linux-stable.git/drivers/block, branch linux-3.16.y

floppy: check FDC index for errors before assigning it

2020-04-28T18:03:42+00:00

commit 2e90ca68b0d2f5548804f22f0dd61145516171e3 upstream.

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 
Cc: Willy Tarreau 
Cc: Dan Carpenter 
Signed-off-by: Linus Torvalds 
Signed-off-by: Ben Hutchings

xen/blkback: Avoid unmapping unmapped grant pages

2020-02-11T20:03:54+00:00

commit f9bd84a8a845d82f9b5a081a7ae68c98a11d2e84 upstream.

For each I/O request, blkback first maps the foreign pages for the
request to its local pages.  If an allocation of a local page for the
mapping fails, it should unmap every mapping already made for the
request.

However, blkback's handling mechanism for the allocation failure does
not mark the remaining foreign pages as unmapped.  Therefore, the unmap
function merely tries to unmap every valid grant page for the request,
including the pages not mapped due to the allocation failure.  On a
system that fails the allocation frequently, this problem leads to
following kernel crash.

  [  372.012538] BUG: unable to handle kernel NULL pointer dereference at 0000000000000001
  [  372.012546] IP: [] gnttab_unmap_refs.part.7+0x1c/0x40
  [  372.012557] PGD 16f3e9067 PUD 16426e067 PMD 0
  [  372.012562] Oops: 0002 [#1] SMP
  [  372.012566] Modules linked in: act_police sch_ingress cls_u32
  ...
  [  372.012746] Call Trace:
  [  372.012752]  [] gnttab_unmap_refs+0x34/0x40
  [  372.012759]  [] xen_blkbk_unmap+0x83/0x150 [xen_blkback]
  ...
  [  372.012802]  [] dispatch_rw_block_io+0x970/0x980 [xen_blkback]
  ...
  Decompressing Linux... Parsing ELF... done.
  Booting the kernel.
  [    0.000000] Initializing cgroup subsys cpuset

This commit fixes this problem by marking the grant pages of the given
request that didn't mapped due to the allocation failure as invalid.

Fixes: c6cc142dac52 ("xen-blkback: use balloon pages for all mappings")

Reviewed-by: David Woodhouse 
Reviewed-by: Maximilian Heyne 
Reviewed-by: Paul Durrant 
Reviewed-by: Roger Pau Monné 
Signed-off-by: SeongJae Park 
Signed-off-by: Jens Axboe 
Signed-off-by: Ben Hutchings

block: drbd: remove a stray unlock in __drbd_send_protocol()

2019-12-19T15:58:58+00:00

commit 8e9c523016cf9983b295e4bc659183d1fa6ef8e0 upstream.

There are two callers of this function and they both unlock the mutex so
this ends up being a double unlock.

Fixes: 44ed167da748 ("drbd: rcu_read_lock() and rcu_dereference() for tconn->net_conf")
Signed-off-by: Dan Carpenter 
Signed-off-by: Jens Axboe 
Signed-off-by: Ben Hutchings

floppy: fix out-of-bounds read in copy_buffer

2019-08-13T11:39:27+00:00

commit da99466ac243f15fbba65bd261bfc75ffa1532b6 upstream.

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 
Tested-by: Willy Tarreau 
Signed-off-by: Linus Torvalds 
Signed-off-by: Ben Hutchings

floppy: fix invalid pointer dereference in drive_name

2019-08-13T11:39:26+00:00

commit 9b04609b784027968348796a18f601aed9db3789 upstream.

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 
Tested-by: Willy Tarreau 
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.16: Drop changes in compat_setdrvprm(), as compat
 ioctls go via fd_ioctl_locked() after translation in compat_ioctl.c.]
Signed-off-by: Ben Hutchings

floppy: fix out-of-bounds read in next_valid_format

2019-08-13T11:39:26+00:00

commit 5635f897ed83fd539df78e98ba69ee91592f9bb8 upstream.

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 
Tested-by: Willy Tarreau 
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.16: Drop changes in compat_setdrvprm(), as compat
 ioctls go via fd_ioctl_locked() after translation in compat_ioctl.c.]
Signed-off-by: Ben Hutchings

floppy: fix div-by-zero in setup_format_params

2019-08-13T11:39:26+00:00

commit f3554aeb991214cbfafd17d55e2bfddb50282e32 upstream.

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 
Tested-by: Willy Tarreau 
Signed-off-by: Linus Torvalds 
Signed-off-by: Ben Hutchings

xsysace: Fix error handling in ace_setup

2019-08-13T11:39:03+00:00

commit 47b16820c490149c2923e8474048f2c6e7557cab upstream.

If xace hardware reports a bad version number, the error handling code
in ace_setup() calls put_disk(), followed by queue cleanup. However, since
the disk data structure has the queue pointer set, put_disk() also
cleans and releases the queue. This results in blk_cleanup_queue()
accessing an already released data structure, which in turn may result
in a crash such as the following.

