Fix redis error reporting

Previously, we assumed that reply->str was NULL
terminated. However, this turned out to be not true,
as users reported crashes in strlen connected to
where reply->str was appended to an std::string.

Use the method recomended by the docs, to read the
length separately.

diff --git a/src/database-redis.cpp b/src/database-redis.cpp
index 196d72f251e307005bde1cb489638b333e47ee77..498e9d39a50169dfa28c864890635bd512263eab 100644 (file)
--- a/src/database-redis.cpp
+++ b/src/database-redis.cpp
@@ -92,7 +92,7 @@ bool Database_Redis::saveBlock(const v3s16 &pos, const std::string &data)
 
        if (reply->type == REDIS_REPLY_ERROR) {
                warningstream << "saveBlock: saving block " << PP(pos)
-                       << " failed: " << reply->str << std::endl;
+                       << " failed: " << std::string(reply->str, reply->len) << std::endl;
                freeReplyObject(reply);
                return false;
        }
@@ -119,7 +119,7 @@ std::string Database_Redis::loadBlock(const v3s16 &pos)
                return str;
        }
        case REDIS_REPLY_ERROR: {
-               std::string errstr = reply->str;
+               std::string errstr(reply->str, reply->len);
                freeReplyObject(reply);
                errorstream << "loadBlock: loading block " << PP(pos)
                        << " failed: " << errstr << std::endl;
@@ -134,7 +134,7 @@ std::string Database_Redis::loadBlock(const v3s16 &pos)
        }
        errorstream << "loadBlock: loading block " << PP(pos)
                << " returned invalid reply type " << reply->type
-               << ": " << reply->str << std::endl;
+               << ": " << std::string(reply->str, reply->len) << std::endl;
        freeReplyObject(reply);
        throw FileNotGoodException(std::string(
                "Redis command 'HGET %s %s' gave invalid reply."));
@@ -151,7 +151,7 @@ bool Database_Redis::deleteBlock(const v3s16 &pos)
                        "Redis command 'HDEL %s %s' failed: ") + ctx->errstr);
        } else if (reply->type == REDIS_REPLY_ERROR) {
                warningstream << "deleteBlock: deleting block " << PP(pos)
-                       << " failed: " << reply->str << std::endl;
+                       << " failed: " << std::string(reply->str, reply->len) << std::endl;
                freeReplyObject(reply);
                return false;
        }
@@ -177,7 +177,8 @@ void Database_Redis::listAllLoadableBlocks(std::vector<v3s16> &dst)
                break;
        case REDIS_REPLY_ERROR:
                throw FileNotGoodException(std::string(
-                       "Failed to get keys from database: ") + reply->str);
+                       "Failed to get keys from database: ") +
+                       std::string(reply->str, reply->len));
        }
        freeReplyObject(reply);
 }