Add reallocarray() for those without it.

config.h.in

@@ -556,6 +556,9 @@
 /* Define to 1 if you have the `random' function. */
 #undef HAVE_RANDOM
 
+/* Define to 1 if you have the `reallocarray' function. */
+#undef HAVE_REALLOCARRAY
+
 /* Define to 1 if you have the `revoke' function. */
 #undef HAVE_REVOKE
 

configure

@@ -2653,6 +2653,7 @@ as_fn_append ac_header_list " sys/stropts.h"
 as_fn_append ac_header_list " sys/sysmacros.h"
 as_fn_append ac_func_list " killpg"
 as_fn_append ac_func_list " nl_langinfo"
+as_fn_append ac_func_list " reallocarray"
 as_fn_append ac_func_list " strftime"
 as_fn_append ac_func_list " tzset"
 as_fn_append ac_func_list " seteuid"
@@ -17921,6 +17922,8 @@ done
 
 
 
+
+
 for ac_func in getgrouplist
 do :
   ac_fn_c_check_func "$LINENO" "getgrouplist" "ac_cv_func_getgrouplist"

configure.ac

@@ -2395,7 +2395,7 @@ dnl
 dnl Function checks
 dnl
 AC_FUNC_GETGROUPS
-AC_CHECK_FUNCS_ONCE([killpg nl_langinfo strftime tzset])
+AC_CHECK_FUNCS_ONCE([killpg nl_langinfo reallocarray strftime tzset])
 AC_CHECK_FUNCS([getgrouplist], [], [
     case "$host_os" in
     aix*)

include/sudo_compat.h

@@ -368,7 +368,7 @@ __dso_public long long sudo_strtonum(const char *, long long, long long, const c
  * All libc replacements are prefixed with "sudo_" to avoid namespace issues.
  */
 
-struct timeval;
+struct passwd;
 struct timespec;
 
 #ifndef HAVE_CLOSEFROM
@@ -479,5 +479,10 @@ __dso_public const char *sudo_getprogname(void);
 # undef getprogname
 # define getprogname() sudo_getprogname()
 #endif /* HAVE_GETPROGNAME */
+#ifndef HAVE_REALLOCARRAY
+__dso_public void *sudo_reallocarray(void *ptr, size_t nmemb, size_t size);
+# undef reallocarray
+# define reallocarray(_a, _b, _c) sudo_reallocarray((_a), (_b), (_c))
+#endif /* HAVE_REALLOCARRAY */
 
 #endif /* _SUDO_COMPAT_H */

lib/util/alloc.c

@@ -48,6 +48,7 @@
 #elif defined(HAVE_INTTYPES_H)
 # include <inttypes.h>
 #endif
+#include <errno.h>
 #include <limits.h>
 
 #define DEFAULT_TEXT_DOMAIN	"sudo"
@@ -257,3 +258,17 @@ sudo_evasprintf_v1(char **ret, const char *fmt, va_list args)
 	sudo_fatal_nodebug(NULL);
     return len;
 }
+
+#ifndef HAVE_REALLOCARRAY
+void *
+sudo_reallocarray(void *ptr, size_t nmemb, size_t size)
+{
+    if (nmemb > SIZE_MAX / size) {
+	errno = EOVERFLOW;
+	return NULL;
+    }
+
+    size *= nmemb;
+    return ptr ? realloc(ptr, size) : malloc(size);
+}
+#endif /* HAVE_REALLOCARRAY */