gsd-2024-26737
Vulnerability from gsd
Modified
2024-02-20 06:02
Details
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix racing between bpf_timer_cancel_and_free and bpf_timer_cancel
The following race is possible between bpf_timer_cancel_and_free
and bpf_timer_cancel. It will lead a UAF on the timer->timer.
bpf_timer_cancel();
spin_lock();
t = timer->time;
spin_unlock();
bpf_timer_cancel_and_free();
spin_lock();
t = timer->timer;
timer->timer = NULL;
spin_unlock();
hrtimer_cancel(&t->timer);
kfree(t);
/* UAF on t */
hrtimer_cancel(&t->timer);
In bpf_timer_cancel_and_free, this patch frees the timer->timer
after a rcu grace period. This requires a rcu_head addition
to the "struct bpf_hrtimer". Another kfree(t) happens in bpf_timer_init,
this does not need a kfree_rcu because it is still under the
spin_lock and timer->timer has not been visible by others yet.
In bpf_timer_cancel, rcu_read_lock() is added because this helper
can be used in a non rcu critical section context (e.g. from
a sleepable bpf prog). Other timer->timer usages in helpers.c
have been audited, bpf_timer_cancel() is the only place where
timer->timer is used outside of the spin_lock.
Another solution considered is to mark a t->flag in bpf_timer_cancel
and clear it after hrtimer_cancel() is done. In bpf_timer_cancel_and_free,
it busy waits for the flag to be cleared before kfree(t). This patch
goes with a straight forward solution and frees timer->timer after
a rcu grace period.
Aliases
{
"gsd": {
"metadata": {
"exploitCode": "unknown",
"remediation": "unknown",
"reportConfidence": "confirmed",
"type": "vulnerability"
},
"osvSchema": {
"aliases": [
"CVE-2024-26737"
],
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix racing between bpf_timer_cancel_and_free and bpf_timer_cancel\n\nThe following race is possible between bpf_timer_cancel_and_free\nand bpf_timer_cancel. It will lead a UAF on the timer-\u003etimer.\n\nbpf_timer_cancel();\n\tspin_lock();\n\tt = timer-\u003etime;\n\tspin_unlock();\n\n\t\t\t\t\tbpf_timer_cancel_and_free();\n\t\t\t\t\t\tspin_lock();\n\t\t\t\t\t\tt = timer-\u003etimer;\n\t\t\t\t\t\ttimer-\u003etimer = NULL;\n\t\t\t\t\t\tspin_unlock();\n\t\t\t\t\t\thrtimer_cancel(\u0026t-\u003etimer);\n\t\t\t\t\t\tkfree(t);\n\n\t/* UAF on t */\n\thrtimer_cancel(\u0026t-\u003etimer);\n\nIn bpf_timer_cancel_and_free, this patch frees the timer-\u003etimer\nafter a rcu grace period. This requires a rcu_head addition\nto the \"struct bpf_hrtimer\". Another kfree(t) happens in bpf_timer_init,\nthis does not need a kfree_rcu because it is still under the\nspin_lock and timer-\u003etimer has not been visible by others yet.\n\nIn bpf_timer_cancel, rcu_read_lock() is added because this helper\ncan be used in a non rcu critical section context (e.g. from\na sleepable bpf prog). Other timer-\u003etimer usages in helpers.c\nhave been audited, bpf_timer_cancel() is the only place where\ntimer-\u003etimer is used outside of the spin_lock.\n\nAnother solution considered is to mark a t-\u003eflag in bpf_timer_cancel\nand clear it after hrtimer_cancel() is done. In bpf_timer_cancel_and_free,\nit busy waits for the flag to be cleared before kfree(t). This patch\ngoes with a straight forward solution and frees timer-\u003etimer after\na rcu grace period.",
"id": "GSD-2024-26737",
"modified": "2024-02-20T06:02:29.189474Z",
"schema_version": "1.4.0"
}
},
"namespaces": {
"cve.org": {
"CVE_data_meta": {
"ASSIGNER": "cve@kernel.org",
"ID": "CVE-2024-26737",
"STATE": "PUBLIC"
},
"affects": {
"vendor": {
"vendor_data": [
{
"product": {
"product_data": [
{
"product_name": "Linux",
"version": {
"version_data": [
{
"version_affected": "\u003c",
"version_name": "b00628b1c7d5",
"version_value": "5268bb02107b"
},
{
"version_value": "not down converted",
"x_cve_json_5_version_data": {
"defaultStatus": "affected",
"versions": [
{
"status": "affected",
"version": "5.15"
},
{
"lessThan": "5.15",
"status": "unaffected",
"version": "0",
"versionType": "custom"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.150",
"versionType": "custom"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.80",
"versionType": "custom"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.19",
"versionType": "custom"
},
{
"lessThanOrEqual": "6.7.*",
"status": "unaffected",
"version": "6.7.7",
"versionType": "custom"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.8",
"versionType": "original_commit_for_fix"
}
]
}
}
]
}
}
]
},
"vendor_name": "Linux"
}
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},
"data_format": "MITRE",
"data_type": "CVE",
"data_version": "4.0",
"description": {
"description_data": [
{
"lang": "eng",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix racing between bpf_timer_cancel_and_free and bpf_timer_cancel\n\nThe following race is possible between bpf_timer_cancel_and_free\nand bpf_timer_cancel. It will lead a UAF on the timer-\u003etimer.\n\nbpf_timer_cancel();\n\tspin_lock();\n\tt = timer-\u003etime;\n\tspin_unlock();\n\n\t\t\t\t\tbpf_timer_cancel_and_free();\n\t\t\t\t\t\tspin_lock();\n\t\t\t\t\t\tt = timer-\u003etimer;\n\t\t\t\t\t\ttimer-\u003etimer = NULL;\n\t\t\t\t\t\tspin_unlock();\n\t\t\t\t\t\thrtimer_cancel(\u0026t-\u003etimer);\n\t\t\t\t\t\tkfree(t);\n\n\t/* UAF on t */\n\thrtimer_cancel(\u0026t-\u003etimer);\n\nIn bpf_timer_cancel_and_free, this patch frees the timer-\u003etimer\nafter a rcu grace period. This requires a rcu_head addition\nto the \"struct bpf_hrtimer\". Another kfree(t) happens in bpf_timer_init,\nthis does not need a kfree_rcu because it is still under the\nspin_lock and timer-\u003etimer has not been visible by others yet.\n\nIn bpf_timer_cancel, rcu_read_lock() is added because this helper\ncan be used in a non rcu critical section context (e.g. from\na sleepable bpf prog). Other timer-\u003etimer usages in helpers.c\nhave been audited, bpf_timer_cancel() is the only place where\ntimer-\u003etimer is used outside of the spin_lock.\n\nAnother solution considered is to mark a t-\u003eflag in bpf_timer_cancel\nand clear it after hrtimer_cancel() is done. In bpf_timer_cancel_and_free,\nit busy waits for the flag to be cleared before kfree(t). This patch\ngoes with a straight forward solution and frees timer-\u003etimer after\na rcu grace period."
