From 49d2c8c6bcf8c926e52c7f510033b6adc31355f5 Mon Sep 17 00:00:00 2001 From: Szabolcs Nagy Date: Thu, 4 Sep 2014 18:29:16 +0200 Subject: 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. --- src/network/dn_expand.c | 15 +++++++++------ 1 file 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-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; } -- cgit v1.2.1