Fix crash when v2 protocol is used.

When read_kind_from_backend() accumulates statistics data, it was not
prepared for v2 protocol case.

Bug report and patch from MCanivez.
https://www.pgpool.net/mantisbt/view.php?id=807
Slightly modified by me.

diff --git a/src/protocol/pool_process_query.c b/src/protocol/pool_process_query.c
index 5c16ea87d30c70b78b11591075227f8fea9ea990..5082d2f31633ac12a06192668f22247633262a24 100644 (file)
--- a/src/protocol/pool_process_query.c
+++ b/src/protocol/pool_process_query.c
@@ -3479,19 +3479,30 @@ read_kind_from_backend(POOL_CONNECTION * frontend, POOL_CONNECTION_POOL * backen
                {
                        if (kind_list[i] == 'E')
                        {
-                               pool_read(CONNECTION(backend, i), &len, sizeof(len));
-                               unread_len = sizeof(len);
-                               unread_p = palloc(ntohl(len));
-                               memcpy(unread_p, &len, sizeof(len));
-                               len = ntohl(len);
-                               len -= 4;
-                               unread_p = repalloc(unread_p, sizeof(len) + len);
-                               p = pool_read2(CONNECTION(backend, i), len);
-                               memcpy(unread_p + sizeof(len), p, len);
-                               unread_len += len;
-                               error_stat_count_up(i, extract_error_kind(unread_p + sizeof(len), PROTO_MAJOR_V3));
-                               pool_unread(CONNECTION(backend, i), unread_p, unread_len);
-                               pfree(unread_p);
+                               int major = MAJOR(CONNECTION(backend, i));
+
+                               if (major == PROTO_MAJOR_V3)
+                               {
+                                       pool_read(CONNECTION(backend, i), &len, sizeof(len));
+                                       unread_len = sizeof(len);
+                                       unread_p = palloc(ntohl(len));
+                                       memcpy(unread_p, &len, sizeof(len));
+                                       len = ntohl(len);
+                                       len -= 4;
+                                       unread_p = repalloc(unread_p, sizeof(len) + len);
+                                       p = pool_read2(CONNECTION(backend, i), len);
+                                       memcpy(unread_p + sizeof(len), p, len);
+                                       unread_len += len;
+                                       error_stat_count_up(i, extract_error_kind(unread_p + sizeof(len), PROTO_MAJOR_V3));
+                                       pool_unread(CONNECTION(backend, i), unread_p, unread_len);
+                                       pfree(unread_p);
+                               }
+                               else if (major == PROTO_MAJOR_V2)
+                               {
+                                       unread_p = pool_read_string(CONNECTION(backend, i), &unread_len, 0);
+                                       error_stat_count_up(i, extract_error_kind(unread_p, PROTO_MAJOR_V2));
+                                       pool_unread(CONNECTION(backend, i), unread_p, unread_len);
+                               }
                        }
                }
        }