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udhcp: fix DNS domanin codec bug: bad compression flag checks

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Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2010-03-24 15:06:23 +01:00
parent 651a2697f7
commit a14a9d73b1
1 changed files with 6 additions and 6 deletions
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12
networking/udhcp/domain_codec.c
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@ -44,14 +44,14 @@ char* FAST_FUNC dname_dec(const uint8_t *cstr, int clen, const char *pre)
while (crtpos < clen) {
c = cstr + crtpos;
if (*c & NS_CMPRSFLGS) {
if ((*c & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
/* pointer */
if (crtpos + 2 > clen) /* no offset to jump to? abort */
return NULL;
if (retpos == 0) /* toplevel? save return spot */
retpos = crtpos + 2;
depth++;
crtpos = ((c[0] & 0x3f) << 8) | (c[1] & 0xff); /* jump */
crtpos = ((c[0] & 0x3f) << 8) | c[1]; /* jump */
} else if (*c) {
/* label */
if (crtpos + *c + 1 > clen) /* label too long? abort */
@ -154,7 +154,7 @@ static int find_offset(const uint8_t *cstr, int clen, const uint8_t *dname)
while (off < clen) {
c = cstr + off;
if ((*c & NS_CMPRSFLGS) != 0) { /* pointer, skip */
if ((*c & NS_CMPRSFLGS) == NS_CMPRSFLGS) { /* pointer, skip */
off += 2;
} else if (*c) { /* label, try matching dname */
inc = *c + 1;
@ -164,8 +164,8 @@ static int find_offset(const uint8_t *cstr, int clen, const uint8_t *dname)
return off;
d += *c + 1;
c += *c + 1;
if ((*c & NS_CMPRSFLGS) != 0) /* pointer, jump */
c = cstr + (((*c & 0x3f) << 8) | (*(c + 1) & 0xff));
if ((*c & NS_CMPRSFLGS) == NS_CMPRSFLGS) /* pointer, jump */
c = cstr + (((c[0] & 0x3f) << 8) | c[1]);
}
off += inc;
} else { /* null, skip */
@ -196,7 +196,7 @@ uint8_t* FAST_FUNC dname_enc(const uint8_t *cstr, int clen, const char *src, int
for (d = dname; *d != 0; d += *d + 1) {
off = find_offset(cstr, clen, d);
if (off >= 0) { /* found a match, add pointer and terminate string */
*d++ = NS_CMPRSFLGS;
*d++ = NS_CMPRSFLGS + (off >> 8);
*d = off;
break;
}