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Security fix, CVE-2017-14491, DNS heap buffer overflow.
Further fix to 0549c73b7e
Handles case when RR name is not a pointer to the question,
only occurs for some auth-mode replies, therefore not
detected by fuzzing (?)
This commit is contained in:
@@ -1086,32 +1086,35 @@ int add_resource_record(struct dns_header *header, char *limit, int *truncp, int
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va_start(ap, format); /* make ap point to 1st unamed argument */
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/* nameoffset (1 or 2) + type (2) + class (2) + ttl (4) + 0 (2) */
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CHECK_LIMIT(12);
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if (nameoffset > 0)
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{
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CHECK_LIMIT(2);
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PUTSHORT(nameoffset | 0xc000, p);
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}
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else
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{
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char *name = va_arg(ap, char *);
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if (name)
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p = do_rfc1035_name(p, name, limit);
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if (!p)
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{
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va_end(ap);
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goto truncated;
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}
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if (name && !(p = do_rfc1035_name(p, name, limit)))
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{
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va_end(ap);
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goto truncated;
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}
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if (nameoffset < 0)
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{
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CHECK_LIMIT(2);
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PUTSHORT(-nameoffset | 0xc000, p);
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}
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else
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*p++ = 0;
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{
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CHECK_LIMIT(1);
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*p++ = 0;
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}
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}
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/* type (2) + class (2) + ttl (4) + rdlen (2) */
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CHECK_LIMIT(10);
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PUTSHORT(type, p);
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PUTSHORT(class, p);
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PUTLONG(ttl, p); /* TTL */
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