6.6-stable review patch. If anyone has any objections, please let me know.
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From: Dan Carpenter dan.carpenter@linaro.org
commit fa332f5dc6fc662ad7d3200048772c96b861cf6b upstream.
The "intf" list iterator is an invalid pointer if the correct "intf->intf_num" is not found. Calling atomic_dec(&intf->nr_users) on and invalid pointer will lead to memory corruption.
We don't really need to call atomic_dec() if we haven't called atomic_add_return() so update the if (intf->in_shutdown) path as well.
Fixes: 8e76741c3d8b ("ipmi: Add a limit on the number of users that may use IPMI") Signed-off-by: Dan Carpenter dan.carpenter@linaro.org Message-ID: aBjMZ8RYrOt6NOgi@stanley.mountain Signed-off-by: Corey Minyard corey@minyard.net [ - Dropped change to the `if (intf->in_shutdown)` block since that logic doesn't exist yet. - Modified out_unlock to release the srcu lock instead of the mutex since we don't have the mutex here yet. ] Signed-off-by: Brendan Jackman jackmanb@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/char/ipmi/ipmi_msghandler.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/char/ipmi/ipmi_msghandler.c +++ b/drivers/char/ipmi/ipmi_msghandler.c @@ -1241,7 +1241,7 @@ int ipmi_create_user(unsigned int } /* Not found, return an error */ rv = -EINVAL; - goto out_kfree; + goto out_unlock;
found: if (atomic_add_return(1, &intf->nr_users) > max_users) { @@ -1283,6 +1283,7 @@ int ipmi_create_user(unsigned int
out_kfree: atomic_dec(&intf->nr_users); +out_unlock: srcu_read_unlock(&ipmi_interfaces_srcu, index); vfree(new_user); return rv;