Merge android-4.9.182 (cb0eff4) into msm-4.9

* refs/heads/tmp-cb0eff4:
  Linux 4.9.182
  tcp: enforce tcp_min_snd_mss in tcp_mtu_probing()
  tcp: add tcp_min_snd_mss sysctl
  tcp: tcp_fragment() should apply sane memory limits
  tcp: limit payload size of sacked skbs
  tcp: reduce tcp_fastretrans_alert() verbosity
  efi/libstub: remove duplicate nokaslr
  BACKPORT: Add support for BPF_FUNC_probe_read_str
  UPSTREAM: binder: check for overflow when alloc for security context
  BACKPORT: binder: fix race between munmap() and direct reclaim

Change-Id: Ia27ee55b392dc481fa27ea6d689022a1047a3ed3
Signed-off-by: jianzhou <jianzhou@codeaurora.org>
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index c88a0a8..12d9a68 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -230,6 +230,14 @@
 	Path MTU discovery (MTU probing).  If MTU probing is enabled,
 	this is the initial MSS used by the connection.
 
+tcp_min_snd_mss - INTEGER
+	TCP SYN and SYNACK messages usually advertise an ADVMSS option,
+	as described in RFC 1122 and RFC 6691.
+	If this ADVMSS option is smaller than tcp_min_snd_mss,
+	it is silently capped to tcp_min_snd_mss.
+
+	Default : 48 (at least 8 bytes of payload per segment)
+
 tcp_congestion_control - STRING
 	Set the congestion control algorithm to be used for new
 	connections. The algorithm "reno" is always available, but
diff --git a/Makefile b/Makefile
index ec95482..45b38f4 100755
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 VERSION = 4
 PATCHLEVEL = 9
-SUBLEVEL = 181
+SUBLEVEL = 182
 EXTRAVERSION =
 NAME = Roaring Lionus
 
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 6107c03..edb108a 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3227,6 +3227,7 @@
 
 	if (target_node && target_node->txn_security_ctx) {
 		u32 secid;
+		size_t added_size;
 
 		security_task_getsecid(proc->tsk, &secid);
 		ret = security_secid_to_secctx(secid, &secctx, &secctx_sz);
@@ -3236,7 +3237,15 @@
 			return_error_line = __LINE__;
 			goto err_get_secctx_failed;
 		}
-		extra_buffers_size += ALIGN(secctx_sz, sizeof(u64));
+		added_size = ALIGN(secctx_sz, sizeof(u64));
+		extra_buffers_size += added_size;
+		if (extra_buffers_size < added_size) {
+			/* integer overflow of extra_buffers_size */
+			return_error = BR_FAILED_REPLY;
+			return_error_param = EINVAL;
+			return_error_line = __LINE__;
+			goto err_bad_extra_size;
+		}
 	}
 
 	trace_binder_transaction(reply, t, target_node);
@@ -3585,6 +3594,7 @@
 	t->buffer->transaction = NULL;
 	binder_alloc_free_buf(&target_proc->alloc, t->buffer);
 err_binder_alloc_buf_failed:
+err_bad_extra_size:
 	if (secctx)
 		security_release_secctx(secctx, secctx_sz);
 err_get_secctx_failed:
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index 34454b0..ce006af 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -891,14 +891,13 @@
 
 	index = page - alloc->pages;
 	page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
+
+	mm = alloc->vma_vm_mm;
+	if (!mmget_not_zero(mm))
+		goto err_mmget;
+	if (!down_write_trylock(&mm->mmap_sem))
+		goto err_down_write_mmap_sem_failed;
 	vma = alloc->vma;
-	if (vma) {
-		if (!mmget_not_zero(alloc->vma_vm_mm))
-			goto err_mmget;
-		mm = alloc->vma_vm_mm;
-		if (!down_write_trylock(&mm->mmap_sem))
-			goto err_down_write_mmap_sem_failed;
-	}
 
 	list_lru_isolate(lru, item);
 	spin_unlock(lock);
@@ -909,10 +908,9 @@
 		zap_page_range(vma, page_addr, PAGE_SIZE, NULL);
 
 		trace_binder_unmap_user_end(alloc, index);
-
-		up_write(&mm->mmap_sem);
-		mmput(mm);
 	}
+	up_write(&mm->mmap_sem);
+	mmput(mm);
 
 	trace_binder_unmap_kernel_start(alloc, index);
 
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index b8ea15a..4fd7dd9 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -434,4 +434,7 @@
 	tp->saved_syn = NULL;
 }
 
+int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from, int pcount,
+		  int shiftlen);
+
 #endif	/* _LINUX_TCP_H */
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 7adf438..bf619a6 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -94,6 +94,7 @@
 #endif
 	int sysctl_tcp_mtu_probing;
 	int sysctl_tcp_base_mss;
+	int sysctl_tcp_min_snd_mss;
 	int sysctl_tcp_probe_threshold;
 	u32 sysctl_tcp_probe_interval;
 
