github - ghsa-rfvx-8c45-w4c7

GHSA-RFVX-8C45-W4C7

Vulnerability from github – Published: 2024-02-27 21:31 – Updated: 2024-11-01 18:31

Details

In the Linux kernel, the following vulnerability has been resolved:

riscv/kprobe: fix kernel panic when invoking sys_read traced by kprobe

The execution of sys_read end up hitting a BUG_ON() in __find_get_block after installing kprobe at sys_read, the BUG message like the following:

[ 65.708663] ------------[ cut here ]------------ [ 65.709987] kernel BUG at fs/buffer.c:1251! [ 65.711283] Kernel BUG [#1] [ 65.712032] Modules linked in: [ 65.712925] CPU: 0 PID: 51 Comm: sh Not tainted 5.12.0-rc4 #1 [ 65.714407] Hardware name: riscv-virtio,qemu (DT) [ 65.715696] epc : __find_get_block+0x218/0x2c8 [ 65.716835] ra : __getblk_gfp+0x1c/0x4a [ 65.717831] epc : ffffffe00019f11e ra : ffffffe00019f56a sp : ffffffe002437930 [ 65.719553] gp : ffffffe000f06030 tp : ffffffe0015abc00 t0 : ffffffe00191e038 [ 65.721290] t1 : ffffffe00191e038 t2 : 000000000000000a s0 : ffffffe002437960 [ 65.723051] s1 : ffffffe00160ad00 a0 : ffffffe00160ad00 a1 : 000000000000012a [ 65.724772] a2 : 0000000000000400 a3 : 0000000000000008 a4 : 0000000000000040 [ 65.726545] a5 : 0000000000000000 a6 : ffffffe00191e000 a7 : 0000000000000000 [ 65.728308] s2 : 000000000000012a s3 : 0000000000000400 s4 : 0000000000000008 [ 65.730049] s5 : 000000000000006c s6 : ffffffe00240f800 s7 : ffffffe000f080a8 [ 65.731802] s8 : 0000000000000001 s9 : 000000000000012a s10: 0000000000000008 [ 65.733516] s11: 0000000000000008 t3 : 00000000000003ff t4 : 000000000000000f [ 65.734434] t5 : 00000000000003ff t6 : 0000000000040000 [ 65.734613] status: 0000000000000100 badaddr: 0000000000000000 cause: 0000000000000003 [ 65.734901] Call Trace: [ 65.735076] [] __find_get_block+0x218/0x2c8 [ 65.735417] [] __ext4_get_inode_loc+0xb2/0x2f6 [ 65.735618] [] ext4_get_inode_loc+0x3a/0x8a [ 65.735802] [] ext4_reserve_inode_write+0x2e/0x8c [ 65.735999] [] __ext4_mark_inode_dirty+0x4c/0x18e [ 65.736208] [] ext4_dirty_inode+0x46/0x66 [ 65.736387] [] __mark_inode_dirty+0x12c/0x3da [ 65.736576] [] touch_atime+0x146/0x150 [ 65.736748] [] filemap_read+0x234/0x246 [ 65.736920] [] generic_file_read_iter+0xc0/0x114 [ 65.737114] [] ext4_file_read_iter+0x42/0xea [ 65.737310] [] new_sync_read+0xe2/0x15a [ 65.737483] [] vfs_read+0xca/0xf2 [ 65.737641] [] ksys_read+0x5e/0xc8 [ 65.737816] [] sys_read+0xe/0x16 [ 65.737973] [] ret_from_syscall+0x0/0x2 [ 65.738858] ---[ end trace fe93f985456c935d ]---

A simple reproducer looks like: echo 'p:myprobe sys_read fd=%a0 buf=%a1 count=%a2' > /sys/kernel/debug/tracing/kprobe_events echo 1 > /sys/kernel/debug/tracing/events/kprobes/myprobe/enable cat /sys/kernel/debug/tracing/trace

Here's what happens to hit that BUG_ON():

1) After installing kprobe at entry of sys_read, the first instruction is replaced by 'ebreak' instruction on riscv64 platform.

