[PATCH RFC 18/23] wifi: ipw2x00: let procfs copy in writes to the debug level

[Christian Brauner]

Implement ->proc_write_buf() so procfs copies in what is written before
it pins the entry, and parse the level from that copy. Writes larger
than PAGE_SIZE - 1 bytes fail with -EINVAL now, and a buffer that can't
be read fails with -EFAULT instead of looking like it was written.

Signed-off-by: Christian Brauner (Amutable) <brauner@xxxxxxxxxx>
---
 drivers/net/wireless/intel/ipw2x00/libipw_module.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/intel/ipw2x00/libipw_module.c b/drivers/net/wireless/intel/ipw2x00/libipw_module.c
index 15d9a5efb581..08cc0d7f57c1 100644
--- a/drivers/net/wireless/intel/ipw2x00/libipw_module.c
+++ b/drivers/net/wireless/intel/ipw2x00/libipw_module.c
@@ -216,14 +216,13 @@ static int debug_level_proc_show(struct seq_file *m, void *v)
 }
 
 static ssize_t debug_level_proc_write(struct file *file,
-		const char __user *buffer, size_t count, loff_t *pos)
+		char *buffer, size_t count, loff_t *pos)
 {
 	char buf[] = "0x00000000\n";
 	size_t len = min(sizeof(buf) - 1, count);
 	unsigned long val;
 
-	if (copy_from_user(buf, buffer, len))
-		return count;
+	memcpy(buf, buffer, len);
 	buf[len] = 0;
 	if (sscanf(buf, "%li", &val) != 1)
 		printk(KERN_INFO DRV_NAME
@@ -236,7 +235,7 @@ static ssize_t debug_level_proc_write(struct file *file,
 
 static const struct proc_ops debug_level_proc_ops = {
 	.proc_show	= debug_level_proc_show,
-	.proc_write	= debug_level_proc_write,
+	.proc_write_buf	= debug_level_proc_write,
 };
 #endif				/* CONFIG_LIBIPW_DEBUG */
 

-- 
2.53.0