kernel/linux.git/drivers/block/floppy.c, branch v4.19.16

floppy: fix race condition in __floppy_read_block_0()

2018-12-01T08:37:32+00:00

[ Upstream commit de7b75d82f70c5469675b99ad632983c50b6f7e7 ] LKP recently reported a hang at bootup in the floppy code: [ 245.678853] INFO: task mount:580 blocked for more than 120 seconds. [ 245.679906] Tainted: G T 4.19.0-rc6-00172-ga9f38e1 #1 [ 245.680959] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 245.682181] mount D 6372 580 1 0x00000004 [ 245.683023] Call Trace: [ 245.683425] __schedule+0x2df/0x570 [ 245.683975] schedule+0x2d/0x80 [ 245.684476] schedule_timeout+0x19d/0x330 [ 245.685090] ? wait_for_common+0xa5/0x170 [ 245.685735] wait_for_common+0xac/0x170 [ 245.686339] ? do_sched_yield+0x90/0x90 [ 245.686935] wait_for_completion+0x12/0x20 [ 245.687571] __floppy_read_block_0+0xfb/0x150 [ 245.688244] ? floppy_resume+0x40/0x40 [ 245.688844] floppy_revalidate+0x20f/0x240 [ 245.689486] check_disk_change+0x43/0x60 [ 245.690087] floppy_open+0x1ea/0x360 [ 245.690653] __blkdev_get+0xb4/0x4d0 [ 245.691212] ? blkdev_get+0x1db/0x370 [ 245.691777] blkdev_get+0x1f3/0x370 [ 245.692351] ? path_put+0x15/0x20 [ 245.692871] ? lookup_bdev+0x4b/0x90 [ 245.693539] blkdev_get_by_path+0x3d/0x80 [ 245.694165] mount_bdev+0x2a/0x190 [ 245.694695] squashfs_mount+0x10/0x20 [ 245.695271] ? squashfs_alloc_inode+0x30/0x30 [ 245.695960] mount_fs+0xf/0x90 [ 245.696451] vfs_kern_mount+0x43/0x130 [ 245.697036] do_mount+0x187/0xc40 [ 245.697563] ? memdup_user+0x28/0x50 [ 245.698124] ksys_mount+0x60/0xc0 [ 245.698639] sys_mount+0x19/0x20 [ 245.699167] do_int80_syscall_32+0x61/0x130 [ 245.699813] entry_INT80_32+0xc7/0xc7 showing that we never complete that read request. The reason is that the completion setup is racy - it initializes the completion event AFTER submitting the IO, which means that the IO could complete before/during the init. If it does, we are passing garbage to complete() and we may sleep forever waiting for the event to occur. Fixes: 7b7b68bba5ef ("floppy: bail out in open() if drive is not responding to block0 read") Reviewed-by: Omar Sandoval Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

floppy: Do not copy a kernel pointer to user memory in FDGETPRM ioctl

2018-09-20T15:09:48+00:00

The final field of a floppy_struct is the field "name", which is a pointer to a string in kernel memory. The kernel pointer should not be copied to user memory. The FDGETPRM ioctl copies a floppy_struct to user memory, including this "name" field. This pointer cannot be used by the user and it will leak a kernel address to user-space, which will reveal the location of kernel code and data and undermine KASLR protection. Model this code after the compat ioctl which copies the returned data to a previously cleared temporary structure on the stack (excluding the name pointer) and copy out to userspace from there. As we already have an inparam union with an appropriate member and that memory is already cleared even for read only calls make use of that as a temporary store. Based on an initial patch by Brian Belleville. CVE-2018-7755 Signed-off-by: Andy Whitcroft Broke up long line. Signed-off-by: Jens Axboe

block/floppy: remove redundant variable dflags

2018-07-09T15:07:52+00:00

Variable dflags is being assigned but is never used hence it is redundant and can be removed. Cleans up clang warning: warning: variable 'dflags' set but not used [-Wunused-but-set-variable] Signed-off-by: Colin Ian King Signed-off-by: Jens Axboe

