Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: isofs: validate Rock Ridge CE continuation extent against volume size rock_continue() reads rs->cont_extent verbatim from the Rock Ridge CE record and passes it to sb_bread() without checking that the block number is within the mounted ISO 9660 volume. commit e595447e177b ("[PATCH] rock.c: handle corrupted directories") added cont_offset and cont_size rejection for the CE continuation but did not validate the extent block number itself. commit f54e18f1b831 ("isofs: Fix infinite looping over CE entries") later capped the CE chain length at RR_MAX_CE_ENTRIES = 32 but again left the block number unchecked. With a crafted ISO mounted via udisks2 (desktop optical auto-mount) or via CAP_SYS_ADMIN mount, rs->cont_extent can therefore point at an out-of-range block or at blocks belonging to an adjacent filesystem on the same block device. sb_bread() on an out-of-range block returns NULL cleanly via the block layer EIO path, so there is no memory-safety violation. For in-range reads of adjacent- filesystem data, the CE buffer is parsed as Rock Ridge records and only the text of SL sub-records reaches userspace through readlink(), which makes the info-leak channel narrow and difficult to exploit; still, rejecting the malformed CE outright matches the rejection shape already present in the same function for cont_offset and cont_size. Add an ISOFS_SB(sb)->s_nzones bounds check to rock_continue() next to the existing offset/size rejection, printing the same corrupted-directory-entry notice.

Affected versions

Linux: f54e18f1b831c92f6512d2eedb224cd63d607d3d through before 8356fb821016797f5677cbeee5ddc0d32a95b4be (git); f54e18f1b831c92f6512d2eedb224cd63d607d3d through before d582e12378bc1637f337622feef762f53c43fd57 (git); f54e18f1b831c92f6512d2eedb224cd63d607d3d through before bf1bc673c587f5ef7e9c09b94aea7c5a7847d4d9 (git); f54e18f1b831c92f6512d2eedb224cd63d607d3d through before c9b37c8b73f6368e4750e5ccb0632c380b43c6e5 (git); f54e18f1b831c92f6512d2eedb224cd63d607d3d through before 22b36fa081f38ab397c7697f9d539211b51a0cfc (git); f54e18f1b831c92f6512d2eedb224cd63d607d3d through before e69da8eeab74b4f4505024c38a17bce060fe7df8 (git); f54e18f1b831c92f6512d2eedb224cd63d607d3d through before ef048470c90bc8c1b8318bb2ce329da9ef64b9fe (git); f54e18f1b831c92f6512d2eedb224cd63d607d3d through before a36d990f591320e9dd379ab30063ebfe91d47e1f (git); 08313e26e06d4aa9ce1cbba1a8e359e9cab9ad56 (git); 212c4d33ca83e2144064fe9c2911607fbed5386f (git); 96e44adce250199ec9b2b928be66365779ff1b59 (git); 1fe5620fcd6c2f0a4a927ee10c8e53196da392f3 (git); fbce0d7dc8965c9fb8d411862040239d4a768c71 (git); 8190393a88f2b0321263a54f2a9eb5a2aa43be7e (git); 486aa789eadcf44ed87f972b209299c516454693 (git); b6d20edb6e7cedb4eedb9e0193d20dd488ebae84 (git); 2.6.32.66 through before 2.6.33 (semver); 3.2.67 through before 3.3 (semver); 3.4.107 through before 3.5 (semver); 3.10.64 through before 3.11 (semver); 3.12.36 through before 3.13 (semver); 3.14.28 through before 3.15 (semver); 3.17.8 through before 3.18 (semver); 3.18.2 through before 3.19 (semver); 3.19; V3.1.6 through before * (custom) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.