MONGOCRYPT-432 Allow keyAltName in encryptedFieldsMap

src/mc-efc-private.h

@@ -37,6 +37,7 @@ typedef enum _supported_query_type_flags {
 typedef struct _mc_EncryptedField_t {
     supported_query_type_flags supported_queries;
     _mongocrypt_buffer_t keyId;
+    const char *keyAltName;
     const char *path;
     struct _mc_EncryptedField_t *next;
 } mc_EncryptedField_t;

src/mc-efc.c

@@ -85,18 +85,46 @@ static bool _parse_field(mc_EncryptedFieldConfig_t *efc, bson_t *field, mongocry
     BSON_ASSERT_PARAM(efc);
     BSON_ASSERT_PARAM(field);
 
-    if (!bson_iter_init_find(&field_iter, field, "keyId")) {
-        CLIENT_ERR("unable to find 'keyId' in 'field' document");
+    bool has_keyid = false;
+    bool has_keyaltname = false;
+    if (bson_iter_init_find(&field_iter, field, "keyId")) {
+        has_keyid = true;
+    }
+    if (bson_iter_init_find(&field_iter, field, "keyAltName")) {
+        has_keyaltname = true;
+    }
+    if (!(has_keyid || has_keyaltname)) {
+        CLIENT_ERR("unable to find 'keyId' or 'keyAltName' in 'field' document");
         return false;
     }
-    if (!BSON_ITER_HOLDS_BINARY(&field_iter)) {
-        CLIENT_ERR("expected 'fields.keyId' to be type binary, got: %d", (int)bson_iter_type(&field_iter));
+    if (has_keyid && has_keyaltname) {
+        CLIENT_ERR("only one of 'keyId' or 'keyAltName may be in 'field' document");
         return false;
     }
+
     _mongocrypt_buffer_t field_keyid;
-    if (!_mongocrypt_buffer_from_uuid_iter(&field_keyid, &field_iter)) {
-        CLIENT_ERR("unable to parse uuid key from 'fields.keyId'");
-        return false;
+    if (has_keyid) {
+        BSON_ASSERT(bson_iter_init_find(&field_iter, field, "keyId"));
+        if (!BSON_ITER_HOLDS_BINARY(&field_iter)) {
+            CLIENT_ERR("expected 'fields.keyId' to be type binary, got: %d", (int)bson_iter_type(&field_iter));
+            return false;
+        }
+        if (!_mongocrypt_buffer_from_uuid_iter(&field_keyid, &field_iter)) {
+            CLIENT_ERR("unable to parse uuid key from 'fields.keyId'");
+            return false;
+        }
+    } else if (has_keyaltname) {
+        BSON_ASSERT(bson_iter_init_find(&field_iter, field, "keyAltName"));
+    }
+
+    const char *keyAltName = "";
+    if (has_keyaltname) {
+        BSON_ASSERT(bson_iter_init_find(&field_iter, field, "keyAltName"));
+        if (!BSON_ITER_HOLDS_UTF8(&field_iter)) {
+            CLIENT_ERR("expected 'fields.keyAltName' to be type UTF-8, got: %d", (int)bson_iter_type(&field_iter));
+            return false;
+        }
+        keyAltName = bson_iter_utf8(&field_iter, NULL);
     }
 
     const char *field_path;
@@ -151,7 +179,12 @@ static bool _parse_field(mc_EncryptedFieldConfig_t *efc, bson_t *field, mongocry
 
     /* Prepend a new mc_EncryptedField_t */
     mc_EncryptedField_t *ef = bson_malloc0(sizeof(mc_EncryptedField_t));
-    _mongocrypt_buffer_copy_to(&field_keyid, &ef->keyId);
+    if (has_keyid) {
+        _mongocrypt_buffer_copy_to(&field_keyid, &ef->keyId);
+    }
+    if (has_keyaltname) {
+        ef->keyAltName = bson_strdup(keyAltName);
+    }
     ef->path = bson_strdup(field_path);
     ef->next = efc->fields;
     ef->supported_queries = query_types;

src/mc-schema-broker-private.h

@@ -19,6 +19,7 @@
 
 #include "mc-efc-private.h" // mc_EncryptedFieldConfig_t
 #include "mongocrypt-cache-collinfo-private.h"
+#include "mongocrypt-key-broker-private.h"
 #include "mongocrypt.h"
 #include <bson/bson.h>
 
