From 4e3bb5a0c91238c151f94581a846ca0942bdba0f Mon Sep 17 00:00:00 2001
From: Levi Neely <lkn@darkstar.example.net>
Date: Sun, 8 Mar 2026 14:33:06 +0100
Subject: [PATCH] Add overflow-safe allocation wrappers to pmem module

---
 pclsync/pmem.c | 9 +++++++++
 pclsync/pmem.h | 2 ++
 2 files changed, 11 insertions(+)

diff --git a/pclsync/pmem.c b/pclsync/pmem.c
index e751eaa..af5f074 100644
--- a/pclsync/pmem.c
+++ b/pclsync/pmem.c
@@ -1,4 +1,6 @@
 #include <sys/mman.h>
+#include <stdlib.h>
+#include <stdint.h>
 
 #include "pcompiler.h"
 #include "psql.h"
@@ -60,3 +62,10 @@ int pmem_munlock(void *ptr, size_t size) {
 void pmem_reset(void *ptr, size_t size) {
   madvise(ptr, size, MADV_DONTNEED);
 }
+
+void *pmem_calloc_safe(size_t nmemb, size_t size) {
+  if (nmemb != 0 && size > SIZE_MAX / nmemb) {
+    return NULL;
+  }
+  return calloc(nmemb, size);
+}
diff --git a/pclsync/pmem.h b/pclsync/pmem.h
index 394ba1e..685c15d 100644
--- a/pclsync/pmem.h
+++ b/pclsync/pmem.h
@@ -2,6 +2,7 @@
 #define __PMEM_H
 
 #include <stddef.h>
+#include <stdint.h>
 
 void *pmem_mmap(size_t size);
 void *pmem_mmap_safe(size_t size);
@@ -9,5 +10,6 @@ int pmem_munmap(void *ptr, size_t size);
 int pmem_mlock(void *ptr, size_t size);
 int pmem_munlock(void *ptr, size_t size);
 void pmem_reset(void *ptr, size_t size);
+void *pmem_calloc_safe(size_t nmemb, size_t size);
 
 #endif
\ No newline at end of file