From 04da2daee383391954b34e7d0fe0281d75447d61 Mon Sep 17 00:00:00 2001
From: Mauro Carvalho Chehab <m.chehab@samsung.com>
Date: Wed, 3 Sep 2014 20:44:04 -0300
Subject: [PATCH] [media] ngene: properly handle __user ptr
Sparse is complaining about ngene's bad usage of a __user ptr:
>> drivers/media/pci/ngene/ngene-dvb.c:62:48: sparse: incorrect type in argument 2 (different address spaces)
drivers/media/pci/ngene/ngene-dvb.c:62:48: expected unsigned char const [usertype] *buf
drivers/media/pci/ngene/ngene-dvb.c:62:48: got char const [noderef] <asn:1>*buf
As this is intercepting a .write() file ops, we can't just memcpy. We need to use
copy_from_user.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
---
drivers/media/dvb-core/dvb_ringbuffer.c | 26 +++++++++++++++++++++++++
drivers/media/dvb-core/dvb_ringbuffer.h | 2 ++
drivers/media/pci/ngene/ngene-dvb.c | 2 +-
3 files changed, 29 insertions(+), 1 deletion(-)
diff --git a/drivers/media/dvb-core/dvb_ringbuffer.c b/drivers/media/dvb-core/dvb_ringbuffer.c
index a5712cd7c65f..1100e98a7b1d 100644
--- a/drivers/media/dvb-core/dvb_ringbuffer.c
+++ b/drivers/media/dvb-core/dvb_ringbuffer.c
@@ -166,6 +166,31 @@ ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf, size_t
return len;
}
+ssize_t dvb_ringbuffer_write_user(struct dvb_ringbuffer *rbuf,
+ const u8 __user *buf, size_t len)
+{
+ int status;
+ size_t todo = len;
+ size_t split;
+
+ split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0;
+
+ if (split > 0) {
+ status = copy_from_user(rbuf->data+rbuf->pwrite, buf, split);
+ if (status)
+ return len - todo;
+ buf += split;
+ todo -= split;
+ rbuf->pwrite = 0;
+ }
+ status = copy_from_user(rbuf->data+rbuf->pwrite, buf, todo);
+ if (status)
+ return len - todo;
+ rbuf->pwrite = (rbuf->pwrite + todo) % rbuf->size;
+
+ return len;
+}
+
ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf, size_t len)
{
int status;
@@ -297,3 +322,4 @@ EXPORT_SYMBOL(dvb_ringbuffer_flush_spinlock_wakeup);
EXPORT_SYMBOL(dvb_ringbuffer_read_user);
EXPORT_SYMBOL(dvb_ringbuffer_read);
EXPORT_SYMBOL(dvb_ringbuffer_write);
+EXPORT_SYMBOL(dvb_ringbuffer_write_user);
diff --git a/drivers/media/dvb-core/dvb_ringbuffer.h b/drivers/media/dvb-core/dvb_ringbuffer.h
index 41f04dae69b6..9e1e11b7c39c 100644
--- a/drivers/media/dvb-core/dvb_ringbuffer.h
+++ b/drivers/media/dvb-core/dvb_ringbuffer.h
@@ -133,6 +133,8 @@ extern void dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf,
*/
extern ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf,
size_t len);
+extern ssize_t dvb_ringbuffer_write_user(struct dvb_ringbuffer *rbuf,
+ const u8 __user *buf, size_t len);
/**
diff --git a/drivers/media/pci/ngene/ngene-dvb.c b/drivers/media/pci/ngene/ngene-dvb.c
index a8a4045f66d7..59bb2858c8d0 100644
--- a/drivers/media/pci/ngene/ngene-dvb.c
+++ b/drivers/media/pci/ngene/ngene-dvb.c
@@ -59,7 +59,7 @@ static ssize_t ts_write(struct file *file, const char __user *buf,
(&dev->tsout_rbuf) >= count) < 0)
return 0;
- dvb_ringbuffer_write(&dev->tsout_rbuf, buf, count);
+ dvb_ringbuffer_write_user(&dev->tsout_rbuf, buf, count);
return count;
}