linux-kernel - Re: [PATCH] dns: Apply a default TTL to records obtained from getaddrinfo()

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Message-ID: <1512927.1589904409@warthog.procyon.org.uk>
Date:   Tue, 19 May 2020 17:06:49 +0100
From:   David Howells <dhowells@...hat.com>
To:     me@...boeckel.net, fweimer@...hat.com
Cc:     dhowells@...hat.com, linux-nfs@...r.kernel.org,
        linux-cifs@...r.kernel.org, linux-afs@...ts.infradead.org,
        ceph-devel@...r.kernel.org, keyrings@...r.kernel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] dns: Apply a default TTL to records obtained from getaddrinfo()

Okay, how about this incremental change, then?  If fixes the typo, only prints
the "READ CONFIG" line in verbose mode, filters escape chars in the config
file and reduces the expiration time to 5s.

David
---
diff --git a/key.dns_resolver.c b/key.dns_resolver.c
index c241eda3..7a7ec424 100644
--- a/key.dns_resolver.c
+++ b/key.dns_resolver.c
@@ -52,7 +52,7 @@ key_serial_t key;
 static int verbose;
 int debug_mode;
 unsigned mask = INET_ALL;
-unsigned int key_expiry = 10 * 60;
+unsigned int key_expiry = 5;
 
 
 /*
@@ -109,7 +109,7 @@ void _error(const char *fmt, ...)
 }
 
 /*
- * Pring a warning to stderr or the syslog
+ * Print a warning to stderr or the syslog
  */
 void warning(const char *fmt, ...)
 {
@@ -454,7 +454,7 @@ static void read_config(void)
 	unsigned int line = 0, u;
 	int n;
 
-	printf("READ CONFIG %s\n", config_file);
+	info("READ CONFIG %s", config_file);
 
 	f = fopen(config_file, "r");
 	if (!f) {
@@ -514,6 +514,16 @@ static void read_config(void)
 			v = p = b;
 			while (*b) {
 				if (esc) {
+					switch (*b) {
+					case ' ':
+					case '\t':
+					case '"':
+					case '\'':
+					case '\\':
+						break;
+					default:
+						goto invalid_escape_char;
+					}
 					esc = false;
 					*p++ = *b++;
 					continue;
@@ -563,6 +573,8 @@ static void read_config(void)
 
 missing_value:
 	error("%s:%u: %s: Missing value", config_file, line, k);
+invalid_escape_char:
+	error("%s:%u: %s: Invalid char in escape", config_file, line, k);
 post_quote_data:
 	error("%s:%u: %s: Data after closing quote", config_file, line, k);
 bad_value:
diff --git a/man/key.dns_resolver.conf.5 b/man/key.dns_resolver.conf.5
index 03d04049..c944ad55 100644
--- a/man/key.dns_resolver.conf.5
+++ b/man/key.dns_resolver.conf.5
@@ -34,7 +34,7 @@ Available options include:
 The number of seconds to set as the expiration on a cached record.  This will
 be overridden if the program manages to retrieve TTL information along with
 the addresses (if, for example, it accesses the DNS directly).  The default is
-600 seconds.  The value must be in the range 1 to INT_MAX.
+5 seconds.  The value must be in the range 1 to INT_MAX.
 .P
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