2) Once kernel reach the 'ebreak' instruction at the entry of sys_read, it trap into the riscv breakpoint handler, where it do something to setup for coming single-step of origin instruction, including backup the 'sstatus' in pt_regs, followed by disable interrupt during single stepping via clear 'SIE' bit of 'sstatus' in pt_regs.

3) Then kernel restore to the instruction slot contains two instructions, one is original instruction at entry of sys_read, the other is 'ebreak'. Here it trigger a 'Instruction page fault' exception (value at 'scause' is '0xc'), if PF is not filled into PageTabe for that slot yet.

4) Again kernel trap into page fault exception handler, where it choose different policy according to the state of running kprobe. Because afte 2) the state is KPROBE_HIT_SS, so kernel reset the current kp ---truncated---

Severity ?

5.5 (Medium)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2021-46957"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-02-27T19:04:06Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nriscv/kprobe: fix kernel panic when invoking sys_read traced by kprobe\n\nThe execution of sys_read end up hitting a BUG_ON() in __find_get_block\nafter installing kprobe at sys_read, the BUG message like the following:\n\n[   65.708663] ------------[ cut here ]------------\n[   65.709987] kernel BUG at fs/buffer.c:1251!\n[   65.711283] Kernel BUG [#1]\n[   65.712032] Modules linked in:\n[   65.712925] CPU: 0 PID: 51 Comm: sh Not tainted 5.12.0-rc4 #1\n[   65.714407] Hardware name: riscv-virtio,qemu (DT)\n[   65.715696] epc : __find_get_block+0x218/0x2c8\n[   65.716835]  ra : __getblk_gfp+0x1c/0x4a\n[   65.717831] epc : ffffffe00019f11e ra : ffffffe00019f56a sp : ffffffe002437930\n[   65.719553]  gp : ffffffe000f06030 tp : ffffffe0015abc00 t0 : ffffffe00191e038\n[   65.721290]  t1 : ffffffe00191e038 t2 : 000000000000000a s0 : ffffffe002437960\n[   65.723051]  s1 : ffffffe00160ad00 a0 : ffffffe00160ad00 a1 : 000000000000012a\n[   65.724772]  a2 : 0000000000000400 a3 : 0000000000000008 a4 : 0000000000000040\n[   65.726545]  a5 : 0000000000000000 a6 : ffffffe00191e000 a7 : 0000000000000000\n[   65.728308]  s2 : 000000000000012a s3 : 0000000000000400 s4 : 0000000000000008\n[   65.730049]  s5 : 000000000000006c s6 : ffffffe00240f800 s7 : ffffffe000f080a8\n[   65.731802]  s8 : 0000000000000001 s9 : 000000000000012a s10: 0000000000000008\n[   65.733516]  s11: 0000000000000008 t3 : 00000000000003ff t4 : 000000000000000f\n[   65.734434]  t5 : 00000000000003ff t6 : 0000000000040000\n[   65.734613] status: 0000000000000100 badaddr: 0000000000000000 cause: 0000000000000003\n[   65.734901] Call Trace:\n[   65.735076] [\u003cffffffe00019f11e\u003e] __find_get_block+0x218/0x2c8\n[   65.735417] [\u003cffffffe00020017a\u003e] __ext4_get_inode_loc+0xb2/0x2f6\n[   65.735618] [\u003cffffffe000201b6c\u003e] ext4_get_inode_loc+0x3a/0x8a\n[   