From d3f0c460ecb0ca5b1ba9c57f443463e1f3f49012 Mon Sep 17 00:00:00 2001 From: Andrew Kelley Date: Mon, 13 Oct 2025 18:06:44 -0700 Subject: [PATCH] std.Io.net.HostName: fix DNS resolution * merge conflict with changing behavior of takeDelimiterExclusive * check bounds before adding to result array --- lib/std/Io/net/HostName.zig | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/lib/std/Io/net/HostName.zig b/lib/std/Io/net/HostName.zig index 94c87ab0a4..4d0df744c4 100644 --- a/lib/std/Io/net/HostName.zig +++ b/lib/std/Io/net/HostName.zig @@ -396,20 +396,24 @@ fn lookupDns(io: Io, lookup_canon_name: []const u8, rc: *const ResolvConf, optio std.posix.RR.A => { const data = record.packet[record.data_off..][0..record.data_len]; if (data.len != 4) return error.InvalidDnsARecord; - options.addresses_buffer[addresses_len] = .{ .ip4 = .{ - .bytes = data[0..4].*, - .port = options.port, - } }; - addresses_len += 1; + if (addresses_len < options.addresses_buffer.len) { + options.addresses_buffer[addresses_len] = .{ .ip4 = .{ + .bytes = data[0..4].*, + .port = options.port, + } }; + addresses_len += 1; + } }, std.posix.RR.AAAA => { const data = record.packet[record.data_off..][0..record.data_len]; if (data.len != 16) return error.InvalidDnsAAAARecord; - options.addresses_buffer[addresses_len] = .{ .ip6 = .{ - .bytes = data[0..16].*, - .port = options.port, - } }; - addresses_len += 1; + if (addresses_len < options.addresses_buffer.len) { + options.addresses_buffer[addresses_len] = .{ .ip6 = .{ + .bytes = data[0..16].*, + .port = options.port, + } }; + addresses_len += 1; + } }, std.posix.RR.CNAME => { _, canonical_name = expand(record.packet, record.data_off, options.canonical_name_buffer) catch @@ -472,6 +476,7 @@ fn lookupHostsReader(host_name: HostName, options: LookupOptions, reader: *Io.Re error.ReadFailed => return error.ReadFailed, error.EndOfStream => break, }; + reader.toss(1); var split_it = std.mem.splitScalar(u8, line, '#'); const no_comment_line = split_it.first();