CVE-2022-49888 (GCVE-0-2022-49888)

Vulnerability from cvelistv5 – Published: 2025-05-01 14:10 – Updated: 2025-05-04 08:47
VLAI?
Title
arm64: entry: avoid kprobe recursion
Summary
In the Linux kernel, the following vulnerability has been resolved: arm64: entry: avoid kprobe recursion The cortex_a76_erratum_1463225_debug_handler() function is called when handling debug exceptions (and synchronous exceptions from BRK instructions), and so is called when a probed function executes. If the compiler does not inline cortex_a76_erratum_1463225_debug_handler(), it can be probed. If cortex_a76_erratum_1463225_debug_handler() is probed, any debug exception or software breakpoint exception will result in recursive exceptions leading to a stack overflow. This can be triggered with the ftrace multiple_probes selftest, and as per the example splat below. This is a regression caused by commit: 6459b8469753e9fe ("arm64: entry: consolidate Cortex-A76 erratum 1463225 workaround") ... which removed the NOKPROBE_SYMBOL() annotation associated with the function. My intent was that cortex_a76_erratum_1463225_debug_handler() would be inlined into its caller, el1_dbg(), which is marked noinstr and cannot be probed. Mark cortex_a76_erratum_1463225_debug_handler() as __always_inline to ensure this. Example splat prior to this patch (with recursive entries elided): | # echo p cortex_a76_erratum_1463225_debug_handler > /sys/kernel/debug/tracing/kprobe_events | # echo p do_el0_svc >> /sys/kernel/debug/tracing/kprobe_events | # echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable | Insufficient stack space to handle exception! | ESR: 0x0000000096000047 -- DABT (current EL) | FAR: 0xffff800009cefff0 | Task stack: [0xffff800009cf0000..0xffff800009cf4000] | IRQ stack: [0xffff800008000000..0xffff800008004000] | Overflow stack: [0xffff00007fbc00f0..0xffff00007fbc10f0] | CPU: 0 PID: 145 Comm: sh Not tainted 6.0.0 #2 | Hardware name: linux,dummy-virt (DT) | pstate: 604003c5 (nZCv DAIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--) | pc : arm64_enter_el1_dbg+0x4/0x20 | lr : el1_dbg+0x24/0x5c | sp : ffff800009cf0000 | x29: ffff800009cf0000 x28: ffff000002c74740 x27: 0000000000000000 | x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 | x23: 00000000604003c5 x22: ffff80000801745c x21: 0000aaaac95ac068 | x20: 00000000f2000004 x19: ffff800009cf0040 x18: 0000000000000000 | x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 | x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 | x11: 0000000000000010 x10: ffff800008c87190 x9 : ffff800008ca00d0 | x8 : 000000000000003c x7 : 0000000000000000 x6 : 0000000000000000 | x5 : 0000000000000000 x4 : 0000000000000000 x3 : 00000000000043a4 | x2 : 00000000f2000004 x1 : 00000000f2000004 x0 : ffff800009cf0040 | Kernel panic - not syncing: kernel stack overflow | CPU: 0 PID: 145 Comm: sh Not tainted 6.0.0 #2 | Hardware name: linux,dummy-virt (DT) | Call trace: | dump_backtrace+0xe4/0x104 | show_stack+0x18/0x4c | dump_stack_lvl+0x64/0x7c | dump_stack+0x18/0x38 | panic+0x14c/0x338 | test_taint+0x0/0x2c | panic_bad_stack+0x104/0x118 | handle_bad_stack+0x34/0x48 | __bad_stack+0x78/0x7c | arm64_enter_el1_dbg+0x4/0x20 | el1h_64_sync_handler+0x40/0x98 | el1h_64_sync+0x64/0x68 | cortex_a76_erratum_1463225_debug_handler+0x0/0x34 ... | el1h_64_sync_handler+0x40/0x98 | el1h_64_sync+0x64/0x68 | cortex_a76_erratum_1463225_debug_handler+0x0/0x34 ... | el1h_64_sync_handler+0x40/0x98 | el1h_64_sync+0x64/0x68 | cortex_a76_erratum_1463225_debug_handler+0x0/0x34 | el1h_64_sync_handler+0x40/0x98 | el1h_64_sync+0x64/0x68 | do_el0_svc+0x0/0x28 | el0t_64_sync_handler+0x84/0xf0 | el0t_64_sync+0x18c/0x190 | Kernel Offset: disabled | CPU features: 0x0080,00005021,19001080 | Memory Limit: none | ---[ end Kernel panic - not syncing: kernel stack overflow ]--- With this patch, cortex_a76_erratum_1463225_debug_handler() is inlined into el1_dbg(), and el1_dbg() cannot be probed: | # echo p cortex_a76_erratum_1463225_debug_handler > /sys/kernel/debug/tracing/kprobe_events | sh: write error: No such file or directory | # grep -w cortex_a76_errat ---truncated---
