Commit 6020d534 authored by Shayne Chen's avatar Shayne Chen Committed by Johannes Berg
Browse files

mac80211: fix incorrect strlen of .write in debugfs 



This fixes strlen mismatch problems happening in some .write callbacks
of debugfs.

When trying to configure airtime_flags in debugfs, an error appeared:
ash: write error: Invalid argument

The error is returned from kstrtou16() since a wrong length makes it
miss the real end of input string.  To fix this, use count as the string
length, and set proper end of string for a char buffer.

The debug print is shown - airtime_flags_write: count = 2, len = 8,
where the actual length is 2, but "len = strlen(buf)" gets 8.

Also cleanup the other similar cases for the sake of consistency.

Signed-off-by: default avatarSujuan Chen <sujuan.chen@mediatek.com>
Signed-off-by: default avatarRyder Lee <ryder.lee@mediatek.com>
Signed-off-by: default avatarShayne Chen <shayne.chen@mediatek.com>
Link: https://lore.kernel.org/r/20210112032028.7482-1-shayne.chen@mediatek.com


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent c2083e28

net/mac80211/debugfs.c

+20 −24
Original line number Diff line number Diff line
@@ -120,18 +120,17 @@ static ssize_t aqm_write(struct file *file, 
{

	struct ieee80211_local *local = file->private_data;

	char buf[100];

	size_t len;



	if (count > sizeof(buf))

	if (count >= sizeof(buf))

		return -EINVAL;



	if (copy_from_user(buf, user_buf, count))

		return -EFAULT;



	buf[sizeof(buf) - 1] = '\0';

	len = strlen(buf);

	if (len > 0 && buf[len-1] == '\n')

		buf[len-1] = 0;

	if (count && buf[count - 1] == '\n')

		buf[count - 1] = '\0';

	else

		buf[count] = '\0';



	if (sscanf(buf, "fq_limit %u", &local->fq.limit) == 1)

		return count;
@@ -177,18 +176,17 @@ static ssize_t airtime_flags_write(struct file *file, 
{

	struct ieee80211_local *local = file->private_data;

	char buf[16];

	size_t len;



	if (count > sizeof(buf))

	if (count >= sizeof(buf))

		return -EINVAL;



	if (copy_from_user(buf, user_buf, count))

		return -EFAULT;



	buf[sizeof(buf) - 1] = 0;

	len = strlen(buf);

	if (len > 0 && buf[len - 1] == '\n')

		buf[len - 1] = 0;

	if (count && buf[count - 1] == '\n')

		buf[count - 1] = '\0';

	else

		buf[count] = '\0';



	if (kstrtou16(buf, 0, &local->airtime_flags))

		return -EINVAL;
@@ -237,20 +235,19 @@ static ssize_t aql_txq_limit_write(struct file *file, 
{

	struct ieee80211_local *local = file->private_data;

	char buf[100];

	size_t len;

	u32 ac, q_limit_low, q_limit_high, q_limit_low_old, q_limit_high_old;

	struct sta_info *sta;



	if (count > sizeof(buf))

	if (count >= sizeof(buf))

		return -EINVAL;



	if (copy_from_user(buf, user_buf, count))

		return -EFAULT;



	buf[sizeof(buf) - 1] = 0;

	len = strlen(buf);

	if (len > 0 && buf[len - 1] == '\n')

		buf[len - 1] = 0;

	if (count && buf[count - 1] == '\n')

		buf[count - 1] = '\0';

	else

		buf[count] = '\0';



	if (sscanf(buf, "%u %u %u", &ac, &q_limit_low, &q_limit_high) != 3)

		return -EINVAL;
@@ -306,18 +303,17 @@ static ssize_t force_tx_status_write(struct file *file, 
{

	struct ieee80211_local *local = file->private_data;

	char buf[3];

	size_t len;



	if (count > sizeof(buf))

	if (count >= sizeof(buf))

		return -EINVAL;



	if (copy_from_user(buf, user_buf, count))

		return -EFAULT;



	buf[sizeof(buf) - 1] = '\0';

	len = strlen(buf);

	if (len > 0 && buf[len - 1] == '\n')

		buf[len - 1] = 0;

	if (count && buf[count - 1] == '\n')

		buf[count - 1] = '\0';

	else

		buf[count] = '\0';



	if (buf[0] == '0' && buf[1] == '\0')

		local->force_tx_status = 0;