Bug 1603042 - Support external PSKs in tstclnt/selfserv. r=jcj

This patch adds support for TLS 1.3 external PSKs in tstclnt and selfserv with the `-z` option.

Command examples:
- `selfserv -D -p 4443 -d . -n localhost.localdomain -w nss -V tls1.3: -H 1 -z 0xAAAAAAAABBBBBBBBCCCCCCCCDDDDDDDD[:label] -m`
- `tstclnt -h 127.0.0.1 -p 4443  -z 0xAAAAAAAABBBBBBBBCCCCCCCCDDDDDDDD[:label] -d . -w nss`

For OpenSSL interop:
- `openssl s_server -nocert -port 4433 -psk AAAAAAAABBBBBBBBCCCCCCCCDDDDDDDD [-psk_identity label]`

Note: If the optional label is omitted, both NSS tools and OpenSSL default to "Client_identity".

Differential Revision: https://phabricator.services.mozilla.com/D75836

5 files changed, 169 insertions, 12 deletions

diff --git a/cmd/lib/basicutil.c b/cmd/lib/basicutil.c
index 345e970ad..476475d90 100644
--- a/cmd/lib/basicutil.c
+++ b/cmd/lib/basicutil.c
@@ -741,7 +741,6 @@ SECU_HexString2SECItem(PLArenaPool *arena, SECItem *item, const char *str)
     int byteval = 0;
     int tmp = PORT_Strlen(str);
 
-    PORT_Assert(arena);
     PORT_Assert(item);
 
     if ((tmp % 2) != 0) {
@@ -762,7 +761,9 @@ SECU_HexString2SECItem(PLArenaPool *arena, SECItem *item, const char *str)
         } else if ((str[i] >= 'A') && (str[i] <= 'F')) {
             tmp = str[i] - 'A' + 10;
         } else {
-            /* item is in arena and gets freed by the caller */
+            if (!arena) {
+                SECITEM_FreeItem(item, PR_FALSE);
+            }
             return NULL;
         }
 
diff --git a/cmd/lib/secutil.c b/cmd/lib/secutil.c
index b05dc7938..605139925 100644
--- a/cmd/lib/secutil.c
+++ b/cmd/lib/secutil.c
@@ -4159,3 +4159,57 @@ exportKeyingMaterials(PRFileDesc *fd,
 
     return SECSuccess;
 }
+
+SECStatus
+readPSK(const char *arg, SECItem *psk, SECItem *label)
+{
+    SECStatus rv = SECFailure;
+    char *str = PORT_Strdup(arg);
+    if (!str) {
+        goto cleanup;
+    }
+
+    char *pskBytes = strtok(str, ":");
+    if (!pskBytes) {
+        goto cleanup;
+    }
+    if (PORT_Strncasecmp(pskBytes, "0x", 2) != 0) {
+        goto cleanup;
+    }
+
+    psk = SECU_HexString2SECItem(NULL, psk, &pskBytes[2]);
+    if (!psk || !psk->data || psk->len != strlen(&str[2]) / 2) {
+        goto cleanup;
+    }
+
+    SECItem labelItem = { siBuffer, NULL, 0 };
+    char *inLabel = strtok(NULL, ":");
+    if (inLabel) {
+        labelItem.data = (unsigned char *)PORT_Strdup(inLabel);
+        if (!labelItem.data) {
+            goto cleanup;
+        }
+        labelItem.len = strlen(inLabel);
+
+        if (PORT_Strncasecmp(inLabel, "0x", 2) == 0) {
+            rv = SECU_SECItemHexStringToBinary(&labelItem);
+            if (rv != SECSuccess) {
+                SECITEM_FreeItem(&labelItem, PR_FALSE);
+                goto cleanup;
+            }
+        }
+        rv = SECSuccess;
+    } else {
+        const PRUint8 defaultLabel[] = { 'C', 'l', 'i', 'e', 'n', 't', '_',
+                                         'i', 'd', 'e', 'n', 't', 'i', 't', 'y' };
+        rv = SECITEM_MakeItem(NULL, &labelItem, defaultLabel,
+                              sizeof(defaultLabel));
+    }
+    if (rv == SECSuccess) {
+        *label = labelItem;
+    }
+
+cleanup:
+    PORT_Free(str);
+    return rv;
+}
diff --git a/cmd/lib/secutil.h b/cmd/lib/secutil.h
index c6da961e7..0bdfa9508 100644
--- a/cmd/lib/secutil.h
+++ b/cmd/lib/secutil.h
@@ -424,6 +424,8 @@ SECStatus exportKeyingMaterials(PRFileDesc *fd,
                                 const secuExporter *exporters,
                                 unsigned int exporterCount);
 
