2022-07-06 06:58:30

by Dan Carpenter

Subject: [PATCH 1/2] wil6210: debugfs: fix info leak in wil_write_file_wmi()

The simple_write_to_buffer() function will succeed if even a single
byte is initialized. However we need to initialize the whole buffer
to prevent information leaks. Just use memdup_user().

Fixes: ff974e408334 ("wil6210: debugfs interface to send raw WMI command")
Signed-off-by: Dan Carpenter <[email protected]>
---
drivers/net/wireless/ath/wil6210/debugfs.c | 14 ++++----------
1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/drivers/net/wireless/ath/wil6210/debugfs.c b/drivers/net/wireless/ath/wil6210/debugfs.c
index 64d6c98174c8..fe84362718de 100644
--- a/drivers/net/wireless/ath/wil6210/debugfs.c
+++ b/drivers/net/wireless/ath/wil6210/debugfs.c
@@ -1012,18 +1012,12 @@ static ssize_t wil_write_file_wmi(struct file *file, const char __user *buf,
u16 cmdid;
int rc, rc1;

- if (cmdlen < 0)
+ if (cmdlen < 0 || *ppos != 0)
return -EINVAL;

- wmi = kmalloc(len, GFP_KERNEL);
- if (!wmi)
- return -ENOMEM;
-
- rc = simple_write_to_buffer(wmi, len, ppos, buf, len);
- if (rc < 0) {
- kfree(wmi);
- return rc;
- }
+ wmi = memdup_user(buf, len);
+ if (IS_ERR(wmi))
+ return PTR_ERR(wmi);

cmd = (cmdlen > 0) ? &wmi[1] : NULL;
cmdid = le16_to_cpu(wmi->command_id);
--
2.35.1

2022-07-06 07:00:46

by Dan Carpenter

Subject: [PATCH 2/2] wil6210: debugfs: replace in wil_link_stats_write() in wil_link_stats_write()

This code has a check for "if (rc != len) {" so it will fail if the
simple_write_to_buffer() does not completely fill the buffer. In
particular it will fail if "*ppos != 0". Although this code works, it is
more complicated than necessary. Just use strndup_user() instead.

Signed-off-by: Dan Carpenter <[email protected]>
---
drivers/net/wireless/ath/wil6210/debugfs.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/net/wireless/ath/wil6210/debugfs.c b/drivers/net/wireless/ath/wil6210/debugfs.c
index fe84362718de..591ba7f61c64 100644
--- a/drivers/net/wireless/ath/wil6210/debugfs.c
+++ b/drivers/net/wireless/ath/wil6210/debugfs.c
@@ -1937,18 +1937,15 @@ static ssize_t wil_link_stats_write(struct file *file, const char __user *buf,
struct wil6210_priv *wil = s->private;
int cid, interval, rc, i;
struct wil6210_vif *vif;
- char *kbuf = kmalloc(len + 1, GFP_KERNEL);
+ char *kbuf;

- if (!kbuf)
- return -ENOMEM;
+ if (*ppos != 0)
+ return -EINVAL;

- rc = simple_write_to_buffer(kbuf, len, ppos, buf, len);
- if (rc != len) {
- kfree(kbuf);
- return rc >= 0 ? -EIO : rc;
- }
+ kbuf = strndup_user(buf, len + 1);
+ if (IS_ERR(kbuf))
+ return -ENOMEM;

- kbuf[len] = '\0';
/* specify cid (use -1 for all cids) and snapshot interval in ms */
rc = sscanf(kbuf, "%d %d", &cid, &interval);
kfree(kbuf);
--
2.35.1

2022-07-06 10:44:55

by Dan Carpenter

Subject: Re: [PATCH 2/2] wil6210: debugfs: replace in wil_link_stats_write() in wil_link_stats_write()

On Wed, Jul 06, 2022 at 09:57:57AM +0300, Dan Carpenter wrote:
> This code has a check for "if (rc != len) {" so it will fail if the
> simple_write_to_buffer() does not completely fill the buffer. In
> particular it will fail if "*ppos != 0". Although this code works, it is
> more complicated than necessary. Just use strndup_user() instead.
>
> Signed-off-by: Dan Carpenter <[email protected]>

NAK. This one is buggy. strndup_user() is too strict. This will break
stuff.

regards,
dan carpenter