159 lines
12 KiB
JSON
159 lines
12 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2023-53478",
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"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"state": "PUBLISHED",
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"assignerShortName": "Linux",
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"dateReserved": "2025-10-01T11:39:39.401Z",
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"datePublished": "2025-10-01T11:42:47.185Z",
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"dateUpdated": "2026-08-05T09:14:16.799Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"shortName": "Linux",
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"dateUpdated": "2026-08-05T09:14:16.799Z"
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},
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"descriptions": [
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{
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"lang": "en",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing/synthetic: Fix races on freeing last_cmd\n\nCurrently, the \"last_cmd\" variable can be accessed by multiple processes\nasynchronously when multiple users manipulate synthetic_events node\nat the same time, it could lead to use-after-free or double-free.\n\nThis patch add \"lastcmd_mutex\" to prevent \"last_cmd\" from being accessed\nasynchronously.\n\n================================================================\n\nIt's easy to reproduce in the KASAN environment by running the two\nscripts below in different shells.\n\nscript 1:\n while :\n do\n echo -n -e '\\x88' > /sys/kernel/tracing/synthetic_events\n done\n\nscript 2:\n while :\n do\n echo -n -e '\\xb0' > /sys/kernel/tracing/synthetic_events\n done\n\n================================================================\ndouble-free scenario:\n\n process A process B\n------------------- ---------------\n1.kstrdup last_cmd\n 2.free last_cmd\n3.free last_cmd(double-free)\n\n================================================================\nuse-after-free scenario:\n\n process A process B\n------------------- ---------------\n1.kstrdup last_cmd\n 2.free last_cmd\n3.tracing_log_err(use-after-free)\n\n================================================================\n\nAppendix 1. KASAN report double-free:\n\nBUG: KASAN: double-free in kfree+0xdc/0x1d4\nFree of addr ***** by task sh/4879\nCall trace:\n ...\n kfree+0xdc/0x1d4\n create_or_delete_synth_event+0x60/0x1e8\n trace_parse_run_command+0x2bc/0x4b8\n synth_events_write+0x20/0x30\n vfs_write+0x200/0x830\n ...\n\nAllocated by task 4879:\n ...\n kstrdup+0x5c/0x98\n create_or_delete_synth_event+0x6c/0x1e8\n trace_parse_run_command+0x2bc/0x4b8\n synth_events_write+0x20/0x30\n vfs_write+0x200/0x830\n ...\n\nFreed by task 5464:\n ...\n kfree+0xdc/0x1d4\n create_or_delete_synth_event+0x60/0x1e8\n trace_parse_run_command+0x2bc/0x4b8\n synth_events_write+0x20/0x30\n vfs_write+0x200/0x830\n ...\n\n================================================================\nAppendix 2. KASAN report use-after-free:\n\nBUG: KASAN: use-after-free in strlen+0x5c/0x7c\nRead of size 1 at addr ***** by task sh/5483\nsh: CPU: 7 PID: 5483 Comm: sh\n ...\n __asan_report_load1_noabort+0x34/0x44\n strlen+0x5c/0x7c\n tracing_log_err+0x60/0x444\n create_or_delete_synth_event+0xc4/0x204\n trace_parse_run_command+0x2bc/0x4b8\n synth_events_write+0x20/0x30\n vfs_write+0x200/0x830\n ...\n\nAllocated by task 5483:\n ...\n kstrdup+0x5c/0x98\n create_or_delete_synth_event+0x80/0x204\n trace_parse_run_command+0x2bc/0x4b8\n synth_events_write+0x20/0x30\n vfs_write+0x200/0x830\n ...\n\nFreed by task 5480:\n ...\n kfree+0xdc/0x1d4\n create_or_delete_synth_event+0x74/0x204\n trace_parse_run_command+0x2bc/0x4b8\n synth_events_write+0x20/0x30\n vfs_write+0x200/0x830\n ..."
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}
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],
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"metrics": [
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{
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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"baseScore": 7.8,
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"baseSeverity": "HIGH"
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},
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"scenarios": [
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{
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"lang": "en",
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"value": "AV:L - The bug is triggered only by write() to the tracefs node /sys/kernel/tracing/synthetic_events (or dynamic_events), which requires local access to the machine's filesystem. There is no network-facing consumer of this code path.\nAC:L - Although it is a race, the attacker owns both sides — simply running two concurrent writers of malformed commands, exactly as the reporter's two-shell reproducer does, and the commit states it reproduces easily. Object size and contents of the raced allocation are fully attacker-chosen, so no condition lies outside the attacker's control.\nPR:L - No capability check exists in the path; access is gated only by DAC on the tracefs file, and tracefs's gid= mount option is explicitly provided so a non-root tracing group (Android/ChromeOS/developer-group deployments) can write these nodes. An unprivileged member of that group can trigger the race with plain writes.\nUI:N - The attacker performs the entire attack with its own write() calls; no victim action, mount, or file-open by another user is needed.\nS:U - The corruption occurs in kernel slab memory and its impact stays within the same kernel security authority, with no crossing of a hypervisor, IOMMU, or sandbox boundary.\nC:H - The use-after-free reads freed heap memory via strlen()/snprintf() in tracing_log_err() and copies it into err->cmd, which userspace can then read back from tracing/error_log — a direct kernel heap infoleak. Combined with the double-free's ability to overlap allocations, arbitrary kernel memory disclosure is achievable.\nI:H - The double-free frees an attacker-sized, attacker-filled kmalloc object twice, corrupting the SLUB freelist and letting two live allocations alias the same memory — a well-known route to arbitrary kernel write and control-flow hijack.\nA:H - The double-free and use-after-free readily produce slab corruption, KASAN BUG reports, and kernel panics, and the race can be re-triggered in a tight loop to reliably crash the system."
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}
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]
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}
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],
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"affected": [
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "unaffected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"kernel/trace/trace_events_synth.c"
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],
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"versions": [
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{
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"version": "27c888da9867725784bad3d6455d6e53b425fa2b",
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"status": "affected",
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{
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"defaultStatus": "affected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"kernel/trace/trace_events_synth.c"
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],
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{
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"version": "5.18",
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"status": "affected"
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{
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"version": "0",
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"lessThan": "5.18",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.1.24",
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"lessThanOrEqual": "6.1.*",
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"status": "unaffected",
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},
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{
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"version": "6.2.11",
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"lessThanOrEqual": "6.2.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.3",
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"lessThanOrEqual": "*",
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"status": "unaffected",
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"versionType": "original_commit_for_fix"
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}
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]
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"references": [
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{
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"url": "https://git.kernel.org/stable/c/9fe183f659a2704255e5d84f6ae308c234a113ec"
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{
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"url": "https://git.kernel.org/stable/c/8826d9e7bd51e7656f78baa4472e8e2f5e7069f0"
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"url": "https://git.kernel.org/stable/c/4ccf11c4e8a8e051499d53a12f502196c97a758e"
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}
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],
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"title": "tracing/synthetic: Fix races on freeing last_cmd",
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