about summary refs log tree commit diff
path: root/src/network
diff options
context:
space:
mode:
authorSzabolcs Nagy <nsz@port70.net>2014-09-04 18:29:16 +0200
committerRich Felker <dalias@aerifal.cx>2015-03-30 01:15:43 -0400
commit83eb88d6c2f91a80ab1a48458d8de18c31c4ebb0 (patch)
tree76c54bdc14240d836cfbd571c0edc2a71a43de3d /src/network
parent53f270f964ef645a3b6936c336d46f807974175b (diff)
downloadmusl-83eb88d6c2f91a80ab1a48458d8de18c31c4ebb0.tar.gz
musl-83eb88d6c2f91a80ab1a48458d8de18c31c4ebb0.tar.xz
musl-83eb88d6c2f91a80ab1a48458d8de18c31c4ebb0.zip
fix dn_expand empty name handling and offsets to 0
Empty name was rejected in dn_expand since commit
56b57f37a46dab432247bf29d96fcb11fbd02a6d
which is a regression as reported by Natanael Copa.

Furthermore if an offset pointer in a compressed name
pointed to a terminating 0 byte (instead of a label)
the returned name was not null terminated.

(cherry picked from commit 49d2c8c6bcf8c926e52c7f510033b6adc31355f5)
Diffstat (limited to 'src/network')
-rw-r--r--src/network/dn_expand.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/src/network/dn_expand.c b/src/network/dn_expand.c
index 849df19a..d9b33936 100644
--- a/src/network/dn_expand.c
+++ b/src/network/dn_expand.c
@@ -4,11 +4,13 @@
 int __dn_expand(const unsigned char *base, const unsigned char *end, const unsigned char *src, char *dest, int space)
 {
 	const unsigned char *p = src;
-	char *dend = dest + (space > 254 ? 254 : space);
+	char *dend, *dbegin = dest;
 	int len = -1, i, j;
-	if (p==end || !*p) return -1;
+	if (p==end || space <= 0) return -1;
+	dend = dest + (space > 254 ? 254 : space);
 	/* detect reference loop using an iteration counter */
 	for (i=0; i < end-base; i+=2) {
+		/* loop invariants: p<end, dest<dend */
 		if (*p & 0xc0) {
 			if (p+1==end) return -1;
 			j = ((p[0] & 0x3f) << 8) | p[1];
@@ -16,11 +18,12 @@ int __dn_expand(const unsigned char *base, const unsigned char *end, const unsig
 			if (j >= end-base) return -1;
 			p = base+j;
 		} else if (*p) {
-			j = *p+1;
-			if (j>=end-p || j>dend-dest) return -1;
-			while (--j) *dest++ = *++p;
-			*dest++ = *++p ? '.' : 0;
+			if (dest != dbegin) *dest++ = '.';
+			j = *p++;
+			if (j >= end-p || j >= dend-dest) return -1;
+			while (j--) *dest++ = *p++;
 		} else {
+			*dest = 0;
 			if (len < 0) len = p+1-src;
 			return len;
 		}