Fix buffer overrun in creating key transport blob according to RFC 9189, 4.2.4.1

Resolves: CVE-2022-29242

diff --git a/e_gost_err.c b/e_gost_err.c
index 2a8320705f8048c5204cf41afdf75c16e6509ca1..e4903f2e052e4bb9264e0bab9b2871dee7605c71 100644 (file)
--- a/e_gost_err.c
+++ b/e_gost_err.c
@@ -150,6 +150,7 @@ static ERR_STRING_DATA GOST_str_reasons[] = {
     {ERR_PACK(0, 0, GOST_R_ERROR_SETTING_PEER_KEY), "error setting peer key"},
     {ERR_PACK(0, 0, GOST_R_INCOMPATIBLE_ALGORITHMS), "incompatible algorithms"},
     {ERR_PACK(0, 0, GOST_R_INCOMPATIBLE_PEER_KEY), "incompatible peer key"},
+    {ERR_PACK(0, 0, GOST_R_INVALID_BUFFER_SIZE), "invalid buffer size"},
     {ERR_PACK(0, 0, GOST_R_INVALID_CIPHER), "invalid cipher"},
     {ERR_PACK(0, 0, GOST_R_INVALID_CIPHER_PARAMS), "invalid cipher params"},
     {ERR_PACK(0, 0, GOST_R_INVALID_CIPHER_PARAM_OID),

diff --git a/e_gost_err.h b/e_gost_err.h
index 19f856cfc335b44983a6c1f3d411d5ea85cacd5c..59f4743b06a720871e4dfc25652fba34fedf9f46 100644 (file)
--- a/e_gost_err.h
+++ b/e_gost_err.h
@@ -129,6 +129,7 @@ void ERR_GOST_error(int function, int reason, char *file, int line);
 # define GOST_R_ERROR_SETTING_PEER_KEY                    139
 # define GOST_R_INCOMPATIBLE_ALGORITHMS                   108
 # define GOST_R_INCOMPATIBLE_PEER_KEY                     109
+# define GOST_R_INVALID_BUFFER_SIZE                       140
 # define GOST_R_INVALID_CIPHER                            134
 # define GOST_R_INVALID_CIPHER_PARAMS                     110
 # define GOST_R_INVALID_CIPHER_PARAM_OID                  111

diff --git a/gost_ec_keyx.c b/gost_ec_keyx.c
index 955858c3c41ac000f7c7485357ebe7e2f3315052..d5806eba0d1779e644affea7112d381c601c01be 100644 (file)
--- a/gost_ec_keyx.c
+++ b/gost_ec_keyx.c
@@ -532,6 +532,7 @@ static int pkey_gost2018_encrypt(EVP_PKEY_CTX *pctx, unsigned char *out,
     int exp_len = 0, iv_len = 0;
     unsigned char *exp_buf = NULL;
     int key_is_ephemeral = 0;
+    int res_len = 0;
 
     switch (data->cipher_nid) {
     case NID_magma_ctr:
@@ -625,8 +626,26 @@ static int pkey_gost2018_encrypt(EVP_PKEY_CTX *pctx, unsigned char *out,
         goto err;
     }
 
-    if ((*out_len = i2d_PSKeyTransport_gost(pst, out ? &out : NULL)) > 0)
+    res_len = i2d_PSKeyTransport_gost(pst, NULL);
+    if (res_len <= 0) {
+        GOSTerr(GOST_F_PKEY_GOST2018_ENCRYPT, ERR_R_ASN1_LIB);
+        goto err;
+    }
+
+    if (out == NULL) {
+        *out_len = res_len;
         ret = 1;
+    } else {
+        if ((size_t)res_len > *out_len) {
+            GOSTerr(GOST_F_PKEY_GOST2018_ENCRYPT, GOST_R_INVALID_BUFFER_SIZE);
+            goto err;
+        }
+        if ((*out_len = i2d_PSKeyTransport_gost(pst, &out)) > 0)
+            ret = 1;
+        else
+            GOSTerr(GOST_F_PKEY_GOST2018_ENCRYPT, ERR_R_ASN1_LIB);
+    }
+
  err:
     OPENSSL_cleanse(expkeys, sizeof(expkeys));
     if (key_is_ephemeral)