Commit ff5d7497 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp: beware of alignments in tcp_get_info() 



With some combinations of user provided flags in netlink command,
it is possible to call tcp_get_info() with a buffer that is not 8-bytes
aligned.

It does matter on some arches, so we need to use put_unaligned() to
store the u64 fields.

Current iproute2 package does not trigger this particular issue.

Fixes: 0df48c26 ("tcp: add tcpi_bytes_acked to tcp_info")
Fixes: 977cb0ec ("tcp: add pacing_rate information into tcp_info")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4f2c6ae5

net/ipv4/tcp.c

+8 −4
Original line number Diff line number Diff line
@@ -279,6 +279,7 @@ 


#include <asm/uaccess.h>

#include <asm/ioctls.h>

#include <asm/unaligned.h>

#include <net/busy_poll.h>



int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
@@ -2638,6 +2639,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info) 
	const struct inet_connection_sock *icsk = inet_csk(sk);

	u32 now = tcp_time_stamp;

	unsigned int start;

	u64 rate64;

	u32 rate;



	memset(info, 0, sizeof(*info));
@@ -2703,15 +2705,17 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info) 
	info->tcpi_total_retrans = tp->total_retrans;



	rate = READ_ONCE(sk->sk_pacing_rate);

	info->tcpi_pacing_rate = rate != ~0U ? rate : ~0ULL;

	rate64 = rate != ~0U ? rate : ~0ULL;

	put_unaligned(rate64, &info->tcpi_pacing_rate);



	rate = READ_ONCE(sk->sk_max_pacing_rate);

	info->tcpi_max_pacing_rate = rate != ~0U ? rate : ~0ULL;

	rate64 = rate != ~0U ? rate : ~0ULL;

	put_unaligned(rate64, &info->tcpi_max_pacing_rate);



	do {

		start = u64_stats_fetch_begin_irq(&tp->syncp);

		info->tcpi_bytes_acked = tp->bytes_acked;

		info->tcpi_bytes_received = tp->bytes_received;

		put_unaligned(tp->bytes_acked, &info->tcpi_bytes_acked);

		put_unaligned(tp->bytes_received, &info->tcpi_bytes_received);

	} while (u64_stats_fetch_retry_irq(&tp->syncp, start));

	info->tcpi_segs_out = tp->segs_out;

	info->tcpi_segs_in = tp->segs_in;

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