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iscsi-target: Disable markers + remove dangerous local scope array usage
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This patch makes iscsi-target explictly disable OFMarker=Yes and IFMarker=yes
parameter key usage during iscsi login by setting IFMarkInt_Reject and
OFMarkInt_Reject values in iscsi_enforce_integrity_rules() to effectively
disable iscsi marker usage.  With this patch, an initiator proposer asking
to enable either marker parameter keys will be issued a 'No' response, and
the target sets OFMarkInt + IFMarkInt parameter key response to 'Irrelevant'.

With markers disabled during iscsi login, this patch removes the problematic
on-stack local-scope array for marker intervals in iscsit_do_rx_data() +
iscsit_do_tx_data(), and other related marker code in iscsi_target_util.c.
This fixes a potentional stack smashing scenario with small range markers
enabled and a large MRDSL as reported by DanC here:

[bug report] target: stack can be smashed
http://www.spinics.net/lists/target-devel/msg00453.html

Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
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Nicholas Bellinger committed Sep 16, 2011
1 parent 784eb99 commit 2ff017f
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Showing 2 changed files with 7 additions and 243 deletions.
2 changes: 1 addition & 1 deletion drivers/target/iscsi/iscsi_target_parameters.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1430,7 +1430,7 @@ static int iscsi_enforce_integrity_rules(
u8 DataSequenceInOrder = 0;
u8 ErrorRecoveryLevel = 0, SessionType = 0;
u8 IFMarker = 0, OFMarker = 0;
u8 IFMarkInt_Reject = 0, OFMarkInt_Reject = 0;
u8 IFMarkInt_Reject = 1, OFMarkInt_Reject = 1;
u32 FirstBurstLength = 0, MaxBurstLength = 0;
struct iscsi_param *param = NULL;

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248 changes: 6 additions & 242 deletions drivers/target/iscsi/iscsi_target_util.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -874,40 +874,6 @@ void iscsit_inc_session_usage_count(struct iscsi_session *sess)
spin_unlock_bh(&sess->session_usage_lock);
}

/*
* Used before iscsi_do[rx,tx]_data() to determine iov and [rx,tx]_marker
* array counts needed for sync and steering.
*/
static int iscsit_determine_sync_and_steering_counts(
struct iscsi_conn *conn,
struct iscsi_data_count *count)
{
u32 length = count->data_length;
u32 marker, markint;

count->sync_and_steering = 1;

marker = (count->type == ISCSI_RX_DATA) ?
conn->of_marker : conn->if_marker;
markint = (count->type == ISCSI_RX_DATA) ?
(conn->conn_ops->OFMarkInt * 4) :
(conn->conn_ops->IFMarkInt * 4);
count->ss_iov_count = count->iov_count;

while (length > 0) {
if (length >= marker) {
count->ss_iov_count += 3;
count->ss_marker_count += 2;

length -= marker;
marker = markint;
} else
length = 0;
}

return 0;
}

/*
* Setup conn->if_marker and conn->of_marker values based upon
* the initial marker-less interval. (see iSCSI v19 A.2)
Expand Down Expand Up @@ -1431,102 +1397,16 @@ static int iscsit_do_rx_data(
struct iscsi_data_count *count)
{
int data = count->data_length, rx_loop = 0, total_rx = 0, iov_len;
u32 rx_marker_val[count->ss_marker_count], rx_marker_iov = 0;
struct kvec iov[count->ss_iov_count], *iov_p;
struct kvec *iov_p;
struct msghdr msg;

if (!conn || !conn->sock || !conn->conn_ops)
return -1;

memset(&msg, 0, sizeof(struct msghdr));

if (count->sync_and_steering) {
int size = 0;
u32 i, orig_iov_count = 0;
u32 orig_iov_len = 0, orig_iov_loc = 0;
u32 iov_count = 0, per_iov_bytes = 0;
u32 *rx_marker, old_rx_marker = 0;
struct kvec *iov_record;

memset(&rx_marker_val, 0,
count->ss_marker_count * sizeof(u32));
memset(&iov, 0, count->ss_iov_count * sizeof(struct kvec));

