| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 31/90] rds: Prevent kernel-infoleak in rds_notify_queue_get() | Date | Mon, 3 Aug 2020 14:18:53 +0200 |
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From: Peilin Ye <yepeilin.cs@gmail.com>
commit bbc8a99e952226c585ac17477a85ef1194501762 upstream.
rds_notify_queue_get() is potentially copying uninitialized kernel stack memory to userspace since the compiler may leave a 4-byte hole at the end of `cmsg`.
In 2016 we tried to fix this issue by doing `= { 0 };` on `cmsg`, which unfortunately does not always initialize that 4-byte hole. Fix it by using memset() instead.
Cc: stable@vger.kernel.org Fixes: f037590fff30 ("rds: fix a leak of kernel memory") Fixes: bdbe6fbc6a2f ("RDS: recv.c") Suggested-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- net/rds/recv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/rds/recv.c +++ b/net/rds/recv.c @@ -450,12 +450,13 @@ static int rds_still_queued(struct rds_s int rds_notify_queue_get(struct rds_sock *rs, struct msghdr *msghdr) { struct rds_notifier *notifier; - struct rds_rdma_notify cmsg = { 0 }; /* fill holes with zero */ + struct rds_rdma_notify cmsg; unsigned int count = 0, max_messages = ~0U; unsigned long flags; LIST_HEAD(copy); int err = 0; + memset(&cmsg, 0, sizeof(cmsg)); /* fill holes with zero */ /* put_cmsg copies to user space and thus may sleep. We can't do this * with rs_lock held, so first grab as many notifications as we can stuff
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