From 356771c0c3c2b8040ba2ae83394460d1402d487b Mon Sep 17 00:00:00 2001
From: Miroslav Lichvar <mlichvar@redhat.com>
Date: Tue, 3 May 2022 13:25:11 +0200
Subject: [PATCH] client: rework command catenation

Use snprintf() instead of strcat() and don't try to parse commands
longer than 2048 characters to make it consistent with the chrony.conf
parser, avoid memory allocation, and not rely on the system ARG_MAX to
keep the length sane.
---
 client.c | 35 ++++++++++++++---------------------
 1 file changed, 14 insertions(+), 21 deletions(-)

diff --git a/client.c b/client.c
index a2c780fd..242bd6df 100644
--- a/client.c
+++ b/client.c
@@ -3245,37 +3245,30 @@ process_line(char *line)
 
 /* ================================================== */
 
+#define MAX_LINE_LENGTH 2048
+
 static int
 process_args(int argc, char **argv, int multi)
 {
-  int total_length, i, ret = 0;
-  char *line;
-
-  total_length = 0;
-  for(i=0; i<argc; i++) {
-    total_length += strlen(argv[i]) + 1;
-  }
-
-  line = (char *) Malloc((2 + total_length) * sizeof(char));
+  char line[MAX_LINE_LENGTH];
+  int i, l, ret = 0;
 
-  for (i = 0; i < argc; i++) {
-    line[0] = '\0';
-    if (multi) {
-      strcat(line, argv[i]);
-    } else {
-      for (; i < argc; i++) {
-        strcat(line, argv[i]);
-        if (i + 1 < argc)
-          strcat(line, " ");
-      }
+  for (i = l = 0; i < argc; i++) {
+    l += snprintf(line + l, sizeof (line) - l, "%s ", argv[i]);
+    if (l >= sizeof (line)) {
+      LOG(LOGS_ERR, "Command too long");
+      return 0;
     }
 
+    if (!multi && i + 1 < argc)
+      continue;
+
     ret = process_line(line);
     if (!ret || quit)
       break;
-  }
 
-  Free(line);
+    l = 0;
+  }
 
   return ret;
 }
-- 
2.47.2