Re: [PATCH 13/26] bpfilter: switch bpfilter_ip_set_sockopt to sockptr_t

['Christoph Hellwig']

On Thu, Jul 23, 2020 at 11:16:16AM +, David Laight wrote:
> From: Christoph Hellwig
> > Sent: 23 July 2020 07:09
> > 
> > This is mostly to prepare for cleaning up the callers, as bpfilter by
> > design can't handle kernel pointers.
> 
> You've failed to fix the sense of the above...

The sense still is correct.

RE: [PATCH 13/26] bpfilter: switch bpfilter_ip_set_sockopt to sockptr_t

[David Laight]

From: Christoph Hellwig
> Sent: 23 July 2020 07:09
> 
> This is mostly to prepare for cleaning up the callers, as bpfilter by
> design can't handle kernel pointers.

You've failed to fix the sense of the above...

David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, 
UK
Registration No: 1397386 (Wales)

[PATCH 13/26] bpfilter: switch bpfilter_ip_set_sockopt to sockptr_t

[Christoph Hellwig]

This is mostly to prepare for cleaning up the callers, as bpfilter by
design can't handle kernel pointers.

Signed-off-by: Christoph Hellwig 
---
 include/linux/bpfilter.h | 6 +++---
 net/bpfilter/bpfilter_kern.c | 6 +++---
 net/ipv4/bpfilter/sockopt.c  | 8 
 net/ipv4/ip_sockglue.c   | 3 ++-
 4 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/include/linux/bpfilter.h b/include/linux/bpfilter.h
index 9b114c718a7617..2ae3c8e1d83c43 100644
--- a/include/linux/bpfilter.h
+++ b/include/linux/bpfilter.h
@@ -4,9 +4,10 @@
 
 #include 
 #include 
+#include 
 
 struct sock;
-int bpfilter_ip_set_sockopt(struct sock *sk, int optname, char __user *optval,
+int bpfilter_ip_set_sockopt(struct sock *sk, int optname, sockptr_t optval,
unsigned int optlen);
 int bpfilter_ip_get_sockopt(struct sock *sk, int optname, char __user *optval,
int __user *optlen);
@@ -16,8 +17,7 @@ struct bpfilter_umh_ops {
struct umd_info info;
/* since ip_getsockopt() can run in parallel, serialize access to umh */
struct mutex lock;
-   int (*sockopt)(struct sock *sk, int optname,
-  char __user *optval,
+   int (*sockopt)(struct sock *sk, int optname, sockptr_t optval,
   unsigned int optlen, bool is_set);
int (*start)(void);
 };
diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
index 00540457e5f4d3..f580c3344cb3ac 100644
--- a/net/bpfilter/bpfilter_kern.c
+++ b/net/bpfilter/bpfilter_kern.c
@@ -60,17 +60,17 @@ static int bpfilter_send_req(struct mbox_request *req)
 }
 
 static int bpfilter_process_sockopt(struct sock *sk, int optname,
-   char __user *optval, unsigned int optlen,
+   sockptr_t optval, unsigned int optlen,
bool is_set)
 {
struct mbox_request req = {
.is_set = is_set,
.pid= current->pid,
.cmd= optname,
-   .addr   = (uintptr_t)optval,
+   .addr   = (uintptr_t)optval.user,
.len= optlen,
};
-   if (uaccess_kernel()) {
+   if (uaccess_kernel() || sockptr_is_kernel(optval)) {
pr_err("kernel access not supported\n");
return -EFAULT;
}
diff --git a/net/ipv4/bpfilter/sockopt.c b/net/ipv4/bpfilter/sockopt.c
index 9063c6767d3410..1b34cb9a7708ec 100644
--- a/net/ipv4/bpfilter/sockopt.c
+++ b/net/ipv4/bpfilter/sockopt.c
@@ -21,8 +21,7 @@ void bpfilter_umh_cleanup(struct umd_info *info)
 }
 EXPORT_SYMBOL_GPL(bpfilter_umh_cleanup);
 
-static int bpfilter_mbox_request(struct sock *sk, int optname,
-char __user *optval,
+static int bpfilter_mbox_request(struct sock *sk, int optname, sockptr_t 
optval,
 unsigned int optlen, bool is_set)
 {
int err;
@@ -52,7 +51,7 @@ static int bpfilter_mbox_request(struct sock *sk, int optname,
return err;
 }
 
-int bpfilter_ip_set_sockopt(struct sock *sk, int optname, char __user *optval,
+int bpfilter_ip_set_sockopt(struct sock *sk, int optname, sockptr_t optval,
unsigned int optlen)
 {
return bpfilter_mbox_request(sk, optname, optval, optlen, true);
@@ -66,7 +65,8 @@ int bpfilter_ip_get_sockopt(struct sock *sk, int optname, 
char __user *optval,
if (get_user(len, optlen))
return -EFAULT;
 
-   return bpfilter_mbox_request(sk, optname, optval, len, false);
+   return bpfilter_mbox_request(sk, optname, USER_SOCKPTR(optval), len,
+false);
 }
 
 static int __init bpfilter_sockopt_init(void)
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 42befbf12846c0..36f746e01741f6 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1414,7 +1414,8 @@ int ip_setsockopt(struct sock *sk, int level,
 #if IS_ENABLED(CONFIG_BPFILTER_UMH)
if (optname >= BPFILTER_IPT_SO_SET_REPLACE &&
optname < BPFILTER_IPT_SET_MAX)
-   err = bpfilter_ip_set_sockopt(sk, optname, optval, optlen);
+   err = bpfilter_ip_set_sockopt(sk, optname, USER_SOCKPTR(optval),
+ optlen);
 #endif
 #ifdef CONFIG_NETFILTER
/* we need to exclude all possible ENOPROTOOPTs except default case */
-- 
2.27.0