65.735802] [\u003cffffffe000203380\u003e] ext4_reserve_inode_write+0x2e/0x8c\n[   65.735999] [\u003cffffffe00020357a\u003e] __ext4_mark_inode_dirty+0x4c/0x18e\n[   65.736208] [\u003cffffffe000206bb0\u003e] ext4_dirty_inode+0x46/0x66\n[   65.736387] [\u003cffffffe000192914\u003e] __mark_inode_dirty+0x12c/0x3da\n[   65.736576] [\u003cffffffe000180dd2\u003e] touch_atime+0x146/0x150\n[   65.736748] [\u003cffffffe00010d762\u003e] filemap_read+0x234/0x246\n[   65.736920] [\u003cffffffe00010d834\u003e] generic_file_read_iter+0xc0/0x114\n[   65.737114] [\u003cffffffe0001f5d7a\u003e] ext4_file_read_iter+0x42/0xea\n[   65.737310] [\u003cffffffe000163f2c\u003e] new_sync_read+0xe2/0x15a\n[   65.737483] [\u003cffffffe000165814\u003e] vfs_read+0xca/0xf2\n[   65.737641] [\u003cffffffe000165bae\u003e] ksys_read+0x5e/0xc8\n[   65.737816] [\u003cffffffe000165c26\u003e] sys_read+0xe/0x16\n[   65.737973] [\u003cffffffe000003972\u003e] ret_from_syscall+0x0/0x2\n[   65.738858] ---[ end trace fe93f985456c935d ]---\n\nA simple reproducer looks like:\n\techo \u0027p:myprobe sys_read fd=%a0 buf=%a1 count=%a2\u0027 \u003e /sys/kernel/debug/tracing/kprobe_events\n\techo 1 \u003e /sys/kernel/debug/tracing/events/kprobes/myprobe/enable\n\tcat /sys/kernel/debug/tracing/trace\n\nHere\u0027s what happens to hit that BUG_ON():\n\n1) After installing kprobe at entry of sys_read, the first instruction\n   is replaced by \u0027ebreak\u0027 instruction on riscv64 platform.\n\n2) Once kernel reach the \u0027ebreak\u0027 instruction at the entry of sys_read,\n   it trap into the riscv breakpoint handler, where it do something to\n   setup for coming single-step of origin instruction, including backup\n   the \u0027sstatus\u0027 in pt_regs, followed by disable interrupt during single\n   stepping via clear \u0027SIE\u0027 bit of \u0027sstatus\u0027 in pt_regs.\n\n3) Then kernel restore to the instruction slot contains two instructions,\n   one is original instruction at entry of sys_read, the other is \u0027ebreak\u0027.\n   Here it trigger a \u0027Instruction page fault\u0027 exception (value at \u0027scause\u0027\n   is \u00270xc\u0027), if PF is not filled into PageTabe for that slot yet.\n\n4) Again kernel trap into page fault exception handler, where it choose\n   different policy according to the state of running kprobe. Because\n   afte 2) the state is KPROBE_HIT_SS, so kernel reset the current kp\n---truncated---",
  "id": "GHSA-rfvx-8c45-w4c7",
  "modified": "2024-11-01T18:31:24Z",
  "published": "2024-02-27T21:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-46957"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b1ebaa0e1318494a7637099a26add50509e37964"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fd0f06590d35c99f98d12c7984897ec4201a6263"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2021-46957 (GCVE-0-2021-46957)

