diff -up Linux-PAM-1.3.1/libpam/include/pam_cc_compat.h.pam-inline-pam-asprintf Linux-PAM-1.3.1/libpam/include/pam_cc_compat.h
--- Linux-PAM-1.3.1/libpam/include/pam_cc_compat.h.pam-inline-pam-asprintf	2025-06-17 10:12:31.039519165 +0200
+++ Linux-PAM-1.3.1/libpam/include/pam_cc_compat.h	2025-06-17 10:17:40.313892315 +0200
@@ -15,6 +15,12 @@
 # define PAM_CLANG_PREREQ(maj, min)	0
 #endif
 
+#if PAM_GNUC_PREREQ(3, 0)
+# define PAM_ATTRIBUTE_MALLOC		__attribute__((__malloc__))
+#else
+# define PAM_ATTRIBUTE_MALLOC		/* empty */
+#endif
+
 #if PAM_GNUC_PREREQ(4, 6)
 # define DIAG_PUSH_IGNORE_CAST_QUAL					\
 	_Pragma("GCC diagnostic push");					\
diff -up Linux-PAM-1.3.1/libpam/include/pam_inline.h.pam-inline-pam-asprintf Linux-PAM-1.3.1/libpam/include/pam_inline.h
--- Linux-PAM-1.3.1/libpam/include/pam_inline.h.pam-inline-pam-asprintf	2025-06-17 10:12:31.039639983 +0200
+++ Linux-PAM-1.3.1/libpam/include/pam_inline.h	2025-06-17 10:19:03.453146173 +0200
@@ -9,6 +9,9 @@
 #define PAM_INLINE_H
 
 #include "pam_cc_compat.h"
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 
 /*
@@ -64,4 +67,37 @@ pam_str_skip_icase_prefix_len(const char
 #define pam_str_skip_icase_prefix(str_, prefix_)	\
 	pam_str_skip_icase_prefix_len((str_), (prefix_), sizeof(prefix_) - 1 + PAM_MUST_BE_ARRAY(prefix_))
 
+static inline char * PAM_FORMAT((printf, 1, 2)) PAM_NONNULL((1)) PAM_ATTRIBUTE_MALLOC
+pam_asprintf(const char *fmt, ...)
+{
+	int rc;
+	char *res;
+	va_list ap;
+
+	va_start(ap, fmt);
+	rc = vasprintf(&res, fmt, ap);
+	va_end(ap);
+
+	return rc < 0 ? NULL : res;
+}
+
+static inline int PAM_FORMAT((printf, 3, 4)) PAM_NONNULL((3))
+pam_snprintf(char *str, size_t size, const char *fmt, ...)
+{
+	int rc;
+	va_list ap;
+
+	va_start(ap, fmt);
+	rc = vsnprintf(str, size, fmt, ap);
+	va_end(ap);
+
+	if (rc < 0 || (unsigned int) rc >= size)
+		return -1;
+	return rc;
+}
+
+#define pam_sprintf(str_, fmt_, ...)						\
+	pam_snprintf((str_), sizeof(str_) + PAM_MUST_BE_ARRAY(str_), (fmt_),	\
+		     ##__VA_ARGS__)
+
 #endif /* PAM_INLINE_H */