From b8bda67f304b7c70dee891b7ca660036793c2a4b Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Fri, 11 Apr 2014 19:35:54 +0000
Subject: Don't blindly increase offsets by the return value of snprintf, if
 there wasn't enough space this will go off the end. Instead clamp to the
 available space. Fixes crash reported by Julien Rebetez.

---
 arguments.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

(limited to 'arguments.c')

diff --git a/arguments.c b/arguments.c
index 5ff7ed2c..ca6cc760 100644
--- a/arguments.c
+++ b/arguments.c
@@ -125,7 +125,7 @@ args_free(struct args *args)
 size_t
 args_print(struct args *args, char *buf, size_t len)
 {
-	size_t		 	 off;
+	size_t		 	 off, used;
 	int			 i;
 	const char		*quotes;
 	struct args_entry	*entry;
@@ -165,9 +165,12 @@ args_print(struct args *args, char *buf, size_t len)
 			quotes = "\"";
 		else
 			quotes = "";
-		off += xsnprintf(buf + off, len - off, "%s-%c %s%s%s",
+		used = xsnprintf(buf + off, len - off, "%s-%c %s%s%s",
 		    off != 0 ? " " : "", entry->flag, quotes, entry->value,
 		    quotes);
+		if (used > len - off)
+			used = len - off;
+		off += used;
 	}
 
 	/* And finally the argument vector. */
@@ -181,8 +184,11 @@ args_print(struct args *args, char *buf, size_t len)
 			quotes = "\"";
 		else
 			quotes = "";
-		off += xsnprintf(buf + off, len - off, "%s%s%s%s",
+		used = xsnprintf(buf + off, len - off, "%s%s%s%s",
 		    off != 0 ? " " : "", quotes, args->argv[i], quotes);
+		if (used > len - off)
+			used = len - off;
+		off += used;
 	}
 
 	return (off);
-- 
cgit