Vulnerability from cvelistv5 – Published: 2024-02-27 18:46 – Updated: 2025-05-04 07:01

Summary

In the Linux kernel, the following vulnerability has been resolved: riscv/kprobe: fix kernel panic when invoking sys_read traced by kprobe The execution of sys_read end up hitting a BUG_ON() in __find_get_block after installing kprobe at sys_read, the BUG message like the following: [ 65.708663] ------------[ cut here ]------------ [ 65.709987] kernel BUG at fs/buffer.c:1251! [ 65.711283] Kernel BUG [#1] [ 65.712032] Modules linked in: [ 65.712925] CPU: 0 PID: 51 Comm: sh Not tainted 5.12.0-rc4 #1 [ 65.714407] Hardware name: riscv-virtio,qemu (DT) [ 65.715696] epc : __find_get_block+0x218/0x2c8 [ 65.716835] ra : __getblk_gfp+0x1c/0x4a [ 65.717831] epc : ffffffe00019f11e ra : ffffffe00019f56a sp : ffffffe002437930 [ 65.719553] gp : ffffffe000f06030 tp : ffffffe0015abc00 t0 : ffffffe00191e038 [ 65.721290] t1 : ffffffe00191e038 t2 : 000000000000000a s0 : ffffffe002437960 [ 65.723051] s1 : ffffffe00160ad00 a0 : ffffffe00160ad00 a1 : 000000000000012a [ 65.724772] a2 : 0000000000000400 a3 : 0000000000000008 a4 : 0000000000000040 [ 65.726545] a5 : 0000000000000000 a6 : ffffffe00191e000 a7 : 0000000000000000 [ 65.728308] s2 : 000000000000012a s3 : 0000000000000400 s4 : 0000000000000008 [ 65.730049] s5 : 000000000000006c s6 : ffffffe00240f800 s7 : ffffffe000f080a8 [ 65.731802] s8 : 0000000000000001 s9 : 000000000000012a s10: 0000000000000008 [ 65.733516] s11: 0000000000000008 t3 : 00000000000003ff t4 : 000000000000000f [ 65.734434] t5 : 00000000000003ff t6 : 0000000000040000 [ 65.734613] status: 0000000000000100 badaddr: 0000000000000000 cause: 0000000000000003 [ 65.734901] Call Trace: [ 65.735076] [<ffffffe00019f11e>] __find_get_block+0x218/0x2c8 [ 65.735417] [<ffffffe00020017a>] __ext4_get_inode_loc+0xb2/0x2f6 [ 65.735618] [<ffffffe000201b6c>] ext4_get_inode_loc+0x3a/0x8a [ 65.735802] [<ffffffe000203380>] ext4_reserve_inode_write+0x2e/0x8c [ 65.735999] [<ffffffe00020357a>] __ext4_mark_inode_dirty+0x4c/0x18e [ 65.736208] [<ffffffe000206bb0>] ext4_dirty_inode+0x46/0x66 [ 65.736387] [<ffffffe000192914>] __mark_inode_dirty+0x12c/0x3da [ 65.736576] [<ffffffe000180dd2>] touch_atime+0x146/0x150 [ 65.736748] [<ffffffe00010d762>] filemap_read+0x234/0x246 [ 65.736920] [<ffffffe00010d834>] generic_file_read_iter+0xc0/0x114 [ 65.737114] [<ffffffe0001f5d7a>] ext4_file_read_iter+0x42/0xea [ 65.737310] [<ffffffe000163f2c>] new_sync_read+0xe2/0x15a [ 65.737483] [<ffffffe000165814>] vfs_read+0xca/0xf2 [ 65.737641] [<ffffffe000165bae>] ksys_read+0x5e/0xc8 [ 65.737816] [<ffffffe000165c26>] sys_read+0xe/0x16 [ 65.737973] [<ffffffe000003972>] ret_from_syscall+0x0/0x2 [ 65.738858] ---[ end trace fe93f985456c935d ]--- A simple reproducer looks like: echo 'p:myprobe sys_read fd=%a0 buf=%a1 count=%a2' > /sys/kernel/debug/tracing/kprobe_events echo 1 > /sys/kernel/debug/tracing/events/kprobes/myprobe/enable cat /sys/kernel/debug/tracing/trace Here's what happens to hit that BUG_ON(): 1) After installing kprobe at entry of sys_read, the first instruction is replaced by 'ebreak' instruction on riscv64 platform. 2) Once kernel reach the 'ebreak' instruction at the entry of sys_read, it trap into the riscv breakpoint handler, where it do something to setup for coming single-step of origin instruction, including backup the 'sstatus' in pt_regs, followed by disable interrupt during single stepping via clear 'SIE' bit of 'sstatus' in pt_regs. 3) Then kernel restore to the instruction slot contains two instructions, one is original instruction at entry of sys_read, the other is 'ebreak'. Here it trigger a 'Instruction page fault' exception (value at 'scause' is '0xc'), if PF is not filled into PageTabe for that slot yet. 4) Again kernel trap into page fault exception handler, where it choose different policy according to the state of running kprobe. Because afte 2) the state is KPROBE_HIT_SS, so kernel reset the current kp ---truncated---

Severity ?

