Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: ksmbd: restore DACL size on check_add_overflow() to avoid malformed ACL check_add_overflow() unconditionally writes the truncated sum into *d even on overflow, per its contract in include/linux/overflow.h. The four check_add_overflow() guards in set_posix_acl_entries_dacl() and set_ntacl_dacl() break out of the ACE-building loops on overflow, but the truncated *size is then consumed downstream at the end of set_ntacl_dacl(): pndacl->size = cpu_to_le16(le16_to_cpu(pndacl->size) + size); This produces an on-wire NT ACL whose pndacl->size under-reports the bytes actually written by the preceding fill_ace_for_sid()/memcpy() calls, yielding a malformed ACL that can trigger out-of-bounds reads when re-parsed by clients or ksmbd itself. Restore *size to its pre-addition value on each overflow branch (via `*size -= ace_sz` / `size -= nt_ace_size`) so that after the break, *size once again holds the cumulative size of the successfully-written ACEs. The committed ACL is then truncated-but-self-consistent rather than malformed. The ksmbd DACL builders are the only check_add_overflow() sites found where an overflow path breaks out of a loop and the destination value is consumed afterward. The other nearby break-style cases either return -EINVAL on overflow (transport_ipc.c) or break without consuming the overflowed destination value afterward (buildid.c).
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 41e53a773db6342ac9a689ee5ba635c31744c9f0 before 8f3a7a499a7d9bb1c0f33fe78c4a4594d7e307f4; affected 8d5729350b236896f51379588d9a690b7fafb8db before f4fcd0c1a243d449307b887fafee23921e9db5ab; affected e1955a94b6f17f4b058afa955a6f187eb3ed7615 before 0bf38372821b1526f31538a7d9811844c55c7f38; affected 5e7b8f3c539d69b2ed5f2408e2f75e68ce7eef43 before 847ecd4eb3c117c3d2f13f1e7ab506543aad8183; affected 299f962c0b02d048fb45d248b4da493d03f3175d before bc90144ce8bb7fcf05ad9417c7adb4e9509d9e13; affected 299f962c0b02d048fb45d248b4da493d03f3175d before bbf0a8e931204ecdab494a88d43b0a24a04285c5; affected ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7; affected 6.1.175 before 6.1.184; affected 6.6.136 before 6.6.148; affected 6.12.84 before 6.12.101; affected 6.18.25 before 6.18.42; affected 7.0.2 before 7.1 |
| Linux / Linux | affected 7.1; unaffected 0 before 7.1; unaffected 6.1.184 through 6.1.*; unaffected 6.6.148 through 6.6.*; unaffected 6.12.101 through 6.12.*; unaffected 6.18.42 through 6.18.*; unaffected 7.1.6 through 7.1.*; unaffected 7.2 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/8f3a7a499a7d9bb1c0f33fe78c4a4594d7e307f4
- https://git.kernel.org/stable/c/f4fcd0c1a243d449307b887fafee23921e9db5ab
- https://git.kernel.org/stable/c/0bf38372821b1526f31538a7d9811844c55c7f38
- https://git.kernel.org/stable/c/847ecd4eb3c117c3d2f13f1e7ab506543aad8183
- https://git.kernel.org/stable/c/bc90144ce8bb7fcf05ad9417c7adb4e9509d9e13
- https://git.kernel.org/stable/c/bbf0a8e931204ecdab494a88d43b0a24a04285c5