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[base] Always close user-provided stream.

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The `FT_Open_Face` documentation states

> If `FT_OPEN_STREAM` is set in `args->flags`, the stream in `args->stream`
> is automatically closed before this function returns any error (including
> `FT_Err_Invalid_Argument`).

However, if the user provides a stream in `args.stream` with
`FT_OPEN_STREAM` set and a `close` function, but then for some reason passes
NULL for `aface` and a non-negative `face_index`, the error
`Invalid_Argument` is returned but the `close` callback will not be called
on the user-provided stream.  This may cause resource leaks if the caller is
depending on the `close` callback to free resources.

The difficulty is that a user may fill out a `FT_StreamRec` and pass its
address as `args.stream`, but the stream isn't really 'live' until
`FT_Stream_New` is called on it (and `memory` is set).  In particular, it
cannot really be cleaned up properly in `ft_open_face_internal` until the
stream pointer has been copied into the `stream` local variable.

* src/base/ftobj.c (ft_open_face_internal): Ensure that user-provided
`args.stream.close` is called even with early errors.
This commit is contained in:
Ben Wagner 2023-01-12 22:43:08 -05:00 committed by Werner Lemberg
parent 13983b058e
commit 0d4f887c79
1 changed files with 9 additions and 1 deletions
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10
src/base/ftobjs.c
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@ -2544,7 +2544,7 @@
/* test for valid `library' delayed to `FT_Stream_New' */
if ( ( !aface && face_index >= 0 ) || !args )
if ( !args )
return FT_THROW( Invalid_Argument );
external_stream = FT_BOOL( ( args->flags & FT_OPEN_STREAM ) &&
@ -2555,6 +2555,14 @@
if ( error )
goto Fail3;
/* Do this error check after `FT_Stream_New` to ensure that the */
/* 'close' callback is called. */
if ( !aface && face_index >= 0 )
{
error = FT_THROW( Invalid_Argument );
goto Fail3;
}
memory = library->memory;
/* If the font driver is specified in the `args' structure, use */