linux-toradex.git/drivers/firewire/core-cdev.c, branch v6.3-rc3

firewire: cdev: use single object to dispatch event for request to IEC 61883-1 FCP region

2023-01-23T08:17:46+00:00

The core function always passes the data of request to the callback of
listener in any case. Additionally, the listener can maintain the lifetime
of data by reference count. In character device, no need to duplicate the
payload of request anymore to copy it to user space.

This commit extends the lifetime of data to obsolete duplication of
payload for request in character device.

Signed-off-by: Takashi Sakamoto 
Link: https://lore.kernel.org/r/20230120090344.296451-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai

firewire: cdev: obsolete NULL check to detect IEC 61883-1 FCP region

2023-01-23T08:17:44+00:00

In the character device, the listener to address space should distinguish
whether the request is to IEC 61883-1 FCP region or not. The user space
application needs to access to the object of request in enough later by
read(2), while the core function releases the object of request in the FCP
case after completing the callback to handler.

The handler guarantees the access safe by some way. It's done by
duplication of the object after NULL check to the request, since core
function passes NULL in the FCP case. It's inconvenient since the object
of request includes some helpful information. It's better to add another
way to check whether the request is to FCP region or not.

Conveniently the file of transaction layer includes local implementation
for the purpose. This commit moves it to module local file and use it
instead of the NULL check, then the result of check is stored to
per-client data for the inbound transaction so that the result can be
referred by later to release the data.

Signed-off-by: Takashi Sakamoto 
Link: https://lore.kernel.org/r/20230120090344.296451-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai

firewire: core: use kref structure to maintain lifetime of data for fw_request structure

2023-01-23T08:17:43+00:00

Developers have acknowledged that maintenance of lifetime for
fw_transaction structure is effective when handling asynchronous
transaction to IEC 61883-1 FCP region, since the core function allows
multiples listeners to the region. Some of them needs to access to the
payload of request in process context after the callback to listener,
while the core function releases the object for the structure just after
completing the callbacks to listeners.

One of the listeners is character device. Current implementation of the
character device duplicates the object for the payload of transaction,
while it's a cost in kernel memory consumption. The lifetime management
can reduce it.

The typical way to maintain the lifetime is reference count. This commit
uses kref structure as a first step for the purpose.

Signed-off-by: Takashi Sakamoto 
Link: https://lore.kernel.org/r/20230120090344.296451-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai

firewire: fix memory leak for payload of request subaction to IEC 61883-1 FCP region

2023-01-17T17:09:21+00:00

This patch is fix for Linux kernel v2.6.33 or later.

For request subaction to IEC 61883-1 FCP region, Linux FireWire subsystem
have had an issue of use-after-free. The subsystem allows multiple
user space listeners to the region, while data of the payload was likely
released before the listeners execute read(2) to access to it for copying
to user space.

The issue was fixed by a commit 281e20323ab7 ("firewire: core: fix
use-after-free regression in FCP handler"). The object of payload is
duplicated in kernel space for each listener. When the listener executes
ioctl(2) with FW_CDEV_IOC_SEND_RESPONSE request, the object is going to
be released.

However, it causes memory leak since the commit relies on call of
release_request() in drivers/firewire/core-cdev.c. Against the
expectation, the function is never called due to the design of
release_client_resource(). The function delegates release task
to caller when called with non-NULL fourth argument. The implementation
of ioctl_send_response() is the case. It should release the object
explicitly.

This commit fixes the bug.

Cc: 
Fixes: 281e20323ab7 ("firewire: core: fix use-after-free regression in FCP handler")
Signed-off-by: Takashi Sakamoto 
Link: https://lore.kernel.org/r/20230117090610.93792-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai

firewire: cdev: fix potential leak of kernel stack due to uninitialized value

2022-06-17T08:43:11+00:00

Recent change brings potential leak of value on kernel stack to userspace
due to uninitialized value.

This commit fixes the bug.

