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>

2 files changed, 23 insertions, 32 deletions

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 39d37d0ef575..3f2263e79e4b 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -3379,7 +3379,7 @@ EXPORT_SYMBOL(neigh_app_ns);
 static int unres_qlen_max = INT_MAX / SKB_TRUESIZE(ETH_FRAME_LEN);
 
 static int proc_unres_qlen(struct ctl_table *ctl, int write,
-			   void __user *buffer, size_t *lenp, loff_t *ppos)
+			   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int size, ret;
 	struct ctl_table tmp = *ctl;
@@ -3443,8 +3443,8 @@ static void neigh_proc_update(struct ctl_table *ctl, int write)
 }
 
 static int neigh_proc_dointvec_zero_intmax(struct ctl_table *ctl, int write,
-					   void __user *buffer,
-					   size_t *lenp, loff_t *ppos)
+					   void *buffer, size_t *lenp,
+					   loff_t *ppos)
 {
 	struct ctl_table tmp = *ctl;
 	int ret;
@@ -3457,8 +3457,8 @@ static int neigh_proc_dointvec_zero_intmax(struct ctl_table *ctl, int write,
 	return ret;
 }
 
-int neigh_proc_dointvec(struct ctl_table *ctl, int write,
-			void __user *buffer, size_t *lenp, loff_t *ppos)
+int neigh_proc_dointvec(struct ctl_table *ctl, int write, void *buffer,
+			size_t *lenp, loff_t *ppos)
 {
 	int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
 
@@ -3467,8 +3467,7 @@ int neigh_proc_dointvec(struct ctl_table *ctl, int write,
 }
 EXPORT_SYMBOL(neigh_proc_dointvec);
 
-int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
-				void __user *buffer,
+int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write, void *buffer,
 				size_t *lenp, loff_t *ppos)
 {
 	int ret = proc_dointvec_jiffies(ctl, write, buffer, lenp, ppos);
@@ -3479,8 +3478,8 @@ int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
 EXPORT_SYMBOL(neigh_proc_dointvec_jiffies);
 
 static int neigh_proc_dointvec_userhz_jiffies(struct ctl_table *ctl, int write,
-					      void __user *buffer,
-					      size_t *lenp, loff_t *ppos)
+					      void *buffer, size_t *lenp,
+					      loff_t *ppos)
 {
 	int ret = proc_dointvec_userhz_jiffies(ctl, write, buffer, lenp, ppos);
 
@@ -3489,8 +3488,7 @@ static int neigh_proc_dointvec_userhz_jiffies(struct ctl_table *ctl, int write,
 }
 
 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
-				   void __user *buffer,
-				   size_t *lenp, loff_t *ppos)
+				   void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int ret = proc_dointvec_ms_jiffies(ctl, write, buffer, lenp, ppos);
 
@@ -3500,8 +3498,8 @@ int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
 EXPORT_SYMBOL(neigh_proc_dointvec_ms_jiffies);
 
 static int neigh_proc_dointvec_unres_qlen(struct ctl_table *ctl, int write,
-					  void __user *buffer,
-					  size_t *lenp, loff_t *ppos)
+					  void *buffer, size_t *lenp,
+					  loff_t *ppos)
 {
 	int ret = proc_unres_qlen(ctl, write, buffer, lenp, ppos);
 
@@ -3510,8 +3508,8 @@ static int neigh_proc_dointvec_unres_qlen(struct ctl_table *ctl, int write,
 }
 
 static int neigh_proc_base_reachable_time(struct ctl_table *ctl, int write,
-					  void __user *buffer,
-					  size_t *lenp, loff_t *ppos)
+					  void *buffer, size_t *lenp,
+					  loff_t *ppos)
 {
 	struct neigh_parms *p = ctl->extra2;
 	int ret;
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 9f9e00ba3ad7..0ddb13a6282b 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -45,7 +45,7 @@ EXPORT_SYMBOL(sysctl_devconf_inherit_init_net);
 
 #ifdef CONFIG_RPS
 static int rps_sock_flow_sysctl(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
+				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	unsigned int orig_size, size;
 	int ret, i;
@@ -115,8 +115,7 @@ static int rps_sock_flow_sysctl(struct ctl_table *table, int write,
 static DEFINE_MUTEX(flow_limit_update_mutex);
 
 static int flow_limit_cpu_sysctl(struct ctl_table *table, int write,
-				 void __user *buffer, size_t *lenp,
-				 loff_t *ppos)
+				 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct sd_flow_limit *cur;
 	struct softnet_data *sd;
@@ -180,10 +179,7 @@ write_unlock:
 		}
 		if (len < *lenp)
 			kbuf[len++] = '\n';
-		if (copy_to_user(buffer, kbuf, len)) {
-			ret = -EFAULT;
-			goto done;
-		}
+		memcpy(buffer, kbuf, len);
 		*lenp = len;
 		*ppos += len;
 	}
@@ -194,8 +190,7 @@ done:
 }
 
 static int flow_limit_table_len_sysctl(struct ctl_table *table, int write,
-				       void __user *buffer, size_t *lenp,
-				       loff_t *ppos)
+				       void *buffer, size_t *lenp, loff_t *ppos)
 {
 	unsigned int old, *ptr;
 	int ret;
@@ -217,7 +212,7 @@ static int flow_limit_table_len_sysctl(struct ctl_table *table, int write,
 
 #ifdef CONFIG_NET_SCHED
 static int set_default_qdisc(struct ctl_table *table, int write,
-			     void __user *buffer, size_t *lenp, loff_t *ppos)
+			     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	char id[IFNAMSIZ];
 	struct ctl_table tbl = {
@@ -236,7 +231,7 @@ static int set_default_qdisc(struct ctl_table *table, int write,
 #endif
 
 static int proc_do_dev_weight(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;
 
@@ -251,7 +246,7 @@ static int proc_do_dev_weight(struct ctl_table *table, int write,
 }
 
 static int proc_do_rss_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 ctl_table fake_table;
 	char buf[NETDEV_RSS_KEY_LEN * 3];
@@ -264,7 +259,7 @@ static int proc_do_rss_key(struct ctl_table *table, int write,
 
 #ifdef CONFIG_BPF_JIT
 static int proc_dointvec_minmax_bpf_enable(struct ctl_table *table, int write,
-					   void __user *buffer, size_t *lenp,
+					   void *buffer, size_t *lenp,
 					   loff_t *ppos)
 {
 	int ret, jit_enable = *(int *)table->data;
@@ -291,8 +286,7 @@ static int proc_dointvec_minmax_bpf_enable(struct ctl_table *table, int write,
 # ifdef CONFIG_HAVE_EBPF_JIT
 static int
 proc_dointvec_minmax_bpf_restricted(struct ctl_table *table, int write,
-				    void __user *buffer, size_t *lenp,
-				    loff_t *ppos)
+				    void *buffer, size_t *lenp, loff_t *ppos)
 {
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
@@ -303,8 +297,7 @@ proc_dointvec_minmax_bpf_restricted(struct ctl_table *table, int write,
 
 static int
 proc_dolongvec_minmax_bpf_restricted(struct ctl_table *table, int write,
-				     void __user *buffer, size_t *lenp,
-				     loff_t *ppos)
+				     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;