From 4af446e7cd0b37bb5d7fa9b73193c68e14239499 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 29 Nov 2012 19:57:01 -0500 Subject: [PATCH] Produce a more useful error message for over-length Unix socket paths. The length of a socket path name is constrained by the size of struct sockaddr_un, and there's not a lot we can do about it since that is a kernel API. However, it would be a good thing if we produced an intelligible error message when the user specifies a socket path that's too long --- and getaddrinfo's standard API is too impoverished to do this in the natural way. So insert explicit tests at the places where we construct a socket path name. Now you'll get an error that makes sense and even tells you what the limit is, rather than something generic like "Non-recoverable failure in name resolution". Per trouble report from Jeremy Drake and a fix idea from Andrew Dunstan. --- src/backend/libpq/pqcomm.c | 8 ++++++++ src/include/libpq/pqcomm.h | 13 +++++++++++++ src/interfaces/libpq/fe-connect.c | 11 ++++++++++- 3 files changed, 31 insertions(+), 1 deletion(-) diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c index 5e86987f22..15a01a8324 100644 --- a/src/backend/libpq/pqcomm.c +++ b/src/backend/libpq/pqcomm.c @@ -308,6 +308,14 @@ StreamServerPort(int family, char *hostName, unsigned short portNumber, * that file path */ UNIXSOCK_PATH(unixSocketPath, portNumber, unixSocketDir); + if (strlen(unixSocketPath) >= UNIXSOCK_PATH_BUFLEN) + { + ereport(LOG, + (errmsg("Unix-domain socket path \"%s\" is too long (maximum %d bytes)", + unixSocketPath, + (int) (UNIXSOCK_PATH_BUFLEN - 1)))); + return STATUS_ERROR; + } if (Lock_AF_UNIX(unixSocketDir, unixSocketPath) != STATUS_OK) return STATUS_ERROR; service = unixSocketPath; diff --git a/src/include/libpq/pqcomm.h b/src/include/libpq/pqcomm.h index 604b5535df..635132dec9 100644 --- a/src/include/libpq/pqcomm.h +++ b/src/include/libpq/pqcomm.h @@ -73,6 +73,19 @@ typedef struct DEFAULT_PGSOCKET_DIR, \ (port)) +/* + * The maximum workable length of a socket path is what will fit into + * struct sockaddr_un. This is usually only 100 or so bytes :-(. + * + * For consistency, always pass a MAXPGPATH-sized buffer to UNIXSOCK_PATH(), + * then complain if the resulting string is >= UNIXSOCK_PATH_BUFLEN bytes. + * (Because the standard API for getaddrinfo doesn't allow it to complain in + * a useful way when the socket pathname is too long, we have to test for + * this explicitly, instead of just letting the subroutine return an error.) + */ +#define UNIXSOCK_PATH_BUFLEN sizeof(((struct sockaddr_un *) NULL)->sun_path) + + /* * These manipulate the frontend/backend protocol version number. * diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c index 9eaf41025b..1386bb791a 100644 --- a/src/interfaces/libpq/fe-connect.c +++ b/src/interfaces/libpq/fe-connect.c @@ -1322,7 +1322,7 @@ static int connectDBStart(PGconn *conn) { int portnum; - char portstr[128]; + char portstr[MAXPGPATH]; struct addrinfo *addrs = NULL; struct addrinfo hint; const char *node; @@ -1384,6 +1384,15 @@ connectDBStart(PGconn *conn) node = NULL; hint.ai_family = AF_UNIX; UNIXSOCK_PATH(portstr, portnum, conn->pgunixsocket); + if (strlen(portstr) >= UNIXSOCK_PATH_BUFLEN) + { + appendPQExpBuffer(&conn->errorMessage, + libpq_gettext("Unix-domain socket path \"%s\" is too long (maximum %d bytes)\n"), + portstr, + (int) (UNIXSOCK_PATH_BUFLEN - 1)); + conn->options_valid = false; + goto connect_errReturn; + } #else /* Without Unix sockets, default to localhost instead */ node = DefaultHost; -- 2.40.0