Reported-by: Dan Carpenter 
Fixes: baa914cd81f5 ("firewire: add kernel API to access CYCLE_TIME register")
Signed-off-by: Takashi Sakamoto 
Link: https://lore.kernel.org/r/20220512112037.103142-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai

Merge branch 'for-linus' into for-next

2022-05-23T05:48:27+00:00

Merge for 5.18-rc1

Signed-off-by: Takashi Iwai

firewire: fix potential uaf in outbound_phy_packet_callback()

2022-04-25T06:01:07+00:00

&e->event and e point to the same address, and &e->event could
be freed in queue_event. So there is a potential uaf issue if
we dereference e after calling queue_event(). Fix this by adding
a temporary variable to maintain e->client in advance, this can
avoid the potential uaf issue.

Cc: 
Signed-off-by: Chengfeng Ye 
Signed-off-by: Takashi Sakamoto 
Link: https://lore.kernel.org/r/20220409041243.603210-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai

firewire: add kernel API to access CYCLE_TIME register

2022-04-05T16:23:04+00:00

1394 OHCI specification defined Isochronous Cycle Timer Register to get
value of CYCLE_TIME register defined by IEEE 1394 for CSR architecture
defined by ISO/IEC 13213. Unit driver can calculate packet time by
compute with the value of CYCLE_TIME and timeStamp field in descriptor
of each isochronous and asynchronous context. The resolution of CYCLE_TIME
is 49.576 MHz, while the one of timeStamp is 8,000 Hz.

Current implementation of Linux FireWire subsystem allows the driver to
get the value of CYCLE_TIMER CSR register by transaction service. The
transaction service has overhead in regard of access to MMIO register.

This commit adds kernel API for unit driver to access the register
directly.

Signed-off-by: Takashi Sakamoto 
Link: https://lore.kernel.org/r/20220405072221.226217-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai

firewire: Remove function callback casts

2021-11-01T18:44:26+00:00

In 1394 OHCI specification, Isochronous Receive DMA context has several
modes. One of mode is 'BufferFill' and Linux FireWire stack uses it to
receive isochronous packets for multiple isochronous channel as
FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL.

The mode is not used by in-kernel driver, while it's available for
userspace. The character device driver in firewire-core includes
cast of function callback for the mode since the type of callback
function is different from the other modes. The case is inconvenient
to effort of Control Flow Integrity builds due to
-Wcast-function-type warning.

This commit removes the cast. A static helper function is newly added
to initialize isochronous context for the mode. The helper function
arranges isochronous context to assign specific callback function
after call of existent kernel API. It's noticeable that the number of
isochronous channel, speed, and the size of header are not required for
the mode. The helper function is used for the mode by character device
driver instead of direct call of existent kernel API.

The same goal can be achieved (in the ioctl_create_iso_context function)
without this helper function as follows:
- Call the fw_iso_context_create function passing NULL to the callback
  parameter.
- Then setting the context->callback.sc or context->callback.mc
  variables based on the a->type value.

However using the helper function created in this patch makes code more
clear and declarative. This way avoid the call to a function with one
purpose to achieved another one.

Co-developed-by: Takashi Sakamoto 
Signed-off-by: Takashi Sakamoto 
Co-developed-by: Stefan Richter 
Signed-off-by: Stefan Richter 
Signed-off-by: Oscar Carter 
Reviewed-by: Takashi Sakamoto 
Testeb-by: Takashi Sakamoto
Signed-off-by: Gustavo A. R. Silva

firewire: ohci: Replace zero-length array with flexible-array

2020-06-16T04:08:31+00:00

There is a regular need in the kernel to provide a way to declare having a
dynamically sized set of trailing elements in a structure. Kernel code should
always use “flexible array members”[1] for these cases. The older style of
one-element or zero-length arrays should no longer be used[2].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://github.com/KSPP/linux/issues/21

Signed-off-by: Gustavo A. R. Silva