kernel/linux.git/drivers/char, branch v6.12.80

Remove WARN_ALL_UNSEEDED_RANDOM kernel config option

2026-03-04T12:21:32+00:00

[ Upstream commit 7dff99b354601dd01829e1511711846e04340a69 ] This config option goes way back - it used to be an internal debug option to random.c (at that point called DEBUG_RANDOM_BOOT), then was renamed and exposed as a config option as CONFIG_WARN_UNSEEDED_RANDOM, and then further renamed to the current CONFIG_WARN_ALL_UNSEEDED_RANDOM. It was all done with the best of intentions: the more limited rate-limited reports were reporting some cases, but if you wanted to see all the gory details, you'd enable this "ALL" option. However, it turns out - perhaps not surprisingly - that when people don't care about and fix the first rate-limited cases, they most certainly don't care about any others either, and so warning about all of them isn't actually helping anything. And the non-ratelimited reporting causes problems, where well-meaning people enable debug options, but the excessive flood of messages that nobody cares about will hide actual real information when things go wrong. I just got a kernel bug report (which had nothing to do with randomness) where two thirds of the the truncated dmesg was just variations of random: get_random_u32 called from __get_random_u32_below+0x10/0x70 with crng_init=0 and in the process early boot messages had been lost (in addition to making the messages that _hadn't_ been lost harder to read). The proper way to find these things for the hypothetical developer that cares - if such a person exists - is almost certainly with boot time tracing. That gives you the option to get call graphs etc too, which is likely a requirement for fixing any problems anyway. See Documentation/trace/boottime-trace.rst for that option. And if we for some reason do want to re-introduce actual printing of these things, it will need to have some uniqueness filtering rather than this "just print it all" model. Fixes: cc1e127bfa95 ("random: remove ratelimiting for in-kernel unseeded randomness") Acked-by: Jason Donenfeld Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

ipmi: ipmb: initialise event handler read bytes

2026-03-04T12:21:31+00:00

[ Upstream commit 9f235ccecd03c436cb1683eac16b12f119e54aa9 ] IPMB doesn't use i2c reads, but the handler needs to set a value. Otherwise an i2c read will return an uninitialised value from the bus driver. Fixes: 63c4eb347164 ("ipmi:ipmb: Add initial support for IPMI over IPMB") Signed-off-by: Matt Johnston Message-ID: <20260113-ipmb-read-init-v1-1-a9cbce7b94e3@codeconstruct.com.au> Signed-off-by: Corey Minyard Signed-off-by: Sasha Levin

char: tpm: cr50: Remove IRQF_ONESHOT

2026-03-04T12:20:58+00:00

[ Upstream commit 1affd29ffbd50125a5492c6be1dbb1f04be18d4f ] Passing IRQF_ONESHOT ensures that the interrupt source is masked until the secondary (threaded) handler is done. If only a primary handler is used then the flag makes no sense because the interrupt can not fire (again) while its handler is running. The flag also prevents force-threading of the primary handler and the irq-core will warn about this. Remove IRQF_ONESHOT from irqflags. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Reviewed-by: Jarkko Sakkinen Link: https://patch.msgid.link/20260128095540.863589-10-bigeasy@linutronix.de Signed-off-by: Sasha Levin

