[PATCH v2 0/1] MR10384: vbscript: Allow hex literals with excess leading zeros.

[Francis De Brabandere (＠francisdb)]

Windows allows any number of leading zeros in hex literals (e.g.
&H000000031 = 49). Wine rejected literals with more than 8 hex
digits regardless of value. Fix by skipping leading zeros before
counting significant digits, so that only actual 32-bit overflow
is rejected.

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  v2: vbscript: Allow hex literals with excess leading zeros.
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10384

[PATCH v2 1/1] vbscript: Allow hex literals with excess leading zeros.

[Francis De Brabandere]

From: Francis De Brabandere <[e-mail]>

Windows allows any number of leading zeros in hex literals (e.g.
&H000000031 = 49). Wine rejected literals with more than 8 hex
digits regardless of value. Fix by skipping leading zeros before
counting significant digits, so that only actual 32-bit overflow
is rejected.
---
 dlls/vbscript/lex.c          | 12 +++++++++---
 dlls/vbscript/tests/lang.vbs | 10 ++++++++++
 dlls/vbscript/tests/run.c    |  5 +++++
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/dlls/vbscript/lex.c b/dlls/vbscript/lex.c
index 8c5c69ea429..fcde5ff1465 100644
--- a/dlls/vbscript/lex.c
+++ b/dlls/vbscript/lex.c
@@ -351,14 +351,20 @@ static int hex_to_int(WCHAR c)
 
 static int parse_hex_literal(parser_ctx_t *ctx, LONG *ret)
 {
-    const WCHAR *begin = ctx->ptr;
+    const WCHAR *begin;
     unsigned l = 0, d;
 
+    /* Skip leading zeros — Windows allows any number of them. */
+    while(ctx->ptr[1] == '0' && hex_to_int(ctx->ptr[2]) != -1)
+        ctx->ptr++;
+
+    begin = ctx->ptr;
+
     while((d = hex_to_int(*++ctx->ptr)) != -1)
         l = l*16 + d;
 
-    if(begin + 9 /* max digits+1 */ < ctx->ptr) {
-        FIXME("invalid literal\n");
+    if(begin + 9 /* max 8 significant digits + 1 */ < ctx->ptr) {
+        WARN("overflow in hex literal\n");
         return 0;
     }
 
diff --git a/dlls/vbscript/tests/lang.vbs b/dlls/vbscript/tests/lang.vbs
index c364f12c00b..949c5842922 100644
--- a/dlls/vbscript/tests/lang.vbs
+++ b/dlls/vbscript/tests/lang.vbs
@@ -62,6 +62,16 @@ Call ok(&hfffe& = 65534, "&hfffe& <> -2")
 Call ok(&hffffffff& = -1, "&hffffffff& <> -1")
 Call ok((&h01or&h02)=3,"&h01or&h02 <> 3")
 
+' Hex literals with excess leading zeros
+Call ok(&H000000031 = 49, "&H000000031 <> 49")
+Call ok(&H0000000000000031 = 49, "&H0000000000000031 <> 49")
+Call ok(&H00000000000000FF = 255, "&H00000000000000FF <> 255")
+Call ok(&H0FFFFFFFF = -1, "&H0FFFFFFFF <> -1")
+Call ok(&H007FFFFFFF = 2147483647, "&H007FFFFFFF <> 2147483647")
+Call ok(&H000000031& = 49, "&H000000031& <> 49")
+Call ok(getVT(&H00000000000000FF) = "VT_I2", "getVT(&H00000000000000FF) is not VT_I2")
+Call ok(getVT(&H007FFFFFFF) = "VT_I4", "getVT(&H007FFFFFFF) is not VT_I4")
+
 ' Test concat when no space and var begins with h
 hi = "y"
 x = "x" &hi
diff --git a/dlls/vbscript/tests/run.c b/dlls/vbscript/tests/run.c
index 8aaafbedf54..3505224e329 100644
--- a/dlls/vbscript/tests/run.c
+++ b/dlls/vbscript/tests/run.c
@@ -2765,6 +2765,11 @@ static void test_parse_errors(void)
             "    throwInt &h87001234&\n"
             "end if\n",
             2, 1
+        },
+        {
+            /* Hex literal overflow */
+            L"x = &H100000001\n",
+            0, 4
         }
     };
     HRESULT hres;
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/10384

[Jacek Caban (＠jacek)]

Jacek Caban (@jacek) commented about dlls/vbscript/lex.c:
> static int parse_hex_literal(parser_ctx_t *ctx, LONG *ret)
>  {
> -    const WCHAR *begin = ctx->ptr;
> +    const WCHAR *begin;
>      unsigned l = 0, d;
>
> +    /* Skip leading zeros — Windows allows any number of them. */
> +    while(ctx->ptr[1] == '0' && hex_to_int(ctx->ptr[2]) != -1)

Why do we need the `hex_to_int` check here? Unless I am missing something, we could skip it.

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https://gitlab.winehq.org/wine/wine/-/merge_requests/10384#note_133467