From 7e282e18a5c8f76e21de70533f8dce1198dd8133 Mon Sep 17 00:00:00 2001
From: Viktor Szakats <commit@vsz.me>
Date: Sun, 9 Mar 2025 00:32:22 +0100
Subject: [PATCH] lib2302: fix crash due to stack overflow on MSVC and clang
 Windows

It fixes test 2302, 2303, 2307 with MSVC and clang on Windows.
GCC Windows builds were not affected.

Failure was caused by stack overflow due to a 1MB+ sized test struct on
stack. Replace it with dynamic allocation.

Also unignore affected tests in GHA/windows.

As seen under WINE with llvm-mingw:
```
$ wine64 libtests.exe lib2302 ws://127.0.0.1:59964/2302 > stdout2302 2> stderr2302
Test: lib2302
URL: ws://127.0.0.1:59964/2302
wine: Unhandled stack overflow at address 000000014007486A (thread 0024), starting debugger...
Unhandled exception: stack overflow in 64-bit code (0x000000014007486a).
```

Ref: #16629 (discovery)
Ref: 1bd5ac998bbc943dbf812b2824ad0f532201734c #16570

Closes #16630
---
 .github/workflows/windows.yml |  5 +----
 tests/libtest/lib2302.c       | 12 +++++++++---
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index a3aeb6bd68..83c61d37b4 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -350,9 +350,6 @@ jobs:
           if [ '${{ matrix.sys }}' != 'msys' ]; then
             TFLAGS+=' ~612'  # SFTP
           fi
-          if [ '${{ matrix.sys }}' = 'clang64' ]; then
-            TFLAGS+=' ~2302 ~2303 ~2307'  # permafail with clang (and also MSVC) (but works with mingw64 and ucrt64)
-          fi
           if [ -x "$(cygpath "${SYSTEMROOT}/System32/curl.exe")" ]; then
             TFLAGS+=" -ac $(cygpath "${SYSTEMROOT}/System32/curl.exe")"
           fi
@@ -923,7 +920,7 @@ jobs:
         timeout-minutes: 10
         run: |
           export CURL_DIRSUFFIX='${{ matrix.type }}'
-          export TFLAGS='-j8 ${{ matrix.tflags }} ~2302 ~2303 ~2307'
+          export TFLAGS='-j8 ${{ matrix.tflags }}'
           TFLAGS+=' ~2310'  # flaky
           PATH="$PWD/bld/lib/${{ matrix.type }}:$PATH:/c/Program Files (x86)/stunnel/bin:/c/Program Files/OpenSSH-Win64"
           PATH="/c/msys64/usr/bin:$PATH"
diff --git a/tests/libtest/lib2302.c b/tests/libtest/lib2302.c
index 415ab9ff1f..ccf8dfb587 100644
--- a/tests/libtest/lib2302.c
+++ b/tests/libtest/lib2302.c
@@ -28,13 +28,15 @@
 
 struct ws_data {
   CURL *easy;
-  char buf[1024*1024];
+  char *buf;
   size_t blen;
   size_t nwrites;
   int has_meta;
   int meta_flags;
 };
 
+#define LIB2302_BUFSIZE (1024 * 1024)
+
 static void flush_data(struct ws_data *wd)
 {
   size_t i;
@@ -66,7 +68,7 @@ static size_t add_data(struct ws_data *wd, const char *buf, size_t blen,
     wd->meta_flags = meta ? meta->flags : 0;
   }
 
-  if(wd->blen + blen > sizeof(wd->buf)) {
+  if(wd->blen + blen > LIB2302_BUFSIZE) {
     return 0;
   }
   memcpy(wd->buf + wd->blen, buf, blen);
@@ -96,13 +98,16 @@ CURLcode test(char *URL)
   CURL *curl;
   CURLcode res = CURLE_OK;
   struct ws_data ws_data;
+  memset(&ws_data, 0, sizeof(ws_data));
 
+  ws_data.buf = (char *)calloc(LIB2302_BUFSIZE, 1);
+  if(!ws_data.buf)
+    return res;
 
   global_init(CURL_GLOBAL_ALL);
 
   curl = curl_easy_init();
   if(curl) {
-    memset(&ws_data, 0, sizeof(ws_data));
     ws_data.easy = curl;
 
     curl_easy_setopt(curl, CURLOPT_URL, URL);
@@ -118,6 +123,7 @@ CURLcode test(char *URL)
     flush_data(&ws_data);
   }
   curl_global_cleanup();
+  free(ws_data.buf);
   return res;
 }
 
-- 
2.47.3