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authorRich Felker <dalias@aerifal.cx>2015-09-25 01:18:42 +0000
committerRich Felker <dalias@aerifal.cx>2015-09-25 01:18:42 +0000
commit2a6e1f0f5a8811d08101df0fd72b9baa27ed430c (patch)
tree2d02596b58ea2a5b9e3b040854ebf3f63e7323c6
parent06bcf9bc941a2f3bf34ac4468644d9693802495b (diff)
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avoid attempting to lookup IP literals as hostnames
previously, __lookup_ipliteral only checked its argument against the requested address family, so IPv4 literals passed through to __lookup_name if the caller asked for only IPv6 results, and likewise for IPv6 literals when the caller asked for only IPv4. this resulted in spurious DNS lookups that reportedly even succeeded with some nameservers. now, __lookup_ipliteral attempts to parse its argument as both IPv4 and IPv6, and returns an error (to stop further search) rather than 0 (no results yet) if the form of the argument mismatches the requested address family. based on patch by Julien Ramseier.
-rw-r--r--src/network/lookup_ipliteral.c59
1 files changed, 32 insertions, 27 deletions
diff --git a/src/network/lookup_ipliteral.c b/src/network/lookup_ipliteral.c
index 7ca70b22..8ed14605 100644
--- a/src/network/lookup_ipliteral.c
+++ b/src/network/lookup_ipliteral.c
@@ -15,38 +15,43 @@ int __lookup_ipliteral(struct address buf[static 1], const char *name, int famil
{
struct in_addr a4;
struct in6_addr a6;
- if (family != AF_INET6 && __inet_aton(name, &a4)>0) {
+ if (__inet_aton(name, &a4) > 0) {
+ if (family == AF_INET6) /* wrong family */
+ return EAI_NONAME;
memcpy(&buf[0].addr, &a4, sizeof a4);
buf[0].family = AF_INET;
buf[0].scopeid = 0;
return 1;
}
- if (family != AF_INET) {
- char tmp[64];
- char *p = strchr(name, '%'), *z;
- unsigned long long scopeid = 0;
- if (p && p-name < 64) {
- memcpy(tmp, name, p-name);
- tmp[p-name] = 0;
- name = tmp;
- }
- if (inet_pton(AF_INET6, name, &a6)<=0) return 0;
- memcpy(&buf[0].addr, &a6, sizeof a6);
- buf[0].family = AF_INET6;
- if (p) {
- if (isdigit(*++p)) scopeid = strtoull(p, &z, 10);
- else z = p-1;
- if (*z) {
- if (!IN6_IS_ADDR_LINKLOCAL(&a6) &&
- !IN6_IS_ADDR_MC_LINKLOCAL(&a6))
- return EAI_NONAME;
- scopeid = if_nametoindex(p);
- if (!scopeid) return EAI_NONAME;
- }
- if (scopeid > UINT_MAX) return EAI_NONAME;
+
+ char tmp[64];
+ char *p = strchr(name, '%'), *z;
+ unsigned long long scopeid = 0;
+ if (p && p-name < 64) {
+ memcpy(tmp, name, p-name);
+ tmp[p-name] = 0;
+ name = tmp;
+ }
+
+ if (inet_pton(AF_INET6, name, &a6) <= 0)
+ return 0;
+ if (family == AF_INET) /* wrong family */
+ return EAI_NONAME;
+
+ memcpy(&buf[0].addr, &a6, sizeof a6);
+ buf[0].family = AF_INET6;
+ if (p) {
+ if (isdigit(*++p)) scopeid = strtoull(p, &z, 10);
+ else z = p-1;
+ if (*z) {
+ if (!IN6_IS_ADDR_LINKLOCAL(&a6) &&
+ !IN6_IS_ADDR_MC_LINKLOCAL(&a6))
+ return EAI_NONAME;
+ scopeid = if_nametoindex(p);
+ if (!scopeid) return EAI_NONAME;
}
- buf[0].scopeid = scopeid;
- return 1;
+ if (scopeid > UINT_MAX) return EAI_NONAME;
}
- return 0;
+ buf[0].scopeid = scopeid;
+ return 1;
}