[newlib-cygwin/cygwin-3_3-branch] Cygwin: resolver: Targets in SRV DNS responses may not be compressed

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=7b1d4c732e474cfba0bcd91b812da90a7298c982

commit 7b1d4c732e474cfba0bcd91b812da90a7298c982
Author: Anton Lavrentiev via Cygwin-patches <cygwin-patches@cygwin.com>
Date:   Tue Jan 18 17:39:16 2022 -0500

    Cygwin: resolver: Targets in SRV DNS responses may not be compressed
    
    RFC2782 clearly says so yet it's a common misconception to perform the
    compression in the violation of the standard.  This patch fixes that

Diff:
---
 winsup/cygwin/libc/minires-os-if.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/winsup/cygwin/libc/minires-os-if.c b/winsup/cygwin/libc/minires-os-if.c
index 1dac816eb..dce856076 100644
--- a/winsup/cygwin/libc/minires-os-if.c
+++ b/winsup/cygwin/libc/minires-os-if.c
@@ -159,6 +159,7 @@ static unsigned char * write_record(unsigned char * ptr, PDNS_RECORD rr,
       PUTSHORT(rr->Data.SRV.wWeight, ptr);
       PUTSHORT(rr->Data.SRV.wPort, ptr);
     }
+    dnptrs = 0;  /* compression not allowed */
     PUTDOMAIN(rr->Data.SRV.pNameTarget, ptr);
     break;
   default: