CVE-2025-38415 (GCVE-0-2025-38415)

Vulnerability from cvelistv5 – Published: 2025-07-25 13:32 – Updated: 2026-05-11 21:27
VLAI
Title
Squashfs: check return result of sb_min_blocksize
Summary
In the Linux kernel, the following vulnerability has been resolved: Squashfs: check return result of sb_min_blocksize Syzkaller reports an "UBSAN: shift-out-of-bounds in squashfs_bio_read" bug. Syzkaller forks multiple processes which after mounting the Squashfs filesystem, issues an ioctl("/dev/loop0", LOOP_SET_BLOCK_SIZE, 0x8000). Now if this ioctl occurs at the same time another process is in the process of mounting a Squashfs filesystem on /dev/loop0, the failure occurs. When this happens the following code in squashfs_fill_super() fails. ---- msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE); msblk->devblksize_log2 = ffz(~msblk->devblksize); ---- sb_min_blocksize() returns 0, which means msblk->devblksize is set to 0. As a result, ffz(~msblk->devblksize) returns 64, and msblk->devblksize_log2 is set to 64. This subsequently causes the UBSAN: shift-out-of-bounds in fs/squashfs/block.c:195:36 shift exponent 64 is too large for 64-bit type 'u64' (aka 'unsigned long long') This commit adds a check for a 0 return by sb_min_blocksize().
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 0aa666190509ffab81c202c5095a166be23961ac , < db7096ea160e40d78c67fce52e7cc51bde049497 (git)
Affected: 0aa666190509ffab81c202c5095a166be23961ac , < 549f9e3d7b60d53808c98b9fde49b4f46d0524a5 (git)
Affected: 0aa666190509ffab81c202c5095a166be23961ac , < 5c51aa862cbeed2f3887f0382a2708956710bd68 (git)
Affected: 0aa666190509ffab81c202c5095a166be23961ac , < 6abf6b78c6fb112eee495f5636ffcc350dd2ce25 (git)
Affected: 0aa666190509ffab81c202c5095a166be23961ac , < 4f99357dadbf9c979ad737156ad4c37fadf7c56b (git)
Affected: 0aa666190509ffab81c202c5095a166be23961ac , < 0aff95d9bc7fb5400ca8af507429c4b067bdb425 (git)
Affected: 0aa666190509ffab81c202c5095a166be23961ac , < 295ab18c2dbce8d0ac6ecf7c5187e16e1ac8b282 (git)
Affected: 0aa666190509ffab81c202c5095a166be23961ac , < 734aa85390ea693bb7eaf2240623d41b03705c84 (git)
Create a notification for this product.
Linux Linux Affected: 2.6.29
Unaffected: 0 , < 2.6.29 (semver)
Unaffected: 5.4.295 , ≤ 5.4.* (semver)
Unaffected: 5.10.239 , ≤ 5.10.* (semver)
Unaffected: 5.15.186 , ≤ 5.15.* (semver)
Unaffected: 6.1.142 , ≤ 6.1.* (semver)
Unaffected: 6.6.94 , ≤ 6.6.* (semver)
Unaffected: 6.12.34 , ≤ 6.12.* (semver)
Unaffected: 6.15.3 , ≤ 6.15.* (semver)
Unaffected: 6.16 , ≤ * (original_commit_for_fix)
Create a notification for this product.
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nSquashfs: check return result of sb_min_blocksize\n\nSyzkaller reports an \"UBSAN: shift-out-of-bounds in squashfs_bio_read\" bug.\n\nSyzkaller forks multiple processes which after mounting the Squashfs\nfilesystem, issues an ioctl(\"/dev/loop0\", LOOP_SET_BLOCK_SIZE, 0x8000). \nNow if this ioctl occurs at the same time another process is in the\nprocess of mounting a Squashfs filesystem on /dev/loop0, the failure\noccurs.  When this happens the following code in squashfs_fill_super()\nfails.\n\n----\nmsblk-\u003edevblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE);\nmsblk-\u003edevblksize_log2 = ffz(~msblk-\u003edevblksize);\n----\n\nsb_min_blocksize() returns 0, which means msblk-\u003edevblksize is set to 0.\n\nAs a result, ffz(~msblk-\u003edevblksize) returns 64, and msblk-\u003edevblksize_log2\nis set to 64.\n\nThis subsequently causes the\n\nUBSAN: shift-out-of-bounds in fs/squashfs/block.c:195:36\nshift exponent 64 is too large for 64-bit type \u0027u64\u0027 (aka\n\u0027unsigned long long\u0027)\n\nThis commit adds a check for a 0 return by sb_min_blocksize()."
