There is a panic in socket ioctl cmd SIOCGSKNS when NET_NS is not enabled.
The reason is that nsfs tries to access ns->ops but the proc_ns_operations
is not implemented in this case.
[7.670023] Unable to handle kernel NULL pointer dereference at virtual address 00000010
[7.670268] pgd = 32b54000
[7.670544] [00000010] *pgd=00000000
[7.671861] Internal error: Oops: 5 [#1] SMP ARM
[7.672315] Modules linked in:
[7.672918] CPU: 0 PID: 1 Comm: systemd Not tainted 5.13.0-rc3-00375-g6799d4f2da49 #16
[7.673309] Hardware name: Generic DT based system
[7.673642] PC is at nsfs_evict+0x24/0x30
[7.674486] LR is at clear_inode+0x20/0x9c
The same to tun SIOCGSKNS command.
To fix this problem, we make get_net_ns() return -EINVAL when NET_NS is
disabled. Meanwhile move it to right place net/core/net_namespace.c.
Signed-off-by: Changbin Du <[email protected]>
Cc: Cong Wang <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: David Laight <[email protected]>
Cc: Christian Brauner <[email protected]>
Suggested-by: Jakub Kicinski <[email protected]>
---
Patch "net: make get_net_ns_by_fd inline if NET_NS is disabled" must be
applied first.
---
include/linux/socket.h | 2 --
include/net/net_namespace.h | 6 ++++++
net/core/net_namespace.c | 12 ++++++++++++
net/socket.c | 13 -------------
4 files changed, 18 insertions(+), 15 deletions(-)
diff --git a/include/linux/socket.h b/include/linux/socket.h
index b8fc5c53ba6f..0d8e3dcb7f88 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -438,6 +438,4 @@ extern int __sys_socketpair(int family, int type, int protocol,
int __user *usockvec);
extern int __sys_shutdown_sock(struct socket *sock, int how);
extern int __sys_shutdown(int fd, int how);
-
-extern struct ns_common *get_net_ns(struct ns_common *ns);
#endif /* _LINUX_SOCKET_H */
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 0a25f95691d9..bdc0459a595e 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -185,6 +185,7 @@ void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid);
void net_ns_barrier(void);
+struct ns_common *get_net_ns(struct ns_common *ns);
struct net *get_net_ns_by_fd(int fd);
#else /* CONFIG_NET_NS */
#include <linux/sched.h>
@@ -206,6 +207,11 @@ static inline void net_ns_get_ownership(const struct net *net,
static inline void net_ns_barrier(void) {}
+static inline struct ns_common *get_net_ns(struct ns_common *ns)
+{
+ return ERR_PTR(-EINVAL);
+}
+
static inline struct net *get_net_ns_by_fd(int fd)
{
return ERR_PTR(-EINVAL);
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 6a0d9583d69c..9b5a767eddd5 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -641,6 +641,18 @@ void __put_net(struct net *net)
}
EXPORT_SYMBOL_GPL(__put_net);
+/**
+ * get_net_ns - increment the refcount of the network namespace
+ * @ns: common namespace (net)
+ *
+ * Returns the net's common namespace.
+ */
+struct ns_common *get_net_ns(struct ns_common *ns)
+{
+ return &get_net(container_of(ns, struct net, ns))->ns;
+}
+EXPORT_SYMBOL_GPL(get_net_ns);
+
struct net *get_net_ns_by_fd(int fd)
{
struct file *file;
diff --git a/net/socket.c b/net/socket.c
index 27e3e7d53f8e..4f2c6d2795d0 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1072,19 +1072,6 @@ static long sock_do_ioctl(struct net *net, struct socket *sock,
* what to do with it - that's up to the protocol still.
*/
-/**
- * get_net_ns - increment the refcount of the network namespace
- * @ns: common namespace (net)
- *
- * Returns the net's common namespace.
- */
-
-struct ns_common *get_net_ns(struct ns_common *ns)
-{
- return &get_net(container_of(ns, struct net, ns))->ns;
-}
-EXPORT_SYMBOL_GPL(get_net_ns);
-
static long sock_ioctl(struct file *file, unsigned cmd, unsigned long arg)
{
struct socket *sock;
--
2.30.2
On Thu, 10 Jun 2021 23:39:41 +0800 Changbin Du wrote:
> There is a panic in socket ioctl cmd SIOCGSKNS when NET_NS is not enabled.
