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iscsi-target: Fix wrong buffer / buffer overrun in iscsi_change_param_value() 

In non-leading connection login, iscsi_login_non_zero_tsih_s1() calls
iscsi_change_param_value() with the buffer it uses to hold the login
PDU, not a temporary buffer.  This leads to the login header getting
corrupted and login failing for non-leading connections in MC/S.

Fix this by adding a wrapper iscsi_change_param_sprintf() that handles
the temporary buffer itself to avoid confusion.  Also handle sending a
reject in case of failure in the wrapper, which lets the calling code
get quite a bit smaller and easier to read.

Finally, bump the size of the temporary buffer from 32 to 64 bytes to be
safe, since "MaxRecvDataSegmentLength=" by itself is 25 bytes; with a
trailing NUL, a value >= 1M will lead to a buffer overrun.  (This isn't
the default but we don't need to run right at the ragged edge here)

Reported-by: Santosh Kulkarni <santosh.kulkarni@calsoftinc.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Roland Dreier 2014-05-29 13:32:30 -07:00 committed by Nicholas Bellinger
parent 6cc44a6fb4
commit 79d59d0808
1 changed files with 31 additions and 39 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

70
drivers/target/iscsi/iscsi_target_login.c
View File

@ -249,6 +249,28 @@ static void iscsi_login_set_conn_values(
mutex_unlock(&auth_id_lock);
}
static __printf(2, 3) int iscsi_change_param_sprintf(
struct iscsi_conn *conn,
const char *fmt, ...)
{
va_list args;
unsigned char buf[64];
memset(buf, 0, sizeof buf);
va_start(args, fmt);
vsnprintf(buf, sizeof buf, fmt, args);
va_end(args);
if (iscsi_change_param_value(buf, conn->param_list, 0) < 0) {
iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
ISCSI_LOGIN_STATUS_NO_RESOURCES);
return -1;
}
return 0;
}
/*
* This is the leading connection of a new session,
* or session reinstatement.
@ -339,7 +361,6 @@ static int iscsi_login_zero_tsih_s2(
{
struct iscsi_node_attrib *na;
struct iscsi_session *sess = conn->sess;
unsigned char buf[32];
bool iser = false;
sess->tpg = conn->tpg;
@ -380,26 +401,16 @@ static int iscsi_login_zero_tsih_s2(
*
* In our case, we have already located the struct iscsi_tiqn at this point.
*/
memset(buf, 0, 32);
sprintf(buf, "TargetPortalGroupTag=%hu", sess->tpg->tpgt);
if (iscsi_change_param_value(buf, conn->param_list, 0) < 0) {
iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
ISCSI_LOGIN_STATUS_NO_RESOURCES);
if (iscsi_change_param_sprintf(conn, "TargetPortalGroupTag=%hu", sess->tpg->tpgt))
return -1;
}
/*
* Workaround for Initiators that have broken connection recovery logic.
*
* "We would really like to get rid of this." Linux-iSCSI.org team
*/
memset(buf, 0, 32);
sprintf(buf, "ErrorRecoveryLevel=%d", na->default_erl);
if (iscsi_change_param_value(buf, conn->param_list, 0) < 0) {
iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
ISCSI_LOGIN_STATUS_NO_RESOURCES);
if (iscsi_change_param_sprintf(conn, "ErrorRecoveryLevel=%d", na->default_erl))
return -1;
}
if (iscsi_login_disable_FIM_keys(conn->param_list, conn) < 0)
return -1;
@ -411,12 +422,9 @@ static int iscsi_login_zero_tsih_s2(
unsigned long mrdsl, off;
int rc;
sprintf(buf, "RDMAExtensions=Yes");
if (iscsi_change_param_value(buf, conn->param_list, 0) < 0) {
iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
ISCSI_LOGIN_STATUS_NO_RESOURCES);
if (iscsi_change_param_sprintf(conn, "RDMAExtensions=Yes"))
return -1;
}
/*
* Make MaxRecvDataSegmentLength PAGE_SIZE aligned for
* Immediate Data + Unsolicitied Data-OUT if necessary..
@ -446,12 +454,8 @@ static int iscsi_login_zero_tsih_s2(
pr_warn("Aligning ISER MaxRecvDataSegmentLength: %lu down"
" to PAGE_SIZE\n", mrdsl);
sprintf(buf, "MaxRecvDataSegmentLength=%lu\n", mrdsl);
if (iscsi_change_param_value(buf, conn->param_list, 0) < 0) {
iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
ISCSI_LOGIN_STATUS_NO_RESOURCES);
if (iscsi_change_param_sprintf(conn, "MaxRecvDataSegmentLength=%lu\n", mrdsl))
return -1;
}
/*
* ISER currently requires that ImmediateData + Unsolicited
* Data be disabled when protection / signature MRs are enabled.
@ -461,19 +465,12 @@ static int iscsi_login_zero_tsih_s2(
(TARGET_PROT_DOUT_STRIP | TARGET_PROT_DOUT_PASS |
TARGET_PROT_DOUT_INSERT)) {
sprintf(buf, "ImmediateData=No");
if (iscsi_change_param_value(buf, conn->param_list, 0) < 0) {
iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
ISCSI_LOGIN_STATUS_NO_RESOURCES);
if (iscsi_change_param_sprintf(conn, "ImmediateData=No"))
return -1;
}
sprintf(buf, "InitialR2T=Yes");
if (iscsi_change_param_value(buf, conn->param_list, 0) < 0) {
iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
ISCSI_LOGIN_STATUS_NO_RESOURCES);
if (iscsi_change_param_sprintf(conn, "InitialR2T=Yes"))
return -1;
}
pr_debug("Forcing ImmediateData=No + InitialR2T=Yes for"
" T10-PI enabled ISER session\n");
}
@ -618,13 +615,8 @@ static int iscsi_login_non_zero_tsih_s2(
*
* In our case, we have already located the struct iscsi_tiqn at this point.
*/
memset(buf, 0, 32);
sprintf(buf, "TargetPortalGroupTag=%hu", sess->tpg->tpgt);
if (iscsi_change_param_value(buf, conn->param_list, 0) < 0) {
iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
ISCSI_LOGIN_STATUS_NO_RESOURCES);
if (iscsi_change_param_sprintf(conn, "TargetPortalGroupTag=%hu", sess->tpg->tpgt))
return -1;
}
return iscsi_login_disable_FIM_keys(conn->param_list, conn);
}