From: Stefan Richter Date: Wed, 10 Aug 2011 22:06:04 +0000 (+0200) Subject: firewire: cdev: fix 32 bit userland on 64 bit kernel compat corner cases X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=9c1176b6a28850703ea6e3a0f0c703f6d6c61cd3;p=mv-sheeva.git firewire: cdev: fix 32 bit userland on 64 bit kernel compat corner cases 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 Reported-by: Clemens Ladisch Signed-off-by: Stefan Richter --- diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c index e6ad3bb6c1a..4799393247c 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) {