From 431b638045814137a2037add85db577a7985b19d Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sat, 27 Aug 2011 14:16:25 -0400 Subject: [PATCH] Ensure we discard unread/unsent data when abandoning a connection attempt. There are assorted situations wherein PQconnectPoll() will abandon a connection attempt and try again with different parameters (eg, SSL versus not SSL). However, the code forgot to discard any pending data in libpq's I/O buffers when doing this. In at least one case (server returns E message during SSL negotiation), there is unread input data which bollixes the next connection attempt. I have not checked to see whether this is possible in the other cases where we close the socket and retry, but it seems like a matter of good defensive programming to add explicit buffer-flushing code to all of them. This is one of several issues exposed by Daniel Farina's report of misbehavior after a server-side fork failure. This has been wrong since forever, so back-patch to all supported branches. --- src/interfaces/libpq/fe-connect.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c index 0efc1700c9..d1e11a66a5 100644 --- a/src/interfaces/libpq/fe-connect.c +++ b/src/interfaces/libpq/fe-connect.c @@ -1911,6 +1911,9 @@ keep_going: /* We will come back to here until there is closesocket(conn->sock); conn->sock = -1; conn->status = CONNECTION_NEEDED; + /* Discard any unread/unsent data */ + conn->inStart = conn->inCursor = conn->inEnd = 0; + conn->outCount = 0; goto keep_going; } else @@ -1948,6 +1951,9 @@ keep_going: /* We will come back to here until there is closesocket(conn->sock); conn->sock = -1; conn->status = CONNECTION_NEEDED; + /* Discard any unread/unsent data */ + conn->inStart = conn->inCursor = conn->inEnd = 0; + conn->outCount = 0; goto keep_going; } } @@ -2061,6 +2067,9 @@ keep_going: /* We will come back to here until there is closesocket(conn->sock); conn->sock = -1; conn->status = CONNECTION_NEEDED; + /* Discard any unread/unsent data */ + conn->inStart = conn->inCursor = conn->inEnd = 0; + conn->outCount = 0; goto keep_going; } @@ -2128,6 +2137,9 @@ keep_going: /* We will come back to here until there is closesocket(conn->sock); conn->sock = -1; conn->status = CONNECTION_NEEDED; + /* Discard any unread/unsent data */ + conn->inStart = conn->inCursor = conn->inEnd = 0; + conn->outCount = 0; goto keep_going; } @@ -2147,6 +2159,9 @@ keep_going: /* We will come back to here until there is closesocket(conn->sock); conn->sock = -1; conn->status = CONNECTION_NEEDED; + /* Discard any unread/unsent data */ + conn->inStart = conn->inCursor = conn->inEnd = 0; + conn->outCount = 0; goto keep_going; } #endif @@ -2308,6 +2323,9 @@ keep_going: /* We will come back to here until there is closesocket(conn->sock); conn->sock = -1; conn->status = CONNECTION_NEEDED; + /* Discard any unread/unsent data */ + conn->inStart = conn->inCursor = conn->inEnd = 0; + conn->outCount = 0; goto keep_going; } } -- 2.40.0