On Dec 15 14:37, Johannes Schindelin via GitGitGadget wrote:
> From: Johannes Schindelin <[email protected]>
>
> When that function was introduced in bb42852062 (Cygwin: pty: Implement
> new pseudo console support., 2020-08-19) (back then, it was added to
> `spawn.cc`, later it was moved to `fhandler/termios.cc` in 32d6a6cb5f
> (Cygwin: pty, console: Encapsulate spawn.cc code related to
> pty/console., 2022-11-19)), it was implemented with strong assumptions
> that neither creating the file handle nor reading 1024 bytes from said
> handle could fail.
>
> This assumption, however, is incorrect. Concretely, I encountered the
> case where `is_console_app()` needed to open an app execution alias,
> failed to do so, and still tried to read from the invalid handle.
>
> Let's add some error handling to that function.
>
> Signed-off-by: Johannes Schindelin <[email protected]>
Fixes: <12-digit-SHA1> ("commit messaage headline")
> ---
> winsup/cygwin/fhandler/termios.cc | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/winsup/cygwin/fhandler/termios.cc
> b/winsup/cygwin/fhandler/termios.cc
> index a3cecdb6f..808d0d435 100644
> --- a/winsup/cygwin/fhandler/termios.cc
> +++ b/winsup/cygwin/fhandler/termios.cc
> @@ -707,10 +707,14 @@ is_console_app (const WCHAR *filename)
> HANDLE h;
> h = CreateFileW (filename, GENERIC_READ, FILE_SHARE_READ,
> NULL, OPEN_EXISTING, 0, NULL);
> + if (h == INVALID_HANDLE_VALUE)
> + return false;
> char buf[1024];
> DWORD n;
> - ReadFile (h, buf, sizeof (buf), &n, 0);
> + BOOL res = ReadFile (h, buf, sizeof (buf), &n, 0);
> CloseHandle (h);
> + if (!res)
> + return false;
> /* The offset of Subsystem is the same for both IMAGE_NT_HEADERS32 and
> IMAGE_NT_HEADERS64, so only IMAGE_NT_HEADERS32 is used here. */
> IMAGE_NT_HEADERS32 *p = (IMAGE_NT_HEADERS32 *) memmem (buf, n, "PE\0\0",
> 4);
> --
> cygwingitgadget
