Hi Krzysztof, On Mon, Oct 08, 2018 at 09:07:24PM +0200, Krzysztof Grzywocz wrote: > From: Krzysztof Grzywocz <kgrzywocz@xxxxx> > > Problem: > On 64bit kernel ELF32bit gets improper value of `SCTP_GET_ASSOC_STATS` (call `getsockopt` on SCTP socket) due to different `struct sctp_assoc_stats` aligment (mostly because of different `_K_SS_ALIGNSIZE`). > > Example: > Sent 1000 bytes, Received 1000 bytes > May result in: > packets sent(sas_opackets): 12884901888 > packets recv(sas_ipackets): 12884901888 > > Patch solution: > Realign struct at the end of `sctp_getsockopt_assoc_stats(..)` when called in compat mode. See patch for details. > > For more details see: https://github.com/kgrzywocz/align_compat32_sctp_assoc_stats > It's missing your S-o-b line, and a couple of style issues below. > > ----- > diff --git a/net/sctp/socket.c b/net/sctp/socket.c > index ce620e87..73963062 100644 > --- a/net/sctp/socket.c > +++ b/net/sctp/socket.c > @@ -6685,6 +6685,65 @@ static int sctp_getsockopt_paddr_thresholds(struct sock *sk, > return 0; > } > > +#ifdef CONFIG_COMPAT > + > +struct __kernel_sockaddr_storage_compat32 { > + __kernel_sa_family_t ss_family; /* address family */ > + /* Following field(s) are implementation specific */ > + char __data[_K_SS_MAXSIZE - sizeof(unsigned short)]; > + /* space to achieve desired size, */ > + /* _SS_MAXSIZE value minus size of ss_family */ > +} __attribute__ ((packed,aligned(4))); /* force desired alignment */ > + > + No need for two new lines here, > +struct sctp_assoc_stats_compat32 { > + int32_t sas_assoc_id; /* Input */ > + /* Transport of observed max RTO */ > + struct __kernel_sockaddr_storage_compat32 sas_obs_rto_ipaddr; > + uint64_t sas_maxrto; /* Maximum Observed RTO for period */ > + uint64_t sas_isacks; /* SACKs received */ > + uint64_t sas_osacks; /* SACKs sent */ > + uint64_t sas_opackets; /* Packets sent */ > + uint64_t sas_ipackets; /* Packets received */ > + uint64_t sas_rtxchunks; /* Retransmitted Chunks */ > + uint64_t sas_outofseqtsns;/* TSN received > next expected */ > + uint64_t sas_idupchunks; /* Dups received (ordered+unordered) */ > + uint64_t sas_gapcnt; /* Gap Acknowledgements Received */ > + uint64_t sas_ouodchunks; /* Unordered data chunks sent */ > + uint64_t sas_iuodchunks; /* Unordered data chunks received */ > + uint64_t sas_oodchunks; /* Ordered data chunks sent */ > + uint64_t sas_iodchunks; /* Ordered data chunks received */ > + uint64_t sas_octrlchunks; /* Control chunks sent */ > + uint64_t sas_ictrlchunks; /* Control chunks received */ > +} __attribute__ ((packed,aligned(4))); > + > + > +static void align_compat32_sctp_assoc_stats(void *sctp_assoc_stats) > +{ > + struct sctp_assoc_stats* p64 = sctp_assoc_stats; > + struct sctp_assoc_stats_compat32* p32 = sctp_assoc_stats; > + > + p32->sas_assoc_id = p64->sas_assoc_id; > + p32->sas_obs_rto_ipaddr.ss_family = p64->sas_obs_rto_ipaddr.ss_family; > + memcpy(p32->sas_obs_rto_ipaddr.__data, p64->sas_obs_rto_ipaddr.__data, sizeof(p32->sas_obs_rto_ipaddr.__data)); > + p32->sas_maxrto = p64->sas_maxrto; > + p32->sas_isacks = p64->sas_isacks; > + p32->sas_osacks = p64->sas_osacks; > + p32->sas_opackets = p64->sas_opackets; > + p32->sas_ipackets = p64->sas_ipackets; > + p32->sas_rtxchunks = p64->sas_rtxchunks; > + p32->sas_outofseqtsns = p64->sas_outofseqtsns; > + p32->sas_idupchunks = p64->sas_idupchunks; > + p32->sas_gapcnt = p64->sas_gapcnt; > + p32->sas_ouodchunks = p64->sas_ouodchunks; > + p32->sas_iuodchunks = p64->sas_iuodchunks; > + p32->sas_oodchunks = p64->sas_oodchunks; > + p32->sas_iodchunks = p64->sas_iodchunks; > + p32->sas_octrlchunks = p64->sas_octrlchunks; > + p32->sas_ictrlchunks = p64->sas_ictrlchunks; You shouldn't need the spaces before the tabs here. checkpatch.pl is giving several warnings because of this. > +} > +#endif > + > /* > * SCTP_GET_ASSOC_STATS > * > @@ -6743,6 +6802,13 @@ static int sctp_getsockopt_assoc_stats(struct sock *sk, int len, > > pr_debug("%s: len:%d, assoc_id:%d\n", __func__, len, sas.sas_assoc_id); > > + #ifdef CONFIG_COMPAT And this ifdef should not be indented. > + if (in_compat_syscall()) { > + pr_debug("%s:running in compat32. Aligningsctp_assoc_stats\n", __func__); > + align_compat32_sctp_assoc_stats(&sas); > + } > + #endif > + > if (copy_to_user(optval, &sas, len)) > return -EFAULT; > >