+SECStatus readPSK(const char *arg, SECItem *psk, SECItem *label);
+
 /*
  *
  *  Error messaging
diff --git a/cmd/selfserv/selfserv.c b/cmd/selfserv/selfserv.c
index 0f500d65c..1584d7ee0 100644
--- a/cmd/selfserv/selfserv.c
+++ b/cmd/selfserv/selfserv.c
@@ -138,6 +138,8 @@ static SECItem bigBuf;
 static int configureDHE = -1;        /* -1: don't configure, 0 disable, >=1 enable*/
 static int configureReuseECDHE = -1; /* -1: don't configure, 0 refresh, >=1 reuse*/
 static int configureWeakDHE = -1;    /* -1: don't configure, 0 disable, >=1 enable*/
+SECItem psk = { siBuffer, NULL, 0 };
+SECItem pskLabel = { siBuffer, NULL, 0 };
 
 static PRThread *acceptorThread;
 
@@ -167,7 +169,7 @@ PrintUsageHeader(const char *progName)
             "         [ T <good|revoked|unknown|badsig|corrupted|none|ocsp>] [-A ca]\n"
             "         [-C SSLCacheEntries] [-S dsa_nickname] [-Q]\n"
             "         [-I groups] [-J signatureschemes] [-e ec_nickname]\n"
-            "         -U [0|1] -H [0|1|2] -W [0|1]\n"
+            "         -U [0|1] -H [0|1|2] -W [0|1] [-z externalPsk]\n"
             "\n",
             progName);
 }
@@ -241,7 +243,11 @@ PrintParameterUsage()
         "     LABEL[:OUTPUT-LENGTH[:CONTEXT]]\n"
         "   where LABEL and CONTEXT can be either a free-form string or\n"
         "   a hex string if it is preceded by \"0x\"; OUTPUT-LENGTH\n"
-        "   is a decimal integer.\n",
+        "   is a decimal integer.\n"
+        "-z Configure a TLS 1.3 External PSK with the given hex string for a key.\n"
+        "   To specify a label, use ':' as a delimiter. For example:\n"
+        "   0xAAAABBBBCCCCDDDD:mylabel. Otherwise, the default label of\n"
+        "  'Client_identity' will be used.\n",
         stderr);
 }
 
@@ -1841,6 +1847,32 @@ handshakeCallback(PRFileDesc *fd, void *client_data)
     }
 }
 
+static SECStatus
+importPsk(PRFileDesc *model_sock)
+{
+    SECU_PrintAsHex(stdout, &psk, "Using External PSK", 0);
+    PK11SlotInfo *slot = NULL;
+    PK11SymKey *symKey = NULL;
+    slot = PK11_GetInternalSlot();
+    if (!slot) {
+        errWarn("PK11_GetInternalSlot failed");
+        return SECFailure;
+    }
+    symKey = PK11_ImportSymKey(slot, CKM_HKDF_KEY_GEN, PK11_OriginUnwrap,
+                               CKA_DERIVE, &psk, NULL);
+    PK11_FreeSlot(slot);
+    if (!symKey) {
+        errWarn("PK11_ImportSymKey failed\n");
+        return SECFailure;
+    }
+
+    SECStatus rv = SSL_AddExternalPsk(model_sock, symKey,
+                                      (const PRUint8 *)pskLabel.data,
+                                      pskLabel.len, ssl_hash_sha256);
+    PK11_FreeSymKey(symKey);
+    return rv;
+}
+
 void
 server_main(
     PRFileDesc *listen_sock,
@@ -2050,6 +2082,13 @@ server_main(
         }
     }
 
