Fix misparsing of empty value in conninfo_uri_parse_params().

After finding an "=" character, the pointer was advanced twice when it
should only advance once.  This is harmless as long as the value after "="
has at least one character; but if it doesn't, we'd miss the terminator
character and include too much in the value.

In principle this could lead to reading off the end of memory.  It does not
seem worth treating as a security issue though, because it would happen on
client side, and besides client logic that's taking conninfo strings from
untrusted sources has much worse security problems than this.

Report and patch received off-list from Thomas Fanghaenel.
Back-patch to 9.2 where the faulty code was introduced.

diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index 6810ee3a3e8a4fbadc4db72330e7f86b8b44fd3e..c11ecaef9b2f8afe1180f405b20763d0c102c172 100644 (file)
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -4965,9 +4965,8 @@ conninfo_uri_parse_params(char *params,
                    ++p;
                break;
            }
-
-           /* Advance, NUL is checked in the 'if' above */
-           ++p;
+           else
+               ++p;            /* Advance over all other bytes. */
        }
 
        keyword = conninfo_uri_decode(keyword, errorMessage);