utils: lockfile: avoid stack overflow for lockfile buffer

See rakshasa/rtorrent#1169
Elegant996 · May 15, 2023 · 565f419 · 565f419
1 parent c11d613
commit 565f419
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/src/utils/lockfile.cc b/src/utils/lockfile.cc
@@ -75,7 +75,8 @@ Lockfile::try_lock() {
   int  pos = ::gethostname(buf, 255);
 
   if (pos == 0) {
-    ::snprintf(buf + std::strlen(buf), 255, ":+%i\n", ::getpid());
+    ssize_t len = std::strlen(buf);
+    ::snprintf(buf + len, 255 - len, ":+%i\n", ::getpid());
     ssize_t __attribute__((unused)) result = ::write(fd, buf, std::strlen(buf));
   }