Fix CVE-2012-2944: upsd can be remotely crashed

NUT server (upsd), from versions 2.4.0 to 2.6.3, are exposed to crashes when receiving random data from the network. This issue is related to the way NUT parses characters, especially from the network. Non printable characters were missed from strings operation (such as strlen), but still copied to the buffer, causing an overflow. Thus, fix NUT parser, to only allow the subset Ascii charset from Space to ~ (Reported by Sebastian Pohle, Alioth bug #313636, CVE-2012-2944) Fossil-ID: SVN r3633
networkupstools · May 29, 2012 · 2d6b472 · 2d6b472
1 parent a52c583
commit 2d6b472
Showing 1 changed file with 7 additions and 0 deletions.
diff --git a/common/parseconf.c b/common/parseconf.c
@@ -171,6 +171,13 @@ static void addchar(PCONF_CTX_t *ctx)
 
 	wbuflen = strlen(ctx->wordbuf);
 
+	/* CVE-2012-2944: only allow the subset Ascii charset from Space to ~ */
+	if ((ctx->ch < 0x20) || (ctx->ch > 0x7f)) {
+		fprintf(stderr, "addchar: discarding invalid character (0x%02x)!\n",
+				ctx->ch);
+		return;
+	}
+
 	if (ctx->wordlen_limit != 0) {
 		if (wbuflen >= ctx->wordlen_limit) {