rndis_query_oid() uses full output buffer size to copy response buffer
from rndis_command()/device. This doesn't cause problems as response buffer
is sized based on output buffer but does copy extra unset bytes.
So change rndis_query_oid() so that only meaningful bytes are being copied.
Also in case of malfunctioning device/cable/etc returned data offset from
device might be wrong so bound check memory access correctly, so add
checks for this.
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@xxxxxxxx>
---
drivers/net/wireless/rndis_wlan.c | 33 +++++++++++++++++++++++++++++----
1 files changed, 29 insertions(+), 4 deletions(-)
diff --git a/drivers/net/wireless/rndis_wlan.c b/drivers/net/wireless/rndis_wlan.c
index 305c106..b275713 100644
--- a/drivers/net/wireless/rndis_wlan.c
+++ b/drivers/net/wireless/rndis_wlan.c
@@ -704,6 +704,7 @@ static int rndis_query_oid(struct usbnet *dev, __le32 oid, void *data, int *len)
struct rndis_query_c *get_c;
} u;
int ret, buflen;
+ int resplen, respoffs, copylen;
buflen = *len + sizeof(*u.get);
if (buflen < CONTROL_BUFFER_SIZE)
@@ -733,11 +734,34 @@ static int rndis_query_oid(struct usbnet *dev, __le32 oid, void *data, int *len)
le32_to_cpu(u.get_c->status));
if (ret == 0) {
- memcpy(data, u.buf + le32_to_cpu(u.get_c->offset) + 8, *len);
+ resplen = le32_to_cpu(u.get_c->len);
+ respoffs = le32_to_cpu(u.get_c->offset) + 8;
- ret = le32_to_cpu(u.get_c->len);
- if (ret > *len)
- *len = ret;
+ if (respoffs > buflen) {
+ /* Device returned data offset outside buffer, error. */
+ devdbg(dev, "rndis_query_oid(%s): received invalid "
+ "data offset: %d > %d", oid_to_string(oid),
+ respoffs, buflen);
+
+ ret = -EINVAL;
+ goto exit_unlock;
+ }
+
+ if ((resplen + respoffs) > buflen) {
+ /* Device would have returned more data if buffer would
+ * have been big enough. Copy just the bits that we got.
+ */
+ copylen = buflen - respoffs;
+ } else {
+ copylen = resplen;
+ }
+
+ if (copylen > *len)
+ copylen = *len;
+
+ memcpy(data, u.buf + respoffs, copylen);
+
+ *len = resplen;
ret = rndis_error_status(u.get_c->status);
if (ret < 0)
@@ -746,6 +770,7 @@ static int rndis_query_oid(struct usbnet *dev, __le32 oid, void *data, int *len)
le32_to_cpu(u.get_c->status), ret);
}
+exit_unlock:
mutex_unlock(&priv->command_lock);
if (u.buf != priv->command_buffer)
--
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