From 69d2cbd0a43d673b03cb80b680b4c919a27057c7 Mon Sep 17 00:00:00 2001 From: Mats Kindahl Date: Thu, 8 Dec 2022 10:00:23 +0100 Subject: Check return value of strdup when starting backend Inside `BackendInitialize`, if `strdup` returns NULL because it is out of memory, this will later trigger a server crash because of dereferencing a null pointer. This commit fixes this by checking the return values of `strdup` and exit the backend with exit status 1 if any of the allocations failed. This will be handled as a normal shutdown in the postmaster, which will report the exiting backend and continue executing. --- src/backend/postmaster/postmaster.c | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index f459dab360..e7739794ae 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -420,6 +420,7 @@ static pid_t StartChildProcess(AuxProcType type); static void StartAutovacuumWorker(void); static void MaybeStartWalReceiver(void); static void InitPostmasterDeathWatchHandle(void); +static char *safe_strdup(const char*); /* * Archiver is allowed to start up at the current postmaster state? @@ -704,7 +705,7 @@ PostmasterMain(int argc, char *argv[]) break; case 'C': - output_config_variable = strdup(optarg); + output_config_variable = safe_strdup(optarg); break; case 'c': @@ -735,7 +736,7 @@ PostmasterMain(int argc, char *argv[]) } case 'D': - userDoption = strdup(optarg); + userDoption = safe_strdup(optarg); break; case 'd': @@ -4275,8 +4276,8 @@ BackendInitialize(Port *port) * Save remote_host and remote_port in port structure (after this, they * will appear in log_line_prefix data for log messages). */ - port->remote_host = strdup(remote_host); - port->remote_port = strdup(remote_port); + port->remote_host = safe_strdup(remote_host); + port->remote_port = safe_strdup(remote_port); /* And now we can issue the Log_connections message, if wanted */ if (Log_connections) @@ -4307,7 +4308,10 @@ BackendInitialize(Port *port) ret == 0 && strspn(remote_host, "0123456789.") < strlen(remote_host) && strspn(remote_host, "0123456789ABCDEFabcdef:") < strlen(remote_host)) - port->remote_hostname = strdup(remote_host); + { + port->remote_hostname = safe_strdup(remote_host); + } + /* * Ready to begin client interaction. We will give up and _exit(1) after @@ -6475,3 +6479,13 @@ InitPostmasterDeathWatchHandle(void) GetLastError()))); #endif /* WIN32 */ } + +char *safe_strdup(const char *str) { + char *result = strdup(str); + if (result == NULL) { + ereport(ERROR, + (errcode(ERRCODE_OUT_OF_MEMORY), + errmsg("out of memory"))); + } + return result; +} -- 2.34.1