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>

3 files changed, 19 insertions, 31 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 30fa42f5997d..a118978d222c 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -2361,8 +2361,7 @@ static int devinet_conf_ifindex(struct net *net, struct ipv4_devconf *cnf)
 }
 
 static int devinet_conf_proc(struct ctl_table *ctl, int write,
-			     void __user *buffer,
-			     size_t *lenp, loff_t *ppos)
+			     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int old_value = *(int *)ctl->data;
 	int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
@@ -2414,8 +2413,7 @@ static int devinet_conf_proc(struct ctl_table *ctl, int write,
 }
 
 static int devinet_sysctl_forward(struct ctl_table *ctl, int write,
-				  void __user *buffer,
-				  size_t *lenp, loff_t *ppos)
+				  void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *valp = ctl->data;
 	int val = *valp;
@@ -2458,8 +2456,7 @@ static int devinet_sysctl_forward(struct ctl_table *ctl, int write,
 }
 
 static int ipv4_doint_and_flush(struct ctl_table *ctl, int write,
-				void __user *buffer,
-				size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int *valp = ctl->data;
 	int val = *valp;
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 788c69d9bfe0..041f4dcac440 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -3336,8 +3336,7 @@ static int ip_rt_gc_elasticity __read_mostly	= 8;
 static int ip_min_valid_pmtu __read_mostly	= IPV4_MIN_MTU;
 
 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
-					void __user *buffer,
-					size_t *lenp, loff_t *ppos)
+		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net = (struct net *)__ctl->extra1;
 
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 81b267e990a1..868e317cc324 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -71,8 +71,7 @@ static void set_local_port_range(struct net *net, int range[2])
 
 /* Validate changes from /proc interface. */
 static int ipv4_local_port_range(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 =
 		container_of(table->data, struct net, ipv4.ip_local_ports.range);
@@ -107,7 +106,7 @@ static int ipv4_local_port_range(struct ctl_table *table, int write,
 
 /* Validate changes from /proc interface. */
 static int ipv4_privileged_ports(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 = container_of(table->data, struct net,
 	    ipv4.sysctl_ip_prot_sock);
@@ -168,8 +167,7 @@ static void set_ping_group_range(struct ctl_table *table, kgid_t low, kgid_t hig
 
 /* Validate changes from /proc interface. */
 static int ipv4_ping_group_range(struct ctl_table *table, int write,
-				 void __user *buffer,
-				 size_t *lenp, loff_t *ppos)
+				 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct user_namespace *user_ns = current_user_ns();
 	int ret;
@@ -204,8 +202,7 @@ static int ipv4_ping_group_range(struct ctl_table *table, int write,
 }
 
 static int ipv4_fwd_update_priority(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;
@@ -221,7 +218,7 @@ static int ipv4_fwd_update_priority(struct ctl_table *table, int write,
 }
 
 static int proc_tcp_congestion_control(struct ctl_table *ctl, int write,
-				       void __user *buffer, size_t *lenp, loff_t *ppos)
+				       void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net = container_of(ctl->data, struct net,
 				       ipv4.tcp_congestion_control);
@@ -241,9 +238,8 @@ static int proc_tcp_congestion_control(struct ctl_table *ctl, int write,
 }
 
 static int proc_tcp_available_congestion_control(struct ctl_table *ctl,
-						 int write,
-						 void __user *buffer, size_t *lenp,
-						 loff_t *ppos)
+						 int write, void *buffer,
+						 size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table tbl = { .maxlen = TCP_CA_BUF_MAX, };
 	int ret;
@@ -258,9 +254,8 @@ static int proc_tcp_available_congestion_control(struct ctl_table *ctl,
 }
 
 static int proc_allowed_congestion_control(struct ctl_table *ctl,
-					   int write,
-					   void __user *buffer, size_t *lenp,
-					   loff_t *ppos)
+					   int write, void *buffer,
+					   size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table tbl = { .maxlen = TCP_CA_BUF_MAX };
 	int ret;
@@ -296,8 +291,7 @@ static int sscanf_key(char *buf, __le32 *key)
 }
 
 static int proc_tcp_fastopen_key(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 = container_of(table->data, struct net,
 	    ipv4.sysctl_tcp_fastopen);
@@ -399,7 +393,7 @@ static void proc_configure_early_demux(int enabled, int protocol)
 }
 
 static int proc_tcp_early_demux(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret = 0;
 
@@ -415,7 +409,7 @@ static int proc_tcp_early_demux(struct ctl_table *table, int write,
 }
 
 static int proc_udp_early_demux(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret = 0;
 
@@ -431,8 +425,7 @@ static int proc_udp_early_demux(struct ctl_table *table, int write,
 }
 
 static int proc_tfo_blackhole_detect_timeout(struct ctl_table *table,
-					     int write,
-					     void __user *buffer,
+					     int write, void *buffer,
 					     size_t *lenp, loff_t *ppos)
 {
 	struct net *net = container_of(table->data, struct net,
@@ -447,8 +440,7 @@ static int proc_tfo_blackhole_detect_timeout(struct ctl_table *table,
 }
 
 static int proc_tcp_available_ulp(struct ctl_table *ctl,
-				  int write,
-				  void __user *buffer, size_t *lenp,
+				  int write, void *buffer, size_t *lenp,
 				  loff_t *ppos)
 {
 	struct ctl_table tbl = { .maxlen = TCP_ULP_BUF_MAX, };
@@ -466,7 +458,7 @@ static int proc_tcp_available_ulp(struct ctl_table *ctl,
 
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 static int proc_fib_multipath_hash_policy(struct ctl_table *table, int write,
-					  void __user *buffer, size_t *lenp,
+					  void *buffer, size_t *lenp,
 					  loff_t *ppos)
 {
 	struct net *net = container_of(table->data, struct net,