mirror of git://git.musl-libc.org/musl
fix dn_expand empty name handling and offsets to 0
Empty name was rejected in dn_expand since commit
56b57f37a4
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.
This commit is contained in:
parent
70729de075
commit
49d2c8c6bc
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@ -4,11 +4,13 @@
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int __dn_expand(const unsigned char *base, const unsigned char *end, const unsigned char *src, char *dest, int space)
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int __dn_expand(const unsigned char *base, const unsigned char *end, const unsigned char *src, char *dest, int space)
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{
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{
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const unsigned char *p = src;
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const unsigned char *p = src;
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char *dend = dest + (space > 254 ? 254 : space);
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char *dend, *dbegin = dest;
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int len = -1, i, j;
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int len = -1, i, j;
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if (p==end || !*p) return -1;
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if (p==end || space <= 0) return -1;
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dend = dest + (space > 254 ? 254 : space);
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/* detect reference loop using an iteration counter */
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/* detect reference loop using an iteration counter */
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for (i=0; i < end-base; i+=2) {
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for (i=0; i < end-base; i+=2) {
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/* loop invariants: p<end, dest<dend */
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if (*p & 0xc0) {
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if (*p & 0xc0) {
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if (p+1==end) return -1;
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if (p+1==end) return -1;
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j = ((p[0] & 0x3f) << 8) | p[1];
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j = ((p[0] & 0x3f) << 8) | p[1];
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@ -16,11 +18,12 @@ int __dn_expand(const unsigned char *base, const unsigned char *end, const unsig
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if (j >= end-base) return -1;
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if (j >= end-base) return -1;
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p = base+j;
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p = base+j;
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} else if (*p) {
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} else if (*p) {
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j = *p+1;
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if (dest != dbegin) *dest++ = '.';
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if (j>=end-p || j>dend-dest) return -1;
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j = *p++;
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while (--j) *dest++ = *++p;
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if (j >= end-p || j >= dend-dest) return -1;
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*dest++ = *++p ? '.' : 0;
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while (j--) *dest++ = *p++;
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} else {
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} else {
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*dest = 0;
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if (len < 0) len = p+1-src;
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if (len < 0) len = p+1-src;
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return len;
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return len;
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}
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}
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