@@ -102,6 +103,12 @@ bool mc_schema_broker_need_more_schemas(const mc_schema_broker_t *sb);
 const mc_EncryptedFieldConfig_t *
 mc_schema_broker_get_encryptedFields(const mc_schema_broker_t *sb, const char *coll, mongocrypt_status_t *status);
 
+// mc_schema_broker_get_encryptedFields returns encryptedFields for a collection if any exists.
+//
+// Returns NULL if none is found.
+const mc_EncryptedFieldConfig_t *
+mc_schema_broker_maybe_get_encryptedFields(const mc_schema_broker_t *sb, const char *coll, mongocrypt_status_t *status);
+
 typedef enum {
     MC_CMD_SCHEMAS_FOR_CRYPT_SHARED, // target the crypt_shared library.
     MC_CMD_SCHEMAS_FOR_MONGOCRYPTD,  // target mongocryptd process.
@@ -118,7 +125,8 @@ typedef enum {
 // - encryptionInformation: for QE.
 //
 // Set cmd_target to the intended command destination. This impacts if/how schema information is added.
-bool mc_schema_broker_add_schemas_to_cmd(const mc_schema_broker_t *sb,
+bool mc_schema_broker_add_schemas_to_cmd(mc_schema_broker_t *sb,
+                                         _mongocrypt_key_broker_t *kb,
                                          bson_t *cmd /* in and out */,
                                          mc_cmd_target_t cmd_target,
                                          mongocrypt_status_t *status);

src/mc-schema-broker.c

@@ -17,6 +17,7 @@
 #include "mc-schema-broker-private.h"
 
 #include "mc-efc-private.h" // mc_EncryptedFieldConfig_t
+#include "mongocrypt-buffer-private.h"
 #include "mongocrypt-cache-collinfo-private.h"
 #include "mongocrypt-key-broker-private.h"
 #include "mongocrypt-private.h"
@@ -607,7 +608,25 @@ mc_schema_broker_get_encryptedFields(const mc_schema_broker_t *sb, const char *c
     return NULL;
 }
 
+const mc_EncryptedFieldConfig_t *
+mc_schema_broker_maybe_get_encryptedFields(const mc_schema_broker_t *sb, const char *coll, mongocrypt_status_t *status) {
+    BSON_ASSERT_PARAM(sb);
+    BSON_ASSERT_PARAM(coll);
+
+    for (const mc_schema_entry_t *it = sb->ll; it != NULL; it = it->next) {
+        if (0 != strcmp(it->coll, coll)) {
+            continue;
+        }
+        if (!it->encryptedFields.set) {
+            return NULL;
+        }
+        return &it->encryptedFields.efc;
+    }
+    return NULL;
+}
+
 static bool append_encryptedFields(const bson_t *encryptedFields,
+                                   _mongocrypt_key_broker_t *kb,
                                    const char *coll,
                                    uint8_t default_strEncodeVersion,
                                    bson_t *out,
@@ -633,7 +652,8 @@ static bool append_encryptedFields(const bson_t *encryptedFields,
 
