From 676d23690fb62b5d51ba5d659935e9f7d9da9f8e Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Fri, 11 Apr 2014 16:15:36 -0400 Subject: net: Fix use after free by removing length arg from sk_data_ready callbacks. Several spots in the kernel perform a sequence like: skb_queue_tail(&sk->s_receive_queue, skb); sk->sk_data_ready(sk, skb->len); But at the moment we place the SKB onto the socket receive queue it can be consumed and freed up. So this skb->len access is potentially to freed up memory. Furthermore, the skb->len can be modified by the consumer so it is possible that the value isn't accurate. And finally, no actual implementation of this callback actually uses the length argument. And since nobody actually cared about it's value, lots of call sites pass arbitrary values in such as '0' and even '1'. So just remove the length argument from the callback, that way there is no confusion whatsoever and all of these use-after-free cases get fixed as a side effect. Based upon a patch by Eric Dumazet and his suggestion to audit this issue tree-wide. Signed-off-by: David S. Miller --- drivers/target/iscsi/iscsi_target_core.h | 2 +- drivers/target/iscsi/iscsi_target_nego.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/target/iscsi') diff --git a/drivers/target/iscsi/iscsi_target_core.h b/drivers/target/iscsi/iscsi_target_core.h index 48f7b3bf4e8c..f452398fe0f0 100644 --- a/drivers/target/iscsi/iscsi_target_core.h +++ b/drivers/target/iscsi/iscsi_target_core.h @@ -556,7 +556,7 @@ struct iscsi_conn { struct completion rx_half_close_comp; /* socket used by this connection */ struct socket *sock; - void (*orig_data_ready)(struct sock *, int); + void (*orig_data_ready)(struct sock *); void (*orig_state_change)(struct sock *); #define LOGIN_FLAGS_READ_ACTIVE 1 #define LOGIN_FLAGS_CLOSED 2 diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c index 582ba84075ec..75b685960e80 100644 --- a/drivers/target/iscsi/iscsi_target_nego.c +++ b/drivers/target/iscsi/iscsi_target_nego.c @@ -375,7 +375,7 @@ static int iscsi_target_do_tx_login_io(struct iscsi_conn *conn, struct iscsi_log return 0; } -static void iscsi_target_sk_data_ready(struct sock *sk, int count) +static void iscsi_target_sk_data_ready(struct sock *sk) { struct iscsi_conn *conn = sk->sk_user_data; bool rc; -- cgit v1.2.3