From: Thanassis Avgerinos thanassis.avgerinos@gmail.com
[ Upstream commit 38762a0763c10c24a4915feee722d7aa6e73eb98 ]
Ensure that packet_buffer_get respects the user_length provided. If the length of the head packet exceeds the user_length, packet_buffer_get will now return 0 to signify to the user that no data were read and a larger buffer size is required. Helps prevent user space overflows.
Signed-off-by: Thanassis Avgerinos thanassis.avgerinos@gmail.com Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/firewire/nosy.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/firewire/nosy.c b/drivers/firewire/nosy.c index 9ee747a85ee49..8bb609085911f 100644 --- a/drivers/firewire/nosy.c +++ b/drivers/firewire/nosy.c @@ -148,10 +148,12 @@ packet_buffer_get(struct client *client, char __user *data, size_t user_length) if (atomic_read(&buffer->size) == 0) return -ENODEV;
- /* FIXME: Check length <= user_length. */ + length = buffer->head->length; + + if (length > user_length) + return 0;
end = buffer->data + buffer->capacity; - length = buffer->head->length;
if (&buffer->head->data[length] < end) { if (copy_to_user(data, buffer->head->data, length))