[   10.681671] BUG: Kernel NULL pointer dereference at 0x00000040
[   10.681826] Faulting instruction address: 0xc0431480
[   10.682072] Oops: Kernel access of bad area, sig: 11 [#1]
[   10.682251] BE PAGE_SIZE=4K PREEMPT Xilinx Virtex440
[   10.682387] Modules linked in:
[   10.682528] CPU: 0 PID: 1 Comm: swapper Tainted: G        W         5.0.0-rc6-next-20190218+ #2
[   10.682733] NIP:  c0431480 LR: c043147c CTR: c0422ad8
[   10.682863] REGS: cf82fbe0 TRAP: 0300   Tainted: G        W          (5.0.0-rc6-next-20190218+)
[   10.683065] MSR:  00029000   CR: 22000222  XER: 00000000
[   10.683236] DEAR: 00000040 ESR: 00000000
[   10.683236] GPR00: c043147c cf82fc90 cf82ccc0 00000000 00000000 00000000 00000002 00000000
[   10.683236] GPR08: 00000000 00000000 c04310bc 00000000 22000222 00000000 c0002c54 00000000
[   10.683236] GPR16: 00000000 00000001 c09aa39c c09021b0 c09021dc 00000007 c0a68c08 00000000
[   10.683236] GPR24: 00000001 ced6d400 ced6dcf0 c0815d9c 00000000 00000000 00000000 cedf0800
[   10.684331] NIP [c0431480] blk_mq_run_hw_queue+0x28/0x114
[   10.684473] LR [c043147c] blk_mq_run_hw_queue+0x24/0x114
[   10.684602] Call Trace:
[   10.684671] [cf82fc90] [c043147c] blk_mq_run_hw_queue+0x24/0x114 (unreliable)
[   10.684854] [cf82fcc0] [c04315bc] blk_mq_run_hw_queues+0x50/0x7c
[   10.685002] [cf82fce0] [c0422b24] blk_set_queue_dying+0x30/0x68
[   10.685154] [cf82fcf0] [c0423ec0] blk_cleanup_queue+0x34/0x14c
[   10.685306] [cf82fd10] [c054d73c] ace_probe+0x3dc/0x508
[   10.685445] [cf82fd50] [c052d740] platform_drv_probe+0x4c/0xb8
[   10.685592] [cf82fd70] [c052abb0] really_probe+0x20c/0x32c
[   10.685728] [cf82fda0] [c052ae58] driver_probe_device+0x68/0x464
[   10.685877] [cf82fdc0] [c052b500] device_driver_attach+0xb4/0xe4
[   10.686024] [cf82fde0] [c052b5dc] __driver_attach+0xac/0xfc
[   10.686161] [cf82fe00] [c0528428] bus_for_each_dev+0x80/0xc0
[   10.686314] [cf82fe30] [c0529b3c] bus_add_driver+0x144/0x234
[   10.686457] [cf82fe50] [c052c46c] driver_register+0x88/0x15c
[   10.686610] [cf82fe60] [c09de288] ace_init+0x4c/0xac
[   10.686742] [cf82fe80] [c0002730] do_one_initcall+0xac/0x330
[   10.686888] [cf82fee0] [c09aafd0] kernel_init_freeable+0x34c/0x478
[   10.687043] [cf82ff30] [c0002c6c] kernel_init+0x18/0x114
[   10.687188] [cf82ff40] [c000f2f0] ret_from_kernel_thread+0x14/0x1c
[   10.687349] Instruction dump:
[   10.687435] 3863ffd4 4bfffd70 9421ffd0 7c0802a6 93c10028 7c9e2378 93e1002c 38810008
[   10.687637] 7c7f1b78 90010034 4bfffc25 813f008c <81290040> 75290100 4182002c 80810008
[   10.688056] ---[ end trace 13c9ff51d41b9d40 ]---

Fix the problem by setting the disk queue pointer to NULL before calling
put_disk(). A more comprehensive fix might be to rearrange the code
to check the hardware version before initializing data structures,
but I don't know if this would have undesirable side effects, and
it would increase the complexity of backporting the fix to older kernels.

Fixes: 74489a91dd43a ("Add support for Xilinx SystemACE CompactFlash interface")
Acked-by: Michal Simek 
Signed-off-by: Guenter Roeck 
Signed-off-by: Jens Axboe 
Signed-off-by: Ben Hutchings

rbd: don't return 0 on unmap if RBD_DEV_FLAG_REMOVING is set

2019-05-02T20:41:17+00:00

commit 85f5a4d666fd9be73856ed16bb36c5af5b406b29 upstream.

There is a window between when RBD_DEV_FLAG_REMOVING is set and when
the device is removed from rbd_dev_list.  During this window, we set
"already" and return 0.

Returning 0 from write(2) can confuse userspace tools because
0 indicates that nothing was written.  In particular, "rbd unmap"
will retry the write multiple times a second:

  10:28:05.463299 write(4, "0", 1)        = 0
  10:28:05.463509 write(4, "0", 1)        = 0
  10:28:05.463720 write(4, "0", 1)        = 0
  10:28:05.463942 write(4, "0", 1)        = 0
  10:28:05.464155 write(4, "0", 1)        = 0

Signed-off-by: Ilya Dryomov 
Tested-by: Dongsheng Yang 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

block/swim3: Fix -EBUSY error when re-opening device after unmount

2019-04-04T15:14:09+00:00

commit 296dcc40f2f2e402facf7cd26cf3f2c8f4b17d47 upstream.

When the block device is opened with FMODE_EXCL, ref_count is set to -1.
This value doesn't get reset when the device is closed which means the
device cannot be opened again. Fix this by checking for refcount <= 0
in the release method.

Reported-and-tested-by: Stan Johnson 
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Finn Thain 
Signed-off-by: Jens Axboe 
Signed-off-by: Ben Hutchings