Use the block_size helper instead of open coding it. Also remove the
check for a 0 block size, as that can't happen.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since the switch of floppy driver to blk-mq, the contended (fdc_busy) case
in floppy_queue_rq() is not handled correctly.
In case we reach floppy_queue_rq() with fdc_busy set (i.e. with the floppy
locked due to another request still being in-flight), we put the request
on the list of requests and return BLK_STS_OK to the block core, without
actually scheduling delayed work / doing further processing of the
request. This means that processing of this request is postponed until
another request comes and passess uncontended.
Which in some cases might actually never happen and we keep waiting
indefinitely. The simple testcase is
for i in `seq 1 2000`; do echo -en $i '\r'; blkid --info /dev/fd0 2> /dev/null; done
run in quemu. That reliably causes blkid eventually indefinitely hanging
in __floppy_read_block_0() waiting for completion, as the BIO callback
never happens, and no further IO is ever submitted on the (non-existent)
floppy device. This was observed reliably on qemu-emulated device.
Fix that by not queuing the request in the contended case, and return
BLK_STS_RESOURCE instead, so that blk core handles the request
rescheduling and let it pass properly non-contended later.
Fixes: a9f38e1dec ("floppy: convert to blk-mq")
Cc: stable@vger.kernel.org
Tested-by: Libor Pechacek <lpechacek@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
UBSAN: array-index-out-of-bounds in drivers/block/floppy.c:1521:45
index 16 is out of range for type 'unsigned char [16]'
Call Trace:
...
setup_rw_floppy+0x5c3/0x7f0
floppy_ready+0x2be/0x13b0
process_one_work+0x2c1/0x5d0
worker_thread+0x56/0x5e0
kthread+0x122/0x170
ret_from_fork+0x35/0x40
From include/uapi/linux/fd.h:
struct floppy_raw_cmd {
...
unsigned char cmd_count;
unsigned char cmd[16];
unsigned char reply_count;
unsigned char reply[16];
...
}
This out-of-bounds access is intentional. The command in struct
floppy_raw_cmd may take up the space initially intended for the reply
and the reply count. It is needed for long 82078 commands such as
RESTORE, which takes 17 command bytes. Initial cmd size is not enough
and since struct setup_rw_floppy is a part of uapi we check that
cmd_count is in [0:16+1+16] in raw_cmd_copyin().
The patch adds union with original cmd,reply_count,reply fields and
fullcmd field of equivalent size. The cmd accesses are turned to
fullcmd where appropriate to suppress UBSAN warning.
Link: https://lore.kernel.org/r/20200501134416.72248-5-efremov@linux.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Denis Efremov <efremov@linux.com>
Use FD_RAW_CMD_SIZE, FD_RAW_REPLY_SIZE defines instead of magic numbers
for cmd & reply buffers of struct floppy_raw_cmd. Remove local to
floppy.c MAX_REPLIES define, as it is now FD_RAW_REPLY_SIZE.
FD_RAW_CMD_FULLSIZE added as we allow command to also fill reply_count
and reply fields.
Link: https://lore.kernel.org/r/20200501134416.72248-4-efremov@linux.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Denis Efremov <efremov@linux.com>
Use FD_AUTODETECT_SIZE for autodetect buffer size in struct
floppy_drive_params instead of a magic number.
Link: https://lore.kernel.org/r/20200501134416.72248-3-efremov@linux.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Denis Efremov <efremov@linux.com>
Remove pr_cont() and use print_hex_dump() in setup_DMA() to print the
contents of the cmd buffer.
Link: https://lore.kernel.org/r/20200501134416.72248-2-efremov@linux.com
Suggested-by: Joe Perches <joe@perches.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Denis Efremov <efremov@linux.com>
When called with a negative drive value, set_fdc() would stick to the
current fdc (which was assumed to reflect the current_drive's FDC). We
do not need this anymore as the last call place with a negative value
was just addressed. Let's make this function always set both current_fdc
and current_drive so that there's no more ambiguity. A few comments
stating this were added to a few non-obvious places.
