include/net/mptcp.h | 4 ++++ net/mptcp/options.c | 38 +++++++++++++++++++++++--------------- 2 files changed, 27 insertions(+), 15 deletions(-)
using packetdrill it's possible to observe that the receiver key contains
random values when clients transmit MP_CAPABLE with data and checksum (as
specified in RFC8684 §3.1). Fix the layout of mptcp_out_options, to avoid
using the skb extension copy when writing the MP_CAPABLE sub-option.
Fixes: d7b269083786 ("mptcp: shrink mptcp_out_options struct")
Link: https://github.com/multipath-tcp/mptcp_net-next/issues/233
Reported-by: Poorva Sonparote <psonparo@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
---
include/net/mptcp.h | 4 ++++
net/mptcp/options.c | 38 +++++++++++++++++++++++---------------
2 files changed, 27 insertions(+), 15 deletions(-)
diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index f83fa48408b3..a925349b4b89 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -71,6 +71,10 @@ struct mptcp_out_options {
struct {
u64 sndr_key;
u64 rcvr_key;
+ u64 data_seq;
+ u32 subflow_seq;
+ u16 data_len;
+ __sum16 csum;
};
struct {
struct mptcp_addr_info addr;
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 422f4acfb3e6..ce27a4afc64a 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -489,7 +489,7 @@ static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb,
* discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and
* TCPOLEN_MPTCP_MPC_ACK
*/
- opts->ext_copy.data_len = data_len;
+ opts->data_len = data_len;
opts->suboptions = OPTION_MPTCP_MPC_ACK;
opts->sndr_key = subflow->local_key;
opts->rcvr_key = subflow->remote_key;
@@ -505,9 +505,9 @@ static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb,
len = TCPOLEN_MPTCP_MPC_ACK_DATA;
if (opts->csum_reqd) {
/* we need to propagate more info to csum the pseudo hdr */
- opts->ext_copy.data_seq = mpext->data_seq;
- opts->ext_copy.subflow_seq = mpext->subflow_seq;
- opts->ext_copy.csum = mpext->csum;
+ opts->data_seq = mpext->data_seq;
+ opts->subflow_seq = mpext->subflow_seq;
+ opts->csum = mpext->csum;
len += TCPOLEN_MPTCP_DSS_CHECKSUM;
}
*size = ALIGN(len, 4);
@@ -1223,25 +1223,30 @@ static void mptcp_set_rwin(const struct tcp_sock *tp)
WRITE_ONCE(msk->rcv_wnd_sent, ack_seq);
}
-static u16 mptcp_make_csum(const struct mptcp_ext *mpext)
+static u16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __sum16 csum)
{
struct csum_pseudo_header header;
- __wsum csum;
/* cfr RFC 8684 3.3.1.:
* the data sequence number used in the pseudo-header is
* always the 64-bit value, irrespective of what length is used in the
* DSS option itself.
*/
- header.data_seq = cpu_to_be64(mpext->data_seq);
- header.subflow_seq = htonl(mpext->subflow_seq);
- header.data_len = htons(mpext->data_len);
+ header.data_seq = cpu_to_be64(data_seq);
+ header.subflow_seq = htonl(subflow_seq);
+ header.data_len = htons(data_len);
header.csum = 0;
- csum = csum_partial(&header, sizeof(header), ~csum_unfold(mpext->csum));
+ csum = csum_partial(&header, sizeof(header), ~csum_unfold(csum));
return (__force u16)csum_fold(csum);
}
+static u16 mptcp_make_csum(const struct mptcp_ext *mpext)
+{
+ return __mptcp_make_csum(mpext->data_seq, mpext->subflow_seq, mpext->data_len,
+ mpext->csum);
+}
+
void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
struct mptcp_out_options *opts)
{
@@ -1332,7 +1337,7 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
len = TCPOLEN_MPTCP_MPC_SYN;
} else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions) {
len = TCPOLEN_MPTCP_MPC_SYNACK;
- } else if (opts->ext_copy.data_len) {
+ } else if (opts->data_len) {
len = TCPOLEN_MPTCP_MPC_ACK_DATA;
if (opts->csum_reqd)
len += TCPOLEN_MPTCP_DSS_CHECKSUM;
@@ -1361,14 +1366,17 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
put_unaligned_be64(opts->rcvr_key, ptr);
ptr += 2;
- if (!opts->ext_copy.data_len)
+ if (!opts->data_len)
goto mp_capable_done;
if (opts->csum_reqd) {
- put_unaligned_be32(opts->ext_copy.data_len << 16 |
- mptcp_make_csum(&opts->ext_copy), ptr);
+ put_unaligned_be32(opts->data_len << 16 |
