diff options
| author | Willy Tarreau <w@1wt.eu> | 2022-04-26 23:41:05 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-04-27 19:41:54 +0300 |
| commit | 233087ca063686964a53c829d547c7571e3f67bf (patch) | |
| tree | be1908213f2f31fc4369d783fbeb3831a4f65707 /drivers/block/Kconfig | |
| parent | 46cf2c613f4b10eb12f749207b0fd2c1bfae3088 (diff) | |
| download | linux-233087ca063686964a53c829d547c7571e3f67bf.tar.xz | |
floppy: disable FDRAWCMD by default
Minh Yuan reported a concurrency use-after-free issue in the floppy code
between raw_cmd_ioctl and seek_interrupt.
[ It turns out this has been around, and that others have reported the
KASAN splats over the years, but Minh Yuan had a reproducer for it and
so gets primary credit for reporting it for this fix - Linus ]
The problem is, this driver tends to break very easily and nowadays,
nobody is expected to use FDRAWCMD anyway since it was used to
manipulate non-standard formats. The risk of breaking the driver is
higher than the risk presented by this race, and accessing the device
requires privileges anyway.
Let's just add a config option to completely disable this ioctl and
leave it disabled by default. Distros shouldn't use it, and only those
running on antique hardware might need to enable it.
Link: https://lore.kernel.org/all/000000000000b71cdd05d703f6bf@google.com/
Link: https://lore.kernel.org/lkml/CAKcFiNC=MfYVW-Jt9A3=FPJpTwCD2PL_ULNCpsCVE5s8ZeBQgQ@mail.gmail.com
Link: https://lore.kernel.org/all/CAEAjamu1FRhz6StCe_55XY5s389ZP_xmCF69k987En+1z53=eg@mail.gmail.com
Reported-by: Minh Yuan <yuanmingbuaa@gmail.com>
Reported-by: syzbot+8e8958586909d62b6840@syzkaller.appspotmail.com
Reported-by: cruise k <cruise4k@gmail.com>
Reported-by: Kyungtae Kim <kt0755@gmail.com>
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Tested-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/block/Kconfig')
| -rw-r--r-- | drivers/block/Kconfig | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig index 519b6d38d4df..fdb81f2794cd 100644 --- a/drivers/block/Kconfig +++ b/drivers/block/Kconfig @@ -33,6 +33,22 @@ config BLK_DEV_FD To compile this driver as a module, choose M here: the module will be called floppy. +config BLK_DEV_FD_RAWCMD + bool "Support for raw floppy disk commands (DEPRECATED)" + depends on BLK_DEV_FD + help + If you want to use actual physical floppies and expect to do + special low-level hardware accesses to them (access and use + non-standard formats, for example), then enable this. + + Note that the code enabled by this option is rarely used and + might be unstable or insecure, and distros should not enable it. + + Note: FDRAWCMD is deprecated and will be removed from the kernel + in the near future. + + If unsure, say N. + config AMIGA_FLOPPY tristate "Amiga floppy support" depends on AMIGA |