+    if (psk.data) {
+        rv = importPsk(model_sock);
+        if (rv != SECSuccess) {
+            errExit("importPsk failed");
+        }
+    }
+
     if (MakeCertOK)
         SSL_BadCertHook(model_sock, myBadCertHandler, NULL);
 
@@ -2291,10 +2330,9 @@ main(int argc, char **argv)
     /* please keep this list of options in ASCII collating sequence.
     ** numbers, then capital letters, then lower case, alphabetical.
     ** XXX: 'B', and 'q' were used in the past but removed
-    **      in 3.28, please leave some time before resuing those.
-    **      'z' was removed in 3.39. */
+    **      in 3.28, please leave some time before resuing those. */
     optstate = PL_CreateOptState(argc, argv,
-                                 "2:A:C:DEGH:I:J:L:M:NP:QRS:T:U:V:W:YZa:bc:d:e:f:g:hi:jk:lmn:op:rst:uvw:x:y");
+                                 "2:A:C:DEGH:I:J:L:M:NP:QRS:T:U:V:W:YZa:bc:d:e:f:g:hi:jk:lmn:op:rst:uvw:x:yz:");
     while ((status = PL_GetNextOpt(optstate)) == PL_OPT_OK) {
         ++optionsFound;
         switch (optstate->option) {
@@ -2516,6 +2554,16 @@ main(int argc, char **argv)
                 zeroRTT = PR_TRUE;
                 break;
 
+            case 'z':
+                rv = readPSK(optstate->value, &psk, &pskLabel);
+                if (rv != SECSuccess) {
+                    PL_DestroyOptState(optstate);
+                    fprintf(stderr, "Bad PSK specified.\n");
+                    Usage(progName);
+                    exit(1);
+                }
+                break;
+
             case 'Q':
                 enableALPN = PR_TRUE;
                 break;
@@ -2871,6 +2919,8 @@ cleanup:
     if (antiReplay) {
         SSL_ReleaseAntiReplayContext(antiReplay);
     }
+    SECITEM_ZfreeItem(&psk, PR_FALSE);
+    SECITEM_ZfreeItem(&pskLabel, PR_FALSE);
     if (NSS_Shutdown() != SECSuccess) {
         SECU_PrintError(progName, "NSS_Shutdown");
         if (loggerThread) {
diff --git a/cmd/tstclnt/tstclnt.c b/cmd/tstclnt/tstclnt.c
index 6fa154106..c37df118e 100644
--- a/cmd/tstclnt/tstclnt.c
+++ b/cmd/tstclnt/tstclnt.c
@@ -109,6 +109,8 @@ SSLNamedGroup *enabledGroups = NULL;
 unsigned int enabledGroupsCount = 0;
 const SSLSignatureScheme *enabledSigSchemes = NULL;
 unsigned int enabledSigSchemeCount = 0;
+SECItem psk = { siBuffer, NULL, 0 };
+SECItem pskLabel = { siBuffer, NULL, 0 };
 
 const char *
 signatureSchemeName(SSLSignatureScheme scheme)
@@ -229,7 +231,7 @@ PrintUsageHeader()
             "  [-r N] [-w passwd] [-W pwfile] [-q [-t seconds]]\n"
             "  [-I groups] [-J signatureschemes]\n"
             "  [-A requestfile] [-L totalconnections] [-P {client,server}]\n"
-            "  [-N encryptedSniKeys] [-Q]\n"
+            "  [-N encryptedSniKeys] [-Q] [-z externalPsk]\n"
             "\n",
             progName);
 }
@@ -325,6 +327,12 @@ PrintParameterUsage()
                     "%-20s a hex string if it is preceded by \"0x\"; OUTPUT-LENGTH\n"
                     "%-20s is a decimal integer.\n",
             "-x", "", "", "", "", "");
+    fprintf(stderr,
+            "%-20s Configure a TLS 1.3 External PSK with the given hex string for a key\n"
+            "%-20s To specify a label, use ':' as a delimiter. For example\n"
+            "%-20s 0xAAAABBBBCCCCDDDD:mylabel. Otherwise, the default label of\n"
+            "%-20s 'Client_identity' will be used.\n",
+            "-z externalPsk", "", "", "");
 }
 
