cve-2021-47089
Vulnerability from cvelistv5
Published
2024-03-04 18:10
Modified
2024-08-04 05:24
Severity
Summary
kfence: fix memory leak when cat kfence objects
References
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"id": "CVE-2021-47089",
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"role": "CISA Coordinator",
"timestamp": "2024-07-24T14:25:46.166024Z",
"version": "2.0.3"
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"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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"dateUpdated": "2024-08-04T05:24:39.939Z",
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"url": "https://git.kernel.org/stable/c/2f06c8293d27f6337f907042c602c9c953988c48"
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"url": "https://git.kernel.org/stable/c/0129ab1f268b6cf88825eae819b9b84aa0a85634"
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"title": "CVE Program Container"
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"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"mm/kfence/core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"status": "affected",
"version": "5.12"
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"status": "unaffected",
"version": "0",
"versionType": "custom"
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"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.12",
"versionType": "custom"
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"status": "unaffected",
"version": "5.16",
"versionType": "original_commit_for_fix"
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"descriptions": [
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"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nkfence: fix memory leak when cat kfence objects\n\nHulk robot reported a kmemleak problem:\n\n unreferenced object 0xffff93d1d8cc02e8 (size 248):\n comm \"cat\", pid 23327, jiffies 4624670141 (age 495992.217s)\n hex dump (first 32 bytes):\n 00 40 85 19 d4 93 ff ff 00 10 00 00 00 00 00 00 .@..............\n 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................\n backtrace:\n seq_open+0x2a/0x80\n full_proxy_open+0x167/0x1e0\n do_dentry_open+0x1e1/0x3a0\n path_openat+0x961/0xa20\n do_filp_open+0xae/0x120\n do_sys_openat2+0x216/0x2f0\n do_sys_open+0x57/0x80\n do_syscall_64+0x33/0x40\n entry_SYSCALL_64_after_hwframe+0x44/0xa9\n unreferenced object 0xffff93d419854000 (size 4096):\n comm \"cat\", pid 23327, jiffies 4624670141 (age 495992.217s)\n hex dump (first 32 bytes):\n 6b 66 65 6e 63 65 2d 23 32 35 30 3a 20 30 78 30 kfence-#250: 0x0\n 30 30 30 30 30 30 30 37 35 34 62 64 61 31 32 2d 0000000754bda12-\n backtrace:\n seq_read_iter+0x313/0x440\n seq_read+0x14b/0x1a0\n full_proxy_read+0x56/0x80\n vfs_read+0xa5/0x1b0\n ksys_read+0xa0/0xf0\n do_syscall_64+0x33/0x40\n entry_SYSCALL_64_after_hwframe+0x44/0xa9\n\nI find that we can easily reproduce this problem with the following\ncommands:\n\n\tcat /sys/kernel/debug/kfence/objects\n\techo scan \u003e /sys/kernel/debug/kmemleak\n\tcat /sys/kernel/debug/kmemleak\n\nThe leaked memory is allocated in the stack below:\n\n do_syscall_64\n do_sys_open\n do_dentry_open\n full_proxy_open\n seq_open ---\u003e alloc seq_file\n vfs_read\n full_proxy_read\n seq_read\n seq_read_iter\n traverse ---\u003e alloc seq_buf\n\nAnd it should have been released in the following process:\n\n do_syscall_64\n syscall_exit_to_user_mode\n exit_to_user_mode_prepare\n task_work_run\n ____fput\n __fput\n full_proxy_release ---\u003e free here\n\nHowever, the release function corresponding to file_operations is not\nimplemented in kfence. As a result, a memory leak occurs. Therefore,\nthe solution to this problem is to implement the corresponding release\nfunction."
