From: Bruno Haible <bruno@clisp.org>
Date: Tue, 16 Sep 2025 14:51:55 +0000 (+0200)
Subject: strerror_r: Ensure a trailing NUL when truncating.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bbd69592e3f8ba4d2777642d143ba53296332ef4;p=thirdparty%2Fgnulib.git

strerror_r: Ensure a trailing NUL when truncating.

* lib/strerror_r.c (strerror_r): Fix use of snprintf.
---

diff --git a/ChangeLog b/ChangeLog
index bbf3ce8741..73b7ff269c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2025-09-16  Bruno Haible  <bruno@clisp.org>
+
+	strerror_r: Ensure a trailing NUL when truncating.
+	* lib/strerror_r.c (strerror_r): Fix use of snprintf.
+
 2025-09-16  Bruno Haible  <bruno@clisp.org>
 
 	strtof: Work around mingw bug with overflow.
diff --git a/lib/strerror_r.c b/lib/strerror_r.c
index 9c0161cd01..b67684ebe6 100644
--- a/lib/strerror_r.c
+++ b/lib/strerror_r.c
@@ -450,10 +450,11 @@ strerror_r (int errnum, char *buf, size_t buflen)
 #endif
 #if defined __HAIKU__
         /* For consistency with perror().  */
-        snprintf (buf, buflen, "Unknown Application Error (%d)", errnum);
+        snprintf (buf, buflen - 1, "Unknown Application Error (%d)", errnum);
 #else
-        snprintf (buf, buflen, "Unknown error %d", errnum);
+        snprintf (buf, buflen - 1, "Unknown error %d", errnum);
 #endif
+        buf[buflen - 1] = '\0';
       }
 
     errno = saved_errno;