UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

mptcp: fix bad handling of 32 bit ack wrap-around 

When receiving 32 bits DSS ack from the peer, the MPTCP need
to expand them to 64 bits value. The current code is buggy
WRT detecting 32 bits ack wrap-around: when the wrap-around
happens the current unsigned 32 bit ack value is lower than
the previous one.

Additionally check for possible reverse wrap and make the helper
visible, so that we could re-use it for the next patch.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/204
Fixes: cc9d256698 ("mptcp: update per unacked sequence on pkt reception")
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2021-06-18 15:02:20 -07:00 committed by David S. Miller
parent d452d48b9f
commit 1502328f17
2 changed files with 21 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
net/mptcp/options.c
View File

@ -896,19 +896,20 @@ reset:
return false;
}
static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit)
u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq)
{
u32 old_ack32, cur_ack32;
u32 old_seq32, cur_seq32;
if (use_64bit)
return cur_ack;
old_seq32 = (u32)old_seq;
cur_seq32 = (u32)cur_seq;
cur_seq = (old_seq & GENMASK_ULL(63, 32)) + cur_seq32;
if (unlikely(cur_seq32 < old_seq32 && before(old_seq32, cur_seq32)))
return cur_seq + (1LL << 32);
old_ack32 = (u32)old_ack;
cur_ack32 = (u32)cur_ack;
cur_ack = (old_ack & GENMASK_ULL(63, 32)) + cur_ack32;
if (unlikely(before(cur_ack32, old_ack32)))
return cur_ack + (1LL << 32);
return cur_ack;
/* reverse wrap could happen, too */
if (unlikely(cur_seq32 > old_seq32 && after(old_seq32, cur_seq32)))
return cur_seq - (1LL << 32);
return cur_seq;
}
static void ack_update_msk(struct mptcp_sock *msk,
@ -926,7 +927,7 @@ static void ack_update_msk(struct mptcp_sock *msk,
* more dangerous than missing an ack
*/
old_snd_una = msk->snd_una;
new_snd_una = expand_ack(old_snd_una, mp_opt->data_ack, mp_opt->ack64);
new_snd_una = mptcp_expand_seq(old_snd_una, mp_opt->data_ack, mp_opt->ack64);
/* ACK for data not even sent yet? Ignore. */
if (after64(new_snd_una, snd_nxt))
@ -963,7 +964,7 @@ bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool us
return false;
WRITE_ONCE(msk->rcv_data_fin_seq,
expand_ack(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit));
mptcp_expand_seq(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit));
WRITE_ONCE(msk->rcv_data_fin, 1);
return true;

8
net/mptcp/protocol.h
View File

@ -593,6 +593,14 @@ int mptcp_setsockopt(struct sock *sk, int level, int optname,
int mptcp_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *option);
u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq);
static inline u64 mptcp_expand_seq(u64 old_seq, u64 cur_seq, bool use_64bit)
{
if (use_64bit)
return cur_seq;
return __mptcp_expand_seq(old_seq, cur_seq);
}
void __mptcp_check_push(struct sock *sk, struct sock *ssk);
void __mptcp_data_acked(struct sock *sk);
void __mptcp_error_report(struct sock *sk);