Description
In the Linux kernel, the following vulnerability has been resolved: ntfs3: cap RESTART_TABLE free-chain walker at rt->used A crafted NTFS3 disk image triggers an in-kernel infinite loop at mount time, hanging the mounting thread and firing the soft-lockup watchdog within ~22s on multi-CPU hosts (panic with kernel.softlockup_panic=1). The bug is reachable from desktop USB auto-mount on distributions where udisks2 routes the NTFS signature to the in-tree ntfs3 driver (Arch family and an increasing fraction of Fedora / openSUSE / RHEL deployments); CAP_SYS_ADMIN-class manual mount elsewhere. check_rstbl()'s second walker iterates the free-entry singly-linked list headed by rt->first_free with no upper bound on iteration count: for (off = ff; off;) { if (off == RESTART_ENTRY_ALLOCATED) return false; off = le32_to_cpu(*(__le32 *)Add2Ptr(rt, off)); if (off > ts - sizeof(__le32)) return false; } The existing guards cover three exits: end-of-list (off == 0), the in-use marker (off == RESTART_ENTRY_ALLOCATED), and out-of-bounds (off > ts - sizeof(__le32)). None of the three prevents an in-bounds cycle. A crafted on-disk RESTART_TABLE whose free chain contains a self-loop or A->B->A cycle whose offsets satisfy: - in range [sizeof(struct RESTART_TABLE), ts - sizeof(__le32)] - (off - sizeof(struct RESTART_TABLE)) % rsize == 0 passes all existing guards and spins the mount-time thread forever. Reproduced in UML by hand-forging a 2 MB NTFS3 image whose journal RESTART_TABLE first_free = 0x18 and whose entry at offset 0x18 stores 0x18 as its next pointer; mount of the forged image with the in-tree ntfs3 driver never returns. Bound the walker by rt->used. Each entry on a legitimate free chain is unique, and the total slot count is ne = le16_to_cpu (rt->used). A traversal that visits more than ne slots is by construction malformed; reject it as a corrupt RESTART_TABLE. After this patch, mount of the forged image returns with -EINVAL and a log_replay failure message, and mkntfs-produced legitimate images mount cleanly (verified in the same UML harness).
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
b46acd6a6a627d876898e1c84d3f84902264b445 to < 8128bec895075253c779d67afdc90ae513265fcaaffectedb46acd6a6a627d876898e1c84d3f84902264b445 to < 7972df425687daa70d971fe6ed415e78683133ddaffectedb46acd6a6a627d876898e1c84d3f84902264b445 to < 7ac4c86915c24c208a0f0611b71d9676686fe756affectedb46acd6a6a627d876898e1c84d3f84902264b445 to < 29b86dbe88cbbef53bb9aaec2e279359f8c450f8affectedb46acd6a6a627d876898e1c84d3f84902264b445 to < 0fad25687d4d3fa1fdd313d31b9cb5817c425029affectedb46acd6a6a627d876898e1c84d3f84902264b445 to < d313416280d41bea272f02a6034dfa88008692a0affectedb46acd6a6a627d876898e1c84d3f84902264b445 to < 9611f644302c07d21bc8af97e3e06a3d30064253affected
Linux Linux
Default version status: affected
5.15affected0 to < 5.15unaffected5.15.212 to ≤ 5.15.*unaffected6.1.178 to ≤ 6.1.*unaffected6.6.145 to ≤ 6.6.*unaffected6.12.97 to ≤ 6.12.*unaffected6.18.40 to ≤ 6.18.*unaffected7.1.5 to ≤ 7.1.*unaffected7.2 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/8128bec895075253c779d67afdc90ae513265fca ↗
- https://git.kernel.org/stable/c/7972df425687daa70d971fe6ed415e78683133dd ↗
- https://git.kernel.org/stable/c/7ac4c86915c24c208a0f0611b71d9676686fe756 ↗
- https://git.kernel.org/stable/c/29b86dbe88cbbef53bb9aaec2e279359f8c450f8 ↗
- https://git.kernel.org/stable/c/0fad25687d4d3fa1fdd313d31b9cb5817c425029 ↗
- https://git.kernel.org/stable/c/d313416280d41bea272f02a6034dfa88008692a0 ↗
- https://git.kernel.org/stable/c/9611f644302c07d21bc8af97e3e06a3d30064253 ↗