On 4/7/21 2:09 AM, Aditya Pakki wrote: > In case of rs failure in rds_send_remove_from_sock(), the 'rm' resource > is freed and later under spinlock, causing potential use-after-free. > Set the free pointer to NULL to avoid undefined behavior. > > Signed-off-by: Aditya Pakki <pakki001@xxxxxxx> > --- > net/rds/message.c | 1 + > net/rds/send.c | 2 +- > 2 files changed, 2 insertions(+), 1 deletion(-) > > diff --git a/net/rds/message.c b/net/rds/message.c > index 071a261fdaab..90ebcfe5fe3b 100644 > --- a/net/rds/message.c > +++ b/net/rds/message.c > @@ -180,6 +180,7 @@ void rds_message_put(struct rds_message *rm) > rds_message_purge(rm); > > kfree(rm); > + rm = NULL; This is a nop really. This does not clear @rm variable in the caller. > } > } > EXPORT_SYMBOL_GPL(rds_message_put); > diff --git a/net/rds/send.c b/net/rds/send.c > index 985d0b7713ac..fe5264b9d4b3 100644 > --- a/net/rds/send.c > +++ b/net/rds/send.c > @@ -665,7 +665,7 @@ static void rds_send_remove_from_sock(struct list_head *messages, int status) > unlock_and_drop: > spin_unlock_irqrestore(&rm->m_rs_lock, flags); > rds_message_put(rm); > - if (was_on_sock) > + if (was_on_sock && rm) > rds_message_put(rm); Maybe the bug is that the refcount has not be elevated when was_on_sock has been set. > } > >
