Commit e2c69490 authored by Guenter Roeck's avatar Guenter Roeck Committed by Corey Minyard
Browse files

ipmi: Fix handling of messages with provided receive message pointer 



Prior to commit b52da405 ("ipmi: Rework user message limit handling"),
i_ipmi_request() used to increase the user reference counter if the receive
message is provided by the caller of IPMI API functions. This is no longer
the case. However, ipmi_free_recv_msg() is still called and decreases the
reference counter. This results in the reference counter reaching zero,
the user data pointer is released, and all kinds of interesting crashes are
seen.

Fix the problem by increasing user reference counter if the receive message
has been provided by the caller.

Fixes: b52da405 ("ipmi: Rework user message limit handling")
Reported-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Message-ID: <20251006201857.3433837-1-linux@roeck-us.net>
Signed-off-by: default avatarCorey Minyard <corey@minyard.net>
parent 4af66c2b

drivers/char/ipmi/ipmi_msghandler.c

+4 −1
Original line number Diff line number Diff line
@@ -2301,8 +2301,11 @@ static int i_ipmi_request(struct ipmi_user *user, 
	if (supplied_recv) {

		recv_msg = supplied_recv;

		recv_msg->user = user;

		if (user)

		if (user) {

			atomic_inc(&user->nr_msgs);

			/* The put happens when the message is freed. */

			kref_get(&user->refcount);

		}

	} else {

		recv_msg = ipmi_alloc_recv_msg(user);

		if (IS_ERR(recv_msg))