1 files changed, 52 insertions, 5 deletions

diff --git a/sql/sql_repl.cc b/sql/sql_repl.cc
index 4b23348b306..4c3abc3c5a8 100644
--- a/sql/sql_repl.cc
+++ b/sql/sql_repl.cc
@@ -3906,6 +3906,7 @@ bool mysql_show_binlog_events(THD* thd)
 {
   Protocol *protocol= thd->protocol;
   List<Item> field_list;
+  char errmsg_buf[MYSYS_ERRMSG_SIZE];
   const char *errmsg = 0;
   bool ret = TRUE;
   /*
@@ -3920,6 +3921,9 @@ bool mysql_show_binlog_events(THD* thd)
   Master_info *mi= 0;
   LOG_INFO linfo;
   LEX_MASTER_INFO *lex_mi= &thd->lex->mi;
+  enum enum_binlog_checksum_alg checksum_alg;
+  my_off_t binlog_size;
+  MY_STAT s;
 
   DBUG_ENTER("mysql_show_binlog_events");
 
@@ -3968,10 +3972,6 @@ bool mysql_show_binlog_events(THD* thd)
       mi= 0;
     }
 
-    /* Validate user given position using checksum */
-    if (lex_mi->pos == pos && !opt_master_verify_checksum)
-      verify_checksum_once= true;
-
     unit->set_limit(thd->lex->current_select);
     limit_start= unit->offset_limit_cnt;
     limit_end= unit->select_limit_cnt;
@@ -3995,6 +3995,17 @@ bool mysql_show_binlog_events(THD* thd)
     if ((file=open_binlog(&log, linfo.log_file_name, &errmsg)) < 0)
       goto err;
 
+    my_stat(linfo.log_file_name, &s, MYF(0));
+    binlog_size= s.st_size;
+    if (lex_mi->pos > binlog_size)
+    {
+      sprintf(errmsg_buf, "Invalid pos specified. Requested from pos:%llu is "
+              "greater than actual file size:%lu\n", lex_mi->pos,
+              (ulong)s.st_size);
+      errmsg= errmsg_buf;
+      goto err;
+    }
+
     /*
       to account binlog event header size
     */
@@ -4046,7 +4057,43 @@ bool mysql_show_binlog_events(THD* thd)
       }
     }
 
-    my_b_seek(&log, pos);
+    if (lex_mi->pos > BIN_LOG_HEADER_SIZE)
+    {
+      checksum_alg= description_event->checksum_alg;
+      /* Validate user given position using checksum */
+      if (checksum_alg != BINLOG_CHECKSUM_ALG_OFF &&
+          checksum_alg != BINLOG_CHECKSUM_ALG_UNDEF)
+      {
+        if (!opt_master_verify_checksum)
+          verify_checksum_once= true;
+        my_b_seek(&log, pos);
+      }
+      else
+      {
+        my_off_t cur_pos= my_b_tell(&log);
+        ulong next_event_len= 0;
+        uchar buff[IO_SIZE];
+        while (cur_pos < pos)
+        {
+          my_b_seek(&log, cur_pos + EVENT_LEN_OFFSET);
+          if (my_b_read(&log, (uchar *)buff, sizeof(next_event_len)))
+          {
+            mysql_mutex_unlock(log_lock);
+            errmsg = "Could not read event_length";
+            goto err;
+          }
+          next_event_len= uint4korr(buff);
+          cur_pos= cur_pos + next_event_len;
+        }
+        if (cur_pos > pos)
+        {
+          mysql_mutex_unlock(log_lock);
+          errmsg= "Invalid input pos specified please provide valid one.";
+          goto err;
+        }
+        my_b_seek(&log, cur_pos);
+      }
+    }
 
     for (event_count = 0;
          (ev = Log_event::read_log_event(&log,