* [PATCH] ipmi: fix use after free in _ipmi_destroy_user()
@ 2022-11-15 13:17 Dan Carpenter
2022-11-15 14:15 ` Corey Minyard
0 siblings, 1 reply; 2+ messages in thread
From: Dan Carpenter @ 2022-11-15 13:17 UTC (permalink / raw)
To: Corey Minyard; +Cc: openipmi-developer, kernel-janitors
The intf_free() function frees the "intf" pointer so we cannot
dereference it again on the next line.
Fixes: cbb79863fc31 ("ipmi: Don't allow device module unload when in use")
Signed-off-by: Dan Carpenter <error27@gmail.com>
---
drivers/char/ipmi/ipmi_msghandler.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index f6b8ca6df9b5..186f1fee7534 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -1330,6 +1330,7 @@ static void _ipmi_destroy_user(struct ipmi_user *user)
unsigned long flags;
struct cmd_rcvr *rcvr;
struct cmd_rcvr *rcvrs = NULL;
+ struct module *owner;
if (!acquire_ipmi_user(user, &i)) {
/*
@@ -1392,8 +1393,9 @@ static void _ipmi_destroy_user(struct ipmi_user *user)
kfree(rcvr);
}
+ owner = intf->owner;
kref_put(&intf->refcount, intf_free);
- module_put(intf->owner);
+ module_put(owner);
}
int ipmi_destroy_user(struct ipmi_user *user)
--
2.35.1
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] ipmi: fix use after free in _ipmi_destroy_user()
2022-11-15 13:17 [PATCH] ipmi: fix use after free in _ipmi_destroy_user() Dan Carpenter
@ 2022-11-15 14:15 ` Corey Minyard
0 siblings, 0 replies; 2+ messages in thread
From: Corey Minyard @ 2022-11-15 14:15 UTC (permalink / raw)
To: Dan Carpenter; +Cc: openipmi-developer, kernel-janitors
On Tue, Nov 15, 2022 at 04:17:43PM +0300, Dan Carpenter wrote:
> The intf_free() function frees the "intf" pointer so we cannot
> dereference it again on the next line.
Thanks. I will request a backport for 5.5 and later.
>
> Fixes: cbb79863fc31 ("ipmi: Don't allow device module unload when in use")
> Signed-off-by: Dan Carpenter <error27@gmail.com>
> ---
> drivers/char/ipmi/ipmi_msghandler.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
> index f6b8ca6df9b5..186f1fee7534 100644
> --- a/drivers/char/ipmi/ipmi_msghandler.c
> +++ b/drivers/char/ipmi/ipmi_msghandler.c
> @@ -1330,6 +1330,7 @@ static void _ipmi_destroy_user(struct ipmi_user *user)
> unsigned long flags;
> struct cmd_rcvr *rcvr;
> struct cmd_rcvr *rcvrs = NULL;
> + struct module *owner;
>
> if (!acquire_ipmi_user(user, &i)) {
> /*
> @@ -1392,8 +1393,9 @@ static void _ipmi_destroy_user(struct ipmi_user *user)
> kfree(rcvr);
> }
>
> + owner = intf->owner;
> kref_put(&intf->refcount, intf_free);
> - module_put(intf->owner);
> + module_put(owner);
> }
>
> int ipmi_destroy_user(struct ipmi_user *user)
> --
> 2.35.1
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-11-15 13:17 [PATCH] ipmi: fix use after free in _ipmi_destroy_user() Dan Carpenter
2022-11-15 14:15 ` Corey Minyard
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