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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-89490

ocfs2: fix readdir position truncation on 32-bit kernels

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix readdir position truncation on 32-bit kernels In ocfs2_dir_foreach_blk_el(), the directory cookie position is rebuilt with ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1)) | offset; `ctx->pos` is loff_t (signed 64-bit), while `sb->s_blocksize` is unsigned long. On 32-bit kernels unsigned long is 32-bit, so the mask ~(sb->s_blocksize - 1) is computed as a 32-bit unsigned value (e.g. 0xfffff000 for a 4 KiB block size). In the AND expression with the 64-bit `ctx->pos`, that unsigned operand is zero-extended to 64 bits per the usual arithmetic conversions, yielding 0x00000000fffff000. The high 32 bits of `ctx->pos` are silently cleared, even though directory size is allowed to exceed 4 GiB. When readdir() crosses the 4 GiB boundary on a 32-bit kernel the position is reset back into the first 4 GiB block, making the re-validation path re-enumerate already-returned dirents indefinitely. This is ocfs2_dir_foreach_blk_el(), the extent-list readdir path taken for all non-inline directories, so a directory large enough to cross 4 GiB reaches it. This is the same class of bug that commit 3dce5bb82c97 ("exfat: Fix bitwise operation having different size") fixed in exfat, and the fix mirrors the equivalent ext4 fix in this series. Cast the operand to loff_t so the mask is 64-bit before the AND: ctx->pos = (ctx->pos & ~((loff_t)sb->s_blocksize - 1)) | offset; 64-bit kernels are unaffected.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • ccd979bdbce9fba8412beb3f1de68a9d0171b12c to < c28dc3407937aa8f225942538cd585c9b28ea65aaffected
  • ccd979bdbce9fba8412beb3f1de68a9d0171b12c to < 94569154ba49f5f85645d2019c8e206213d8404eaffected
  • ccd979bdbce9fba8412beb3f1de68a9d0171b12c to < 1ae7029823ae4c91664cb32eec7fb8dd5e1a337aaffected
  • ccd979bdbce9fba8412beb3f1de68a9d0171b12c to < f9dd5cad8d09110ddff2db1fe756aae93c7552ffaffected
  • ccd979bdbce9fba8412beb3f1de68a9d0171b12c to < 1001fb3b69a11eaa0dc7c7428f6edfa48b88997aaffected
  • ccd979bdbce9fba8412beb3f1de68a9d0171b12c to < c0c165487a2ea5a37ddcdab4259157b7a527129caffected
  • ccd979bdbce9fba8412beb3f1de68a9d0171b12c to < b53e2b271eeb6040c2a4a78230c570dc41cdcfa4affected
  • ccd979bdbce9fba8412beb3f1de68a9d0171b12c to < a63308ab426f3a3c7e33b02c150ea59054620261affected

Linux Linux

Default version status: affected

  • 2.6.16affected
  • 0 to < 2.6.16unaffected
  • 5.10.270 to ≤ 5.10.*unaffected
  • 5.15.221 to ≤ 5.15.*unaffected
  • 6.1.188 to ≤ 6.1.*unaffected
  • 6.6.157 to ≤ 6.6.*unaffected
  • 6.12.109 to ≤ 6.12.*unaffected
  • 6.18.50 to ≤ 6.18.*unaffected
  • 7.2.4 to ≤ 7.2.*unaffected
  • 7.3 to ≤ *unaffected

References