[PATCH 12/24] 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 | 8 ++++----
 net/ipv4/bpfilter/sockopt.c  | 8 ++++----
 net/ipv4/ip_sockglue.c       | 3 ++-
 4 files changed, 13 insertions(+), 12 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 713b4b3d02005d..52f8d0bc3f6b29 100644
--- a/net/bpfilter/bpfilter_kern.c
+++ b/net/bpfilter/bpfilter_kern.c
@@ -32,7 +32,7 @@ static void __stop_umh(void)
 }
 
 static int __bpfilter_process_sockopt(struct sock *sk, int optname,
-                                     char __user *optval,
+                                     sockptr_t optval,
                                      unsigned int optlen, bool is_set)
 {
        struct mbox_request req;
@@ -41,7 +41,7 @@ static int __bpfilter_process_sockopt(struct sock *sk, int 
optname,
        ssize_t n;
        int ret = -EFAULT;
 
-       if (uaccess_kernel()) {
+       if (uaccess_kernel() || sockptr_is_kernel(optval)) {
                pr_err("kernel access not supported\n");
                return -EFAULT;
        }
@@ -49,7 +49,7 @@ static int __bpfilter_process_sockopt(struct sock *sk, int 
optname,
        req.is_set = is_set;
        req.pid = current->pid;
        req.cmd = optname;
-       req.addr = (__force long)optval;
+       req.addr = (__force long)optval.user;
        req.len = optlen;
        if (!bpfilter_ops.info.tgid)
                goto out;
@@ -87,7 +87,7 @@ static int start_umh(void)
        pr_info("Loaded bpfilter_umh pid %d\n", pid_nr(bpfilter_ops.info.tgid));
 
        /* health check that usermode process started correctly */
-       if (__bpfilter_process_sockopt(NULL, 0, NULL, 0, 0) != 0) {
+       if (__bpfilter_process_sockopt(NULL, 0, USER_SOCKPTR(NULL), 0, 0)) {
                shutdown_umh();
                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