block drivers/block: Use octal not symbolic permissions

2018-05-24T19:38:59+00:00

Convert the S_ symbolic permissions to their octal equivalents as using octal and not symbolic permissions is preferred by many as more readable. see: https://lkml.org/lkml/2016/8/2/1945 Done with automated conversion via: $ ./scripts/checkpatch.pl -f --types=SYMBOLIC_PERMS --fix-inplace Miscellanea: o Wrapped modified multi-line calls to a single line where appropriate o Realign modified multi-line calls to open parenthesis Signed-off-by: Joe Perches Signed-off-by: Jens Axboe

genhd: Rename get_disk() to get_disk_and_module()

2018-02-26T16:48:42+00:00

Rename get_disk() to get_disk_and_module() to make sure what the function does. It's not a great name but at least it is now clear that put_disk() is not it's counterpart. Signed-off-by: Jan Kara Signed-off-by: Jens Axboe

block/floppy: Convert callback to pass timer_list

2017-11-15T03:10:35+00:00

In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to passing in the timer pointer explicitly. Calculate the drive from the offset of the timer in the timer list. Cc: Jiri Kosina Cc: Jens Axboe Cc: Ming Lei Cc: Al Viro Cc: Geliang Tang Cc: Thomas Gleixner Signed-off-by: Kees Cook Signed-off-by: Jens Axboe

floppy: consolidate the dummy fd_cacheflush definition

2017-10-19T14:37:08+00:00

Only mips defines this helper, so remove all the other arch definitions. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

block: replace bi_bdev with a gendisk pointer and partitions index

2017-08-23T18:49:55+00:00

This way we don't need a block_device structure to submit I/O. The block_device has different life time rules from the gendisk and request_queue and is usually only available when the block device node is open. Other callers need to explicitly create one (e.g. the lightnvm passthrough code, or the new nvme multipathing code). For the actual I/O path all that we need is the gendisk, which exists once per block device. But given that the block layer also does partition remapping we additionally need a partition index, which is used for said remapping in generic_make_request. Note that all the block drivers generally want request_queue or sometimes the gendisk, so this removes a layer of indirection all over the stack. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

Merge branch 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2017-07-07T03:57:13+00:00

Pull misc compat stuff updates from Al Viro: "This part is basically untangling various compat stuff. Compat syscalls moved to their native counterparts, getting rid of quite a bit of double-copying and/or set_fs() uses. A lot of field-by-field copyin/copyout killed off. - kernel/compat.c is much closer to containing just the copyin/copyout of compat structs. Not all compat syscalls are gone from it yet, but it's getting there. - ipc/compat_mq.c killed off completely. - block/compat_ioctl.c cleaned up; floppy compat ioctls moved to drivers/block/floppy.c where they belong. Yes, there are several drivers that implement some of the same ioctls. Some are m68k and one is 32bit-only pmac. drivers/block/floppy.c is the only one in that bunch that can be built on biarch" * 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: mqueue: move compat syscalls to native ones usbdevfs: get rid of field-by-field copyin compat_hdio_ioctl: get rid of set_fs() take floppy compat ioctls to sodding floppy.c ipmi: get rid of field-by-field __get_user() ipmi: get COMPAT_IPMICTL_RECEIVE_MSG in sync with the native one rt_sigtimedwait(): move compat to native select: switch compat_{get,put}_fd_set() to compat_{get,put}_bitmap() put_compat_rusage(): switch to copy_to_user() sigpending(): move compat to native getrlimit()/setrlimit(): move compat to native times(2): move compat to native compat_{get,put}_bitmap(): use unsafe_{get,put}_user() fb_get_fscreeninfo(): don't bother with do_fb_ioctl() do_sigaltstack(): lift copying to/from userland into callers take compat_sys_old_getrlimit() to native syscall trim __ARCH_WANT_SYS_OLD_GETRLIMIT

take floppy compat ioctls to sodding floppy.c

2017-06-29T22:17:39+00:00

all other drivers recognizing those ioctls are very much *not* biarch. Signed-off-by: Al Viro