CVE-2025-21845

Published Mar 12, 2025

Last updated 5 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: mtd: spi-nor: sst: Fix SST write failure 'commit 18bcb4aa54ea ("mtd: spi-nor: sst: Factor out common write operation to `sst_nor_write_data()`")' introduced a bug where only one byte of data is written, regardless of the number of bytes passed to sst_nor_write_data(), causing a kernel crash during the write operation. Ensure the correct number of bytes are written as passed to sst_nor_write_data(). Call trace: [ 57.400180] ------------[ cut here ]------------ [ 57.404842] While writing 2 byte written 1 bytes [ 57.409493] WARNING: CPU: 0 PID: 737 at drivers/mtd/spi-nor/sst.c:187 sst_nor_write_data+0x6c/0x74 [ 57.418464] Modules linked in: [ 57.421517] CPU: 0 UID: 0 PID: 737 Comm: mtd_debug Not tainted 6.12.0-g5ad04afd91f9 #30 [ 57.429517] Hardware name: Xilinx Versal A2197 Processor board revA - x-prc-02 revA (DT) [ 57.437600] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 57.444557] pc : sst_nor_write_data+0x6c/0x74 [ 57.448911] lr : sst_nor_write_data+0x6c/0x74 [ 57.453264] sp : ffff80008232bb40 [ 57.456570] x29: ffff80008232bb40 x28: 0000000000010000 x27: 0000000000000001 [ 57.463708] x26: 000000000000ffff x25: 0000000000000000 x24: 0000000000000000 [ 57.470843] x23: 0000000000010000 x22: ffff80008232bbf0 x21: ffff000816230000 [ 57.477978] x20: ffff0008056c0080 x19: 0000000000000002 x18: 0000000000000006 [ 57.485112] x17: 0000000000000000 x16: 0000000000000000 x15: ffff80008232b580 [ 57.492246] x14: 0000000000000000 x13: ffff8000816d1530 x12: 00000000000004a4 [ 57.499380] x11: 000000000000018c x10: ffff8000816fd530 x9 : ffff8000816d1530 [ 57.506515] x8 : 00000000fffff7ff x7 : ffff8000816fd530 x6 : 0000000000000001 [ 57.513649] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000 [ 57.520782] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0008049b0000 [ 57.527916] Call trace: [ 57.530354] sst_nor_write_data+0x6c/0x74 [ 57.534361] sst_nor_write+0xb4/0x18c [ 57.538019] mtd_write_oob_std+0x7c/0x88 [ 57.541941] mtd_write_oob+0x70/0xbc [ 57.545511] mtd_write+0x68/0xa8 [ 57.548733] mtdchar_write+0x10c/0x290 [ 57.552477] vfs_write+0xb4/0x3a8 [ 57.555791] ksys_write+0x74/0x10c [ 57.559189] __arm64_sys_write+0x1c/0x28 [ 57.563109] invoke_syscall+0x54/0x11c [ 57.566856] el0_svc_common.constprop.0+0xc0/0xe0 [ 57.571557] do_el0_svc+0x1c/0x28 [ 57.574868] el0_svc+0x30/0xcc [ 57.577921] el0t_64_sync_handler+0x120/0x12c [ 57.582276] el0t_64_sync+0x190/0x194 [ 57.585933] ---[ end trace 0000000000000000 ]--- [pratyush@kernel.org: add Cc stable tag]
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
NVD-CWE-noinfo

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: cgroup: Avoid iteration of dying tasks with zero refcount The commit 260fbcb92bbea ("cgroup: Move dying_tasks cleanup from cgroup_task_release() to cgroup_task_free()") extended the lifetime of tasks on the dying_tasks list. The iterators have provision to go through dying_tasks because of dying threadgroup leaders or explicit CSS_TASK_ITER_WITH_DEAD, however, it was expected that such tasks can obtain a new reference (that is possible before cgroup_task_release()/put_task_struct_rcu_user()). The tasks after cgroup_task_release() and before cgroup_task_free() are subject to race when they may or may not have ->usage count > 0. The race window is between css_task_iter_next() invocations when css_set_lock is released and we may arrive at a new ->task_pos. The iterator should not attempt to resurrect tasks whose ->usage count dropped to zero. (When that happens, __put_task_struct_rcu_cb() is already imminent and the returned task_struct would could be used after free.) As for the fix, we cannot simply check the signal->live count of a task on the dying list because that won't distinguish regular zombies waiting to be reaped from RCU remnant tasks that are going to be free'd. Therefore add an extra check to rule out ->usage==0 tasks from any iteration. The repeat: loop in css_task_iter_advance() doesn't consider ->usage count, so add a new loop to css_task_iter_next() to skip de-used tasks on the dying_list. Rough illustration of the possible race R (reader of cgroup.procs) T (thread) L (group leader) --------------------------------- -------------------------------- -------------------------------- L exits, signal->live > 0 cgroup_task_dead(L) css_set_skip_task_iters() // skips only cset->tasks list_add_tail(&L->cg_list, &cset->dying_tasks) css_task_iter_next() take css_set_lock css_task_iter_advance() leader && signal->live != 0 => it->task_pos = &L->cg_list release css_set_lock T exits --signal->live == 0 cgroup_task_dead(T) // css_set_lock release_task(T) cgroup_task_release(T) release_task(L) // zap_leader cgroup_task_release(L) put_task_struct_rcu_user(L) ...RCU... put_task_struct(L) L->usage = 0 /* L still on dying_tasks */ ...RCU... __put_task_struct(L) css_task_iter_next() // another iteration take css_set_lock it->task_pos = &L->cg_list get_task_struct(L) => addition on 0 drop css_set_lock cgroup_task_free(L) css_set_skip_task_iters() // dying skip comes too late free_task(L) cgroup_procs_show() task_pid_vnr(L)•CVE-2026-98163