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 96c2b19..6b7f988 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -53,6 +53,8 @@
 
 #define MAX_TCP_HEADER	(128 + MAX_HEADER)
 #define MAX_TCP_OPTION_SPACE 40
+#define TCP_MIN_SND_MSS		48
+#define TCP_MIN_GSO_SIZE	(TCP_MIN_SND_MSS - MAX_TCP_OPTION_SPACE)
 
 /*
  * Never offer a window over 32767 without using window scaling. Some
diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h
index 3442a26..56e3460 100644
--- a/include/uapi/linux/snmp.h
+++ b/include/uapi/linux/snmp.h
@@ -282,6 +282,7 @@
 	LINUX_MIB_TCPKEEPALIVE,			/* TCPKeepAlive */
 	LINUX_MIB_TCPMTUPFAIL,			/* TCPMTUPFail */
 	LINUX_MIB_TCPMTUPSUCCESS,		/* TCPMTUPSuccess */
+	LINUX_MIB_TCPWQUEUETOOBIG,		/* TCPWqueueTooBig */
 	__LINUX_MIB_MAX
 };
 
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 7cc06f2..c7aab15 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -81,6 +81,35 @@
 	.arg3_type	= ARG_ANYTHING,
 };
 
+BPF_CALL_3(bpf_probe_read_str, void *, dst, u32, size, const void *, unsafe_ptr)
+{
+	int ret;
+
+	/*
+	 * The strncpy_from_unsafe() call will likely not fill the entire
+	 * buffer, but that's okay in this circumstance as we're probing
+	 * arbitrary memory anyway similar to bpf_probe_read() and might
+	 * as well probe the stack. Thus, memory is explicitly cleared
+	 * only in error case, so that improper users ignoring return
+	 * code altogether don't copy garbage; otherwise length of string
+	 * is returned that can be used for bpf_perf_event_output() et al.
+	 */
+	ret = strncpy_from_unsafe(dst, unsafe_ptr, size);
+	if (unlikely(ret < 0))
+		memset(dst, 0, size);
+
+	return ret;
+}
+
+static const struct bpf_func_proto bpf_probe_read_str_proto = {
+	.func           = bpf_probe_read_str,
+	.gpl_only       = true,
+	.ret_type       = RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_RAW_STACK,
+	.arg2_type	= ARG_CONST_STACK_SIZE,
+	.arg3_type	= ARG_ANYTHING,
+};
+
 BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src,
 	   u32, size)
 {
@@ -434,6 +463,8 @@
 		return &bpf_map_delete_elem_proto;
 	case BPF_FUNC_probe_read:
 		return &bpf_probe_read_proto;
+	case BPF_FUNC_probe_read_str:
+		return &bpf_probe_read_str_proto;
 	case BPF_FUNC_ktime_get_ns:
 		return &bpf_ktime_get_ns_proto;
 	case BPF_FUNC_tail_call:
diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index ec48d8ea..8b22139 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -306,6 +306,7 @@
 	SNMP_MIB_ITEM("TCPKeepAlive", LINUX_MIB_TCPKEEPALIVE),
 	SNMP_MIB_ITEM("TCPMTUPFail", LINUX_MIB_TCPMTUPFAIL),
 	SNMP_MIB_ITEM("TCPMTUPSuccess", LINUX_MIB_TCPMTUPSUCCESS),
+	SNMP_MIB_ITEM("TCPWqueueTooBig", LINUX_MIB_TCPWQUEUETOOBIG),
 	SNMP_MIB_SENTINEL
 };
 
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 76da06e..50f4945 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -35,6 +35,8 @@
 static int ip_local_port_range_max[] = { 65535, 65535 };
 static int tcp_adv_win_scale_min = -31;
 static int tcp_adv_win_scale_max = 31;
+static int tcp_min_snd_mss_min = TCP_MIN_SND_MSS;
+static int tcp_min_snd_mss_max = 65535;
 static int ip_ttl_min = 1;
 static int ip_ttl_max = 255;
 static int tcp_syn_retries_min = 1;
@@ -891,6 +893,15 @@
 		.proc_handler	= proc_dointvec,
 	},
 	{
+		.procname	= "tcp_min_snd_mss",
+		.data		= &init_net.ipv4.sysctl_tcp_min_snd_mss,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &tcp_min_snd_mss_min,
+		.extra2		= &tcp_min_snd_mss_max,
+	},
+	{
 		.procname	= "tcp_probe_threshold",
 		.data		= &init_net.ipv4.sysctl_tcp_probe_threshold,
 		.maxlen		= sizeof(int),
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index a0e1fc1..ac398b72 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3359,6 +3359,7 @@
 	unsigned long limit;
 	unsigned int i;
 
