gsd-2023-52568
Vulnerability from gsd
Modified
2024-03-03 06:01
Details
In the Linux kernel, the following vulnerability has been resolved:
x86/sgx: Resolves SECS reclaim vs. page fault for EAUG race
The SGX EPC reclaimer (ksgxd) may reclaim the SECS EPC page for an
enclave and set secs.epc_page to NULL. The SECS page is used for EAUG
and ELDU in the SGX page fault handler. However, the NULL check for
secs.epc_page is only done for ELDU, not EAUG before being used.
Fix this by doing the same NULL check and reloading of the SECS page as
needed for both EAUG and ELDU.
The SECS page holds global enclave metadata. It can only be reclaimed
when there are no other enclave pages remaining. At that point,
virtually nothing can be done with the enclave until the SECS page is
paged back in.
An enclave can not run nor generate page faults without a resident SECS
page. But it is still possible for a #PF for a non-SECS page to race
with paging out the SECS page: when the last resident non-SECS page A
triggers a #PF in a non-resident page B, and then page A and the SECS
both are paged out before the #PF on B is handled.
Hitting this bug requires that race triggered with a #PF for EAUG.
Following is a trace when it happens.
BUG: kernel NULL pointer dereference, address: 0000000000000000
RIP: 0010:sgx_encl_eaug_page+0xc7/0x210
Call Trace:
? __kmem_cache_alloc_node+0x16a/0x440
? xa_load+0x6e/0xa0
sgx_vma_fault+0x119/0x230
__do_fault+0x36/0x140
do_fault+0x12f/0x400
__handle_mm_fault+0x728/0x1110
handle_mm_fault+0x105/0x310
do_user_addr_fault+0x1ee/0x750
? __this_cpu_preempt_check+0x13/0x20
exc_page_fault+0x76/0x180
asm_exc_page_fault+0x27/0x30
Aliases
{
"gsd": {
"metadata": {
"exploitCode": "unknown",
"remediation": "unknown",
"reportConfidence": "confirmed",
"type": "vulnerability"
},
"osvSchema": {
"aliases": [
"CVE-2023-52568"
],
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/sgx: Resolves SECS reclaim vs. page fault for EAUG race\n\nThe SGX EPC reclaimer (ksgxd) may reclaim the SECS EPC page for an\nenclave and set secs.epc_page to NULL. The SECS page is used for EAUG\nand ELDU in the SGX page fault handler. However, the NULL check for\nsecs.epc_page is only done for ELDU, not EAUG before being used.\n\nFix this by doing the same NULL check and reloading of the SECS page as\nneeded for both EAUG and ELDU.\n\nThe SECS page holds global enclave metadata. It can only be reclaimed\nwhen there are no other enclave pages remaining. At that point,\nvirtually nothing can be done with the enclave until the SECS page is\npaged back in.\n\nAn enclave can not run nor generate page faults without a resident SECS\npage. But it is still possible for a #PF for a non-SECS page to race\nwith paging out the SECS page: when the last resident non-SECS page A\ntriggers a #PF in a non-resident page B, and then page A and the SECS\nboth are paged out before the #PF on B is handled.\n\nHitting this bug requires that race triggered with a #PF for EAUG.\nFollowing is a trace when it happens.\n\nBUG: kernel NULL pointer dereference, address: 0000000000000000\nRIP: 0010:sgx_encl_eaug_page+0xc7/0x210\nCall Trace:\n ? __kmem_cache_alloc_node+0x16a/0x440\n ? xa_load+0x6e/0xa0\n sgx_vma_fault+0x119/0x230\n __do_fault+0x36/0x140\n do_fault+0x12f/0x400\n __handle_mm_fault+0x728/0x1110\n handle_mm_fault+0x105/0x310\n do_user_addr_fault+0x1ee/0x750\n ? __this_cpu_preempt_check+0x13/0x20\n exc_page_fault+0x76/0x180\n asm_exc_page_fault+0x27/0x30",
"id": "GSD-2023-52568",
"modified": "2024-03-03T06:01:51.670884Z",
"schema_version": "1.4.0"
}
},
"namespaces": {
"cve.org": {
"CVE_data_meta": {
"ASSIGNER": "cve@kernel.org",
"ID": "CVE-2023-52568",
"STATE": "PUBLIC"
},
"affects": {
"vendor": {
"vendor_data": [
{
"product": {
"product_data": [
{
"product_name": "Linux",
"version": {
"version_data": [
{
"version_affected": "\u003c",
"version_name": "5a90d2c3f5ef",
"version_value": "811ba2ef0cb6"
},
{
"version_value": "not down converted",
"x_cve_json_5_version_data": {
"defaultStatus": "affected",
"versions": [
{
"status": "affected",
"version": "6.0"
},
{
"lessThan": "6.0",
"status": "unaffected",
"version": "0",
"versionType": "custom"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.56",
"versionType": "custom"
},
{
"lessThanOrEqual": "6.5.*",
"status": "unaffected",
"version": "6.5.6",
"versionType": "custom"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.6",
"versionType": "original_commit_for_fix"
}
]
}
}
]
}
}
]
},
"vendor_name": "Linux"
}
]
}
},
