From: Andrej Shadura andrew.shadura@collabora.co.uk
commit 22d65765f211cc83186fd8b87521159f354c0da9 upstream.
Since the actual_length calculation is performed unsigned, packets shorter than 7 bytes (e.g. packets without data or otherwise truncated) or non-received packets ("zero" bytes) can cause buffer overflow.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=214437 Fixes: 42337b9d4d958("HID: add driver for U2F Zero built-in LED and RNG") Signed-off-by: Andrej Shadura andrew.shadura@collabora.co.uk Signed-off-by: Jiri Kosina jkosina@suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/hid/hid-u2fzero.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/hid/hid-u2fzero.c +++ b/drivers/hid/hid-u2fzero.c @@ -198,7 +198,9 @@ static int u2fzero_rng_read(struct hwrng }
ret = u2fzero_recv(dev, &req, &resp); - if (ret < 0) + + /* ignore errors or packets without data */ + if (ret < offsetof(struct u2f_hid_msg, init.data)) return 0;
/* only take the minimum amount of data it is safe to take */