gsd-2021-47119
Vulnerability from gsd
Modified
2024-03-05 06:03
Details
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix memory leak in ext4_fill_super
Buffer head references must be released before calling kill_bdev();
otherwise the buffer head (and its page referenced by b_data) will not
be freed by kill_bdev, and subsequently that bh will be leaked.
If blocksizes differ, sb_set_blocksize() will kill current buffers and
page cache by using kill_bdev(). And then super block will be reread
again but using correct blocksize this time. sb_set_blocksize() didn't
fully free superblock page and buffer head, and being busy, they were
not freed and instead leaked.
This can easily be reproduced by calling an infinite loop of:
systemctl start <ext4_on_lvm>.mount, and
systemctl stop <ext4_on_lvm>.mount
... since systemd creates a cgroup for each slice which it mounts, and
the bh leak get amplified by a dying memory cgroup that also never
gets freed, and memory consumption is much more easily noticed.
Aliases
{ "gsd": { "metadata": { "exploitCode": "unknown", "remediation": "unknown", "reportConfidence": "confirmed", "type": "vulnerability" }, "osvSchema": { "aliases": [ "CVE-2021-47119" ], "details": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix memory leak in ext4_fill_super\n\nBuffer head references must be released before calling kill_bdev();\notherwise the buffer head (and its page referenced by b_data) will not\nbe freed by kill_bdev, and subsequently that bh will be leaked.\n\nIf blocksizes differ, sb_set_blocksize() will kill current buffers and\npage cache by using kill_bdev(). And then super block will be reread\nagain but using correct blocksize this time. sb_set_blocksize() didn\u0027t\nfully free superblock page and buffer head, and being busy, they were\nnot freed and instead leaked.\n\nThis can easily be reproduced by calling an infinite loop of:\n\n systemctl start \u003cext4_on_lvm\u003e.mount, and\n systemctl stop \u003cext4_on_lvm\u003e.mount\n\n... since systemd creates a cgroup for each slice which it mounts, and\nthe bh leak get amplified by a dying memory cgroup that also never\ngets freed, and memory consumption is much more easily noticed.", "id": "GSD-2021-47119", "modified": "2024-03-05T06:03:55.103085Z", "schema_version": "1.4.0" } }, "namespaces": { "cve.org": { "CVE_data_meta": { "ASSIGNER": "cve@kernel.org", "ID": "CVE-2021-47119", "STATE": "PUBLIC" }, "affects": { "vendor": { "vendor_data": [ { "product": { "product_data": [ { "product_name": "Linux", "version": { "version_data": [ { "version_affected": "\u003c", "version_name": "ac27a0ec112a", "version_value": "01d349a481f0" }, { "version_value": "not down converted", "x_cve_json_5_version_data": { "defaultStatus": "affected", "versions": [ { "status": "affected", "version": "2.6.19" }, { "lessThan": "2.6.19", "status": "unaffected", "version": "0", "versionType": "custom" }, { "lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.43", "versionType": "custom" }, { "lessThanOrEqual": "5.12.*", "status": "unaffected", "version": "5.12.10", "versionType": "custom" }, { "lessThanOrEqual": "*", "status": "unaffected", "version": "5.13", "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\next4: fix memory leak in ext4_fill_super\n\nBuffer head references must be released before calling kill_bdev();\notherwise the buffer head (and its page referenced by b_data) will not\nbe freed by kill_bdev, and subsequently that bh will be leaked.\n\nIf blocksizes differ, sb_set_blocksize() will kill current buffers and\npage cache by using kill_bdev(). And then super block will be reread\nagain but using correct blocksize this time. sb_set_blocksize() didn\u0027t\nfully free superblock page and buffer head, and being busy, they were\nnot freed and instead leaked.\n\nThis can easily be reproduced by calling an infinite loop of:\n\n systemctl start \u003cext4_on_lvm\u003e.mount, and\n systemctl stop \u003cext4_on_lvm\u003e.mount\n\n... since systemd creates a cgroup for each slice which it mounts, and\nthe bh leak get amplified by a dying memory cgroup that also never\ngets freed, and memory consumption is much more easily noticed." } ] }, "generator": { "engine": "bippy-8df59b4913de" }, "problemtype": { "problemtype_data": [ { "description": [ { "lang": "eng", "value": "n/a" } ] } ] }, "references": { "reference_data": [ { "name": "https://git.kernel.org/stable/c/01d349a481f0591230300a9171330136f9159bcd", "refsource": "MISC", "url": "https://git.kernel.org/stable/c/01d349a481f0591230300a9171330136f9159bcd" }, { "name": "https://git.kernel.org/stable/c/1385b23396d511d5233b8b921ac3058b3f86a5e1", "refsource": "MISC", "url": "https://git.kernel.org/stable/c/1385b23396d511d5233b8b921ac3058b3f86a5e1" }, { "name": "https://git.kernel.org/stable/c/afd09b617db3786b6ef3dc43e28fe728cfea84df", "refsource": "MISC", "url": "https://git.kernel.org/stable/c/afd09b617db3786b6ef3dc43e28fe728cfea84df" } ] } }, "nvd.nist.gov": { "cve": { "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix memory leak in ext4_fill_super\n\nBuffer head references must be released before calling kill_bdev();\notherwise the buffer head (and its page referenced by b_data) will not\nbe freed by kill_bdev, and subsequently that bh will be leaked.\n\nIf blocksizes differ, sb_set_blocksize() will kill current buffers and\npage cache by using kill_bdev(). And then super block will be reread\nagain but using correct blocksize this time. sb_set_blocksize() didn\u0027t\nfully free superblock page and buffer head, and being busy, they were\nnot freed and instead leaked.\n\nThis can easily be reproduced by calling an infinite loop of:\n\n systemctl start \u003cext4_on_lvm\u003e.mount, and\n systemctl stop \u003cext4_on_lvm\u003e.mount\n\n... since systemd creates a cgroup for each slice which it mounts, and\nthe bh leak get amplified by a dying memory cgroup that also never\ngets freed, and memory consumption is much more easily noticed." } ], "id": "CVE-2021-47119", "lastModified": "2024-03-17T22:38:29.433", "metrics": {}, "published": "2024-03-15T21:15:07.013", "references": [ { "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/01d349a481f0591230300a9171330136f9159bcd" }, { "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/1385b23396d511d5233b8b921ac3058b3f86a5e1" }, { "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/afd09b617db3786b6ef3dc43e28fe728cfea84df" } ], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Awaiting Analysis" } } } }
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Sightings
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Nomenclature
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