kernel/linux.git/drivers/char/tpm/tpm-dev.c, branch v5.10.264

tpm: Make the TPM character devices non-seekable

2026-07-24T13:49:12+00:00

commit f20d61c22bcaf172d6790b6500e3838e532e71c8 upstream. The TPM character devices expose a sequential command/response interface, but their open handlers leave FMODE_PREAD and FMODE_PWRITE enabled. After a command leaves a response pending, pread(fd, buf, 16, 0x1400) passes 0x1400 as *off to tpm_common_read(). The transfer length is bounded by response_length, but the offset is used unchecked when forming data_buffer + *off. A sufficiently large offset therefore causes an out-of-bounds heap read through copy_to_user() and, if the copy succeeds, an out-of-bounds zero-write through the following memset(). Positional I/O does not provide coherent semantics for this interface. An arbitrary pread offset cannot represent how much of a response has been consumed sequentially. The write callback always stores a command at the start of data_buffer, while pwrite() does not update file->f_pos and can leave the sequential read cursor stale. Call nonseekable_open() from both open handlers. This removes FMODE_PREAD and FMODE_PWRITE, causing positional reads and writes to fail with -ESPIPE before reaching the TPM callbacks, and explicitly marks the files non-seekable. Normal read() and write() continue to use the existing sequential f_pos cursor, leaving the response state machine unchanged. Tested on Linux 6.12 with KASAN and a swtpm TPM2 device: - sequential partial reads returned the complete response - pread() and preadv() with offset 0x1400 returned -ESPIPE - pwrite() and pwritev() with offset zero returned -ESPIPE - the pending response remained intact after the rejected operations - a subsequent normal command/response cycle completed normally - no KASAN report was produced. Fixes: 9488585b21be ("tpm: add support for partial reads") Link: https://lore.kernel.org/all/20260710090217.191289-1-yong010301@gmail.com/ Cc: stable@vger.kernel.org Signed-off-by: Jaewon Yang Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441

2019-06-05T15:37:17+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation version 2 of the license extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 315 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Armijn Hemel Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de Signed-off-by: Greg Kroah-Hartman

tpm: add support for nonblocking operation

2018-10-05T10:47:33+00:00

Currently the TPM driver only supports blocking calls, which doesn't allow asynchronous IO operations to the TPM hardware. This patch changes it and adds support for nonblocking write and a new poll function to enable applications, which want to take advantage of this. Tested-by: Philip Tricca Signed-off-by: Tadeusz Struk Reviewed-by: Jarkko Sakkinen Signed-off--by: Jarkko Sakkinen

tpm: add ptr to the tpm_space struct to file_priv

2018-10-05T10:47:33+00:00

Add a ptr to struct tpm_space to the file_priv and consolidate of the write operations for the two interfaces. Signed-off-by: Tadeusz Struk Tested-by: Philip Tricca Reviewed-by: Jarkko Sakkinen Signed-off--by: Jarkko Sakkinen

tpm: split out tpm-dev.c into tpm-dev.c and tpm-common-dev.c

2017-04-03T19:46:01+00:00

Signed-off-by: James Bottomley Tested-by: Jarkko Sakkinen Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen

tpm: infrastructure for TPM spaces

2017-04-03T19:46:01+00:00

Added an ability to virtualize TPM commands into an isolated context that we call a TPM space because the word context is already heavily used in the TPM specification. Both the handle areas and bodies (where necessary) are virtualized. The mechanism works by adding a new parameter struct tpm_space to the tpm_transmit() function. This new structure contains the list of virtual handles and a buffer of page size (currently) for backing storage. When tpm_transmit() is called with a struct tpm_space instance it will execute the following sequence: 1. Take locks. 2. Load transient objects from the backing storage by using ContextLoad and map virtual handles to physical handles. 3. Perform the transaction. 4. Save transient objects to backing storage by using ContextSave and map resulting physical handle to virtual handle if there is such. This commit does not implement virtualization support for hmac and policy sessions. Signed-off-by: Jarkko Sakkinen Tested-by: James Bottomley Reviewed-by: James Bottomley

tpm: Begin the process to deprecate user_read_timer

2017-02-03T20:03:14+00:00

For a long time the cdev read/write interface had this strange idea that userspace had to read the result within 60 seconds otherwise it is discarded. Perhaps this made sense under some older locking regime, but in the modern kernel it is not required and is just dangerous. Since something may be relying on this, double the timeout and print a warning. We can remove the code in a few years, but this should be enough to prevent new users. Suggested-by: James Bottomley Signed-off-by: Jason Gunthorpe Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen

tpm: fix a race condition in tpm2_unseal_trusted()

2016-09-15T13:04:21+00:00

Unseal and load operations should be done as an atomic operation. This commit introduces unlocked tpm_transmit() so that tpm2_unseal_trusted() can do the locking by itself. Fixes: 0fe5480303a1 ("keys, trusted: seal/unseal with TPM 2.0 chips") Cc: stable@vger.kernel.org Signed-off-by: Jarkko Sakkinen Reviewed-by: Jason Gunthorpe

tpm: Provide strong locking for device removal

2016-06-25T14:26:35+00:00

Add a read/write semaphore around the ops function pointers so ops can be set to null when the driver un-registers. Previously the tpm core expected module locking to be enough to ensure that tpm_unregister could not be called during certain times, however that hasn't been sufficient for a long time. Introduce a read/write semaphore around 'ops' so the core can set it to null when unregistering. This provides a strong fence around the driver callbacks, guaranteeing to the driver that no callbacks are running or will run again. For now the ops_lock is placed very high in the call stack, it could be pushed down and made more granular in future if necessary. Signed-off-by: Jason Gunthorpe Reviewed-by: Stefan Berger Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen

tpm: Get rid of chip->pdev

2016-06-25T14:26:35+00:00

This is a hold over from before the struct device conversion. - All prints should be using &chip->dev, which is the Linux standard. This changes prints to use tpm0 as the device name, not the PnP/etc ID. - The few places involving sysfs/modules that really do need the parent just use chip->dev.parent instead - We no longer need to get_device(pdev) in any places since it is no longer used by any of the code. The kref on the parent is held by the device core during device_add and dropped in device_del Signed-off-by: Jason Gunthorpe Signed-off-by: Stefan Berger Tested-by: Stefan Berger Reviewed-by: Jarkko Sakkinen Tested-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen