From: Guenter Roeck <linux@roeck-us.net> stable inclusion from stable-v6.6.113 commit ca603d157694a49b2e3aa6579f15faef75e44c93 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ID6BW8 CVE: CVE-2025-40202 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit e2c69490dda5d4c9f1bfbb2898989c8f3530e354 upstream Prior to commit b52da4054ee0 ("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: b52da4054ee0 ("ipmi: Rework user message limit handling") Reported-by: Eric Dumazet <edumazet@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Message-ID: <20251006201857.3433837-1-linux@roeck-us.net> Signed-off-by: Corey Minyard <corey@minyard.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yi Yang <yiyang13@huawei.com> --- drivers/char/ipmi/ipmi_msghandler.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c index 980a5988f662..389151379b59 100644 --- a/drivers/char/ipmi/ipmi_msghandler.c +++ b/drivers/char/ipmi/ipmi_msghandler.c @@ -2317,8 +2317,11 @@ 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)) -- 2.25.1