iov_record = count->iov;
orig_iov_count = count->iov_count;
rx_marker = &conn->of_marker;

i = 0;
size = data;
orig_iov_len = iov_record[orig_iov_loc].iov_len;
while (size > 0) {
pr_debug("rx_data: #1 orig_iov_len %u,"
" orig_iov_loc %u\n", orig_iov_len, orig_iov_loc);
pr_debug("rx_data: #2 rx_marker %u, size"
" %u\n", *rx_marker, size);

if (orig_iov_len >= *rx_marker) {
iov[iov_count].iov_len = *rx_marker;
iov[iov_count++].iov_base =
(iov_record[orig_iov_loc].iov_base +
per_iov_bytes);

iov[iov_count].iov_len = (MARKER_SIZE / 2);
iov[iov_count++].iov_base =
&rx_marker_val[rx_marker_iov++];
iov[iov_count].iov_len = (MARKER_SIZE / 2);
iov[iov_count++].iov_base =
&rx_marker_val[rx_marker_iov++];
old_rx_marker = *rx_marker;

/*
* OFMarkInt is in 32-bit words.
*/
*rx_marker = (conn->conn_ops->OFMarkInt * 4);
size -= old_rx_marker;
orig_iov_len -= old_rx_marker;
per_iov_bytes += old_rx_marker;

pr_debug("rx_data: #3 new_rx_marker"
" %u, size %u\n", *rx_marker, size);
} else {
iov[iov_count].iov_len = orig_iov_len;
iov[iov_count++].iov_base =
(iov_record[orig_iov_loc].iov_base +
per_iov_bytes);

per_iov_bytes = 0;
*rx_marker -= orig_iov_len;
size -= orig_iov_len;

if (size)
orig_iov_len =
iov_record[++orig_iov_loc].iov_len;

pr_debug("rx_data: #4 new_rx_marker"
" %u, size %u\n", *rx_marker, size);
}
}
data += (rx_marker_iov * (MARKER_SIZE / 2));

iov_p = &iov[0];
iov_len = iov_count;

if (iov_count > count->ss_iov_count) {
pr_err("iov_count: %d, count->ss_iov_count:"
" %d\n", iov_count, count->ss_iov_count);
return -1;
}
if (rx_marker_iov > count->ss_marker_count) {
pr_err("rx_marker_iov: %d, count->ss_marker"
"_count: %d\n", rx_marker_iov,
count->ss_marker_count);
return -1;
}
} else {
iov_p = count->iov;
iov_len = count->iov_count;
}
iov_p = count->iov;
iov_len = count->iov_count;

while (total_rx < data) {
rx_loop = kernel_recvmsg(conn->sock, &msg, iov_p, iov_len,
Expand All @@ -1541,16 +1421,6 @@ static int iscsit_do_rx_data(
rx_loop, total_rx, data);
}

if (count->sync_and_steering) {
int j;
for (j = 0; j < rx_marker_iov; j++) {
pr_debug("rx_data: #5 j: %d, offset: %d\n",
j, rx_marker_val[j]);
conn->of_marker_offset = rx_marker_val[j];
}
total_rx -= (rx_marker_iov * (MARKER_SIZE / 2));
}

return total_rx;
}

Expand All @@ -1559,8 +1429,7 @@ static int iscsit_do_tx_data(
struct iscsi_data_count *count)
{
int data = count->data_length, total_tx = 0, tx_loop = 0, iov_len;
u32 tx_marker_val[count->ss_marker_count], tx_marker_iov = 0;
struct kvec iov[count->ss_iov_count], *iov_p;
struct kvec *iov_p;
struct msghdr msg;

if (!conn || !conn->sock || !conn->conn_ops)
Expand All @@ -1573,98 +1442,8 @@ static int iscsit_do_tx_data(

memset(&msg, 0, sizeof(struct msghdr));

if (count->sync_and_steering) {
int size = 0;
u32 i, orig_iov_count = 0;
u32 orig_iov_len = 0, orig_iov_loc = 0;
u32 iov_count = 0, per_iov_bytes = 0;
u32 *tx_marker, old_tx_marker = 0;
struct kvec *iov_record;

memset(&tx_marker_val, 0,
count->ss_marker_count * sizeof(u32));
memset(&iov, 0, count->ss_iov_count * sizeof(struct kvec));

iov_record = count->iov;
orig_iov_count = count->iov_count;
tx_marker = &conn->if_marker;

i = 0;
size = data;
orig_iov_len = iov_record[orig_iov_loc].iov_len;
while (size > 0) {
pr_debug("tx_data: #1 orig_iov_len %u,"
" orig_iov_loc %u\n", orig_iov_len, orig_iov_loc);
pr_debug("tx_data: #2 tx_marker %u, size"
" %u\n", *tx_marker, size);

if (orig_iov_len >= *tx_marker) {
iov[iov_count].iov_len = *tx_marker;
iov[iov_count++].iov_base =
(iov_record[orig_iov_loc].iov_base +
per_iov_bytes);

tx_marker_val[tx_marker_iov] =
(size - *tx_marker);
iov[iov_count].iov_len = (MARKER_SIZE / 2);
iov[iov_count++].iov_base =
&tx_marker_val[tx_marker_iov++];
iov[iov_count].iov_len = (MARKER_SIZE / 2);
iov[iov_count++].iov_base =
&tx_marker_val[tx_marker_iov++];
old_tx_marker = *tx_marker;

/*
* IFMarkInt is in 32-bit words.
*/
*tx_marker = (conn->conn_ops->IFMarkInt * 4);
size -= old_tx_marker;
orig_iov_len -= old_tx_marker;
per_iov_bytes += old_tx_marker;

pr_debug("tx_data: #3 new_tx_marker"
" %u, size %u\n", *tx_marker, size);
pr_debug("tx_data: #4 offset %u\n",
tx_marker_val[tx_marker_iov-1]);
} else {
iov[iov_count].iov_len = orig_iov_len;
iov[iov_count++].iov_base
= (iov_record[orig_iov_loc].iov_base +
per_iov_bytes);

per_iov_bytes = 0;
*tx_marker -= orig_iov_len;
size -= orig_iov_len;

if (size)
orig_iov_len =
iov_record[++orig_iov_loc].iov_len;

pr_debug("tx_data: #5 new_tx_marker"
" %u, size %u\n", *tx_marker, size);
}
}

data += (tx_marker_iov * (MARKER_SIZE / 2));

iov_p = &iov[0];
iov_len = iov_count;

if (iov_count > count->ss_iov_count) {
pr_err("iov_count: %d, count->ss_iov_count:"
" %d\n", iov_count, count->ss_iov_count);
return -1;
}
if (tx_marker_iov > count->ss_marker_count) {
pr_err("tx_marker_iov: %d, count->ss_marker"
"_count: %d\n", tx_marker_iov,
count->ss_marker_count);
return -1;
}
} else {
iov_p = count->iov;
iov_len = count->iov_count;
}
iov_p = count->iov;
iov_len = count->iov_count;

while (total_tx < data) {
tx_loop = kernel_sendmsg(conn->sock, &msg, iov_p, iov_len,
Expand All @@ -1679,9 +1458,6 @@ static int iscsit_do_tx_data(
tx_loop, total_tx, data);
}

if (count->sync_and_steering)
total_tx -= (tx_marker_iov * (MARKER_SIZE / 2));

return total_tx;
}

Expand All @@ -1702,12 +1478,6 @@ int rx_data(
c.data_length = data;
c.type = ISCSI_RX_DATA;

if (conn->conn_ops->OFMarker &&
(conn->conn_state >= TARG_CONN_STATE_LOGGED_IN)) {
if (iscsit_determine_sync_and_steering_counts(conn, &c) < 0)
return -1;
}

return iscsit_do_rx_data(conn, &c);
}

Expand All @@ -1728,12 +1498,6 @@ int tx_data(
c.data_length = data;
c.type = ISCSI_TX_DATA;

if (conn->conn_ops->IFMarker &&
(conn->conn_state >= TARG_CONN_STATE_LOGGED_IN)) {
if (iscsit_determine_sync_and_steering_counts(conn, &c) < 0)
return -1;
}

return iscsit_do_tx_data(conn, &c);
}

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