HID: u2fzero: ignore incomplete packets without data

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>
This commit is contained in:
Andrej Shadura 2021-09-16 17:33:11 +01:00 committed by Jiri Kosina
parent d46ef750ed
commit 22d65765f2

View File

@ -198,7 +198,9 @@ static int u2fzero_rng_read(struct hwrng *rng, void *data,
}
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 */