Link: https://lore.kernel.org/r/20200410101904.14652-3-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
This macro equals -1 and is used as an alternative for current_drive when
calling reschedule_timeout(), which in turn needs to remap it. This only
adds obfuscation, let's simply use current_drive.
Link: https://lore.kernel.org/r/20200410101904.14652-2-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
In floppy_resume() we don't properly reinitialize all FDCs, instead
we reinitialize the current FDC once per available FDC because value
-1 is passed to user_reset_fdc(). Let's simply save the current drive
and properly reinitialize each FDC.
Link: https://lore.kernel.org/r/20200410101904.14652-1-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
There's no need to iterate on current_fdc in do_floppy_init() anymore,
in the first case it's only used as an array index to access fdc_state[],
so let's get rid of this confusing assignment. The second case is a bit
trickier because user_reset_fdc() needs to already know current_fdc when
called with drive==-1 due to this call chain:
user_reset_fdc()
lock_fdc()
set_fdc()
drive<0 ==> new_fdc = current_fdc
Note that current_drive is not used in this code part and may even not
match a unit belonging to current_fdc. Instead of passing -1 we can
simply pass the first drive of the FDC being initialized, which is even
cleaner as it will allow the function chain above to consistently assign
both variables.
Link: https://lore.kernel.org/r/20200410093023.14499-1-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
The locking in the driver is far from being obvious, with unlocking
automatically happening at end of operations scheduled by interrupt,
especially for the error paths where one does not necessarily expect
that such an interrupt may be triggered. Let's add a few comments
about what to expect at certain places to avoid misdetecting bugs
which are not.
Link: https://lore.kernel.org/r/20200331094054.24441-24-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Both floppy_grab_irq_and_dma() and floppy_release_irq_and_dma() used to
iterate on the global variable while setting up or freeing resources.
Now that they exclusively rely on functions which take the fdc as an
argument, so let's not touch the global one anymore.
Link: https://lore.kernel.org/r/20200331094054.24441-23-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.
Link: https://lore.kernel.org/r/20200331094054.24441-22-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Now the drive is passed in argument so that the function does not
use current_drive anymore.
Link: https://lore.kernel.org/r/20200331094054.24441-21-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Now the fdc and drive are passed in argument so that the function does
not use current_fdc nor current_drive anymore.
Link: https://lore.kernel.org/r/20200331094054.24441-20-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Now the fdc and drive are passed in argument so that the function does
not use current_fdc nor current_drive anymore.
Link: https://lore.kernel.org/r/20200331094054.24441-19-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.
Link: https://lore.kernel.org/r/20200331094054.24441-18-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.
It's worth noting that there's still a single raw_cmd pointer
specific to the current fdc. It may make sense to have one per
fdc in the future. In addition, cont->done() still relies on the
current drive and current raw_cmd.
Link: https://lore.kernel.org/r/20200331094054.24441-17-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.
Link: https://lore.kernel.org/r/20200331094054.24441-16-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.
It's worth noting that there's still a single reply_buffer[] which
will store the result for the current fdc. It may or may not make
sense to implement one buffer per fdc in the future.
Link: https://lore.kernel.org/r/20200331094054.24441-15-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.
Link: https://lore.kernel.org/r/20200331094054.24441-14-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.
Link: https://lore.kernel.org/r/20200331094054.24441-13-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.
Link: https://lore.kernel.org/r/20200331094054.24441-12-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.
Link: https://lore.kernel.org/r/20200331094054.24441-11-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Now the fdc and drive are passed in argument so that the function does
not use current_fdc nor current_drive anymore.
Link: https://lore.kernel.org/r/20200331094054.24441-10-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Currently we have architecture-specific fd_inb() and fd_outb() functions
or macros, taking just a port which is in fact made of a base address and
a register. The base address is FDC-specific and derived from the local or
global "fdc" variable through the FD_IOPORT macro used in the base address
calculation.
