From: Thanassis Avgerinos <thanassis.avgerinos@xxxxxxxxx>
[ 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@xxxxxxxxx>
Signed-off-by: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 b0d671db178a8..ea31ac7ac1ca9 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))
--
2.43.0