     // Copy all values. Check if state collections are present.
     while (bson_iter_next(&iter)) {
-        if (strcmp(bson_iter_key(&iter), "escCollection") == 0) {
+        const char *iter_key = bson_iter_key(&iter);
+        if (strcmp(iter_key, "escCollection") == 0) {
             has_escCollection = true;
         }
         if (strcmp(bson_iter_key(&iter), "ecocCollection") == 0) {
@@ -645,8 +665,92 @@ static bool append_encryptedFields(const bson_t *encryptedFields,
         if (strcmp(bson_iter_key(&iter), "strEncodeVersion") == 0) {
             has_strEncodeVersion = true;
         }
-        TRY_BSON_OR(BSON_APPEND_VALUE(out, bson_iter_key(&iter), bson_iter_value(&iter))) {
-            goto fail;
+        /* Special-case the "fields" array: copy each element but omit the
+         * "keyAltName" key from each subdocument. For other keys, copy as-is. */
+        if (0 == strcmp(iter_key, "fields") && BSON_ITER_HOLDS_ARRAY(&iter)) {
+            uint32_t array_len = 0;
+            const uint8_t *array_data = NULL;
+            bson_t array_bson;
+
+            bson_iter_array(&iter, &array_len, &array_data);
+            bson_init_static(&array_bson, array_data, array_len);
+
+            bson_t new_array;
+            TRY_BSON_OR(BSON_APPEND_ARRAY_BEGIN(out, "fields", &new_array)) {
+                goto fail;
+            }
+
+            bson_iter_t arr_it;
+            if (!bson_iter_init(&arr_it, &array_bson)) {
+                CLIENT_ERR("failed to iterate 'fields' array");
+                goto fail;
+            }
+
+            size_t idx = 0;
+            while (bson_iter_next(&arr_it)) {
+                char idx_str[32];
+                const char *idx_str_ptr;
+                const size_t ret = bson_uint32_to_string((uint32_t)idx, &idx_str_ptr, idx_str, sizeof idx_str);
+                BSON_ASSERT(ret > 0 && ret <= (int)sizeof idx_str);
+
+                if (BSON_ITER_HOLDS_DOCUMENT(&arr_it)) {
+                    uint32_t doc_len = 0;
+                    const uint8_t *doc_data = NULL;
+                    bson_iter_document(&arr_it, &doc_len, &doc_data);
+                    bson_t elem_doc;
+                    bson_init_static(&elem_doc, doc_data, doc_len);
+
+                    bson_t new_doc;
+                    char *keyAltName_dup = NULL;
+
+                    /* Extract keyAltName (if present) and strdup it so caller can
+                     * derive a keyId from it. */
+                    bson_iter_t doc_it2;
+                    if (bson_iter_init(&doc_it2, &elem_doc)) {
+                        if (bson_iter_find(&doc_it2, "keyAltName") && BSON_ITER_HOLDS_UTF8(&doc_it2)) {
+                            const char *kan = bson_iter_utf8(&doc_it2, NULL);
+                            if (kan) {
+                                keyAltName_dup = bson_strdup(kan);
+                            }
+                        }
+                    }
+
+                    bson_init(&new_doc);
+                    /* Copy elem_doc into new_doc excluding "keyAltName". */
+                    bson_copy_to_excluding_noinit(&elem_doc, &new_doc, "keyAltName", NULL);
+
+                    if (keyAltName_dup) {
+                        _mongocrypt_buffer_t unused, key_id_out;
+                        bson_value_t key_alt_name_v;
+                        _bson_value_from_string(keyAltName_dup, &key_alt_name_v);
+                        BSON_ASSERT(_mongocrypt_key_broker_decrypted_key_by_name(kb, &key_alt_name_v, &unused, &key_id_out));
+                        bson_append_binary(&new_doc, "keyId", -1, key_id_out.subtype, key_id_out.data, key_id_out.len);
+                    }
+
+                    TRY_BSON_OR(bson_append_document(&new_array, idx_str_ptr, -1, &new_doc)) {
+                        bson_destroy(&new_doc);
+                        bson_free(keyAltName_dup);
+                        goto fail;
+                    }
+                    bson_destroy(&new_doc);
+                    bson_free(keyAltName_dup);
+                } else {
+                    /* Non-document elements: copy as-is. */
+                    TRY_BSON_OR(BSON_APPEND_VALUE(&new_array, idx_str, bson_iter_value(&arr_it))) {
+                        goto fail;
+                    }
+                }
+
+                idx++;
+            }
+
+            TRY_BSON_OR(bson_append_array_end(out, &new_array)) {
+                goto fail;
+            }
+        } else {
+            TRY_BSON_OR(BSON_APPEND_VALUE(out, iter_key, bson_iter_value(&iter))) {
+                goto fail;
+            }
         }
     }
 
@@ -687,6 +791,7 @@ static bool append_encryptedFields(const bson_t *encryptedFields,
 }
 
 static bool append_encryptionInformation(const mc_schema_broker_t *sb,
+                                         _mongocrypt_key_broker_t *kb,
                                          const char *cmd_name,
                                          bson_t *out,
                                          mongocrypt_status_t *status) {
@@ -728,7 +833,7 @@ static bool append_encryptionInformation(const mc_schema_broker_t *sb,
             encryptedFields = &se->encryptedFields.bson;
             default_strEncodeVersion = se->encryptedFields.efc.str_encode_version;
         }
-        if (!append_encryptedFields(encryptedFields, se->coll, default_strEncodeVersion, &ns_to_schema_bson, status)) {
+        if (!append_encryptedFields(encryptedFields, kb, se->coll, default_strEncodeVersion, &ns_to_schema_bson, status)) {
             goto loop_fail;
         }
 