5.5 (Medium)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CWE

CWE-noinfo Not enough information

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/fd0f06590d35c99f9…
	https://git.kernel.org/stable/c/b1ebaa0e1318494a7…

Impacted products

Vendor

Product

Version

Linux

Affected: c22b0bcb1dd024cb9caad9230e3a387d8b061df5 , < fd0f06590d35c99f98d12c7984897ec4201a6263 (git)
Affected: c22b0bcb1dd024cb9caad9230e3a387d8b061df5 , < b1ebaa0e1318494a7637099a26add50509e37964 (git)

Linux

Affected: 5.12
Unaffected: 0 , < 5.12 (semver)
Unaffected: 5.12.3 , ≤ 5.12.* (semver)
Unaffected: 5.13 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 5.5,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2021-46957",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-02-28T19:51:51.883818Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "description": "CWE-noinfo Not enough information",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2024-11-01T14:30:14.111Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T05:17:43.012Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/fd0f06590d35c99f98d12c7984897ec4201a6263"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/b1ebaa0e1318494a7637099a26add50509e37964"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/riscv/kernel/probes/kprobes.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "fd0f06590d35c99f98d12c7984897ec4201a6263",
              "status": "affected",
              "version": "c22b0bcb1dd024cb9caad9230e3a387d8b061df5",
              "versionType": "git"
            },
            {
              "lessThan": "b1ebaa0e1318494a7637099a26add50509e37964",
              "status": "affected",
              "version": "c22b0bcb1dd024cb9caad9230e3a387d8b061df5",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/riscv/kernel/probes/kprobes.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": "5.12.*",
              "status": "unaffected",
              "version": "5.12.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.13",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.12.3",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.13",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nriscv/kprobe: fix kernel panic when invoking sys_read traced by kprobe\n\nThe execution of sys_read end up hitting a BUG_ON() in __find_get_block\nafter installing kprobe at sys_read, the BUG message like the following:\n\n[   65.708663] ------------[ cut here ]------------\n[   65.709987] kernel BUG at fs/buffer.c:1251!\n[   65.711283] Kernel BUG [#1]\n[   65.712032] Modules linked in:\n[   65.712925] CPU: 0 PID: 51 Comm: sh Not tainted 5.12.0-rc4 #1\n[   65.714407] Hardware name: riscv-virtio,qemu (DT)\n[   65.715696] epc : __find_get_block+0x218/0x2c8\n[   65.716835]  ra : __getblk_gfp+0x1c/0x4a\n[   65.717831] epc : ffffffe00019f11e ra : ffffffe00019f56a sp : ffffffe002437930\n[   65.719553]  gp : ffffffe000f06030 tp : ffffffe0015abc00 t0 : ffffffe00191e038\n[   65.721290]  t1 : ffffffe00191e038 t2 : 000000000000000a s0 : ffffffe002437960\n[   65.723051]  s1 : ffffffe00160ad00 a0 : ffffffe00160ad00 a1 : 000000000000012a\n[   65.724772]  a2 : 0000000000000400 a3 : 0000000000000008 a4 : 0000000000000040\n[   65.726545]  a5 : 0000000000000000 a6 : ffffffe00191e000 a7 : 0000000000000000\n[   65.728308]  s2 : 000000000000012a s3 : 0000000000000400 s4 : 0000000000000008\n[   65.730049]  s5 : 000000000000006c s6 : ffffffe00240f800 s7 : ffffffe000f080a8\n[   65.731802]  s8 : 0000000000000001 s9 : 000000000000012a s10: 0000000000000008\n[   65.733516]  s11: 0000000000000008 t3 : 00000000000003ff t4 : 000000000000000f\n[   65.734434]  