This change splits this by explicitly passing the FDC's base address and
the register separately to fd_outb() and fd_inb(). It affects the
following archs:
- x86, alpha, mips, powerpc, parisc, arm, m68k:
simple remap of port -> base+reg
- sparc32: use of reg only, since the base address was already masked
out and the FDC controller is known from a static struct.
- sparc64: like x86 for PCI, like sparc32 for 82077
Some archs use inline functions and others macros. This was not
unified in order to minimize the number of changes to review. For the
same reason checkpatch still spews a few warnings about things that
were already there before.
The parisc still uses hard-coded register values and could be cleaned up
by taking the register definitions.
The sparc per-controller inb/outb functions could further be refined
to explicitly take an FDC register instead of a port in argument but it
was not needed yet and may be cleaned later.
Link: https://lore.kernel.org/r/20200331094054.24441-2-w@1wt.eu
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Ian Molton <spyro@f2s.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: x86@kernel.org
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
This is done in order to remove the confusion that arises at some places
in the code where local variables or arguments shadow the global variable.
It is already visible that some places are a bit awkward and iterate over
the global variable, for the sole reason that they used to rely on it being
named "fdc" in order to get the correct address when using FD_DOR. These
ones are easy to spot by searching for "for (current_fdc...".
Some more cleanup is definitely possible. For example
"fdc_state[current_fdc].somefield" is used all over the code and would
probably be better with "fdc_state->somefield" with fdc_state being set
when current_fdc is assigned. This would require to pass the pointer to
the current state instead of the current_fdc to the I/O functions.
Link: https://lore.kernel.org/r/20200301195555.11154-7-w@1wt.eu
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
FDC registers FD_STATUS, FD_DATA, FD_DOR, FD_DIR and FD_DCR used to be
defined relative to FD_IOPORT, which is the FDC's base address, itself
a macro depending on the "fdc" local or global variable.
This patch changes this so that the register macros above now only
reference the address offset, and that the FDC's address is explicitly
passed in each call to fd_inb() and fd_outb(), thus removing the macro.
With this change there is no more implicit usage of the local/global
"fdc" variable.
One place in the ARM code used to check if the port was equal to FD_DOR,
this was changed to testing the register by applying a mask to the port,
as was already done in the sparc code.
There are still occurrences of fd_inb() and fd_outb() in the PARISC
code and these ones remain unaffected since they already used to work
with a base address and a register offset.
The sparc, m68k and parisc code could now be slightly cleaned up to
benefit from the macro definitions above instead of the equivalent
hard-coded values.
Link: https://lore.kernel.org/r/20200301195555.11154-6-w@1wt.eu
Cc: Ian Molton <spyro@f2s.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
These two functions replace fd_inb() and fd_outb() in that they take
the FDC in argument. This will ease the separation of the base address
and the port everywhere the code is used.
Link: https://lore.kernel.org/r/20200301195555.11154-5-w@1wt.eu
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Several macros were used to access reply_buffer[] at discrete positions
without making it obvious they were relying on this. These ones have
been replaced by their offset in the reply buffer to make these accesses
more obvious.
Link: https://lore.kernel.org/r/20200224212352.8640-11-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Various macros were used to access raw_cmd for R/W or format commands
without making it obvious that raw_cmd->cmd[] was used. Let's expand
the macros to make this more obvious.
Link: https://lore.kernel.org/r/20200224212352.8640-10-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This macro doesn't bring much value and only slightly obfuscates the
code by silently using global variable "current_drive", let's expand it.
Link: https://lore.kernel.org/r/20200224212352.8640-9-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This macro doesn't bring much value and only slightly obfuscates the
code by silently using global variable "current_drive", let's expand it.
Link: https://lore.kernel.org/r/20200224212352.8640-8-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This macro doesn't bring much value and only slightly obfuscates the
code by silently using global variable "current_drive", let's expand it.