@@ -778,6 +883,7 @@ static const char *get_cmd_name(const bson_t *cmd, mongocrypt_status_t *status)
 }
 
 static bool insert_encryptionInformation(const mc_schema_broker_t *sb,
+                                         _mongocrypt_key_broker_t *kb,
                                          const char *cmd_name,
                                          bson_t *cmd /* in and out */,
                                          mc_cmd_target_t cmd_target,
@@ -841,7 +947,7 @@ static bool insert_encryptionInformation(const mc_schema_broker_t *sb,
                 goto fail;
             }
             // And append `encryptionInformation`.
-            if (!append_encryptionInformation(sb, cmd_name, &nsInfo_array_0, status)) {
+            if (!append_encryptionInformation(sb, kb, cmd_name, &nsInfo_array_0, status)) {
                 goto fail;
             }
             if (!bson_append_document_end(&nsInfo_array, &nsInfo_array_0)) {
@@ -891,7 +997,7 @@ static bool insert_encryptionInformation(const mc_schema_broker_t *sb,
             bson_copy_to(&tmp, &explain);
         }
 
-        if (!append_encryptionInformation(sb, cmd_name, &explain, status)) {
+        if (!append_encryptionInformation(sb, kb, cmd_name, &explain, status)) {
             goto fail;
         }
 
@@ -914,7 +1020,7 @@ static bool insert_encryptionInformation(const mc_schema_broker_t *sb,
     //    "<command name>": { ... }
     //    "encryptionInformation": {}
     // }
-    if (!append_encryptionInformation(sb, cmd_name, cmd, status)) {
+    if (!append_encryptionInformation(sb, kb, cmd_name, cmd, status)) {
         goto fail;
     }
 
@@ -1032,7 +1138,8 @@ static bool insert_csfleEncryptionSchemas(const mc_schema_broker_t *sb,
     return true;
 }
 
-bool mc_schema_broker_add_schemas_to_cmd(const mc_schema_broker_t *sb,
+bool mc_schema_broker_add_schemas_to_cmd(mc_schema_broker_t *sb,
+                                         _mongocrypt_key_broker_t *kb,
                                          bson_t *cmd /* in and out */,
                                          mc_cmd_target_t cmd_target,
                                          mongocrypt_status_t *status) {
@@ -1053,6 +1160,18 @@ bool mc_schema_broker_add_schemas_to_cmd(const mc_schema_broker_t *sb,
         if (it->encryptedFields.set) {
             has_encryptedFields = true;
             coll_with_encryptedFields = it->coll;
+            for (mc_EncryptedField_t *f = it->encryptedFields.efc.fields; f != NULL; f = f->next) {
+                if (f->keyAltName) {
+                    bson_value_t key_alt_name;
+                    _mongocrypt_buffer_t unused;
+                    _bson_value_from_string(f->keyAltName, &key_alt_name);
+                    const bool r = _mongocrypt_key_broker_decrypted_key_by_name(kb, &key_alt_name, &unused, &f->keyId);
+                    if (!r) {
+                        CLIENT_ERR("Could not find key by keyAltName: %s", f->keyAltName);
+                        return false;
+                    }
+                }
+            }
         } else if (it->jsonSchema.set) {
             has_jsonSchema = true;
             coll_with_jsonSchema = it->coll;
@@ -1061,7 +1180,7 @@ bool mc_schema_broker_add_schemas_to_cmd(const mc_schema_broker_t *sb,
 
     if (has_encryptedFields && has_jsonSchema) {
         if (sb->schema_mixing_is_supported) {
-            return insert_encryptionInformation(sb, cmd_name, cmd, cmd_target, status)
+            return insert_encryptionInformation(sb, kb, cmd_name, cmd, cmd_target, status)
                 && insert_csfleEncryptionSchemas(sb, cmd, cmd_target, status);
         }
 
@@ -1078,7 +1197,7 @@ bool mc_schema_broker_add_schemas_to_cmd(const mc_schema_broker_t *sb,
 
     if (has_encryptedFields) {
         // Use encryptionInformation.
-        return insert_encryptionInformation(sb, cmd_name, cmd, cmd_target, status);
+        return insert_encryptionInformation(sb, kb, cmd_name, cmd, cmd_target, status);
     }
 
     if (has_jsonSchema) {
@@ -1089,7 +1208,7 @@ bool mc_schema_broker_add_schemas_to_cmd(const mc_schema_broker_t *sb,
     // Collections have no QE or CSFLE schemas.
     if (0 == strcmp(cmd_name, "bulkWrite")) {
         // "bulkWrite" does not support the jsonSchema field. Use encryptionInformation with empty schemas.
-        return insert_encryptionInformation(sb, cmd_name, cmd, cmd_target, status);
+        return insert_encryptionInformation(sb, kb, cmd_name, cmd, cmd_target, status);
     }
 
     // Use csfleEncryptionSchemas / jsonSchema with empty schemas.