 static void
@@ -1230,6 +1238,31 @@ connectToServer(PRFileDesc *s, PRPollDesc *pollset)
     return SECSuccess;
 }
 
+static SECStatus
+importPsk(PRFileDesc *s)
+{
+    SECU_PrintAsHex(stdout, &psk, "Using External PSK", 0);
+    PK11SlotInfo *slot = NULL;
+    PK11SymKey *symKey = NULL;
+    slot = PK11_GetInternalSlot();
+    if (!slot) {
+        SECU_PrintError(progName, "PK11_GetInternalSlot failed");
+        return SECFailure;
+    }
+    symKey = PK11_ImportSymKey(slot, CKM_HKDF_KEY_GEN, PK11_OriginUnwrap,
+                               CKA_DERIVE, &psk, NULL);
+    PK11_FreeSlot(slot);
+    if (!symKey) {
+        SECU_PrintError(progName, "PK11_ImportSymKey failed");
+        return SECFailure;
+    }
+
+    SECStatus rv = SSL_AddExternalPsk(s, symKey, (const PRUint8 *)pskLabel.data,
+                                      pskLabel.len, ssl_hash_sha256);
+    PK11_FreeSymKey(symKey);
+    return rv;
+}
+
 static int
 run()
 {
@@ -1498,6 +1531,15 @@ run()
         }
     }
 
+    if (psk.data) {
+        rv = importPsk(s);
+        if (rv != SECSuccess) {
+            SECU_PrintError(progName, "importPsk failed");
+            error = 1;
+            goto done;
+        }
+    }
+
     serverCertAuth.dbHandle = CERT_GetDefaultCertDB();
 
     SSL_AuthCertificateHook(s, ownAuthCertificate, &serverCertAuth);
@@ -1752,11 +1794,8 @@ main(int argc, char **argv)
         }
     }
 
-    /* Note: 'z' was removed in 3.39
-     * Please leave some time before reusing these.
-     */
     optstate = PL_CreateOptState(argc, argv,
-                                 "46A:BCDEFGHI:J:KL:M:N:OP:QR:STUV:W:X:YZa:bc:d:fgh:m:n:op:qr:st:uvw:x:");
+                                 "46A:BCDEFGHI:J:KL:M:N:OP:QR:STUV:W:X:YZa:bc:d:fgh:m:n:op:qr:st:uvw:x:z:");
     while ((optstatus = PL_GetNextOpt(optstate)) == PL_OPT_OK) {
         switch (optstate->option) {
             case '?':
@@ -2015,6 +2054,15 @@ main(int argc, char **argv)
                     Usage();
                 }
                 break;
+
+            case 'z':
+                rv = readPSK(optstate->value, &psk, &pskLabel);
+                if (rv != SECSuccess) {
+                    PL_DestroyOptState(optstate);
+                    fprintf(stderr, "Bad PSK specified.\n");
+                    Usage();
+                }
+                break;
         }
     }
     PL_DestroyOptState(optstate);
@@ -2210,6 +2258,8 @@ done:
     PORT_Free(host);
     PORT_Free(zeroRttData);
     PORT_Free(encryptedSNIKeys);
+    SECITEM_ZfreeItem(&psk, PR_FALSE);
+    SECITEM_ZfreeItem(&pskLabel, PR_FALSE);
 
     if (enabledGroups) {
         PORT_Free(enabledGroups);