Link: https://lore.kernel.org/r/20200224212352.8640-7-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This macro doesn't bring much value and only slightly obfuscates the
code by silently using local variable "drive", let's expand it.
Link: https://lore.kernel.org/r/20200224212352.8640-6-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This macro doesn't bring much value and only slightly obfuscates the
code by silently using local variable "drive", let's expand it.
Link: https://lore.kernel.org/r/20200224212352.8640-5-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This macro doesn't bring much value and only slightly obfuscates the
code by silently using local variable "drive", let's expand it.
Link: https://lore.kernel.org/r/20200224212352.8640-4-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This macro doesn't bring much value and only slightly obfuscates the
code by silently using local variable "drive", let's expand it.
Link: https://lore.kernel.org/r/20200224212352.8640-3-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Macro FDCS silently uses identifier "fdc" which may be either the
global one or a local one. Let's expand the macro to make this more
obvious.
Link: https://lore.kernel.org/r/20200224212352.8640-2-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Jordy Zomer reported a KASAN out-of-bounds read in the floppy driver in
wait_til_ready().
Which on the face of it can't happen, since as Willy Tarreau points out,
the function does no particular memory access. Except through the FDCS
macro, which just indexes a static allocation through teh current fdc,
which is always checked against N_FDC.
Except the checking happens after we've already assigned the value.
The floppy driver is a disgrace (a lot of it going back to my original
horrd "design"), and has no real maintainer. Nobody has the hardware,
and nobody really cares. But it still gets used in virtual environment
because it's one of those things that everybody supports.
The whole thing should be re-written, or at least parts of it should be
seriously cleaned up. The 'current fdc' index, which is used by the
FDCS macro, and which is often shadowed by a local 'fdc' variable, is a
prime example of how not to write code.
But because nobody has the hardware or the motivation, let's just fix up
the immediate problem with a nasty band-aid: test the fdc index before
actually assigning it to the static 'fdc' variable.
Reported-by: Jordy Zomer <jordy@simplyhacker.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Various block drivers implement the CDROMMULTISESSION,
CDROM_GET_CAPABILITY, and CDROMEJECT ioctl commands, relying on the
block layer to handle compat_ioctl mode for them.
Move this into the drivers directly as a preparation for simplifying
the block layer later.
When only integer arguments or no arguments are passed, the
same handler can be used for .ioctl and .compat_ioctl, and
when only pointer arguments are passed, the newly added
blkdev_compat_ptr_ioctl can be used.
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Merge floppy ioctl verification fixes from Denis Efremov.
This also marks the floppy driver as orphaned - it turns out that Jiri
no longer has working hardware.
Actual working physical floppy hardware is getting hard to find, and
while Willy was able to test this, I think the driver can be considered
pretty much dead from an actual hardware standpoint. The hardware that
is still sold seems to be mainly USB-based, which doesn't use this
legacy driver at all.
The old floppy disk controller is still emulated in various VM
environments, so the driver isn't going away, but let's see if anybody
is interested to step up to maintain it.
The lack of hardware also likely means that the ioctl range verification
fixes are probably mostly relevant to anybody using floppies in a
virtual environment. Which is probably also going away in favor of USB
storage emulation, but who knows.
Will Decon reviewed the patches but I'm not rebasing them just for that,
so I'll add a
Reviewed-by: Will Deacon <will@kernel.org>
here instead.
* floppy:
MAINTAINERS: mark floppy.c orphaned
floppy: fix out-of-bounds read in copy_buffer
floppy: fix invalid pointer dereference in drive_name
floppy: fix out-of-bounds read in next_valid_format
floppy: fix div-by-zero in setup_format_params
This fixes a global out-of-bounds read access in the copy_buffer
function of the floppy driver.
The FDDEFPRM ioctl allows one to set the geometry of a disk. The sect
and head fields (unsigned int) of the floppy_drive structure are used to
compute the max_sector (int) in the make_raw_rw_request function. It is
possible to overflow the max_sector. Next, max_sector is passed to the
copy_buffer function and used in one of the memcpy calls.
