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| author | Richard Gibson <richard.gibson@gmail.com> | 2016-10-22 00:21:18 -0400 |
|---|---|---|
| committer | Russ Cox <rsc@golang.org> | 2016-11-11 14:56:10 +0000 |
| commit | 9a5bddd7ed57596a259f3896dd31ea30e331027d (patch) | |
| tree | a4e0ab8a0e4452ca678dc0f88f9e5bfc227ac5fc /src/net/dnsclient_unix.go | |
| parent | add721ef91ed533cf578ff7a604124e377329ae4 (diff) | |
| download | go-9a5bddd7ed57596a259f3896dd31ea30e331027d.tar.gz go-9a5bddd7ed57596a259f3896dd31ea30e331027d.zip | |
net: bring domain name length checks into RFC compliance
The 255-octet limit applies to wire format, not presentation format.
Fixes #17549
Change-Id: I2b5181c53fba32fea60178e0d8df9114aa992b55
Reviewed-on: https://go-review.googlesource.com/31722
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Diffstat (limited to 'src/net/dnsclient_unix.go')
| -rw-r--r-- | src/net/dnsclient_unix.go | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/src/net/dnsclient_unix.go b/src/net/dnsclient_unix.go index dd39a78f45..2980302849 100644 --- a/src/net/dnsclient_unix.go +++ b/src/net/dnsclient_unix.go @@ -362,14 +362,21 @@ func (conf *dnsConfig) nameList(name string) []string { return nil } + // Check name length (see isDomainName). + l := len(name) + rooted := l > 0 && name[l-1] == '.' + if l > 254 || l == 254 && rooted { + return nil + } + // If name is rooted (trailing dot), try only that name. - rooted := len(name) > 0 && name[len(name)-1] == '.' if rooted { return []string{name} } hasNdots := count(name, '.') >= conf.ndots name += "." + l++ // Build list of search choices. names := make([]string, 0, 1+len(conf.search)) @@ -377,9 +384,11 @@ func (conf *dnsConfig) nameList(name string) []string { if hasNdots { names = append(names, name) } - // Try suffixes. + // Try suffixes that are not too long (see isDomainName). for _, suffix := range conf.search { - names = append(names, name+suffix) + if l+len(suffix) <= 254 { + names = append(names, name+suffix) + } } // Try unsuffixed, if not tried first above. if !hasNdots { |