net: convert %p usage to %pK

The %pK format specifier is designed to hide exposed kernel pointers,
specifically via /proc interfaces.  Exposing these pointers provides an
easy target for kernel write vulnerabilities, since they reveal the
locations of writable structures containing easily triggerable function
pointers.  The behavior of %pK depends on the kptr_restrict sysctl.

If kptr_restrict is set to 0, no deviation from the standard %p behavior
occurs.  If kptr_restrict is set to 1, the default, if the current user
(intended to be a reader via seq_printf(), etc.) does not have CAP_SYSLOG
(currently in the LSM tree), kernel pointers using %pK are printed as 0's.
 If kptr_restrict is set to 2, kernel pointers using %pK are printed as
0's regardless of privileges.  Replacing with 0's was chosen over the
default "(null)", which cannot be parsed by userland %p, which expects
"(nil)".

The supporting code for kptr_restrict and %pK are currently in the -mm
tree.  This patch converts users of %p in net/ to %pK.  Cases of printing
pointers to the syslog are not covered, since this would eliminate useful
information for postmortem debugging and the reading of the syslog is
already optionally protected by the dmesg_restrict sysctl.

Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Cc: James Morris <jmorris@namei.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Thomas Graf <tgraf@infradead.org>
Cc: Eugene Teo <eugeneteo@kernel.org>
Cc: Kees Cook <kees.cook@canonical.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David S. Miller <davem@davemloft.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Eric Paris <eparis@parisplace.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/atm/proc.c b/net/atm/proc.c
index f85da077..be3afde 100644
--- a/net/atm/proc.c
+++ b/net/atm/proc.c
@@ -191,7 +191,7 @@
 {
 	struct sock *sk = sk_atm(vcc);
 
-	seq_printf(seq, "%p ", vcc);
+	seq_printf(seq, "%pK ", vcc);
 	if (!vcc->dev)
 		seq_printf(seq, "Unassigned    ");
 	else
@@ -218,7 +218,7 @@
 {
 	if (!vcc->dev)
 		seq_printf(seq, sizeof(void *) == 4 ?
-			   "N/A@%p%10s" : "N/A@%p%2s", vcc, "");
+			   "N/A@%pK%10s" : "N/A@%pK%2s", vcc, "");
 	else
 		seq_printf(seq, "%3d %3d %5d         ",
 			   vcc->dev->number, vcc->vpi, vcc->vci);
diff --git a/net/can/bcm.c b/net/can/bcm.c
index cced806..184a657 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -165,9 +165,9 @@
 	struct bcm_sock *bo = bcm_sk(sk);
 	struct bcm_op *op;
 
-	seq_printf(m, ">>> socket %p", sk->sk_socket);
-	seq_printf(m, " / sk %p", sk);
-	seq_printf(m, " / bo %p", bo);
+	seq_printf(m, ">>> socket %pK", sk->sk_socket);
+	seq_printf(m, " / sk %pK", sk);
+	seq_printf(m, " / bo %pK", bo);
 	seq_printf(m, " / dropped %lu", bo->dropped_usr_msgs);
 	seq_printf(m, " / bound %s", bcm_proc_getifname(ifname, bo->ifindex));
 	seq_printf(m, " <<<\n");
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 11e17804..c9893d4 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -979,7 +979,7 @@
 	      srcp  = inet->inet_num;
 
 	seq_printf(seq, "%4d: %08X:%04X %08X:%04X"
-		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p %d\n",
+		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %d\n",
 		i, src, srcp, dest, destp, sp->sk_state,
 		sk_wmem_alloc_get(sp),
 		sk_rmem_alloc_get(sp),
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 3c8d9b6..a7d6671 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2371,7 +2371,7 @@
 	int ttd = req->expires - jiffies;
 
 	seq_printf(f, "%4d: %08X:%04X %08X:%04X"
-		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p%n",
+		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %pK%n",
 		i,
 		ireq->loc_addr,
 		ntohs(inet_sk(sk)->inet_sport),
@@ -2426,7 +2426,7 @@
 		rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
 
 	seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
-			"%08X %5d %8d %lu %d %p %lu %lu %u %u %d%n",
+			"%08X %5d %8d %lu %d %pK %lu %lu %u %u %d%n",
 		i, src, srcp, dest, destp, sk->sk_state,
 		tp->write_seq - tp->snd_una,
 		rx_queue,
@@ -2461,7 +2461,7 @@
 	srcp  = ntohs(tw->tw_sport);
 
 	seq_printf(f, "%4d: %08X:%04X %08X:%04X"
-		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p%n",
+		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK%n",
 		i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
 		3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
 		atomic_read(&tw->tw_refcnt), tw, len);
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 599374f..abca870 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2090,7 +2090,7 @@
 	__u16 srcp	  = ntohs(inet->inet_sport);
 
 	seq_printf(f, "%5d: %08X:%04X %08X:%04X"
-		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p %d%n",
+		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %d%n",
 		bucket, src, srcp, dest, destp, sp->sk_state,
 		sk_wmem_alloc_get(sp),
 		sk_rmem_alloc_get(sp),
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index ae64984..cc7313b 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -1240,7 +1240,7 @@
 	srcp  = inet_sk(sp)->inet_num;
 	seq_printf(seq,
 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
-		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p %d\n",
+		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %d\n",
 		   i,
 		   src->s6_addr32[0], src->s6_addr32[1],
 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 8683664..d1fd287 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -2036,7 +2036,7 @@
 
