kdfs/pkcs12kdf.c | 4 +++-
 providers/implementations/kdfs/scrypt.c    | 4 +++-
 providers/implementations/kdfs/sshkdf.c    | 1 +
 6 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/providers/implementations/kdfs/krb5kdf.c b/providers/implementations/kdfs/krb5kdf.c
index f8d4baa568..2c887f0eb9 100644
--- a/providers/implementations/kdfs/krb5kdf.c
+++ b/providers/implementations/kdfs/krb5kdf.c
@@ -98,6 +98,7 @@ static int krb5kdf_set_membuf(unsigned char **dst, size_t *dst_len,
 {
     OPENSSL_clear_free(*dst, *dst_len);
     *dst = NULL;
+    *dst_len = 0;
     return OSSL_PARAM_get_octet_string(p, (void **)dst, 0, dst_len);
 }
 
diff --git a/providers/implementations/kdfs/pbkdf1.c b/providers/implementations/kdfs/pbkdf1.c
index c93ff9b3eb..b9b164c4e2 100644
--- a/providers/implementations/kdfs/pbkdf1.c
+++ b/providers/implementations/kdfs/pbkdf1.c
@@ -134,13 +134,15 @@ static int kdf_pbkdf1_set_membuf(unsigned char **buffer, size_t *buflen,
                              const OSSL_PARAM *p)
 {
     OPENSSL_clear_free(*buffer, *buflen);
+    *buffer = NULL;
+    *buflen = 0;
+
     if (p->data_size == 0) {
         if ((*buffer = OPENSSL_malloc(1)) == NULL) {
             ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
             return 0;
         }
     } else if (p->data != NULL) {
-        *buffer = NULL;
         if (!OSSL_PARAM_get_octet_string(p, (void **)buffer, 0, buflen))
             return 0;
     }
diff --git a/providers/implementations/kdfs/pbkdf2.c b/providers/implementations/kdfs/pbkdf2.c
index 16acf300ea..b9e865f8ec 100644
--- a/providers/implementations/kdfs/pbkdf2.c
+++ b/providers/implementations/kdfs/pbkdf2.c
@@ -126,13 +126,15 @@ static int pbkdf2_set_membuf(unsigned char **buffer, size_t *buflen,
                              const OSSL_PARAM *p)
 {
     OPENSSL_clear_free(*buffer, *buflen);
+    *buffer = NULL;
+    *buflen = 0;
+
     if (p->data_size == 0) {
         if ((*buffer = OPENSSL_malloc(1)) == NULL) {
             ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
             return 0;
         }
     } else if (p->data != NULL) {
-        *buffer = NULL;
         if (!OSSL_PARAM_get_octet_string(p, (void **)buffer, 0, buflen))
             return 0;
     }
diff --git a/providers/implementations/kdfs/pkcs12kdf.c b/providers/implementations/kdfs/pkcs12kdf.c
index 7f461fe022..a29a618ee8 100644
--- a/providers/implementations/kdfs/pkcs12kdf.c
+++ b/providers/implementations/kdfs/pkcs12kdf.c
@@ -182,13 +182,15 @@ static int pkcs12kdf_set_membuf(unsigned char **buffer, size_t *buflen,
                              const OSSL_PARAM *p)
 {
     OPENSSL_clear_free(*buffer, *buflen);
+    *buffer = NULL;
+    *buflen = 0;
+
     if (p->data_size == 0) {
         if ((*buffer = OPENSSL_malloc(1)) == NULL) {
             ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
             return 0;
         }
     } else if (p->data != NULL) {
-        *buffer = NULL;
         if (!OSSL_PARAM_get_octet_string(p, (void **)buffer, 0, buflen))
             return 0;
     }
diff --git a/providers/implementations/kdfs/scrypt.c b/providers/implementations/kdfs/scrypt.c
index 2bbea0c7cc..a7072f785f 100644
--- a/providers/implementations/kdfs/scrypt.c
+++ b/providers/implementations/kdfs/scrypt.c
@@ -108,13 +108,15 @@ static int scrypt_set_membuf(unsigned char **buffer, size_t *buflen,
                              const OSSL_PARAM *p)
 {
     OPENSSL_clear_free(*buffer, *buflen);
+    *buffer = NULL;
+    *buflen = 0;
+
     if (p->data_size == 0) {
         if ((*buffer = OPENSSL_malloc(1)) == NULL) {
             ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
             return 0;
         }
     } else if (p->data != NULL) {
-        *buffer = NULL;
         if (!OSSL_PARAM_get_octet_string(p, (void **)buffer, 0, buflen))
             return 0;
     }
diff --git a/providers/implementations/kdfs/sshkdf.c b/providers/implementations/kdfs/sshkdf.c
index 93a7a64fb5..be23c2143d 100644
--- a/providers/implementations/kdfs/sshkdf.c
+++ b/providers/implementations/kdfs/sshkdf.c
@@ -91,6 +91,7 @@ static int sshkdf_set_membuf(unsigned char **dst, size_t *dst_len,
 {
     OPENSSL_clear_free(*dst, *dst_len);
     *dst = NULL;
+    *dst_len = 0;
     return OSSL_PARAM_get_octet_string(p, (void **)dst, 0, dst_len);
 }