[PATCH v5] net: wwan: t7xx: validate port_count against message length in t7xx_port_enum_msg_handler

Pavitra Jha
2026-04-23T15:07:51Z

t7xx_port_enum_msg_handler() uses the modem-supplied port_count field as
a loop bound over port_msg->data[] without checking that the message buffer
contains sufficient data. A modem sending port_count=65535 in a 12-byte
buffer triggers a slab-out-of-bounds read of up to 262140 bytes.

Add a struct_size() check after extracting port_count and before the loop.
Pass msg_len to t7xx_port_enum_msg_handler() and use it to validate
the message size before accessing port_msg->data[].
Pass msg_len from both call sites: skb->len at the DPMAIF path after
skb_pull(), and the captured rt_feature->data_len at the handshake path.

Fixes: 39d439047f1d ("net: wwan: t7xx: Add control DMA interface")
Cc: stable@vger.kernel.org
Signed-off-by: Pavitra Jha <jhapavitra98@gmail.com>
---
drivers/net/wwan/t7xx/t7xx_modem_ops.c | 10 +++++++---
drivers/net/wwan/t7xx/t7xx_port_ctrl_msg.c | 12 ++++++++++--
drivers/net/wwan/t7xx/t7xx_port_proxy.h | 2 +-
3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wwan/t7xx/t7xx_modem_ops.c b/drivers/net/wwan/t7xx/t7xx_modem_ops.c
index 7968e208d..dc90691ef 100644
--- a/drivers/net/wwan/t7xx/t7xx_modem_ops.c
+++ b/drivers/net/wwan/t7xx/t7xx_modem_ops.c
@@ -453,12 +453,14 @@ static int t7xx_parse_host_rt_data(struct t7xx_fsm_ctl *ctl, struct t7xx_sys_inf
{
enum mtk_feature_support_type ft_spt_st, ft_spt_cfg;
struct mtk_runtime_feature *rt_feature;
+ size_t feat_data_len;
int i, offset;

offset = sizeof(struct feature_query);
for (i = 0; i < FEATURE_COUNT && offset < data_length; i++) {
rt_feature = data + offset;
- offset += sizeof(*rt_feature) + le32_to_cpu(rt_feature->data_len);
+ feat_data_len = le32_to_cpu(rt_feature->data_len);
+ offset += sizeof(*rt_feature) + feat_data_len;

ft_spt_cfg = FIELD_GET(FEATURE_MSK, core->feature_set[i]);
if (ft_spt_cfg != MTK_FEATURE_MUST_BE_SUPPORTED)
@@ -468,8 +470,10 @@ static int t7xx_parse_host_rt_data(struct t7xx_fsm_ctl *ctl, struct t7xx_sys_inf
if (ft_spt_st != MTK_FEATURE_MUST_BE_SUPPORTED)
return -EINVAL;

- if (i == RT_ID_MD_PORT_ENUM || i == RT_ID_AP_PORT_ENUM)
- t7xx_port_enum_msg_handler(ctl->md, rt_feature->data);
+ if (i == RT_ID_MD_PORT_ENUM || i == RT_ID_AP_PORT_ENUM) {
+ t7xx_port_enum_msg_handler(ctl->md, rt_feature->data,
+ feat_data_len);
+ }
}

return 0;
diff --git a/drivers/net/wwan/t7xx/t7xx_port_ctrl_msg.c b/drivers/net/wwan/t7xx/t7xx_port_ctrl_msg.c
index ae632ef96..fa2428444 100644
--- a/drivers/net/wwan/t7xx/t7xx_port_ctrl_msg.c
+++ b/drivers/net/wwan/t7xx/t7xx_port_ctrl_msg.c
@@ -117,6 +117,7 @@ static int fsm_ee_message_handler(struct t7xx_port *port, struct t7xx_fsm_ctl *c
* t7xx_port_enum_msg_handler() - Parse the port enumeration message to create/remove nodes.
* @md: Modem context.
* @msg: Message.
+ * @msg_len: Length of @msg in bytes.
*
* Used to control create/remove device node.
*
@@ -124,7 +125,7 @@ static int fsm_ee_message_handler(struct t7xx_port *port, struct t7xx_fsm_ctl *c
* * 0 - Success.
* * -EFAULT - Message check failure.
*/
-int t7xx_port_enum_msg_handler(struct t7xx_modem *md, void *msg)
+int t7xx_port_enum_msg_handler(struct t7xx_modem *md, void *msg, size_t msg_len)
{
struct device *dev = &md->t7xx_dev->pdev->dev;
unsigned int version, port_count, i;
@@ -141,6 +142,13 @@ int t7xx_port_enum_msg_handler(struct t7xx_modem *md, void *msg)
}

port_count = FIELD_GET(PORT_MSG_PRT_CNT, le32_to_cpu(port_msg->info));
+
+ if (msg_len < struct_size(port_msg, data, port_count)) {
+ dev_err(dev, "Port enum msg too short: need %zu, have %zu\n",
+ struct_size(port_msg, data, port_count), msg_len);
+ return -EINVAL;
+ }
+
for (i = 0; i < port_count; i++) {
u32 port_info = le32_to_cpu(port_msg->data[i]);
unsigned int ch_id;
@@ -191,7 +199,7 @@ static int control_msg_handler(struct t7xx_port *port, struct sk_buff *skb)

case CTL_ID_PORT_ENUM:
skb_pull(skb, sizeof(*ctrl_msg_h));
- ret = t7xx_port_enum_msg_handler(ctl->md, (struct port_msg *)skb->data);
+ ret = t7xx_port_enum_msg_handler(ctl->md, (struct port_msg *)skb->data, skb->len);
if (!ret)
ret = port_ctl_send_msg_to_md(port, CTL_ID_PORT_ENUM, 0);
else
diff --git a/drivers/net/wwan/t7xx/t7xx_port_proxy.h b/drivers/net/wwan/t7xx/t7xx_port_proxy.h
index f0918b36e..7c3190bf0 100644
--- a/drivers/net/wwan/t7xx/t7xx_port_proxy.h
+++ b/drivers/net/wwan/t7xx/t7xx_port_proxy.h
@@ -103,7 +103,7 @@ void t7xx_port_proxy_reset(struct port_proxy *port_prox);
void t7xx_port_proxy_uninit(struct port_proxy *port_prox);
int t7xx_port_proxy_init(struct t7xx_modem *md);
void t7xx_port_proxy_md_status_notify(struct port_proxy *port_prox, unsigned int state);
-int t7xx_port_enum_msg_handler(struct t7xx_modem *md, void *msg);
+int t7xx_port_enum_msg_handler(struct t7xx_modem *md, void *msg, size_t msg_len);
int t7xx_port_proxy_chl_enable_disable(struct port_proxy *port_prox, unsigned int ch_id,
bool en_flag);
void t7xx_port_proxy_set_cfg(struct t7xx_modem *md, enum port_cfg_id cfg_id);
--
2.53.0