 	seq_printf(seq,
 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
-		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p\n",
+		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
 		   i,
 		   src->s6_addr32[0], src->s6_addr32[1],
 		   src->s6_addr32[2], src->s6_addr32[3],
@@ -2087,7 +2087,7 @@
 
 	seq_printf(seq,
 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
-		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p %lu %lu %u %u %d\n",
+		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %lu %lu %u %u %d\n",
 		   i,
 		   src->s6_addr32[0], src->s6_addr32[1],
 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
@@ -2129,7 +2129,7 @@
 
 	seq_printf(seq,
 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
-		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p\n",
+		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
 		   i,
 		   src->s6_addr32[0], src->s6_addr32[1],
 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index fc0c42a..41f8c9c 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1391,7 +1391,7 @@
 	srcp  = ntohs(inet->inet_sport);
 	seq_printf(seq,
 		   "%5d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
-		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p %d\n",
+		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %d\n",
 		   bucket,
 		   src->s6_addr32[0], src->s6_addr32[1],
 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
diff --git a/net/key/af_key.c b/net/key/af_key.c
index d62401c..8f92cf8 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -3656,7 +3656,7 @@
 	if (v == SEQ_START_TOKEN)
 		seq_printf(f ,"sk       RefCnt Rmem   Wmem   User   Inode\n");
 	else
-		seq_printf(f ,"%p %-6d %-6u %-6u %-6u %-6lu\n",
+		seq_printf(f, "%pK %-6d %-6u %-6u %-6u %-6lu\n",
 			       s,
 			       atomic_read(&s->sk_refcnt),
 			       sk_rmem_alloc_get(s),
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 5fe4f3b..6ef64ad 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1985,7 +1985,7 @@
 		struct sock *s = v;
 		struct netlink_sock *nlk = nlk_sk(s);
 
-		seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %-8d %-8d %-8lu\n",
+		seq_printf(seq, "%pK %-3d %-6d %08x %-8d %-8d %pK %-8d %-8d %-8lu\n",
 			   s,
 			   s->sk_protocol,
 			   nlk->pid,
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 549527b..925f715 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2706,7 +2706,7 @@
 		const struct packet_sock *po = pkt_sk(s);
 
 		seq_printf(seq,
-			   "%p %-6d %-4d %04x   %-5d %1d %-6u %-6u %-6lu\n",
+			   "%pK %-6d %-4d %04x   %-5d %1d %-6u %-6u %-6lu\n",
 			   s,
 			   atomic_read(&s->sk_refcnt),
 			   s->sk_type,
diff --git a/net/phonet/socket.c b/net/phonet/socket.c
index 8c5bfce..ab07711 100644
--- a/net/phonet/socket.c
+++ b/net/phonet/socket.c
@@ -607,7 +607,7 @@
 		struct pn_sock *pn = pn_sk(sk);
 
 		seq_printf(seq, "%2d %04X:%04X:%02X %02X %08X:%08X %5d %lu "
-			"%d %p %d%n",
+			"%d %pK %d%n",
 			sk->sk_protocol, pn->sobject, pn->dobject,
 			pn->resource, sk->sk_state,
 			sk_wmem_alloc_get(sk), sk_rmem_alloc_get(sk),
diff --git a/net/sctp/proc.c b/net/sctp/proc.c
index 61aacfb..05a6ce2 100644
--- a/net/sctp/proc.c
+++ b/net/sctp/proc.c
@@ -212,7 +212,7 @@
 	sctp_for_each_hentry(epb, node, &head->chain) {
 		ep = sctp_ep(epb);
 		sk = epb->sk;
-		seq_printf(seq, "%8p %8p %-3d %-3d %-4d %-5d %5d %5lu ", ep, sk,
+		seq_printf(seq, "%8pK %8pK %-3d %-3d %-4d %-5d %5d %5lu ", ep, sk,
 			   sctp_sk(sk)->type, sk->sk_state, hash,
 			   epb->bind_addr.port,
 			   sock_i_uid(sk), sock_i_ino(sk));
@@ -316,7 +316,7 @@
 		assoc = sctp_assoc(epb);
 		sk = epb->sk;
 		seq_printf(seq,
-			   "%8p %8p %-3d %-3d %-2d %-4d "
+			   "%8pK %8pK %-3d %-3d %-2d %-4d "
 			   "%4d %8d %8d %7d %5lu %-5d %5d ",
 			   assoc, sk, sctp_sk(sk)->type, sk->sk_state,
 			   assoc->state, hash,
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index b1d75be..0722a25 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2254,7 +2254,7 @@
 		struct unix_sock *u = unix_sk(s);
 		unix_state_lock(s);
 
-		seq_printf(seq, "%p: %08X %08X %08X %04X %02X %5lu",
+		seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
 			s,
 			atomic_read(&s->sk_refcnt),
 			0,