firmware_loader: EFI firmware loader must handle pre-allocated buffer

The EFI platform firmware fallback would clobber any pre-allocated
buffers. Instead, correctly refuse to reallocate when too small (as
already done in the sysfs fallback), or perform allocation normally
when needed.

Fixes: e4c2c0ff00 ("firmware: Add new platform fallback mechanism and firmware_request_platform()")
Cc: stable@vger.kernel.org
Acked-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200724213640.389191-4-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Kees Cook 2020-07-24 14:36:24 -07:00 committed by Greg Kroah-Hartman
parent 4505e2154e
commit 4fb60b158a

View file

@ -25,7 +25,10 @@ int firmware_fallback_platform(struct fw_priv *fw_priv, u32 opt_flags)
if (rc)
return rc; /* rc == -ENOENT when the fw was not found */
fw_priv->data = vmalloc(size);
if (fw_priv->data && size > fw_priv->allocated_size)
return -ENOMEM;
if (!fw_priv->data)
fw_priv->data = vmalloc(size);
if (!fw_priv->data)
return -ENOMEM;