linux-stable.git/drivers/nvmem/core.c, branch linux-4.9.y

nvmem: Fix shift-out-of-bound (UBSAN) with byte size cells

2021-10-27T07:33:58+00:00

commit 5d388fa01fa6eb310ac023a363a6cb216d9d8fe9 upstream.

If a cell has 'nbits' equal to a multiple of BITS_PER_BYTE the logic

 *p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);

will become undefined behavior because nbits modulo BITS_PER_BYTE is 0, and we
subtract one from that making a large number that is then shifted more than the
number of bits that fit into an unsigned long.

UBSAN reports this problem:

 UBSAN: shift-out-of-bounds in drivers/nvmem/core.c:1386:8
 shift exponent 64 is too large for 64-bit type 'unsigned long'
 CPU: 6 PID: 7 Comm: kworker/u16:0 Not tainted 5.15.0-rc3+ #9
 Hardware name: Google Lazor (rev3+) with KB Backlight (DT)
 Workqueue: events_unbound deferred_probe_work_func
 Call trace:
  dump_backtrace+0x0/0x170
  show_stack+0x24/0x30
  dump_stack_lvl+0x64/0x7c
  dump_stack+0x18/0x38
  ubsan_epilogue+0x10/0x54
  __ubsan_handle_shift_out_of_bounds+0x180/0x194
  __nvmem_cell_read+0x1ec/0x21c
  nvmem_cell_read+0x58/0x94
  nvmem_cell_read_variable_common+0x4c/0xb0
  nvmem_cell_read_variable_le_u32+0x40/0x100
  a6xx_gpu_init+0x170/0x2f4
  adreno_bind+0x174/0x284
  component_bind_all+0xf0/0x264
  msm_drm_bind+0x1d8/0x7a0
  try_to_bring_up_master+0x164/0x1ac
  __component_add+0xbc/0x13c
  component_add+0x20/0x2c
  dp_display_probe+0x340/0x384
  platform_probe+0xc0/0x100
  really_probe+0x110/0x304
  __driver_probe_device+0xb8/0x120
  driver_probe_device+0x4c/0xfc
  __device_attach_driver+0xb0/0x128
  bus_for_each_drv+0x90/0xdc
  __device_attach+0xc8/0x174
  device_initial_probe+0x20/0x2c
  bus_probe_device+0x40/0xa4
  deferred_probe_work_func+0x7c/0xb8
  process_one_work+0x128/0x21c
  process_scheduled_works+0x40/0x54
  worker_thread+0x1ec/0x2a8
  kthread+0x138/0x158
  ret_from_fork+0x10/0x20

Fix it by making sure there are any bits to mask out.

Fixes: 69aba7948cbe ("nvmem: Add a simple NVMEM framework for consumers")
Cc: Douglas Anderson 
Cc: stable@vger.kernel.org
Signed-off-by: Stephen Boyd 
Signed-off-by: Srinivas Kandagatla 
Link: https://lore.kernel.org/r/20211013124511.18726-1-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

nvmem: core: return error code instead of NULL from nvmem_device_get

2019-11-25T08:52:16+00:00

[ Upstream commit ca6ac25cecf0e740d7cc8e03e0ebbf8acbeca3df ]

nvmem_device_get() should return ERR_PTR() on error or valid pointer
on success, but one of the code path seems to return NULL, so fix it.

Reported-by: Niklas Cassel 
Signed-off-by: Srinivas Kandagatla 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

nvmem: Use the same permissions for eeprom as for nvmem

2019-09-21T05:14:08+00:00

commit e70d8b287301eb6d7c7761c6171c56af62110ea3 upstream.

The compatibility "eeprom" attribute is currently root-only no
matter what the configuration says. The "nvmem" attribute does
respect the setting of the root_only configuration bit, so do the
same for "eeprom".

Signed-off-by: Jean Delvare 
Fixes: b6c217ab9be6 ("nvmem: Add backwards compatibility support for older EEPROM drivers.")
Reviewed-by: Bartosz Golaszewski 
Cc: Andrew Lunn 
Cc: Srinivas Kandagatla 
Cc: Arnd Bergmann 
Link: https://lore.kernel.org/r/20190728184255.563332e6@endymion
Signed-off-by: Greg Kroah-Hartman

nvmem: core: fix read buffer in place

2019-06-22T06:17:15+00:00

[ Upstream commit 2fe518fecb3a4727393be286db9804cd82ee2d91 ]

When the bit_offset in the cell is zero, the pointer to the msb will
not be properly initialized (ie, will still be pointing to the first
byte in the buffer).

This being the case, if there are bits to clear in the msb, those will
be left untouched while the mask will incorrectly clear bit positions
on the first byte.

This commit also makes sure that any byte unused in the cell is
cleared.

Signed-off-by: Jorge Ramirez-Ortiz 
Signed-off-by: Srinivas Kandagatla 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

nvmem: properly handle returned value nvmem_reg_read

2018-08-03T05:55:22+00:00

[ Upstream commit 50808bfcc14b854775a9f1d0abe3dac2babcf5c3 ]

Function nvmem_reg_read can return a non zero value indicating an error.
This returned value must be read and error propagated to
nvmem_cell_prepare_write_buffer. Silence the following gcc warning (W=1):

drivers/nvmem/core.c:1093:9: warning: variable 'rc' set but
 not used [-Wunused-but-set-variable]

Signed-off-by: Mathieu Malaterre 
Signed-off-by: Srinivas Kandagatla 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

nvmem: core: fix leaks on registration errors

2017-07-21T05:42:22+00:00

commit 3360acdf839170b612f5b212539694c20e3f16d0 upstream.

