Date: Thu, 11 Aug 2011 00:06:04 +0200
commit 9c1176b6a28850703ea6e3a0f0c703f6d6c61cd3 upstream.
Clemens points out that we need to use compat_ptr() in order to safely
cast from u64 to addresses of a 32-bit usermode client.
Before, our conversion went wrong
- in practice if the client cast from pointer to integer such that
sign-extension happened, (libraw1394 and libdc1394 at least were not
doing that, IOW were not affected)
or
- in theory on s390 (which doesn't have FireWire though) and on the
tile architecture, regardless of what the client does.
The bug would usually be observed as the initial get_info ioctl failing
with "Bad address" (EFAULT).
Reported-by: Carl Karsten <[email protected]>
Reported-by: Clemens Ladisch <[email protected]>
Signed-off-by: Stefan Richter <[email protected]>
---
ABI compat fix.
This fix was released in 3.1 and should have been marked for stable backmerge.
Please add it to the 3.0-longterm series.
drivers/firewire/core-cdev.c | 24 +++++++++++++++++++++---
1 files changed, 21 insertions(+), 3 deletions(-)
diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index e6ad3bb..4799393 100644
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -216,15 +216,33 @@ struct inbound_phy_packet_event {
struct fw_cdev_event_phy_packet phy_packet;
};
-static inline void __user *u64_to_uptr(__u64 value)
+#ifdef CONFIG_COMPAT
+static void __user *u64_to_uptr(u64 value)
+{
+ if (is_compat_task())
+ return compat_ptr(value);
+ else
+ return (void __user *)(unsigned long)value;
+}
+
+static u64 uptr_to_u64(void __user *ptr)
+{
+ if (is_compat_task())
+ return ptr_to_compat(ptr);
+ else
+ return (u64)(unsigned long)ptr;
+}
+#else
+static inline void __user *u64_to_uptr(u64 value)
{
return (void __user *)(unsigned long)value;
}
-static inline __u64 uptr_to_u64(void __user *ptr)
+static inline u64 uptr_to_u64(void __user *ptr)
{
- return (__u64)(unsigned long)ptr;
+ return (u64)(unsigned long)ptr;
}
+#endif /* CONFIG_COMPAT */
static int fw_device_op_open(struct inode *inode, struct file *file)
{
--
1.7.3.4
--
Stefan Richter
-=====-===-- --== -==-=
http://arcgraph.de/sr/
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