> The reason is that nsfs tries to access ns->ops but the proc_ns_operations
> is not implemented in this case.
>
> [7.670023] Unable to handle kernel NULL pointer dereference at virtual address 00000010
> [7.670268] pgd = 32b54000
> [7.670544] [00000010] *pgd=00000000
> [7.671861] Internal error: Oops: 5 [#1] SMP ARM
> [7.672315] Modules linked in:
> [7.672918] CPU: 0 PID: 1 Comm: systemd Not tainted 5.13.0-rc3-00375-g6799d4f2da49 #16
> [7.673309] Hardware name: Generic DT based system
> [7.673642] PC is at nsfs_evict+0x24/0x30
> [7.674486] LR is at clear_inode+0x20/0x9c
>
> The same to tun SIOCGSKNS command.
>
> To fix this problem, we make get_net_ns() return -EINVAL when NET_NS is
> disabled. Meanwhile move it to right place net/core/net_namespace.c.
I'm assuming you went from EOPNOTSUPP to EINVAL to follow what the
existing helpers in the header do?
Acked-by: Jakub Kicinski <[email protected]>
Thanks!
From: Changbin Du <[email protected]>
Date: Thu, 10 Jun 2021 23:39:41 +0800
> There is a panic in socket ioctl cmd SIOCGSKNS when NET_NS is not enabled.
> The reason is that nsfs tries to access ns->ops but the proc_ns_operations
> is not implemented in this case.
>
> [7.670023] Unable to handle kernel NULL pointer dereference at virtual address 00000010
> [7.670268] pgd = 32b54000
> [7.670544] [00000010] *pgd=00000000
> [7.671861] Internal error: Oops: 5 [#1] SMP ARM
> [7.672315] Modules linked in:
> [7.672918] CPU: 0 PID: 1 Comm: systemd Not tainted 5.13.0-rc3-00375-g6799d4f2da49 #16
> [7.673309] Hardware name: Generic DT based system
> [7.673642] PC is at nsfs_evict+0x24/0x30
> [7.674486] LR is at clear_inode+0x20/0x9c
>
> The same to tun SIOCGSKNS command.
>
> To fix this problem, we make get_net_ns() return -EINVAL when NET_NS is
> disabled. Meanwhile move it to right place net/core/net_namespace.c.
>
> Signed-off-by: Changbin Du <[email protected]>
> Cc: Cong Wang <[email protected]>
> Cc: Jakub Kicinski <[email protected]>
> Cc: David Laight <[email protected]>
> Cc: Christian Brauner <[email protected]>
> Suggested-by: Jakub Kicinski <[email protected]>
As this is a bug fix please rebase on the 'net' tree and provide a proper Fixes: tag.
Thank you.
On Thu, Jun 10, 2021 at 10:51:12AM -0700, Jakub Kicinski wrote:
> On Thu, 10 Jun 2021 23:39:41 +0800 Changbin Du wrote:
> > There is a panic in socket ioctl cmd SIOCGSKNS when NET_NS is not enabled.
> > The reason is that nsfs tries to access ns->ops but the proc_ns_operations
> > is not implemented in this case.
> >
> > [7.670023] Unable to handle kernel NULL pointer dereference at virtual address 00000010
> > [7.670268] pgd = 32b54000
> > [7.670544] [00000010] *pgd=00000000
> > [7.671861] Internal error: Oops: 5 [#1] SMP ARM
> > [7.672315] Modules linked in:
> > [7.672918] CPU: 0 PID: 1 Comm: systemd Not tainted 5.13.0-rc3-00375-g6799d4f2da49 #16
> > [7.673309] Hardware name: Generic DT based system
> > [7.673642] PC is at nsfs_evict+0x24/0x30
> > [7.674486] LR is at clear_inode+0x20/0x9c
> >
> > The same to tun SIOCGSKNS command.
> >
> > To fix this problem, we make get_net_ns() return -EINVAL when NET_NS is
> > disabled. Meanwhile move it to right place net/core/net_namespace.c.
>
> I'm assuming you went from EOPNOTSUPP to EINVAL to follow what the
> existing helpers in the header do?
>
yes, make them behaviour in the same manner.
> Acked-by: Jakub Kicinski <[email protected]>
>
> Thanks!
--
Cheers,
Changbin Du