From 34f280b66c382d6240ca92c516cc1d65c80e736f Mon Sep 17 00:00:00 2001 From: Willy Tarreau Date: Fri, 22 May 2026 06:01:49 +0000 Subject: [PATCH] CLEANUP: resolvers: use read_n32() instead of open-coded big-endian read In resolv_validate_dns_response(), the second DNS record parsing path manually constructs a 32-bit big-endian TTL value from four individual bytes using the expression: reader[0] * 16777216 + reader[1] * 65536 + reader[2] * 256 + reader[3] We have read_n32() to do this, and it's more robust against unexpected signedness surprises (which should not happen right here since reader is unsigned char and we use -fwrapv so the result is defined). Also, let's make the ttl an uint instead of an int. The TTL is only retrieved and not used for now, so better clean it now. --- include/haproxy/resolvers-t.h | 2 +- src/resolvers.c | 6 ++---- 2 files changed, 3 insertions(+), 5 deletions(-) diff --git a/include/haproxy/resolvers-t.h b/include/haproxy/resolvers-t.h index e89f5b547..3bdf5237e 100644 --- a/include/haproxy/resolvers-t.h +++ b/include/haproxy/resolvers-t.h @@ -114,7 +114,7 @@ struct resolv_answer_item { char name[DNS_MAX_NAME_SIZE+1]; /* answer name */ int16_t type; /* question type */ int16_t class; /* query class */ - int32_t ttl; /* response TTL */ + uint32_t ttl; /* response TTL */ int16_t priority; /* SRV type priority */ uint16_t weight; /* SRV type weight */ uint16_t port; /* SRV type port */ diff --git a/src/resolvers.c b/src/resolvers.c index ee49fb8f9..4362b00c9 100644 --- a/src/resolvers.c +++ b/src/resolvers.c @@ -1236,8 +1236,7 @@ static int resolv_validate_dns_response(unsigned char *resp, unsigned char *bufe if (reader + 4 > bufend) goto invalid_resp; - answer_record->ttl = reader[0] * 16777216 + reader[1] * 65536 - + reader[2] * 256 + reader[3]; + answer_record->ttl = read_n32(reader); reader += 4; /* Now reading data len */ @@ -1498,8 +1497,7 @@ static int resolv_validate_dns_response(unsigned char *resp, unsigned char *bufe if (reader + 4 > bufend) goto invalid_resp; - answer_record->ttl = reader[0] * 16777216 + reader[1] * 65536 - + reader[2] * 256 + reader[3]; + answer_record->ttl = read_n32(reader); reader += 4; /* Now reading data len */