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net/smc: tolerate future SMCD versions

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CLC proposal messages of future SMCD versions could be larger than SMCD
V1 CLC proposal messages.
To enable toleration in SMC V1 the receival of CLC proposal messages
is adapted:
* accept larger length values in CLC proposal
* check trailing eye catcher for incoming CLC proposal with V1 length only
* receive the whole CLC proposal even in cases it does not fit into the
  V1 buffer

Fixes: e7b7a64a84 ("smc: support variable CLC proposal messages")
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ursula Braun 2020-07-08 17:05:15 +02:00 committed by David S. Miller
parent 82087c0330
commit fb4f79264c
2 changed files with 34 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
net/smc/smc_clc.c
View File

@ -27,6 +27,7 @@
#define SMCR_CLC_ACCEPT_CONFIRM_LEN 68
#define SMCD_CLC_ACCEPT_CONFIRM_LEN 48
#define SMC_CLC_RECV_BUF_LEN 100
/* eye catcher "SMCR" EBCDIC for CLC messages */
static const char SMC_EYECATCHER[4] = {'\xe2', '\xd4', '\xc3', '\xd9'};
@ -36,7 +37,7 @@ static const char SMCD_EYECATCHER[4] = {'\xe2', '\xd4', '\xc3', '\xc4'};
/* check if received message has a correct header length and contains valid
* heading and trailing eyecatchers
*/
static bool smc_clc_msg_hdr_valid(struct smc_clc_msg_hdr *clcm)
static bool smc_clc_msg_hdr_valid(struct smc_clc_msg_hdr *clcm, bool check_trl)
{
struct smc_clc_msg_proposal_prefix *pclc_prfx;
struct smc_clc_msg_accept_confirm *clc;
@ -49,12 +50,9 @@ static bool smc_clc_msg_hdr_valid(struct smc_clc_msg_hdr *clcm)
return false;
switch (clcm->type) {
case SMC_CLC_PROPOSAL:
if (clcm->path != SMC_TYPE_R && clcm->path != SMC_TYPE_D &&
clcm->path != SMC_TYPE_B)
return false;
pclc = (struct smc_clc_msg_proposal *)clcm;
pclc_prfx = smc_clc_proposal_get_prefix(pclc);
if (ntohs(pclc->hdr.length) !=
if (ntohs(pclc->hdr.length) <
sizeof(*pclc) + ntohs(pclc->iparea_offset) +
sizeof(*pclc_prfx) +
pclc_prfx->ipv6_prefixes_cnt *
@ -86,7 +84,8 @@ static bool smc_clc_msg_hdr_valid(struct smc_clc_msg_hdr *clcm)
default:
return false;
}
if (memcmp(trl->eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER)) &&
if (check_trl &&
memcmp(trl->eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER)) &&
memcmp(trl->eyecatcher, SMCD_EYECATCHER, sizeof(SMCD_EYECATCHER)))
return false;
return true;
@ -276,7 +275,8 @@ int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
struct msghdr msg = {NULL, 0};
int reason_code = 0;
struct kvec vec = {buf, buflen};
int len, datlen;
int len, datlen, recvlen;
bool check_trl = true;
int krflags;
/* peek the first few bytes to determine length of data to receive
@ -320,10 +320,7 @@ int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
}
datlen = ntohs(clcm->length);
if ((len < sizeof(struct smc_clc_msg_hdr)) ||
(datlen > buflen) ||
(clcm->version != SMC_CLC_V1) ||
(clcm->path != SMC_TYPE_R && clcm->path != SMC_TYPE_D &&
clcm->path != SMC_TYPE_B) ||
(clcm->version < SMC_CLC_V1) ||
((clcm->type != SMC_CLC_DECLINE) &&
(clcm->type != expected_type))) {
smc->sk.sk_err = EPROTO;
@ -331,16 +328,38 @@ int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
goto out;
}
if (clcm->type == SMC_CLC_PROPOSAL && clcm->path == SMC_TYPE_N)
reason_code = SMC_CLC_DECL_VERSMISMAT; /* just V2 offered */
/* receive the complete CLC message */
memset(&msg, 0, sizeof(struct msghdr));
iov_iter_kvec(&msg.msg_iter, READ, &vec, 1, datlen);
if (datlen > buflen) {
check_trl = false;
recvlen = buflen;
} else {
recvlen = datlen;
}
iov_iter_kvec(&msg.msg_iter, READ, &vec, 1, recvlen);
krflags = MSG_WAITALL;
len = sock_recvmsg(smc->clcsock, &msg, krflags);
if (len < datlen || !smc_clc_msg_hdr_valid(clcm)) {
if (len < recvlen || !smc_clc_msg_hdr_valid(clcm, check_trl)) {
smc->sk.sk_err = EPROTO;
reason_code = -EPROTO;
goto out;
}
datlen -= len;
while (datlen) {
u8 tmp[SMC_CLC_RECV_BUF_LEN];
vec.iov_base = &tmp;
vec.iov_len = SMC_CLC_RECV_BUF_LEN;
/* receive remaining proposal message */
recvlen = datlen > SMC_CLC_RECV_BUF_LEN ?
SMC_CLC_RECV_BUF_LEN : datlen;
iov_iter_kvec(&msg.msg_iter, READ, &vec, 1, recvlen);
len = sock_recvmsg(smc->clcsock, &msg, krflags);
datlen -= len;
}
if (clcm->type == SMC_CLC_DECLINE) {
struct smc_clc_msg_decline *dclc;

2
net/smc/smc_clc.h
View File

@ -25,6 +25,7 @@
#define SMC_CLC_V1 0x1 /* SMC version */
#define SMC_TYPE_R 0 /* SMC-R only */
#define SMC_TYPE_D 1 /* SMC-D only */
#define SMC_TYPE_N 2 /* neither SMC-R nor SMC-D */
#define SMC_TYPE_B 3 /* SMC-R and SMC-D */
#define CLC_WAIT_TIME (6 * HZ) /* max. wait time on clcsock */
#define CLC_WAIT_TIME_SHORT HZ /* short wait time on clcsock */
@ -46,6 +47,7 @@
#define SMC_CLC_DECL_ISMVLANERR 0x03090000 /* err to reg vlan id on ism dev */
#define SMC_CLC_DECL_NOACTLINK 0x030a0000 /* no active smc-r link in lgr */
#define SMC_CLC_DECL_NOSRVLINK 0x030b0000 /* SMC-R link from srv not found */
#define SMC_CLC_DECL_VERSMISMAT 0x030c0000 /* SMC version mismatch */
#define SMC_CLC_DECL_SYNCERR 0x04000000 /* synchronization error */
#define SMC_CLC_DECL_PEERDECL 0x05000000 /* peer declined during handshake */
#define SMC_CLC_DECL_INTERR 0x09990000 /* internal error */