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

[Christoph Hellwig <hch@xxxxxx>]

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

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 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 <uapi/linux/bpfilter.h>
 #include <linux/usermode_driver.h>
+#include <linux/sockptr.h>
 
 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