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When this happens the following code in squashfs_fill_super()\\nfails.\\n\\n----\\nmsblk-\u003edevblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE);\\nmsblk-\u003edevblksize_log2 = ffz(~msblk-\u003edevblksize);\\n----\\n\\nsb_min_blocksize() returns 0, which means msblk-\u003edevblksize is set to 0.\\n\\nAs a result, ffz(~msblk-\u003edevblksize) returns 64, and msblk-\u003edevblksize_log2\\nis set to 64.\\n\\nThis subsequently causes the\\n\\nUBSAN: shift-out-of-bounds in fs/squashfs/block.c:195:36\\nshift exponent 64 is too large for 64-bit type \u0027u64\u0027 (aka\\n\u0027unsigned long long\u0027)\\n\\nThis commit adds a check for a 0 return by sb_min_blocksize().\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: Squashfs: comprobar el resultado devuelto de sb_min_blocksize. Syzkaller informa del error \\\"UBSAN: desplazamiento fuera de los l\u00edmites en squashfs_bio_read\\\". Syzkaller bifurca varios procesos que, tras montar el sistema de archivos Squashfs, emiten una instrucci\u00f3n ioctl(\\\"/dev/loop0\\\", LOOP_SET_BLOCK_SIZE, 0x8000). Si esta instrucci\u00f3n ioctl se produce al mismo tiempo que otro proceso est\u00e1 montando un sistema de archivos Squashfs en /dev/loop0, se produce el fallo. En este caso, el siguiente c\u00f3digo en squashfs_fill_super() falla: ---- msblk-\u0026gt;devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE); msblk-\u0026gt;devblksize_log2 = ffz(~msblk-\u0026gt;devblksize); ---- sb_min_blocksize() devuelve 0, lo que significa que msblk-\u0026gt;devblksize est\u00e1 establecido en 0. Como resultado, ffz(~msblk-\u0026gt;devblksize) devuelve 64 y msblk-\u0026gt;devblksize_log2 est\u00e1 establecido en 64. Esto posteriormente provoca el UBSAN: shift-out-of-bounds en fs/squashfs/block.c:195:36 el exponente de desplazamiento 64 es demasiado grande para el tipo de 64 bits \u0027u64\u0027 (tambi\u00e9n conocido como \u0027unsigned long long\u0027) Esta confirmaci\u00f3n agrega una comprobaci\u00f3n para un retorno de 0 por sb_min_blocksize().\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-787\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"2.6.29\",\"versionEndExcluding\":\"5.4.295\",\"matchCriteriaId\":\"D5BDC9F5-7B03-44B2-BD32-CD273F349554\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.5\",\"versionEndExcluding\":\"5.10.239\",\"matchCriteriaId\":\"C3D14F4C-A21E-465D-A928-5CCE684E2B98\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.11\",\"versionEndExcluding\":\"5.15.186\",\"matchCriteriaId\":\"D96F2C0D-0D4A-4658-AD34-D8A626EA422D\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.16\",\"versionEndExcluding\":\"6.1.142\",\"matchCriteriaId\":\"459B4E94-FE0E-434D-B782-95E3A5FFC6B1\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.2\",\"versionEndExcluding\":\"6.6.94\",\"matchCriteriaId\":\"304E3F01-7D7A-4908-994E-7F95C5C00B06\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.7\",\"versionEndExcluding\":\"6.12.34\",\"matchCriteriaId\":\"4FFA54AA-CDFE-4591-BD07-72813D0948F4\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.13\",\"versionEndExcluding\":\"6.15.3\",\"matchCriteriaId\":\"0541C761-BD5E-4C1A-8432-83B375D7EB92\"}]}]},{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"FA6FEEC2-9F11-4643-8827-749718254FED\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0aff95d9bc7fb5400ca8af507429c4b067bdb425\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/295ab18c2dbce8d0ac6ecf7c5187e16e1ac8b282\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/4f99357dadbf9c979ad737156ad4c37fadf7c56b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/549f9e3d7b60d53808c98b9fde49b4f46d0524a5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/5c51aa862cbeed2f3887f0382a2708956710bd68\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/6abf6b78c6fb112eee495f5636ffcc350dd2ce25\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/734aa85390ea693bb7eaf2240623d41b03705c84\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/db7096ea160e40d78c67fce52e7cc51bde049497\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Third Party Advisory\",\"Mailing List\"]},{\"url\":\"https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Third Party Advisory\",\"Mailing List\"]}]}}"
  }
}


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