From: Luis Chamberlain <mcgrof@xxxxxxxxxx> [ Upstream commit f7a07f7b96033df7709042ff38e998720a3f7119 ] The firmware_loader can be used with a pre-allocated buffer through the use of the API calls: o request_firmware_into_buf() o request_partial_firmware_into_buf() If the firmware was built-in and present, our current check for if the built-in firmware fits into the pre-allocated buffer does not return any errors, and we proceed to tell the caller that everything worked fine. It's a lie and no firmware would end up being copied into the pre-allocated buffer. So if the caller trust the result it may end up writing a bunch of 0's to a device! Fix this by making the function that checks for the pre-allocated buffer return non-void. Since the typical use case is when no pre-allocated buffer is provided make this return successfully for that case. If the built-in firmware does *not* fit into the pre-allocated buffer size return a failure as we should have been doing before. I'm not aware of users of the built-in firmware using the API calls with a pre-allocated buffer, as such I doubt this fixes any real life issue. But you never know... perhaps some oddball private tree might use it. In so far as upstream is concerned this just fixes our code for correctness. Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx> Link: https://lore.kernel.org/r/20210917182226.3532898-2-mcgrof@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/base/firmware_loader/main.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c index bdbedc6660a87..ef904b8b112e6 100644 --- a/drivers/base/firmware_loader/main.c +++ b/drivers/base/firmware_loader/main.c @@ -100,12 +100,15 @@ static struct firmware_cache fw_cache; extern struct builtin_fw __start_builtin_fw[]; extern struct builtin_fw __end_builtin_fw[]; -static void fw_copy_to_prealloc_buf(struct firmware *fw, +static bool fw_copy_to_prealloc_buf(struct firmware *fw, void *buf, size_t size) { - if (!buf || size < fw->size) - return; + if (!buf) + return true; + if (size < fw->size) + return false; memcpy(buf, fw->data, fw->size); + return true; } static bool fw_get_builtin_firmware(struct firmware *fw, const char *name, @@ -117,9 +120,7 @@ static bool fw_get_builtin_firmware(struct firmware *fw, const char *name, if (strcmp(name, b_fw->name) == 0) { fw->size = b_fw->size; fw->data = b_fw->data; - fw_copy_to_prealloc_buf(fw, buf, size); - - return true; + return fw_copy_to_prealloc_buf(fw, buf, size); } } -- 2.33.0
