From: Anton Lavrentiev <lavr@ncbi.nlm.nih.gov>
To: cygwin-patches@cygwin.com
Subject: [PATCH 1/2] Cygwin: resolver: Fix to match response ID with request ID
Date: Tue, 18 Jan 2022 17:39:15 -0500 [thread overview]
Message-ID: <20220118223916.43814-2-lavr@ncbi.nlm.nih.gov> (raw)
In-Reply-To: <20220118223916.43814-1-lavr@ncbi.nlm.nih.gov>
In case when the native OS resolver is used (via os_query) the returned
response ID is always 0. It should actually match the ID passed in to
res_send() in the DNS request header. This patch fixes that
---
winsup/cygwin/libc/minires-os-if.c | 6 +++++-
winsup/cygwin/libc/minires.c | 7 ++++++-
2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/winsup/cygwin/libc/minires-os-if.c b/winsup/cygwin/libc/minires-os-if.c
index c4183db9c..8d3178f70 100644
--- a/winsup/cygwin/libc/minires-os-if.c
+++ b/winsup/cygwin/libc/minires-os-if.c
@@ -189,10 +189,14 @@ static int cygwin_query(res_state statp, const char * DomName, int Class, int Ty
DWORD section;
int len, counts[4] = {0, 0, 0, 0}, debug = statp->options & RES_DEBUG;
unsigned char * dnptrs[256], * ptr;
+ unsigned short Id = 0;
dnptrs[0] = AnsPtr;
dnptrs[1] = NULL;
+ if (AnsLength >= 2)
+ memcpy(&Id, AnsPtr, 2);
+
memset(AnsPtr, 0, AnsLength);
if (Class != ns_c_in) {
@@ -294,7 +298,7 @@ static int cygwin_query(res_state statp, const char * DomName, int Class, int Ty
done:
if (HFIXEDSZ <= AnsLength) {
ptr = AnsPtr;
- PUTSHORT(0, ptr); /* Id */
+ PUTSHORT(Id, ptr);
PUTSHORT((QR << 8) + RA + RD, ptr);
for (section = 0; section < DIM(counts); section++) {
PUTSHORT(counts[section], ptr);
diff --git a/winsup/cygwin/libc/minires.c b/winsup/cygwin/libc/minires.c
index fdc6087f5..b540f6a1b 100644
--- a/winsup/cygwin/libc/minires.c
+++ b/winsup/cygwin/libc/minires.c
@@ -450,6 +450,8 @@ int res_nsend( res_state statp, const unsigned char * MsgPtr,
ptr += len;
GETSHORT(Type, ptr);
GETSHORT(Class, ptr);
+ if (AnsLength >= 2)
+ memcpy(AnsPtr, MsgPtr, 2);
return ((os_query_t *) statp->os_query)(statp, DomName, Class, Type, AnsPtr, AnsLength);
}
else {
@@ -709,8 +711,11 @@ int res_nquery( res_state statp, const char * DomName, int Class, int Type,
statp->res_h_errno = NETDB_SUCCESS;
/* If a hook exists to a native implementation, use it */
- if (statp->os_query)
+ if (statp->os_query) {
+ if (AnsLength >= 2)
+ memset(AnsPtr, 0/*Id*/, 2);
return ((os_query_t *) statp->os_query)(statp, DomName, Class, Type, AnsPtr, AnsLength);
+ }
if ((len = res_nmkquery (statp, QUERY, DomName, Class, Type,
0, 0, 0, packet, PACKETSZ)) < 0)
--
2.33.0
next prev parent reply other threads:[~2022-01-18 22:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-18 22:39 Cygwin: resolver: more fixes Anton Lavrentiev
2022-01-18 22:39 ` Anton Lavrentiev [this message]
2022-01-18 22:39 ` [PATCH 2/2] Cygwin: resolver: Targets in SRV DNS responses may not be compressed Anton Lavrentiev
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