[SCSI] libiscsi_tcp: fix max_r2t manipulation

Problem description from Xi Wang:
A large max_r2t could lead to integer overflow in subsequent call to
iscsi_tcp_r2tpool_alloc(), allocating a smaller buffer than expected
and leading to out-of-bounds write.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Mike Christie 2012-01-26 21:13:10 -06:00 committed by James Bottomley
parent df1c7baba1
commit 1304be5fe0
6 changed files with 24 additions and 26 deletions

View File

@ -2148,11 +2148,10 @@ int cxgbi_set_conn_param(struct iscsi_cls_conn *cls_conn,
enum iscsi_param param, char *buf, int buflen)
{
struct iscsi_conn *conn = cls_conn->dd_data;
struct iscsi_session *session = conn->session;
struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
struct cxgbi_conn *cconn = tcp_conn->dd_data;
struct cxgbi_sock *csk = cconn->cep->csk;
int value, err = 0;
int err;
log_debug(1 << CXGBI_DBG_ISCSI,
"cls_conn 0x%p, param %d, buf(%d) %s.\n",
@ -2174,15 +2173,7 @@ int cxgbi_set_conn_param(struct iscsi_cls_conn *cls_conn,
conn->datadgst_en, 0);
break;
case ISCSI_PARAM_MAX_R2T:
sscanf(buf, "%d", &value);
if (value <= 0 || !is_power_of_2(value))
return -EINVAL;
if (session->max_r2t == value)
break;
iscsi_tcp_r2tpool_free(session);
err = iscsi_set_param(cls_conn, param, buf, buflen);
if (!err && iscsi_tcp_r2tpool_alloc(session))
return -ENOMEM;
return iscsi_tcp_set_max_r2t(conn, buf);
case ISCSI_PARAM_MAX_RECV_DLENGTH:
err = iscsi_set_param(cls_conn, param, buf, buflen);
if (!err)

View File

@ -684,10 +684,8 @@ static int iscsi_sw_tcp_conn_set_param(struct iscsi_cls_conn *cls_conn,
int buflen)
{
struct iscsi_conn *conn = cls_conn->dd_data;
struct iscsi_session *session = conn->session;
struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
int value;
switch(param) {
case ISCSI_PARAM_HDRDGST_EN:
@ -699,16 +697,7 @@ static int iscsi_sw_tcp_conn_set_param(struct iscsi_cls_conn *cls_conn,
sock_no_sendpage : tcp_sw_conn->sock->ops->sendpage;
break;
case ISCSI_PARAM_MAX_R2T:
sscanf(buf, "%d", &value);
if (value <= 0 || !is_power_of_2(value))
return -EINVAL;
if (session->max_r2t == value)
break;
iscsi_tcp_r2tpool_free(session);
iscsi_set_param(cls_conn, param, buf, buflen);
if (iscsi_tcp_r2tpool_alloc(session))
return -ENOMEM;
break;
return iscsi_tcp_set_max_r2t(conn, buf);
default:
return iscsi_set_param(cls_conn, param, buf, buflen);
}

View File

@ -3201,7 +3201,7 @@ int iscsi_set_param(struct iscsi_cls_conn *cls_conn,
sscanf(buf, "%d", &session->initial_r2t_en);
break;
case ISCSI_PARAM_MAX_R2T:
sscanf(buf, "%d", &session->max_r2t);
sscanf(buf, "%hu", &session->max_r2t);
break;
case ISCSI_PARAM_IMM_DATA_EN:
sscanf(buf, "%d", &session->imm_data_en);

View File

@ -1170,6 +1170,24 @@ void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
}
EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf)
{
struct iscsi_session *session = conn->session;
unsigned short r2ts = 0;
sscanf(buf, "%hu", &r2ts);
if (session->max_r2t == r2ts)
return 0;
if (!r2ts || !is_power_of_2(r2ts))
return -EINVAL;
session->max_r2t = r2ts;
iscsi_tcp_r2tpool_free(session);
return iscsi_tcp_r2tpool_alloc(session);
}
EXPORT_SYMBOL_GPL(iscsi_tcp_set_max_r2t);
void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
struct iscsi_stats *stats)
{

View File

@ -268,7 +268,7 @@ struct iscsi_session {
int lu_reset_timeout;
int tgt_reset_timeout;
int initial_r2t_en;
unsigned max_r2t;
unsigned short max_r2t;
int imm_data_en;
unsigned first_burst;
unsigned max_burst;

View File

@ -128,7 +128,7 @@ extern void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn);
/* misc helpers */
extern int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session);
extern void iscsi_tcp_r2tpool_free(struct iscsi_session *session);
extern int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf);
extern void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
struct iscsi_stats *stats);
#endif /* LIBISCSI_TCP_H */