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"dateUpdated": "2024-05-29T05:01:53.887Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"references": [
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"url": "https://git.kernel.org/stable/c/2f06c8293d27f6337f907042c602c9c953988c48"
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"url": "https://git.kernel.org/stable/c/0129ab1f268b6cf88825eae819b9b84aa0a85634"
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"title": "kfence: fix memory leak when cat kfence objects",
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"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2021-47089",
"datePublished": "2024-03-04T18:10:27.495Z",
"dateReserved": "2024-02-29T22:33:44.300Z",
"dateUpdated": "2024-08-04T05:24:39.939Z",
"state": "PUBLISHED"
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"meta": {
"nvd": "{\"cve\":{\"id\":\"CVE-2021-47089\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2024-03-04T18:15:07.560\",\"lastModified\":\"2024-03-05T13:41:01.900\",\"vulnStatus\":\"Awaiting Analysis\",\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nkfence: fix memory leak when cat kfence objects\\n\\nHulk robot reported a kmemleak problem:\\n\\n unreferenced object 0xffff93d1d8cc02e8 (size 248):\\n comm \\\"cat\\\", pid 23327, jiffies 4624670141 (age 495992.217s)\\n hex dump (first 32 bytes):\\n 00 40 85 19 d4 93 ff ff 00 10 00 00 00 00 00 00 .@..............\\n 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................\\n backtrace:\\n seq_open+0x2a/0x80\\n full_proxy_open+0x167/0x1e0\\n do_dentry_open+0x1e1/0x3a0\\n path_openat+0x961/0xa20\\n do_filp_open+0xae/0x120\\n do_sys_openat2+0x216/0x2f0\\n do_sys_open+0x57/0x80\\n do_syscall_64+0x33/0x40\\n entry_SYSCALL_64_after_hwframe+0x44/0xa9\\n unreferenced object 0xffff93d419854000 (size 4096):\\n comm \\\"cat\\\", pid 23327, jiffies 4624670141 (age 495992.217s)\\n hex dump (first 32 bytes):\\n 6b 66 65 6e 63 65 2d 23 32 35 30 3a 20 30 78 30 kfence-#250: 0x0\\n 30 30 30 30 30 30 30 37 35 34 62 64 61 31 32 2d 0000000754bda12-\\n backtrace:\\n seq_read_iter+0x313/0x440\\n seq_read+0x14b/0x1a0\\n full_proxy_read+0x56/0x80\\n vfs_read+0xa5/0x1b0\\n ksys_read+0xa0/0xf0\\n do_syscall_64+0x33/0x40\\n entry_SYSCALL_64_after_hwframe+0x44/0xa9\\n\\nI find that we can easily reproduce this problem with the following\\ncommands:\\n\\n\\tcat /sys/kernel/debug/kfence/objects\\n\\techo scan \u003e /sys/kernel/debug/kmemleak\\n\\tcat /sys/kernel/debug/kmemleak\\n\\nThe leaked memory is allocated in the stack below:\\n\\n do_syscall_64\\n do_sys_open\\n do_dentry_open\\n full_proxy_open\\n seq_open ---\u003e alloc seq_file\\n vfs_read\\n full_proxy_read\\n seq_read\\n seq_read_iter\\n traverse ---\u003e alloc seq_buf\\n\\nAnd it should have been released in the following process:\\n\\n do_syscall_64\\n syscall_exit_to_user_mode\\n exit_to_user_mode_prepare\\n task_work_run\\n ____fput\\n __fput\\n full_proxy_release ---\u003e free here\\n\\nHowever, the release function corresponding to file_operations is not\\nimplemented in kfence. As a result, a memory leak occurs. Therefore,\\nthe solution to this problem is to implement the corresponding release\\nfunction.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: kfence: repara la p\u00e9rdida de memoria cuando los objetos cat kfence Hulk robot inform\u00f3 un problema kmemleak: objeto sin referencia 0xffff93d1d8cc02e8 (tama\u00f1o 248): comm \\\"cat\\\", pid 23327, jiffies 4624670141 (edad 495992.217s ) volcado hexadecimal (primeros 32 bytes): 00 40 85 19 d4 93 ff ff 00 10 00 00 00 00 00 00 .@.............. 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................. rastreo inverso: seq_open+0x2a/0x80 full_proxy_open+0x167/0x1e0 do_dentry_open+0x1e1/0x3a0 path_openat+0x961/0xa20 do_filp_open+0xae/0x120 do_sys_openat2+0x216/0x2f0 do_sys_open+0x57/0x80 do_syscall_64+0x33/0x40 Entry_SYSCALL_64_after_hwframe+0x44/0xa9 objeto sin referencia 0xffff93d419854000 (tama\u00f1o 4096): comm \\\"cat\\\", pid 23327, Jiffies 4624670141 (edad 495992,217 s) volcado hexadecimal (primeros 32 bytes) : 6b 66 65 6e 63 65 2d 23 32 35 30 3a 20 30 78 30 kfence-#250: 0x0 30 30 30 30 30 30 30 37 35 34 62 64 61 31 32 2d 0000000754bda1 2- rastreo inverso: seq_read_iter+0x313/0x440 seq_read+ 0x14b/0x1a0 full_proxy_read+0x56/0x80 vfs_read+0xa5/0x1b0 ksys_read+0xa0/0xf0 do_syscall_64+0x33/0x40 Entry_SYSCALL_64_after_hwframe+0x44/0xa9 Creo que podemos reproducir f\u00e1cilmente este problema con los siguientes comandos: cat /sys/kernel/ depurar/ kfence/objects echo scan \u0026gt; /sys/kernel/debug/kmemleak cat /sys/kernel/debug/kmemleak La memoria filtrada se asigna en la pila siguiente: do_syscall_64 do_sys_open do_dentry_open full_proxy_open seq_open ---\u0026gt; alloc seq_file vfs_read full_proxy_read seq_read seq_read_iter traverse - --\u0026gt; alloc seq_buf Y deber\u00eda haberse liberado en el siguiente proceso: do_syscall_64 syscall_exit_to_user_mode exit_to_user_mode_prepare task_work_run ____fput __fput full_proxy_release ---\u0026gt; free aqu\u00ed Sin embargo, la funci\u00f3n de liberaci\u00f3n correspondiente a file_operatives no est\u00e1 implementada en kfence. Como resultado, se produce una p\u00e9rdida de memoria. Por tanto, la soluci\u00f3n a este problema es implementar la funci\u00f3n de liberaci\u00f3n correspondiente.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0129ab1f268b6cf88825eae819b9b84aa0a85634\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/2f06c8293d27f6337f907042c602c9c953988c48\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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