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 6459b8469753e9feaa8b34691d097cffad905931 , < 71d6c33fe223255f4416a01514da2c0bc3e283e7 (git)
Affected: 6459b8469753e9feaa8b34691d097cffad905931 , < db66629d43b2d12cb43b004a4ca6be1d03228e97 (git)
Affected: 6459b8469753e9feaa8b34691d097cffad905931 , < 024f4b2e1f874934943eb2d3d288ebc52c79f55c (git)
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    Linux Linux Affected: 5.12
Unaffected: 0 , < 5.12 (semver)
Unaffected: 5.15.78 , ≤ 5.15.* (semver)
Unaffected: 6.0.8 , ≤ 6.0.* (semver)
Unaffected: 6.1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/kernel/entry-common.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "71d6c33fe223255f4416a01514da2c0bc3e283e7",
              "status": "affected",
              "version": "6459b8469753e9feaa8b34691d097cffad905931",
              "versionType": "git"
            },
            {
              "lessThan": "db66629d43b2d12cb43b004a4ca6be1d03228e97",
              "status": "affected",
              "version": "6459b8469753e9feaa8b34691d097cffad905931",
              "versionType": "git"
            },
            {
              "lessThan": "024f4b2e1f874934943eb2d3d288ebc52c79f55c",
              "status": "affected",
              "version": "6459b8469753e9feaa8b34691d097cffad905931",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/kernel/entry-common.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.12"
            },
            {
              "lessThan": "5.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.78",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.0.*",
              "status": "unaffected",
              "version": "6.0.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.78",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.0.8",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: entry: avoid kprobe recursion\n\nThe cortex_a76_erratum_1463225_debug_handler() function is called when\nhandling debug exceptions (and synchronous exceptions from BRK\ninstructions), and so is called when a probed function executes. If the\ncompiler does not inline cortex_a76_erratum_1463225_debug_handler(), it\ncan be probed.\n\nIf cortex_a76_erratum_1463225_debug_handler() is probed, any debug\nexception or software breakpoint exception will result in recursive\nexceptions leading to a stack overflow. This can be triggered with the\nftrace multiple_probes selftest, and as per the example splat below.\n\nThis is a regression caused by commit:\n\n  6459b8469753e9fe (\"arm64: entry: consolidate Cortex-A76 erratum 1463225 workaround\")\n\n... which removed the NOKPROBE_SYMBOL() annotation associated with the\nfunction.\n\nMy intent was that cortex_a76_erratum_1463225_debug_handler() would be\ninlined into its caller, el1_dbg(), which is marked noinstr and cannot\nbe probed. Mark cortex_a76_erratum_1463225_debug_handler() as\n__always_inline to ensure this.