hwrng: core - use RCU and work_struct to fix race condition

2026-03-04T12:19:40+00:00

[ Upstream commit cc2f39d6ac48e6e3cb2d6240bc0d6df839dd0828 ] Currently, hwrng_fill is not cleared until the hwrng_fillfn() thread exits. Since hwrng_unregister() reads hwrng_fill outside the rng_mutex lock, a concurrent hwrng_unregister() may call kthread_stop() again on the same task. Additionally, if hwrng_unregister() is called immediately after hwrng_register(), the stopped thread may have never been executed. Thus, hwrng_fill remains dirty even after hwrng_unregister() returns. In this case, subsequent calls to hwrng_register() will fail to start new threads, and hwrng_unregister() will call kthread_stop() on the same freed task. In both cases, a use-after-free occurs: refcount_t: addition on 0; use-after-free. WARNING: ... at lib/refcount.c:25 refcount_warn_saturate+0xec/0x1c0 Call Trace: kthread_stop+0x181/0x360 hwrng_unregister+0x288/0x380 virtrng_remove+0xe3/0x200 This patch fixes the race by protecting the global hwrng_fill pointer inside the rng_mutex lock, so that hwrng_fillfn() thread is stopped only once, and calls to kthread_run() and kthread_stop() are serialized with the lock held. To avoid deadlock in hwrng_fillfn() while being stopped with the lock held, we convert current_rng to RCU, so that get_current_rng() can read current_rng without holding the lock. To remove the lock from put_rng(), we also delay the actual cleanup into a work_struct. Since get_current_rng() no longer returns ERR_PTR values, the IS_ERR() checks are removed from its callers. With hwrng_fill protected by the rng_mutex lock, hwrng_fillfn() can no longer clear hwrng_fill itself. Therefore, if hwrng_fillfn() returns directly after current_rng is dropped, kthread_stop() would be called on a freed task_struct later. To fix this, hwrng_fillfn() calls schedule() now to keep the task alive until being stopped. The kthread_stop() call is also moved from hwrng_unregister() to drop_current_rng(), ensuring kthread_stop() is called on all possible paths where current_rng becomes NULL, so that the thread would not wait forever. Fixes: be4000bc4644 ("hwrng: create filler thread") Suggested-by: Herbert Xu Signed-off-by: Lianjie Wang Signed-off-by: Herbert Xu Signed-off-by: Sasha Levin

hwrng: core - Allow runtime disabling of the HW RNG

2026-03-04T12:19:40+00:00

[ Upstream commit e74b96d77da9eb5ee1b603c937c2adab5134a04b ] The HW RNG core allows for manual selection of which RNG device to use, but does not allow for no device to be enabled. It may be desirable to do this on systems with only a single suitable hardware RNG, where we need exclusive access to other functionality on this device. In particular when performing TPM firmware upgrades this lets us ensure the kernel does not try to access the device. Before: root@debian-qemu-efi:~# grep "" /sys/devices/virtual/misc/hw_random/rng_* /sys/devices/virtual/misc/hw_random/rng_available:tpm-rng-0 /sys/devices/virtual/misc/hw_random/rng_current:tpm-rng-0 /sys/devices/virtual/misc/hw_random/rng_quality:1024 /sys/devices/virtual/misc/hw_random/rng_selected:0 After: root@debian-qemu-efi:~# grep "" /sys/devices/virtual/misc/hw_random/rng_* /sys/devices/virtual/misc/hw_random/rng_available:tpm-rng-0 none /sys/devices/virtual/misc/hw_random/rng_current:tpm-rng-0 /sys/devices/virtual/misc/hw_random/rng_quality:1024 /sys/devices/virtual/misc/hw_random/rng_selected:0 root@debian-qemu-efi:~# echo none > /sys/devices/virtual/misc/hw_random/rng_current root@debian-qemu-efi:~# grep "" /sys/devices/virtual/misc/hw_random/rng_* /sys/devices/virtual/misc/hw_random/rng_available:tpm-rng-0 none /sys/devices/virtual/misc/hw_random/rng_current:none grep: /sys/devices/virtual/misc/hw_random/rng_quality: No such device /sys/devices/virtual/misc/hw_random/rng_selected:1 (Observe using bpftrace no calls to TPM being made) root@debian-qemu-efi:~# echo "" > /sys/devices/virtual/misc/hw_random/rng_current root@debian-qemu-efi:~# grep "" /sys/devices/virtual/misc/hw_random/rng_* /sys/devices/virtual/misc/hw_random/rng_available:tpm-rng-0 none /sys/devices/virtual/misc/hw_random/rng_current:tpm-rng-0 /sys/devices/virtual/misc/hw_random/rng_quality:1024 /sys/devices/virtual/misc/hw_random/rng_selected:0 (Observe using bpftrace that calls to the TPM resume) Signed-off-by: Jonathan McDowell Signed-off-by: Herbert Xu Stable-dep-of: cc2f39d6ac48 ("hwrng: core - use RCU and work_struct to fix race condition") Signed-off-by: Sasha Levin

