Eric Pouech : dbghelp: Better handle very long C++ qualified identifiers in dwarf.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 542ccaaf8459133cbb552b7e969d5e1143150eb7
URL:    https://gitlab.winehq.org/wine/wine/-/commit/542ccaaf8459133cbb552b7e969d5e1...

Author: Eric Pouech 
Date:   Tue May 30 19:03:08 2023 +0200

dbghelp: Better handle very long C++ qualified identifiers in dwarf.

This fixes some crashes especially when dealing with very long C++ names
(like template classes).

Fortunately, dwarf internals don't require type lookup by name (eg.
on forward declaration), so the impact of thrashing some names is limited.

It's very likely native doesn't store directly these very long names
(it could either store the qualified mangled name - which can be way shorter
for template classes - or use the names in lexical hierarchy: both boil down
to storing less information, and recompute it (unmangle or class hierarchy
walk) upon request).
But this would need a proper C++ support in dbghelp. Not for today.

Signed-off-by: Eric Pouech

---

dlls/dbghelp/dwarf.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/dlls/dbghelp/dwarf.c b/dlls/dbghelp/dwarf.c
index 1402ffcb941..46da2968dbb 100644
--- a/dlls/dbghelp/dwarf.c
+++ b/dlls/dbghelp/dwarf.c
@@ -1177,7 +1177,10 @@ static const char* dwarf2_get_cpp_name(dwarf2_debug_info_t* di, const char* name
     }

if (!di->unit_ctx->cpp_name)
+    {
         di->unit_ctx->cpp_name = pool_alloc(&di->unit_ctx->pool, MAX_SYM_NAME);
+        if (!di->unit_ctx->cpp_name) return name;
+    }
     last = di->unit_ctx->cpp_name + MAX_SYM_NAME - strlen(name) - 1;
     strcpy(last, name);

@@ -1194,7 +1197,11 @@ static const char* dwarf2_get_cpp_name(dwarf2_debug_info_t* di, const char* name
             {
                 size_t  len = strlen(diname.u.string);
                 last -= 2 + len;
-                if (last < di->unit_ctx->cpp_name) return NULL;
+                if (last < di->unit_ctx->cpp_name)
+                {
+                    WARN("Too long C++ qualified identifier for %s... using unqualified identifier\n", name);
+                    return name;
+                }
                 memcpy(last, diname.u.string, len);
                 last[len] = last[len + 1] = ':';
             }