}
]
},
"generator": {
"engine": "bippy-d3b290d2becc"
},
"problemtype": {
"problemtype_data": [
{
"description": [
{
"lang": "eng",
"value": "n/a"
}
]
}
]
},
"references": {
"reference_data": [
{
"name": "https://git.kernel.org/stable/c/5268bb02107b9eedfdcd51db75b407d10043368c",
"refsource": "MISC",
"url": "https://git.kernel.org/stable/c/5268bb02107b9eedfdcd51db75b407d10043368c"
},
{
"name": "https://git.kernel.org/stable/c/addf5e297e6cbf5341f9c07720693ca9ba0057b5",
"refsource": "MISC",
"url": "https://git.kernel.org/stable/c/addf5e297e6cbf5341f9c07720693ca9ba0057b5"
},
{
"name": "https://git.kernel.org/stable/c/8327ed12e8ebc5436bfaa1786c49988894f9c8a6",
"refsource": "MISC",
"url": "https://git.kernel.org/stable/c/8327ed12e8ebc5436bfaa1786c49988894f9c8a6"
},
{
"name": "https://git.kernel.org/stable/c/7d80a9e745fa5b47da3bca001f186c02485c7c33",
"refsource": "MISC",
"url": "https://git.kernel.org/stable/c/7d80a9e745fa5b47da3bca001f186c02485c7c33"
},
{
"name": "https://git.kernel.org/stable/c/0281b919e175bb9c3128bd3872ac2903e9436e3f",
"refsource": "MISC",
"url": "https://git.kernel.org/stable/c/0281b919e175bb9c3128bd3872ac2903e9436e3f"
}
]
}
},
"nvd.nist.gov": {
"cve": {
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix racing between bpf_timer_cancel_and_free and bpf_timer_cancel\n\nThe following race is possible between bpf_timer_cancel_and_free\nand bpf_timer_cancel. It will lead a UAF on the timer-\u003etimer.\n\nbpf_timer_cancel();\n\tspin_lock();\n\tt = timer-\u003etime;\n\tspin_unlock();\n\n\t\t\t\t\tbpf_timer_cancel_and_free();\n\t\t\t\t\t\tspin_lock();\n\t\t\t\t\t\tt = timer-\u003etimer;\n\t\t\t\t\t\ttimer-\u003etimer = NULL;\n\t\t\t\t\t\tspin_unlock();\n\t\t\t\t\t\thrtimer_cancel(\u0026t-\u003etimer);\n\t\t\t\t\t\tkfree(t);\n\n\t/* UAF on t */\n\thrtimer_cancel(\u0026t-\u003etimer);\n\nIn bpf_timer_cancel_and_free, this patch frees the timer-\u003etimer\nafter a rcu grace period. This requires a rcu_head addition\nto the \"struct bpf_hrtimer\". Another kfree(t) happens in bpf_timer_init,\nthis does not need a kfree_rcu because it is still under the\nspin_lock and timer-\u003etimer has not been visible by others yet.\n\nIn bpf_timer_cancel, rcu_read_lock() is added because this helper\ncan be used in a non rcu critical section context (e.g. from\na sleepable bpf prog). Other timer-\u003etimer usages in helpers.c\nhave been audited, bpf_timer_cancel() is the only place where\ntimer-\u003etimer is used outside of the spin_lock.\n\nAnother solution considered is to mark a t-\u003eflag in bpf_timer_cancel\nand clear it after hrtimer_cancel() is done. In bpf_timer_cancel_and_free,\nit busy waits for the flag to be cleared before kfree(t). This patch\ngoes with a straight forward solution and frees timer-\u003etimer after\na rcu grace period."
}
],
"id": "CVE-2024-26737",
"lastModified": "2024-04-03T17:24:18.150",
"metrics": {},
"published": "2024-04-03T17:15:51.243",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/0281b919e175bb9c3128bd3872ac2903e9436e3f"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/5268bb02107b9eedfdcd51db75b407d10043368c"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/7d80a9e745fa5b47da3bca001f186c02485c7c33"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/8327ed12e8ebc5436bfaa1786c49988894f9c8a6"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/addf5e297e6cbf5341f9c07720693ca9ba0057b5"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Awaiting Analysis"
}
}
}
}
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