sysctl: pass kernel pointers to ->proc_handler

Instead of having all the sysctl handlers deal with user pointers, which
is rather hairy in terms of the BPF interaction, copy the input to and
from  userspace in common code.  This also means that the strings are
always NUL-terminated by the common code, making the API a little bit
safer.

As most handler just pass through the data to one of the common handlers
a lot of the changes are mechnical.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

4 files changed, 18 insertions, 26 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 24e319dfb510..9d0e89bccb90 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -6108,9 +6108,8 @@ static void ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp)
 
 #ifdef CONFIG_SYSCTL
 
-static
-int addrconf_sysctl_forward(struct ctl_table *ctl, int write,
-			   void __user *buffer, size_t *lenp, loff_t *ppos)
+static int addrconf_sysctl_forward(struct ctl_table *ctl, int write,
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *valp = ctl->data;
 	int val = *valp;
@@ -6134,9 +6133,8 @@ int addrconf_sysctl_forward(struct ctl_table *ctl, int write,
 	return ret;
 }
 
-static
-int addrconf_sysctl_mtu(struct ctl_table *ctl, int write,
-			void __user *buffer, size_t *lenp, loff_t *ppos)
+static int addrconf_sysctl_mtu(struct ctl_table *ctl, int write,
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct inet6_dev *idev = ctl->extra1;
 	int min_mtu = IPV6_MIN_MTU;
@@ -6206,9 +6204,8 @@ static int addrconf_disable_ipv6(struct ctl_table *table, int *p, int newf)
 	return 0;
 }
 
-static
-int addrconf_sysctl_disable(struct ctl_table *ctl, int write,
-			    void __user *buffer, size_t *lenp, loff_t *ppos)
+static int addrconf_sysctl_disable(struct ctl_table *ctl, int write,
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *valp = ctl->data;
 	int val = *valp;
@@ -6232,9 +6229,8 @@ int addrconf_sysctl_disable(struct ctl_table *ctl, int write,
 	return ret;
 }
 
-static
-int addrconf_sysctl_proxy_ndp(struct ctl_table *ctl, int write,
-			      void __user *buffer, size_t *lenp, loff_t *ppos)
+static int addrconf_sysctl_proxy_ndp(struct ctl_table *ctl, int write,
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *valp = ctl->data;
 	int ret;
@@ -6275,7 +6271,7 @@ int addrconf_sysctl_proxy_ndp(struct ctl_table *ctl, int write,
 }
 
 static int addrconf_sysctl_addr_gen_mode(struct ctl_table *ctl, int write,
-					 void __user *buffer, size_t *lenp,
+					 void *buffer, size_t *lenp,
 					 loff_t *ppos)
 {
 	int ret = 0;
@@ -6337,7 +6333,7 @@ out:
 }
 
 static int addrconf_sysctl_stable_secret(struct ctl_table *ctl, int write,
-					 void __user *buffer, size_t *lenp,
+					 void *buffer, size_t *lenp,
 					 loff_t *ppos)
 {
 	int err;
@@ -6404,8 +6400,7 @@ out:
 
 static
 int addrconf_sysctl_ignore_routes_with_linkdown(struct ctl_table *ctl,
-						int write,
-						void __user *buffer,
+						int write, void *buffer,
 						size_t *lenp,
 						loff_t *ppos)
 {
@@ -6505,10 +6500,8 @@ int addrconf_disable_policy(struct ctl_table *ctl, int *valp, int val)
 	return 0;
 }
 
-static
-int addrconf_sysctl_disable_policy(struct ctl_table *ctl, int write,
-				   void __user *buffer, size_t *lenp,
-				   loff_t *ppos)
+static int addrconf_sysctl_disable_policy(struct ctl_table *ctl, int write,
+				   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *valp = ctl->data;
 	int val = *valp;
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 1ecd4e9b0bdf..58f1255295d3 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1835,7 +1835,8 @@ static void ndisc_warn_deprecated_sysctl(struct ctl_table *ctl,
 	}
 }
 
-int ndisc_ifinfo_sysctl_change(struct ctl_table *ctl, int write, void __user *buffer, size_t *lenp, loff_t *ppos)
+int ndisc_ifinfo_sysctl_change(struct ctl_table *ctl, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
 {
 	struct net_device *dev = ctl->extra1;
 	struct inet6_dev *idev;
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 310cbddaa533..acdb31e38412 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -6088,9 +6088,8 @@ static int rt6_stats_seq_show(struct seq_file *seq, void *v)
 
 #ifdef CONFIG_SYSCTL
 
-static
-int ipv6_sysctl_rtcache_flush(struct ctl_table *ctl, int write,
-			      void __user *buffer, size_t *lenp, loff_t *ppos)
+static int ipv6_sysctl_rtcache_flush(struct ctl_table *ctl, int write,
+			      void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net;
 	int delay;
diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c
index 63b657aa8d29..fac2135aa47b 100644
--- a/net/ipv6/sysctl_net_ipv6.c
+++ b/net/ipv6/sysctl_net_ipv6.c
@@ -26,8 +26,7 @@ static int auto_flowlabels_min;
 static int auto_flowlabels_max = IP6_AUTO_FLOW_LABEL_MAX;
 
 static int proc_rt6_multipath_hash_policy(struct ctl_table *table, int write,
-					  void __user *buffer, size_t *lenp,
-					  loff_t *ppos)
+					  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net;
 	int ret;