An unprivileged user could trigger the bug if the device is accessible,
but requires a floppy disk to be inserted.
The patch adds the check for the .sect * .head multiplication for not
overflowing in the set_geometry function.
The bug was found by syzkaller.
Signed-off-by: Denis Efremov <efremov@ispras.ru>
Tested-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This fixes the invalid pointer dereference in the drive_name function of
the floppy driver.
The native_format field of the struct floppy_drive_params is used as
floppy_type array index in the drive_name function. Thus, the field
should be checked the same way as the autodetect field.
To trigger the bug, one could use a value out of range and set the drive
parameters with the FDSETDRVPRM ioctl. Next, FDGETDRVTYP ioctl should
be used to call the drive_name. A floppy disk is not required to be
inserted.
CAP_SYS_ADMIN is required to call FDSETDRVPRM.
The patch adds the check for a value of the native_format field to be in
the '0 <= x < ARRAY_SIZE(floppy_type)' range of the floppy_type array
indices.
The bug was found by syzkaller.
Signed-off-by: Denis Efremov <efremov@ispras.ru>
Tested-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This fixes a global out-of-bounds read access in the next_valid_format
function of the floppy driver.
The values from autodetect field of the struct floppy_drive_params are
used as indices for the floppy_type array in the next_valid_format
function 'floppy_type[DP->autodetect[probed_format]].sect'.
To trigger the bug, one could use a value out of range and set the drive
parameters with the FDSETDRVPRM ioctl. A floppy disk is not required to
be inserted.
CAP_SYS_ADMIN is required to call FDSETDRVPRM.
The patch adds the check for values of the autodetect field to be in the
'0 <= x < ARRAY_SIZE(floppy_type)' range of the floppy_type array indices.
The bug was found by syzkaller.
Signed-off-by: Denis Efremov <efremov@ispras.ru>
Tested-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This fixes a divide by zero error in the setup_format_params function of
the floppy driver.
Two consecutive ioctls can trigger the bug: The first one should set the
drive geometry with such .sect and .rate values for the F_SECT_PER_TRACK
to become zero. Next, the floppy format operation should be called.
A floppy disk is not required to be inserted. An unprivileged user
could trigger the bug if the device is accessible.
The patch checks F_SECT_PER_TRACK for a non-zero value in the
set_geometry function. The proper check should involve a reasonable
upper limit for the .sect and .rate fields, but it could change the
UAPI.
The patch also checks F_SECT_PER_TRACK in the setup_format_params, and
cancels the formatting operation in case of zero.
The bug was found by syzkaller.
Signed-off-by: Denis Efremov <efremov@ispras.ru>
Tested-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rename the blockdev documentation files to ReST, add an
index for them and adjust in order to produce a nice html
output via the Sphinx build system.
The drbd sub-directory contains some graphs and data flows.
Add those too to the documentation.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
clang warns about unusual code in floppy.c that looks like it
was intended to be a bit mask operation, checking for a specific
bit in the UDP->cmos variable (FLOPPY1_TYPE expands to '4' on
ARM):
drivers/block/floppy.c:3902:17: error: use of logical '&&' with constant operand [-Werror,-Wconstant-logical-operand]
if (!UDP->cmos && FLOPPY1_TYPE)
^ ~~~~~~~~~~~~
drivers/block/floppy.c:3902:17: note: use '&' for a bitwise operation
if (!UDP->cmos && FLOPPY1_TYPE)
The check here is redundant anyway, if FLOPPY1_TYPE is zero, then
assigning it to a zero UDP->cmos field does not change anything,
so removing the extra check here has no effect other than shutting
up the warning.
On x86, this will no longer read a hardware register, as the
FLOPPY1_TYPE macro is not expanded if UDP->cmos is already
zero, but the result is the same.
Cc: Robert Elliott <elliott@hpe.com>
Cc: Keith Busch <kbusch@kernel.org>
Link: https://patchwork.kernel.org/patch/10851841/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