+	BUILD_BUG_ON(TCP_MIN_SND_MSS <= MAX_TCP_OPTION_SPACE);
 	BUILD_BUG_ON(sizeof(struct tcp_skb_cb) >
 		     FIELD_SIZEOF(struct sk_buff, cb));
 
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 6c42ffc..435450f 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1321,7 +1321,7 @@
 	TCP_SKB_CB(skb)->seq += shifted;
 
 	tcp_skb_pcount_add(prev, pcount);
-	BUG_ON(tcp_skb_pcount(skb) < pcount);
+	WARN_ON_ONCE(tcp_skb_pcount(skb) < pcount);
 	tcp_skb_pcount_add(skb, -pcount);
 
 	/* When we're adding to gso_segs == 1, gso_size will be zero,
@@ -1388,6 +1388,21 @@
 	return !skb_headlen(skb) && skb_is_nonlinear(skb);
 }
 
+int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from,
+		  int pcount, int shiftlen)
+{
+	/* TCP min gso_size is 8 bytes (TCP_MIN_GSO_SIZE)
+	 * Since TCP_SKB_CB(skb)->tcp_gso_segs is 16 bits, we need
+	 * to make sure not storing more than 65535 * 8 bytes per skb,
+	 * even if current MSS is bigger.
+	 */
+	if (unlikely(to->len + shiftlen >= 65535 * TCP_MIN_GSO_SIZE))
+		return 0;
+	if (unlikely(tcp_skb_pcount(to) + pcount > 65535))
+		return 0;
+	return skb_shift(to, from, shiftlen);
+}
+
 /* Try collapsing SACK blocks spanning across multiple skbs to a single
  * skb.
  */
@@ -1399,6 +1414,7 @@
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct sk_buff *prev;
 	int mss;
+	int next_pcount;
 	int pcount = 0;
 	int len;
 	int in_sack;
@@ -1496,7 +1512,7 @@
 	if (!after(TCP_SKB_CB(skb)->seq + len, tp->snd_una))
 		goto fallback;
 
-	if (!skb_shift(prev, skb, len))
+	if (!tcp_skb_shift(prev, skb, pcount, len))
 		goto fallback;
 	if (!tcp_shifted_skb(sk, skb, state, pcount, len, mss, dup_sack))
 		goto out;
@@ -1515,11 +1531,11 @@
 		goto out;
 
 	len = skb->len;
-	if (skb_shift(prev, skb, len)) {
-		pcount += tcp_skb_pcount(skb);
-		tcp_shifted_skb(sk, skb, state, tcp_skb_pcount(skb), len, mss, 0);
+	next_pcount = tcp_skb_pcount(skb);
+	if (tcp_skb_shift(prev, skb, next_pcount, len)) {
+		pcount += next_pcount;
+		tcp_shifted_skb(sk, skb, state, next_pcount, len, mss, 0);
 	}
-
 out:
 	state->fack_count += pcount;
 	return prev;
@@ -2838,9 +2854,9 @@
 	bool do_lost = is_dupack || ((flag & FLAG_DATA_SACKED) &&
 				    (tcp_fackets_out(tp) > tp->reordering));
 
-	if (WARN_ON(!tp->packets_out && tp->sacked_out))
+	if (!tp->packets_out && tp->sacked_out)
 		tp->sacked_out = 0;
-	if (WARN_ON(!tp->sacked_out && tp->fackets_out))
+	if (!tp->sacked_out && tp->fackets_out)
 		tp->fackets_out = 0;
 
 	/* Now state machine starts.
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 0116d9e..d6a9526 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2470,6 +2470,7 @@
 	net->ipv4.sysctl_tcp_ecn_fallback = 1;
 
 	net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
+	net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
 	net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
 	net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
 
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 8d31f60..c1fd321 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1185,6 +1185,11 @@
 	if (nsize < 0)
 		nsize = 0;
 
+	if (unlikely((sk->sk_wmem_queued >> 1) > sk->sk_sndbuf)) {
+		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPWQUEUETOOBIG);
+		return -ENOMEM;
+	}
+
 	if (skb_unclone(skb, gfp))
 		return -ENOMEM;
 
@@ -1355,8 +1360,7 @@
 	mss_now -= icsk->icsk_ext_hdr_len;
 
 	/* Then reserve room for full set of TCP options and 8 bytes of data */
-	if (mss_now < 48)
-		mss_now = 48;
+	mss_now = max(mss_now, sock_net(sk)->ipv4.sysctl_tcp_min_snd_mss);
 	return mss_now;
 }
 
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index 93fbace..d962922 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -172,6 +172,7 @@
 			mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low) >> 1;
 			mss = min(net->ipv4.sysctl_tcp_base_mss, mss);
 			mss = max(mss, 68 - tp->tcp_header_len);
+			mss = max(mss, net->ipv4.sysctl_tcp_min_snd_mss);
 			icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss);
 			tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
 		}