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: Sujuan Chen <[email protected]>
Signed-off-by: Ryder Lee <[email protected]>
Signed-off-by: Shayne Chen <[email protected]>
---
v2:
- fix r/w buffer OOB
- put buf[count] = '\0' to an else
---
net/mac80211/debugfs.c | 44 +++++++++++++++++++-----------------------
1 file changed, 20 insertions(+), 24 deletions(-)
diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index 48f144f107d5..9e723d943421 100644
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -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;
--
2.29.2