ghsa-2xmx-r7cc-9x6c
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
tracing/osnoise: Fix crash in timerlat_dump_stack()
We have observed kernel panics when using timerlat with stack saving, with the following dmesg output:
memcpy: detected buffer overflow: 88 byte write of buffer size 0 WARNING: CPU: 2 PID: 8153 at lib/string_helpers.c:1032 __fortify_report+0x55/0xa0 CPU: 2 UID: 0 PID: 8153 Comm: timerlatu/2 Kdump: loaded Not tainted 6.15.3-200.fc42.x86_64 #1 PREEMPT(lazy) Call Trace: ? trace_buffer_lock_reserve+0x2a/0x60 __fortify_panic+0xd/0xf __timerlat_dump_stack.cold+0xd/0xd timerlat_dump_stack.part.0+0x47/0x80 timerlat_fd_read+0x36d/0x390 vfs_read+0xe2/0x390 ? syscall_exit_to_user_mode+0x1d5/0x210 ksys_read+0x73/0xe0 do_syscall_64+0x7b/0x160 ? exc_page_fault+0x7e/0x1a0 entry_SYSCALL_64_after_hwframe+0x76/0x7e
__timerlat_dump_stack() constructs the ftrace stack entry like this:
struct stack_entry *entry; ... memcpy(&entry->caller, fstack->calls, size); entry->size = fstack->nr_entries;
Since commit e7186af7fb26 ("tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure"), struct stack_entry marks its caller field with __counted_by(size). At the time of the memcpy, entry->size contains garbage from the ringbuffer, which under some circumstances is zero, triggering a kernel panic by buffer overflow.
Populate the size field before the memcpy so that the out-of-bounds check knows the correct size. This is analogous to __ftrace_trace_stack().
{
"affected": [],
"aliases": [
"CVE-2025-38493"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-07-28T12:15:31Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing/osnoise: Fix crash in timerlat_dump_stack()\n\nWe have observed kernel panics when using timerlat with stack saving,\nwith the following dmesg output:\n\nmemcpy: detected buffer overflow: 88 byte write of buffer size 0\nWARNING: CPU: 2 PID: 8153 at lib/string_helpers.c:1032 __fortify_report+0x55/0xa0\nCPU: 2 UID: 0 PID: 8153 Comm: timerlatu/2 Kdump: loaded Not tainted 6.15.3-200.fc42.x86_64 #1 PREEMPT(lazy)\nCall Trace:\n \u003cTASK\u003e\n ? trace_buffer_lock_reserve+0x2a/0x60\n __fortify_panic+0xd/0xf\n __timerlat_dump_stack.cold+0xd/0xd\n timerlat_dump_stack.part.0+0x47/0x80\n timerlat_fd_read+0x36d/0x390\n vfs_read+0xe2/0x390\n ? syscall_exit_to_user_mode+0x1d5/0x210\n ksys_read+0x73/0xe0\n do_syscall_64+0x7b/0x160\n ? exc_page_fault+0x7e/0x1a0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\n__timerlat_dump_stack() constructs the ftrace stack entry like this:\n\nstruct stack_entry *entry;\n...\nmemcpy(\u0026entry-\u003ecaller, fstack-\u003ecalls, size);\nentry-\u003esize = fstack-\u003enr_entries;\n\nSince commit e7186af7fb26 (\"tracing: Add back FORTIFY_SOURCE logic to\nkernel_stack event structure\"), struct stack_entry marks its caller\nfield with __counted_by(size). At the time of the memcpy, entry-\u003esize\ncontains garbage from the ringbuffer, which under some circumstances is\nzero, triggering a kernel panic by buffer overflow.\n\nPopulate the size field before the memcpy so that the out-of-bounds\ncheck knows the correct size. This is analogous to\n__ftrace_trace_stack().",
"id": "GHSA-2xmx-r7cc-9x6c",
"modified": "2025-07-28T12:30:36Z",
"published": "2025-07-28T12:30:36Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38493"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7bb9ea515cda027c9e717e27fefcf34f092e7c41"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/823d798900481875ba6c68217af028c5ffd2976b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/85a3bce695b361d85fc528e6fbb33e4c8089c806"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fbf90f5aa7ac7cddc69148a71d58f12c8709ce2b"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
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