Make sure to deregister and release the nvmem device and underlying
memory on registration errors.

Note that the private data must be freed using put_device() once the
struct device has been initialised.

Also note that there's a related reference leak in the deregistration
function as reported by Mika Westerberg which is being fixed separately.

Fixes: b6c217ab9be6 ("nvmem: Add backwards compatibility support for older EEPROM drivers.")
Fixes: eace75cfdcf7 ("nvmem: Add a simple NVMEM framework for nvmem providers")
Cc: Andrew Lunn 
Cc: Srinivas Kandagatla 
Cc: Mika Westerberg 
Signed-off-by: Johan Hovold 
Acked-by: Andrey Smirnov 
Signed-off-by: Srinivas Kandagatla 
Signed-off-by: Greg Kroah-Hartman

remove lots of IS_ERR_VALUE abuses

2016-05-27T22:26:11+00:00

Most users of IS_ERR_VALUE() in the kernel are wrong, as they
pass an 'int' into a function that takes an 'unsigned long'
argument. This happens to work because the type is sign-extended
on 64-bit architectures before it gets converted into an
unsigned type.

However, anything that passes an 'unsigned short' or 'unsigned int'
argument into IS_ERR_VALUE() is guaranteed to be broken, as are
8-bit integers and types that are wider than 'unsigned long'.

Andrzej Hajda has already fixed a lot of the worst abusers that
were causing actual bugs, but it would be nice to prevent any
users that are not passing 'unsigned long' arguments.

This patch changes all users of IS_ERR_VALUE() that I could find
on 32-bit ARM randconfig builds and x86 allmodconfig. For the
moment, this doesn't change the definition of IS_ERR_VALUE()
because there are probably still architecture specific users
elsewhere.

Almost all the warnings I got are for files that are better off
using 'if (err)' or 'if (err < 0)'.
The only legitimate user I could find that we get a warning for
is the (32-bit only) freescale fman driver, so I did not remove
the IS_ERR_VALUE() there but changed the type to 'unsigned long'.
For 9pfs, I just worked around one user whose calling conventions
are so obscure that I did not dare change the behavior.

I was using this definition for testing:

 #define IS_ERR_VALUE(x) ((unsigned long*)NULL == (typeof (x)*)NULL && \
       unlikely((unsigned long long)(x) >= (unsigned long long)(typeof(x))-MAX_ERRNO))

which ends up making all 16-bit or wider types work correctly with
the most plausible interpretation of what IS_ERR_VALUE() was supposed
to return according to its users, but also causes a compile-time
warning for any users that do not pass an 'unsigned long' argument.

I suggested this approach earlier this year, but back then we ended
up deciding to just fix the users that are obviously broken. After
the initial warning that caused me to get involved in the discussion
(fs/gfs2/dir.c) showed up again in the mainline kernel, Linus
asked me to send the whole thing again.

[ Updated the 9p parts as per Al Viro  - Linus ]

Signed-off-by: Arnd Bergmann 
Cc: Andrzej Hajda 
Cc: Andrew Morton 
Link: https://lkml.org/lkml/2016/1/7/363
Link: https://lkml.org/lkml/2016/5/27/486
Acked-by: Srinivas Kandagatla  # For nvmem part
Signed-off-by: Linus Torvalds

nvmem: core: remove regmap dependency

2016-05-01T21:01:00+00:00

nvmem uses regmap_raw_read/write apis to read/write data from providers,
regmap raw apis stopped working with recent kernels which removed raw
accessors on mmio bus. This resulted in broken nvmem for providers
which are based on regmap mmio bus. This issue can be fixed temporarly
by moving to other regmap apis, but we might hit same issue in future.
Moving to interfaces based on read/write callbacks from providers would
be more robust.

This patch removes regmap dependency from nvmem and introduces
read/write callbacks from the providers.

Without this patch nvmem providers like qfprom based on regmap mmio
bus would not work.

Reported-by: Rajendra Nayak 
Signed-off-by: Srinivas Kandagatla 
Signed-off-by: Greg Kroah-Hartman

nvmem: Add backwards compatibility support for older EEPROM drivers.

2016-03-02T00:55:48+00:00

Older drivers made an 'eeprom' file available in the /sys device
directory. Have the NVMEM core provide this to retain backwards
compatibility.

Signed-off-by: Andrew Lunn 
Acked-by: Srinivas Kandagatla 
Signed-off-by: Greg Kroah-Hartman

nvmem: Add flag to export NVMEM to root only

2016-03-02T00:55:48+00:00

Legacy AT24, AT25 EEPROMs are exported in sys so that only root can
read the contents. The EEPROMs may contain sensitive information. Add
a flag so the provide can indicate that NVMEM should also restrict
access to root only.

Signed-off-by: Andrew Lunn 
Acked-by: Srinivas Kandagatla 
Signed-off-by: Greg Kroah-Hartman