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Commit 3373d6d0 authored by Yuchung Cheng's avatar Yuchung Cheng Committed by Greg Kroah-Hartman
Browse files

tcp: fix Fast Open key endianness 



[ Upstream commit c860e997e9170a6d68f9d1e6e2cf61f572191aaf ]

Fast Open key could be stored in different endian based on the CPU.
Previously hosts in different endianness in a server farm using
the same key config (sysctl value) would produce different cookies.
This patch fixes it by always storing it as little endian to keep
same API for LE hosts.

Reported-by: default avatarDaniele Iamartino <danielei@google.com>
Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4f5f7bce

net/ipv4/sysctl_net_ipv4.c

+13 −5
Original line number Diff line number Diff line
@@ -258,8 +258,9 @@ static int proc_tcp_fastopen_key(struct ctl_table *ctl, int write, 
{

	struct ctl_table tbl = { .maxlen = (TCP_FASTOPEN_KEY_LENGTH * 2 + 10) };

	struct tcp_fastopen_context *ctxt;

	int ret;

	u32  user_key[4]; /* 16 bytes, matching TCP_FASTOPEN_KEY_LENGTH */

	__le32 key[4];

	int ret, i;



	tbl.data = kmalloc(tbl.maxlen, GFP_KERNEL);

	if (!tbl.data)
@@ -268,11 +269,14 @@ static int proc_tcp_fastopen_key(struct ctl_table *ctl, int write, 
	rcu_read_lock();

	ctxt = rcu_dereference(tcp_fastopen_ctx);

	if (ctxt)

		memcpy(user_key, ctxt->key, TCP_FASTOPEN_KEY_LENGTH);

		memcpy(key, ctxt->key, TCP_FASTOPEN_KEY_LENGTH);

	else

		memset(user_key, 0, sizeof(user_key));

		memset(key, 0, sizeof(key));

	rcu_read_unlock();



	for (i = 0; i < ARRAY_SIZE(key); i++)

		user_key[i] = le32_to_cpu(key[i]);



	snprintf(tbl.data, tbl.maxlen, "%08x-%08x-%08x-%08x",

		user_key[0], user_key[1], user_key[2], user_key[3]);

	ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
@@ -288,7 +292,11 @@ static int proc_tcp_fastopen_key(struct ctl_table *ctl, int write, 
		 * first invocation of tcp_fastopen_cookie_gen

		 */

		tcp_fastopen_init_key_once(false);

		tcp_fastopen_reset_cipher(user_key, TCP_FASTOPEN_KEY_LENGTH);



		for (i = 0; i < ARRAY_SIZE(user_key); i++)

			key[i] = cpu_to_le32(user_key[i]);



		tcp_fastopen_reset_cipher(key, TCP_FASTOPEN_KEY_LENGTH);

	}



bad_key: