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* [newlib-cygwin/cygwin-3_3-branch] Cygwin: resolver: A few fixes for cygwin_query()
@ 2022-01-19 7:55 Corinna Vinschen
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From: Corinna Vinschen @ 2022-01-19 7:55 UTC (permalink / raw)
To: cygwin-cvs
https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=b4ed35e2d75f9b4c0a77e26346e8647eaa739c6c
commit b4ed35e2d75f9b4c0a77e26346e8647eaa739c6c
Author: Anton Lavrentiev via Cygwin-patches <cygwin-patches@cygwin.com>
Date: Tue Jan 18 16:34:34 2022 -0500
Cygwin: resolver: A few fixes for cygwin_query()
- Make sure the answer buffer is properly cleared so there is no trailing
garbage when the response does not fit entirely in;
- Make sure an internal decomp failure gets reported correctly (w/return code -1);
- Make sure that the buffer is not overrun when filling out the header.
Diff:
---
winsup/cygwin/libc/minires-os-if.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)
diff --git a/winsup/cygwin/libc/minires-os-if.c b/winsup/cygwin/libc/minires-os-if.c
index 55adff22e..a71c37414 100644
--- a/winsup/cygwin/libc/minires-os-if.c
+++ b/winsup/cygwin/libc/minires-os-if.c
@@ -193,6 +193,8 @@ static int cygwin_query(res_state statp, const char * DomName, int Class, int Ty
dnptrs[0] = AnsPtr;
dnptrs[1] = NULL;
+ memset(AnsPtr, 0, AnsLength);
+
if (Class != ns_c_in) {
errno = ENOSYS;
statp->res_h_errno = NETDB_INTERNAL;
@@ -214,7 +216,7 @@ static int cygwin_query(res_state statp, const char * DomName, int Class, int Ty
switch (res) {
case ERROR_INVALID_NAME:
errno = EINVAL;
- statp->res_h_errno = NETDB_INTERNAL;;
+ statp->res_h_errno = NETDB_INTERNAL;
break;
case ERROR_TIMEOUT:
statp->res_h_errno = TRY_AGAIN;
@@ -259,8 +261,9 @@ static int cygwin_query(res_state statp, const char * DomName, int Class, int Ty
/* No question. Adopt the first name as the name in the question */
if ((len = dn_comp(rr->pName, ptr, AnsLength - 4,
dnptrs, &dnptrs[DIM(dnptrs) - 1])) < 0) {
- ptr = NULL;
- break;
+ statp->res_h_errno = NETDB_INTERNAL; /* dn_comp sets errno */
+ len = -1;
+ goto done;
}
ptr += len;
PUTSHORT(Type, ptr);
@@ -289,11 +292,13 @@ static int cygwin_query(res_state statp, const char * DomName, int Class, int Ty
len = ptr - AnsPtr;
done:
- ptr = AnsPtr;
- PUTSHORT(0, ptr); /* Id */
- PUTSHORT((QR << 8) + RA + RD, ptr);
- for (section = 0; section < DIM(counts); section++) {
- PUTSHORT(counts[section], ptr);
+ if (HFIXEDSZ <= AnsLength) {
+ ptr = AnsPtr;
+ PUTSHORT(0, ptr); /* Id */
+ PUTSHORT((QR << 8) + RA + RD, ptr);
+ for (section = 0; section < DIM(counts); section++) {
+ PUTSHORT(counts[section], ptr);
+ }
}
return len;
}
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2022-01-19 7:55 [newlib-cygwin/cygwin-3_3-branch] Cygwin: resolver: A few fixes for cygwin_query() Corinna Vinschen
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