2021-01-05 05:54:01

by Qinglang Miao

Subject: [PATCH v2] net: qrtr: fix null-ptr-deref in qrtr_ns_remove

A null-ptr-deref bug is reported by Hulk Robot like this:
--------------
KASAN: null-ptr-deref in range [0x0000000000000128-0x000000000000012f]
Call Trace:
qrtr_ns_remove+0x22/0x40 [ns]
qrtr_proto_fini+0xa/0x31 [qrtr]
__x64_sys_delete_module+0x337/0x4e0
do_syscall_64+0x34/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x468ded
--------------

When qrtr_ns_init fails in qrtr_proto_init, qrtr_ns_remove which would
be called later on would raise a null-ptr-deref because qrtr_ns.workqueue
has been destroyed.

Fix it by making qrtr_ns_init have a return value and adding a check in
qrtr_proto_init.

Reported-by: Hulk Robot <[email protected]>
Signed-off-by: Qinglang Miao <[email protected]>
---
v1->v2: remove redundant braces for single statement blocks.

net/qrtr/ns.c | 7 ++++---
net/qrtr/qrtr.c | 16 +++++++++++-----
net/qrtr/qrtr.h | 2 +-
3 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/net/qrtr/ns.c b/net/qrtr/ns.c
index 56aaf8cb6..8d00dfe81 100644
--- a/net/qrtr/ns.c
+++ b/net/qrtr/ns.c
@@ -755,7 +755,7 @@ static void qrtr_ns_data_ready(struct sock *sk)
queue_work(qrtr_ns.workqueue, &qrtr_ns.work);
}

-void qrtr_ns_init(void)
+int qrtr_ns_init(void)
{
struct sockaddr_qrtr sq;
int ret;
@@ -766,7 +766,7 @@ void qrtr_ns_init(void)
ret = sock_create_kern(&init_net, AF_QIPCRTR, SOCK_DGRAM,
PF_QIPCRTR, &qrtr_ns.sock);
if (ret < 0)
- return;
+ return ret;

ret = kernel_getsockname(qrtr_ns.sock, (struct sockaddr *)&sq);
if (ret < 0) {
@@ -797,12 +797,13 @@ void qrtr_ns_init(void)
if (ret < 0)
goto err_wq;

- return;
+ return 0;

err_wq:
destroy_workqueue(qrtr_ns.workqueue);
err_sock:
sock_release(qrtr_ns.sock);
+ return ret;
}
EXPORT_SYMBOL_GPL(qrtr_ns_init);

diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
index f4ab3ca6d..b34358282 100644
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -1287,13 +1287,19 @@ static int __init qrtr_proto_init(void)
return rc;

rc = sock_register(&qrtr_family);
- if (rc) {
- proto_unregister(&qrtr_proto);
- return rc;
- }
+ if (rc)
+ goto err_proto;

- qrtr_ns_init();
+ rc = qrtr_ns_init();
+ if (rc)
+ goto err_sock;

+ return 0;
+
+err_sock:
+ sock_unregister(qrtr_family.family);
+err_proto:
+ proto_unregister(&qrtr_proto);
return rc;
}
postcore_initcall(qrtr_proto_init);
diff --git a/net/qrtr/qrtr.h b/net/qrtr/qrtr.h
index dc2b67f17..3f2d28696 100644
--- a/net/qrtr/qrtr.h
+++ b/net/qrtr/qrtr.h
@@ -29,7 +29,7 @@ void qrtr_endpoint_unregister(struct qrtr_endpoint *ep);

int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len);

-void qrtr_ns_init(void);
+int qrtr_ns_init(void);

void qrtr_ns_remove(void);

--
2.23.0

2021-01-06 00:53:09

by David Miller

Subject: Re: [PATCH v2] net: qrtr: fix null-ptr-deref in qrtr_ns_remove

From: Qinglang Miao <[email protected]>
Date: Tue, 5 Jan 2021 13:57:54 +0800

> A null-ptr-deref bug is reported by Hulk Robot like this:
> --------------
> KASAN: null-ptr-deref in range [0x0000000000000128-0x000000000000012f]
> Call Trace:
> qrtr_ns_remove+0x22/0x40 [ns]
> qrtr_proto_fini+0xa/0x31 [qrtr]
> __x64_sys_delete_module+0x337/0x4e0
> do_syscall_64+0x34/0x80
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x468ded
> --------------
>
> When qrtr_ns_init fails in qrtr_proto_init, qrtr_ns_remove which would
> be called later on would raise a null-ptr-deref because qrtr_ns.workqueue
> has been destroyed.
>
> Fix it by making qrtr_ns_init have a return value and adding a check in
> qrtr_proto_init.
>
> Reported-by: Hulk Robot <[email protected]>
> Signed-off-by: Qinglang Miao <[email protected]>
> ---
> v1->v2: remove redundant braces for single statement blocks.

Applied.