t5 : 00000000000003ff t6 : 0000000000040000\n[   65.734613] status: 0000000000000100 badaddr: 0000000000000000 cause: 0000000000000003\n[   65.734901] Call Trace:\n[   65.735076] [\u003cffffffe00019f11e\u003e] __find_get_block+0x218/0x2c8\n[   65.735417] [\u003cffffffe00020017a\u003e] __ext4_get_inode_loc+0xb2/0x2f6\n[   65.735618] [\u003cffffffe000201b6c\u003e] ext4_get_inode_loc+0x3a/0x8a\n[   65.735802] [\u003cffffffe000203380\u003e] ext4_reserve_inode_write+0x2e/0x8c\n[   65.735999] [\u003cffffffe00020357a\u003e] __ext4_mark_inode_dirty+0x4c/0x18e\n[   65.736208] [\u003cffffffe000206bb0\u003e] ext4_dirty_inode+0x46/0x66\n[   65.736387] [\u003cffffffe000192914\u003e] __mark_inode_dirty+0x12c/0x3da\n[   65.736576] [\u003cffffffe000180dd2\u003e] touch_atime+0x146/0x150\n[   65.736748] [\u003cffffffe00010d762\u003e] filemap_read+0x234/0x246\n[   65.736920] [\u003cffffffe00010d834\u003e] generic_file_read_iter+0xc0/0x114\n[   65.737114] [\u003cffffffe0001f5d7a\u003e] ext4_file_read_iter+0x42/0xea\n[   65.737310] [\u003cffffffe000163f2c\u003e] new_sync_read+0xe2/0x15a\n[   65.737483] [\u003cffffffe000165814\u003e] vfs_read+0xca/0xf2\n[   65.737641] [\u003cffffffe000165bae\u003e] ksys_read+0x5e/0xc8\n[   65.737816] [\u003cffffffe000165c26\u003e] sys_read+0xe/0x16\n[   65.737973] [\u003cffffffe000003972\u003e] ret_from_syscall+0x0/0x2\n[   65.738858] ---[ end trace fe93f985456c935d ]---\n\nA simple reproducer looks like:\n\techo \u0027p:myprobe sys_read fd=%a0 buf=%a1 count=%a2\u0027 \u003e /sys/kernel/debug/tracing/kprobe_events\n\techo 1 \u003e /sys/kernel/debug/tracing/events/kprobes/myprobe/enable\n\tcat /sys/kernel/debug/tracing/trace\n\nHere\u0027s what happens to hit that BUG_ON():\n\n1) After installing kprobe at entry of sys_read, the first instruction\n   is replaced by \u0027ebreak\u0027 instruction on riscv64 platform.\n\n2) Once kernel reach the \u0027ebreak\u0027 instruction at the entry of sys_read,\n   it trap into the riscv breakpoint handler, where it do something to\n   setup for coming single-step of origin instruction, including backup\n   the \u0027sstatus\u0027 in pt_regs, followed by disable interrupt during single\n   stepping via clear \u0027SIE\u0027 bit of \u0027sstatus\u0027 in pt_regs.\n\n3) Then kernel restore to the instruction slot contains two instructions,\n   one is original instruction at entry of sys_read, the other is \u0027ebreak\u0027.\n   Here it trigger a \u0027Instruction page fault\u0027 exception (value at \u0027scause\u0027\n   is \u00270xc\u0027), if PF is not filled into PageTabe for that slot yet.\n\n4) Again kernel trap into page fault exception handler, where it choose\n   different policy according to the state of running kprobe. Because\n   afte 2) the state is KPROBE_HIT_SS, so kernel reset the current kp\n---truncated---"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-05-04T07:01:09.813Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/fd0f06590d35c99f98d12c7984897ec4201a6263"
        },
        {
          "url": "https://git.kernel.org/stable/c/b1ebaa0e1318494a7637099a26add50509e37964"
        }
      ],
      "title": "riscv/kprobe: fix kernel panic when invoking sys_read traced by kprobe",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-46957",
    "datePublished": "2024-02-27T18:46:58.701Z",
    "dateReserved": "2024-02-27T18:42:55.937Z",
    "dateUpdated": "2025-05-04T07:01:09.813Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
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.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-RFVX-8C45-W4C7

CVE-2021-46957 (GCVE-0-2021-46957)

Tags

Sightings

Nomenclature