1 files changed, 143 insertions, 0 deletions
diff --git a/security/nss/lib/certdb/xbsconst.c b/security/nss/lib/certdb/xbsconst.c
new file mode 100644
index 000000000..4f01f51f4
--- /dev/null
+++ b/security/nss/lib/certdb/xbsconst.c
@@ -0,0 +1,143 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * X.509 v3 Basic Constraints Extension
+ */
+
+#include "prtypes.h"
+#include <limits.h> /* for LONG_MAX */
+#include "seccomon.h"
+#include "secdert.h"
+#include "secoidt.h"
+#include "secasn1t.h"
+#include "secasn1.h"
+#include "certt.h"
+#include "secder.h"
+#include "prprf.h"
+#include "secerr.h"
+
+typedef struct EncodedContext {
+    SECItem isCA;
+    SECItem pathLenConstraint;
+    SECItem encodedValue;
+    PLArenaPool *arena;
+} EncodedContext;
+
+static const SEC_ASN1Template CERTBasicConstraintsTemplate[] = {
+    { SEC_ASN1_SEQUENCE, 0, NULL, sizeof(EncodedContext) },
+    { SEC_ASN1_OPTIONAL | SEC_ASN1_BOOLEAN, /* XXX DER_DEFAULT */
+      offsetof(EncodedContext, isCA) },
+    { SEC_ASN1_OPTIONAL | SEC_ASN1_INTEGER,
+      offsetof(EncodedContext, pathLenConstraint) },
+    { 0 }
+};
+
+static unsigned char hexTrue = 0xff;
+static unsigned char hexFalse = 0x00;
+
+#define GEN_BREAK(status) \
+    rv = status;          \
+    break;
+
+SECStatus
+CERT_EncodeBasicConstraintValue(PLArenaPool *arena, CERTBasicConstraints *value,
+                                SECItem *encodedValue)
+{
+    EncodedContext encodeContext;
+    PLArenaPool *our_pool = NULL;
+    SECStatus rv = SECSuccess;
+
+    do {
+        PORT_Memset(&encodeContext, 0, sizeof(encodeContext));
+        if (!value->isCA && value->pathLenConstraint >= 0) {
+            PORT_SetError(SEC_ERROR_EXTENSION_VALUE_INVALID);
+            GEN_BREAK(SECFailure);
+        }
+
+        encodeContext.arena = arena;
+        if (value->isCA == PR_TRUE) {
+            encodeContext.isCA.data = &hexTrue;
+            encodeContext.isCA.len = 1;
+        }
+
+        /* If the pathLenConstraint is less than 0, then it should be
+         * omitted from the encoding.
+         */
+        if (value->isCA && value->pathLenConstraint >= 0) {
+            our_pool = PORT_NewArena(SEC_ASN1_DEFAULT_ARENA_SIZE);
+            if (our_pool == NULL) {
+                PORT_SetError(SEC_ERROR_NO_MEMORY);
+                GEN_BREAK(SECFailure);
+            }
+            if (SEC_ASN1EncodeUnsignedInteger(
+                    our_pool, &encodeContext.pathLenConstraint,
+                    (unsigned long)value->pathLenConstraint) == NULL) {
+                PORT_SetError(SEC_ERROR_NO_MEMORY);
+                GEN_BREAK(SECFailure);
+            }
+        }
+        if (SEC_ASN1EncodeItem(arena, encodedValue, &encodeContext,
+                               CERTBasicConstraintsTemplate) == NULL) {
+            GEN_BREAK(SECFailure);
+        }
+    } while (0);
+    if (our_pool)
+        PORT_FreeArena(our_pool, PR_FALSE);
+    return (rv);
+}
+
+SECStatus
+CERT_DecodeBasicConstraintValue(CERTBasicConstraints *value,
+                                const SECItem *encodedValue)
+{
+    EncodedContext decodeContext;
+    PORTCheapArenaPool tmpArena;
+    SECStatus rv = SECSuccess;
+
+    do {
+        PORT_Memset(&decodeContext, 0, sizeof(decodeContext));
+        /* initialize the value just in case we got "0x30 00", or when the
+           pathLenConstraint is omitted.
+         */
+        decodeContext.isCA.data = &hexFalse;
+        decodeContext.isCA.len = 1;
+
+        PORT_InitCheapArena(&tmpArena, SEC_ASN1_DEFAULT_ARENA_SIZE);
+
+        rv = SEC_QuickDERDecodeItem(&tmpArena.arena, &decodeContext,
+                                    CERTBasicConstraintsTemplate, encodedValue);
+        if (rv == SECFailure)
+            break;
+
+        value->isCA = decodeContext.isCA.data
+                          ? (PRBool)(decodeContext.isCA.data[0] != 0)
+                          : PR_FALSE;
+        if (decodeContext.pathLenConstraint.data == NULL) {
+            /* if the pathLenConstraint is not encoded, and the current setting
+              is CA, then the pathLenConstraint should be set to a negative
+              number
+              for unlimited certificate path.
+             */
+            if (value->isCA)
+                value->pathLenConstraint = CERT_UNLIMITED_PATH_CONSTRAINT;
+        } else if (value->isCA) {
+            long len = DER_GetInteger(&decodeContext.pathLenConstraint);
+            if (len < 0 || len == LONG_MAX) {
+                PORT_SetError(SEC_ERROR_BAD_DER);
+                GEN_BREAK(SECFailure);
+            }
+            value->pathLenConstraint = len;
+        } else {
+            /* here we get an error where the subject is not a CA, but
+               the pathLenConstraint is set */
+            PORT_SetError(SEC_ERROR_BAD_DER);
+            GEN_BREAK(SECFailure);
+            break;
+        }
+    } while (0);
+
+    PORT_DestroyCheapArena(&tmpArena);
+    return (rv);
+}