\n\nExample splat prior to this patch (with recursive entries elided):\n\n| # echo p cortex_a76_erratum_1463225_debug_handler \u003e /sys/kernel/debug/tracing/kprobe_events\n| # echo p do_el0_svc \u003e\u003e /sys/kernel/debug/tracing/kprobe_events\n| # echo 1 \u003e /sys/kernel/debug/tracing/events/kprobes/enable\n| Insufficient stack space to handle exception!\n| ESR: 0x0000000096000047 -- DABT (current EL)\n| FAR: 0xffff800009cefff0\n| Task stack:     [0xffff800009cf0000..0xffff800009cf4000]\n| IRQ stack:      [0xffff800008000000..0xffff800008004000]\n| Overflow stack: [0xffff00007fbc00f0..0xffff00007fbc10f0]\n| CPU: 0 PID: 145 Comm: sh Not tainted 6.0.0 #2\n| Hardware name: linux,dummy-virt (DT)\n| pstate: 604003c5 (nZCv DAIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)\n| pc : arm64_enter_el1_dbg+0x4/0x20\n| lr : el1_dbg+0x24/0x5c\n| sp : ffff800009cf0000\n| x29: ffff800009cf0000 x28: ffff000002c74740 x27: 0000000000000000\n| x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000\n| x23: 00000000604003c5 x22: ffff80000801745c x21: 0000aaaac95ac068\n| x20: 00000000f2000004 x19: ffff800009cf0040 x18: 0000000000000000\n| x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000\n| x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000\n| x11: 0000000000000010 x10: ffff800008c87190 x9 : ffff800008ca00d0\n| x8 : 000000000000003c x7 : 0000000000000000 x6 : 0000000000000000\n| x5 : 0000000000000000 x4 : 0000000000000000 x3 : 00000000000043a4\n| x2 : 00000000f2000004 x1 : 00000000f2000004 x0 : ffff800009cf0040\n| Kernel panic - not syncing: kernel stack overflow\n| CPU: 0 PID: 145 Comm: sh Not tainted 6.0.0 #2\n| Hardware name: linux,dummy-virt (DT)\n| Call trace:\n|  dump_backtrace+0xe4/0x104\n|  show_stack+0x18/0x4c\n|  dump_stack_lvl+0x64/0x7c\n|  dump_stack+0x18/0x38\n|  panic+0x14c/0x338\n|  test_taint+0x0/0x2c\n|  panic_bad_stack+0x104/0x118\n|  handle_bad_stack+0x34/0x48\n|  __bad_stack+0x78/0x7c\n|  arm64_enter_el1_dbg+0x4/0x20\n|  el1h_64_sync_handler+0x40/0x98\n|  el1h_64_sync+0x64/0x68\n|  cortex_a76_erratum_1463225_debug_handler+0x0/0x34\n...\n|  el1h_64_sync_handler+0x40/0x98\n|  el1h_64_sync+0x64/0x68\n|  cortex_a76_erratum_1463225_debug_handler+0x0/0x34\n...\n|  el1h_64_sync_handler+0x40/0x98\n|  el1h_64_sync+0x64/0x68\n|  cortex_a76_erratum_1463225_debug_handler+0x0/0x34\n|  el1h_64_sync_handler+0x40/0x98\n|  el1h_64_sync+0x64/0x68\n|  do_el0_svc+0x0/0x28\n|  el0t_64_sync_handler+0x84/0xf0\n|  el0t_64_sync+0x18c/0x190\n| Kernel Offset: disabled\n| CPU features: 0x0080,00005021,19001080\n| Memory Limit: none\n| ---[ end Kernel panic - not syncing: kernel stack overflow ]---\n\nWith this patch, cortex_a76_erratum_1463225_debug_handler() is inlined\ninto el1_dbg(), and el1_dbg() cannot be probed:\n\n| # echo p cortex_a76_erratum_1463225_debug_handler \u003e /sys/kernel/debug/tracing/kprobe_events\n| sh: write error: No such file or directory\n| # grep -w cortex_a76_errat\n---truncated---"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-05-04T08:47:50.503Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/71d6c33fe223255f4416a01514da2c0bc3e283e7"
        },
        {
          "url": "https://git.kernel.org/stable/c/db66629d43b2d12cb43b004a4ca6be1d03228e97"
        },
        {
          "url": "https://git.kernel.org/stable/c/024f4b2e1f874934943eb2d3d288ebc52c79f55c"
        }
      ],
      "title": "arm64: entry: avoid kprobe recursion",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2022-49888",
    "datePublished": "2025-05-01T14:10:33.183Z",
    "dateReserved": "2025-05-01T14:05:17.242Z",
    "dateUpdated": "2025-05-04T08:47:50.503Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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