+ __mptcp_make_csum(opts->data_seq,
+ opts->subflow_seq,
+ opts->data_len,
+ opts->csum), ptr);
} else {
- put_unaligned_be32(opts->ext_copy.data_len << 16 |
+ put_unaligned_be32(opts->data_len << 16 |
TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
}
ptr += 1;
--
2.31.1
Hi Davide, On 21/10/2021 16:51, Davide Caratti wrote: > using packetdrill it's possible to observe that the receiver key contains > random values when clients transmit MP_CAPABLE with data and checksum (as > specified in RFC8684 §3.1). Fix the layout of mptcp_out_options, to avoid > using the skb extension copy when writing the MP_CAPABLE sub-option. The CI found an issue with it: Reported-by: Tessares CI <no-reply@tessares.net> Cheers, Matt (PS: this includes a test for patchew) -- Tessares | Belgium | Hybrid Access Solutions www.tessares.net
On Thu, 21 Oct 2021, Davide Caratti wrote: > using packetdrill it's possible to observe that the receiver key contains > random values when clients transmit MP_CAPABLE with data and checksum (as > specified in RFC8684 §3.1). Fix the layout of mptcp_out_options, to avoid > using the skb extension copy when writing the MP_CAPABLE sub-option. > > Fixes: d7b269083786 ("mptcp: shrink mptcp_out_options struct") > Link: https://github.com/multipath-tcp/mptcp_net-next/issues/233 We generally use a "Closes:" tag for the github issues URL. > Reported-by: Poorva Sonparote <psonparo@redhat.com> > Signed-off-by: Davide Caratti <dcaratti@redhat.com> > --- > include/net/mptcp.h | 4 ++++ > net/mptcp/options.c | 38 +++++++++++++++++++++++--------------- > 2 files changed, 27 insertions(+), 15 deletions(-) > > diff --git a/include/net/mptcp.h b/include/net/mptcp.h > index f83fa48408b3..a925349b4b89 100644 > --- a/include/net/mptcp.h > +++ b/include/net/mptcp.h > @@ -71,6 +71,10 @@ struct mptcp_out_options { > struct { > u64 sndr_key; > u64 rcvr_key; > + u64 data_seq; > + u32 subflow_seq; > + u16 data_len; > + __sum16 csum; > }; > struct { > struct mptcp_addr_info addr; > diff --git a/net/mptcp/options.c b/net/mptcp/options.c > index 422f4acfb3e6..ce27a4afc64a 100644 > --- a/net/mptcp/options.c > +++ b/net/mptcp/options.c > @@ -489,7 +489,7 @@ static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb, > * discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and > * TCPOLEN_MPTCP_MPC_ACK > */ There's an 'ext_copy' to edit out in the first line of this comment ^ (which is just before the above context lines) > - opts->ext_copy.data_len = data_len; > + opts->data_len = data_len; > opts->suboptions = OPTION_MPTCP_MPC_ACK; > opts->sndr_key = subflow->local_key; > opts->rcvr_key = subflow->remote_key; > @@ -505,9 +505,9 @@ static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb, > len = TCPOLEN_MPTCP_MPC_ACK_DATA; > if (opts->csum_reqd) { > /* we need to propagate more info to csum the pseudo hdr */ > - opts->ext_copy.data_seq = mpext->data_seq; > - opts->ext_copy.subflow_seq = mpext->subflow_seq; > - opts->ext_copy.csum = mpext->csum; > + opts->data_seq = mpext->data_seq; > + opts->subflow_seq = mpext->subflow_seq; > + opts->csum = mpext->csum; > len += TCPOLEN_MPTCP_DSS_CHECKSUM; > } > *size = ALIGN(len, 4); > @@ -1223,25 +1223,30 @@ static void mptcp_set_rwin(const struct tcp_sock *tp) > WRITE_ONCE(msk->rcv_wnd_sent, ack_seq); > } > > -static u16 mptcp_make_csum(const struct mptcp_ext *mpext) > +static u16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __sum16 csum) > { > struct csum_pseudo_header header; > - __wsum csum; As the CI automation noticed, still need a __wsum to store the return value of csum_partial below. This is looking like the right way to go, with the noted few fixes. Thanks! > > /* cfr RFC 8684 3.3.1.: > * the data sequence number used in the pseudo-header is > * always the 64-bit value, irrespective of what length is used in the > * DSS option itself. > */ > - header.data_seq = cpu_to_be64(mpext->data_seq); > - header.subflow_seq = htonl(mpext->subflow_seq); > - header.data_len = htons(mpext->data_len); > + header.data_seq = cpu_to_be64(data_seq); > + header.subflow_seq = htonl(subflow_seq); > + header.data_len = htons(data_len); > header.csum = 0; > > - csum = csum_partial(&header, sizeof(header), ~csum_unfold(mpext->csum)); > + csum = csum_partial(&header, sizeof(header), ~csum_unfold(csum)); > return (__force u16)csum_fold(csum); > } > > +static u16 mptcp_make_csum(const struct mptcp_ext *mpext) > +{ > + return __mptcp_make_csum(mpext->data_seq, mpext->subflow_seq, mpext->data_len, > + mpext->csum); > +} > + > void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp, > struct mptcp_out_options *opts) > { > @@ -1332,7 +1337,7 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp, > len = TCPOLEN_MPTCP_MPC_SYN; > } else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions) { > len = TCPOLEN_MPTCP_MPC_SYNACK; > - } else if (opts->ext_copy.data_len) { > + } else if (opts->data_len) { > len = TCPOLEN_MPTCP_MPC_ACK_DATA; > if (opts->csum_reqd) > len += TCPOLEN_MPTCP_DSS_CHECKSUM; > @@ -1361,14 +1366,17 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp, > > put_unaligned_be64(opts->rcvr_key, ptr); > ptr += 2; > - if (!opts->ext_copy.data_len) > + if (!opts->data_len) > goto mp_capable_done; > > if (opts->csum_reqd) { > - put_unaligned_be32(opts->ext_copy.data_len << 16 | > - mptcp_make_csum(&opts->ext_copy), ptr); > + put_unaligned_be32(opts->data_len << 16 | > + __mptcp_make_csum(opts->data_seq, > + opts->subflow_seq, > + opts->data_len, > + opts->csum), ptr); > } else { > - put_unaligned_be32(opts->ext_copy.data_len << 16 | > + put_unaligned_be32(opts->data_len << 16 | > TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); > } > ptr += 1; > -- > 2.31.1 > > -- Mat Martineau Intel
Hi Davide, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on mptcp/export] [also build test WARNING on linus/master v5.15-rc7 next-20211025] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Davide-Caratti/mptcp-fix-corrupt-receiver-key-in-MPC-data-checksum/20211021-225325 base: https://github.com/multipath-tcp/mptcp_net-next.git export config: x86_64-randconfig-s022-20211025 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce: # apt-get install sparse # sparse version: v0.6.4-dirty # https://github.com/0day-ci/linux/commit/2293fadbec3d2e7e3c7f7da01c14f3ffa63c0e17 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Davide-Caratti/mptcp-fix-corrupt-receiver-key-in-MPC-data-checksum/20211021-225325 git checkout 2293fadbec3d2e7e3c7f7da01c14f3ffa63c0e17 # save the attached .config to linux build tree make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@intel.com> sparse warnings: (new ones prefixed by >>) >> net/mptcp/options.c:1240:14: sparse: sparse: incorrect type in assignment (different base types) @@ expected restricted __sum16 [usertype] csum @@ got restricted __wsum @@ net/mptcp/options.c:1240:14: sparse: expected restricted __sum16 [usertype] csum net/mptcp/options.c:1240:14: sparse: got restricted __wsum >> net/mptcp/options.c:1241:39: sparse: sparse: incorrect type in argument 1 (different base types) @@ expected restricted __wsum [usertype] sum @@ got restricted __sum16 [usertype] csum @@ net/mptcp/options.c:1241:39: sparse: expected restricted __wsum [usertype] sum net/mptcp/options.c:1241:39: sparse: got restricted __sum16 [usertype] csum vim +1240 net/mptcp/options.c 1225 1226 static u16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __sum16 csum) 1227 { 1228 struct csum_pseudo_header header; 1229 1230 /* cfr RFC 8684 3.3.1.: 1231 * the data sequence number used in the pseudo-header is 1232 * always the 64-bit value, irrespective of what length is used in the 1233 * DSS option itself. 1234 */ 1235 header.data_seq = cpu_to_be64(data_seq); 1236 header.subflow_seq = htonl(subflow_seq); 1237 header.data_len = htons(data_len); 1238 header.csum = 0; 1239 > 1240 csum = csum_partial(&header, sizeof(header), ~csum_unfold(csum)); > 1241 return (__force u16)csum_fold(csum); 1242 } 1243 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
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