tpm: st33zp24: Fix missing cleanup on get_burstcount() error

2026-03-04T12:19:24+00:00

[ Upstream commit 3e91b44c93ad2871f89fc2a98c5e4fe6ca5db3d9 ] get_burstcount() can return -EBUSY on timeout. When this happens, st33zp24_send() returns directly without releasing the locality acquired earlier. Use goto out_err to ensure proper cleanup when get_burstcount() fails. Fixes: bf38b8710892 ("tpm/tpm_i2c_stm_st33: Split tpm_i2c_tpm_st33 in 2 layers (core + phy)") Signed-off-by: Alper Ak Signed-off-by: Jarkko Sakkinen Signed-off-by: Sasha Levin

tpm: tpm_i2c_infineon: Fix locality leak on get_burstcount() failure

2026-03-04T12:19:24+00:00

[ Upstream commit bbd6e97c836cbeb9606d7b7e5dcf8a1d89525713 ] get_burstcount() can return -EBUSY on timeout. When this happens, the function returns directly without releasing the locality that was acquired at the beginning of tpm_tis_i2c_send(). Use goto out_err to ensure proper cleanup when get_burstcount() fails. Fixes: aad628c1d91a ("char/tpm: Add new driver for Infineon I2C TIS TPM") Signed-off-by: Alper Ak Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen Signed-off-by: Sasha Levin

tpm: Compare HMAC values in constant time

2026-01-30T09:28:44+00:00

[ Upstream commit 2c2615c8423890b5ef8e0a186b65607ef5fdeda1 ] In tpm_buf_check_hmac_response(), compare the HMAC values in constant time using crypto_memneq() instead of in variable time using memcmp(). This is worthwhile to follow best practices and to be consistent with MAC comparisons elsewhere in the kernel. However, in this driver the side channel seems to have been benign: the HMAC input data is guaranteed to always be unique, which makes the usual MAC forgery via timing side channel not possible. Specifically, the HMAC input data in tpm_buf_check_hmac_response() includes the "our_nonce" field, which was generated by the kernel earlier, remains under the control of the kernel, and is unique for each call to tpm_buf_check_hmac_response(). Signed-off-by: Eric Biggers Signed-off-by: Jarkko Sakkinen Stable-dep-of: 6342969dafbc ("keys/trusted_keys: fix handle passed to tpm_buf_append_name during unseal") Signed-off-by: Sasha Levin

tpm2-sessions: Fix out of range indexing in name_size

2026-01-17T15:31:29+00:00

commit 6e9722e9a7bfe1bbad649937c811076acf86e1fd upstream. 'name_size' does not have any range checks, and it just directly indexes with TPM_ALG_ID, which could lead into memory corruption at worst. Address the issue by only processing known values and returning -EINVAL for unrecognized values. Make also 'tpm_buf_append_name' and 'tpm_buf_fill_hmac_session' fallible so that errors are detected before causing any spurious TPM traffic. End also the authorization session on failure in both of the functions, as the session state would be then by definition corrupted. Cc: stable@vger.kernel.org # v6.10+ Fixes: 1085b8276bb4 ("tpm: Add the rest of the session HMAC API") Reviewed-by: Jonathan McDowell Signed-off-by: Jarkko Sakkinen Signed-off-by: Greg Kroah-Hartman

virtio_console: fix order of fields cols and rows

2026-01-11T14:25:21+00:00

commit 5326ab737a47278dbd16ed3ee7380b26c7056ddd upstream. According to section 5.3.6.2 (Multiport Device Operation) of the virtio spec(version 1.2) a control buffer with the event VIRTIO_CONSOLE_RESIZE is followed by a virtio_console_resize struct containing cols then rows. The kernel implements this the wrong way around (rows then cols) resulting in the two values being swapped. Signed-off-by: Maximilian Immanuel Brandtner Message-Id: <20250324144300.905535-1-maxbr@linux.ibm.com> Signed-off-by: Michael S. Tsirkin Cc: Filip Hejsek Signed-off-by: Greg Kroah-Hartman