Re: [PATCH v2] ntdll: Fix wrong string size alloc when loading libraries

[Nikolay Sivov]

On 07.08.2017 20:41, Carlos Palminha wrote:
> Fixed some nasty unhandled exceptions when loading libraries
> that don't have .dll extension.
>
> Problem was caused by wrong string size calculation.
>
> v2: Now properly takes into account strlen * sizeof WCHAR
> Signed-off-by: Carlos Palminha
>
> dlls/ntdll/loader.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/dlls/ntdll/loader.c b/dlls/ntdll/loader.c
> index dd1f74c0fc..83dd6d378e 100644
> --- a/dlls/ntdll/loader.c
> +++ b/dlls/ntdll/loader.c
> @@ -2141,7 +2141,7 @@ static NTSTATUS find_dll_file( const WCHAR *load_path, const WCHAR *libname,
>      if (!(ext = strrchrW( libname, '.')) || strchrW( ext, '/' ) || strchrW( ext, '\'))
>      {
>          if (!(dllname = RtlAllocateHeap( GetProcessHeap(), 0,
> -
>                                     (strlenW(libname) * sizeof(WCHAR)) + sizeof(dllW) )))
> -
>                                     (strlenW(libname) * sizeof(WCHAR)) + (strlenW(dllW) * sizeof(WCHAR)) )))
>        return STATUS_NO_MEMORY;
>    strcpyW( dllname, libname );
>    strcatW( dllname, dllW );

This is still shorter than it is now:

sizeof(dllW) is 5 * sizeof(WCHAR) vs strlenW(dllW) * sizeof(WCHAR) == 4
* sizeof(WCHAR).

[PATCH v2] ntdll: Fix wrong string size alloc when loading libraries

[Carlos Palminha]

On 07-08-2017 19:55, Nikolay Sivov wrote:
> On 07.08.2017 20:41, Carlos Palminha wrote:
> > Fixed some nasty unhandled exceptions when loading libraries
> > that don't have .dll extension.
> >
> > Problem was caused by wrong string size calculation.
> >
> > v2: Now properly takes into account strlen * sizeof WCHAR
> > Signed-off-by: Carlos Palminha
> >
> > dlls/ntdll/loader.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/dlls/ntdll/loader.c b/dlls/ntdll/loader.c
> > index dd1f74c0fc..83dd6d378e 100644
> > --- a/dlls/ntdll/loader.c
> > +++ b/dlls/ntdll/loader.c
> > @@ -2141,7 +2141,7 @@ static NTSTATUS find_dll_file( const WCHAR *load_path, const WCHAR *libname,
> >      if (!(ext = strrchrW( libname, '.')) || strchrW( ext, '/' ) || strchrW( ext, '\'))
> >      {
> >          if (!(dllname = RtlAllocateHeap( GetProcessHeap(), 0,
> > -
> >                                     (strlenW(libname) * sizeof(WCHAR)) + sizeof(dllW) )))
> > -
> >                                     (strlenW(libname) * sizeof(WCHAR)) + (strlenW(dllW) * sizeof(WCHAR)) )))
> >        return STATUS_NO_MEMORY;
> >    strcpyW( dllname, libname );
> >    strcatW( dllname, dllW );
>
> This is still shorter than it is now:
>
> sizeof(dllW) is 5 * sizeof(WCHAR) vs strlenW(dllW) * sizeof(WCHAR) == 4
> - sizeof(WCHAR).

yep, you are right!

Somehow with my "patch" i stop getting the "Program Error" window with the exception.
But after i realized i still got the exception "silently" in the logs.

Need to better understand why its crashing around that Alloc.

Regards,
C.Palminha