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| author | Rich Felker <dalias@aerifal.cx> | 2014-06-03 01:46:40 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2014-06-03 01:46:40 -0400 |
| commit | d85d261ee601f7ccf0bb19c38c69e406a664fe8e (patch) | |
| tree | 84050e89d696caeb81cca49c11a00e8590b8d3c6 /src/network | |
| parent | ac2a7893427b6c94f05609d214178f8d5a18b333 (diff) | |
| download | musl-d85d261ee601f7ccf0bb19c38c69e406a664fe8e.tar.gz musl-d85d261ee601f7ccf0bb19c38c69e406a664fe8e.tar.xz musl-d85d261ee601f7ccf0bb19c38c69e406a664fe8e.zip | |
fix negative response and non-response handling for dns queries
previously, all failures to obtain at least one address were treated as nonexistant names (EAI_NONAME). this failed to account for the possibility of transient failures (no response at all, or a response with rcode of 2, server failure) or permanent failures that do not indicate the nonexistence of the requested name. only an rcode of 3 should be treated as an indication of nonexistence.
Diffstat (limited to 'src/network')
| -rw-r--r-- | src/network/lookup_name.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/src/network/lookup_name.c b/src/network/lookup_name.c index 8d41627a..02920930 100644 --- a/src/network/lookup_name.c +++ b/src/network/lookup_name.c @@ -151,7 +151,10 @@ static int name_from_dns(struct address buf[static MAXADDRS], char canon[static for (i=0; i<nq; i++) __dns_parse(abuf[i], alens[i], dns_parse_callback, &ctx); - return ctx.cnt; + if (ctx.cnt) return ctx.cnt; + if (alens[0] < 4 || (abuf[0][3] & 15) == 2) return EAI_AGAIN; + if ((abuf[0][3] & 15) == 3) return EAI_NONAME; + return EAI_FAIL; } int __lookup_name(struct address buf[static MAXADDRS], char canon[static 256], const char *name, int family, int flags) |