"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\nx86/sgx: Resolves SECS reclaim vs. page fault for EAUG race\n\nThe SGX EPC reclaimer (ksgxd) may reclaim the SECS EPC page for an\nenclave and set secs.epc_page to NULL. The SECS page is used for EAUG\nand ELDU in the SGX page fault handler. However, the NULL check for\nsecs.epc_page is only done for ELDU, not EAUG before being used.\n\nFix this by doing the same NULL check and reloading of the SECS page as\nneeded for both EAUG and ELDU.\n\nThe SECS page holds global enclave metadata. It can only be reclaimed\nwhen there are no other enclave pages remaining. At that point,\nvirtually nothing can be done with the enclave until the SECS page is\npaged back in.\n\nAn enclave can not run nor generate page faults without a resident SECS\npage. But it is still possible for a #PF for a non-SECS page to race\nwith paging out the SECS page: when the last resident non-SECS page A\ntriggers a #PF in a non-resident page B, and then page A and the SECS\nboth are paged out before the #PF on B is handled.\n\nHitting this bug requires that race triggered with a #PF for EAUG.\nFollowing is a trace when it happens.\n\nBUG: kernel NULL pointer dereference, address: 0000000000000000\nRIP: 0010:sgx_encl_eaug_page+0xc7/0x210\nCall Trace:\n ? __kmem_cache_alloc_node+0x16a/0x440\n ? xa_load+0x6e/0xa0\n sgx_vma_fault+0x119/0x230\n __do_fault+0x36/0x140\n do_fault+0x12f/0x400\n __handle_mm_fault+0x728/0x1110\n handle_mm_fault+0x105/0x310\n do_user_addr_fault+0x1ee/0x750\n ? __this_cpu_preempt_check+0x13/0x20\n exc_page_fault+0x76/0x180\n asm_exc_page_fault+0x27/0x30"
}
]
},
"generator": {
"engine": "bippy-4986f5686161"
},
"problemtype": {
"problemtype_data": [
{
"description": [
{
"lang": "eng",
"value": "n/a"
}
]
}
]
},
"references": {
"reference_data": [
{
"name": "https://git.kernel.org/stable/c/811ba2ef0cb6402672e64ba1419d6ef95aa3405d",
"refsource": "MISC",
"url": "https://git.kernel.org/stable/c/811ba2ef0cb6402672e64ba1419d6ef95aa3405d"
},
{
"name": "https://git.kernel.org/stable/c/1348f7f15d7c7798456856bee74a4235c2da994e",
"refsource": "MISC",
"url": "https://git.kernel.org/stable/c/1348f7f15d7c7798456856bee74a4235c2da994e"
},
{
"name": "https://git.kernel.org/stable/c/c6c2adcba50c2622ed25ba5d5e7f05f584711358",
"refsource": "MISC",
"url": "https://git.kernel.org/stable/c/c6c2adcba50c2622ed25ba5d5e7f05f584711358"
}
]
}
},
"nvd.nist.gov": {
"cve": {
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/sgx: Resolves SECS reclaim vs. page fault for EAUG race\n\nThe SGX EPC reclaimer (ksgxd) may reclaim the SECS EPC page for an\nenclave and set secs.epc_page to NULL. The SECS page is used for EAUG\nand ELDU in the SGX page fault handler. However, the NULL check for\nsecs.epc_page is only done for ELDU, not EAUG before being used.\n\nFix this by doing the same NULL check and reloading of the SECS page as\nneeded for both EAUG and ELDU.\n\nThe SECS page holds global enclave metadata. It can only be reclaimed\nwhen there are no other enclave pages remaining. At that point,\nvirtually nothing can be done with the enclave until the SECS page is\npaged back in.\n\nAn enclave can not run nor generate page faults without a resident SECS\npage. But it is still possible for a #PF for a non-SECS page to race\nwith paging out the SECS page: when the last resident non-SECS page A\ntriggers a #PF in a non-resident page B, and then page A and the SECS\nboth are paged out before the #PF on B is handled.\n\nHitting this bug requires that race triggered with a #PF for EAUG.\nFollowing is a trace when it happens.\n\nBUG: kernel NULL pointer dereference, address: 0000000000000000\nRIP: 0010:sgx_encl_eaug_page+0xc7/0x210\nCall Trace:\n ? __kmem_cache_alloc_node+0x16a/0x440\n ? xa_load+0x6e/0xa0\n sgx_vma_fault+0x119/0x230\n __do_fault+0x36/0x140\n do_fault+0x12f/0x400\n __handle_mm_fault+0x728/0x1110\n handle_mm_fault+0x105/0x310\n do_user_addr_fault+0x1ee/0x750\n ? __this_cpu_preempt_check+0x13/0x20\n exc_page_fault+0x76/0x180\n asm_exc_page_fault+0x27/0x30"
}
],
"id": "CVE-2023-52568",
"lastModified": "2024-03-04T13:58:23.447",
"metrics": {},
"published": "2024-03-02T22:15:49.120",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/1348f7f15d7c7798456856bee74a4235c2da994e"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/811ba2ef0cb6402672e64ba1419d6ef95aa3405d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c6c2adcba50c2622ed25ba5d5e7f05f584711358"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Awaiting Analysis"
}
}
}
}
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- Confirmed: The vulnerability is confirmed from an analyst perspective.
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