Description
In the Linux kernel, the following vulnerability has been resolved: exfat: bound uniname advance in exfat_find_dir_entry() In exfat_find_dir_entry(), each TYPE_EXTEND (file name) entry advances the output pointer by a fixed amount while the loop guard only tracks the accumulated name length: if (++order == 2) uniname = p_uniname->name; else uniname += EXFAT_FILE_NAME_LEN; len = exfat_extract_uni_name(ep, entry_uniname); name_len += len; unichar = *(uniname+len); *(uniname+len) = 0x0; uniname grows by EXFAT_FILE_NAME_LEN (15) per name entry, but name_len grows only by the actual extracted length, which is shorter when a name fragment contains an early NUL. The only guard is `name_len >= MAX_NAME_LENGTH`, so a crafted directory with many short name fragments lets uniname run far past the p_uniname->name[MAX_NAME_LENGTH + 3] buffer while name_len stays small, causing an out-of-bounds read and write at *(uniname+len). The sibling extractor exfat_get_uniname_from_ext_entry() already stops on a short fragment (the lockstep `len != EXFAT_FILE_NAME_LEN` guard added in commit d42334578eba ("exfat: check if filename entries exceeds max filename length")); exfat_find_dir_entry() never got the equivalent. Track the per-entry write offset as a count and reject a fragment once the offset, or the offset plus the extracted length, would exceed MAX_NAME_LENGTH, before forming the output pointer.
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
ca06197382bde0a3bc20215595d1c9ce20c6e341 to < 72a2589d82eb001c94b74bcfe6f9a599bd9bef60affectedca06197382bde0a3bc20215595d1c9ce20c6e341 to < fae76a94b35ee8c0e2eb6f64caca01d75c6d34e4affectedca06197382bde0a3bc20215595d1c9ce20c6e341 to < cf85180b8a015029ee147694eaf4e0b3537e9432affectedca06197382bde0a3bc20215595d1c9ce20c6e341 to < ce4736c1e6c4cfbf1ac409a8c328a0b69546c9a0affectedca06197382bde0a3bc20215595d1c9ce20c6e341 to < 727bf7783a2936ffd55c628dddfd69343e511dcfaffectedca06197382bde0a3bc20215595d1c9ce20c6e341 to < 33c0b96d7e1672be1de0053786637ea46fb81507affectedca06197382bde0a3bc20215595d1c9ce20c6e341 to < c8e041c68c0bbb73aa62371ee63947bb6949d8b2affectedca06197382bde0a3bc20215595d1c9ce20c6e341 to < 3a1230e7b043c62737b05a3e9275ca83a43ad20aaffected
Linux Linux
Default version status: affected
5.7affected0 to < 5.7unaffected5.10.261 to ≤ 5.10.*unaffected5.15.212 to ≤ 5.15.*unaffected6.1.178 to ≤ 6.1.*unaffected6.6.145 to ≤ 6.6.*unaffected6.12.96 to ≤ 6.12.*unaffected6.18.39 to ≤ 6.18.*unaffected7.1.4 to ≤ 7.1.*unaffected7.2 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/72a2589d82eb001c94b74bcfe6f9a599bd9bef60 ↗
- https://git.kernel.org/stable/c/fae76a94b35ee8c0e2eb6f64caca01d75c6d34e4 ↗
- https://git.kernel.org/stable/c/cf85180b8a015029ee147694eaf4e0b3537e9432 ↗
- https://git.kernel.org/stable/c/ce4736c1e6c4cfbf1ac409a8c328a0b69546c9a0 ↗
- https://git.kernel.org/stable/c/727bf7783a2936ffd55c628dddfd69343e511dcf ↗
- https://git.kernel.org/stable/c/33c0b96d7e1672be1de0053786637ea46fb81507 ↗
- https://git.kernel.org/stable/c/c8e041c68c0bbb73aa62371ee63947bb6949d8b2 ↗
- https://git.kernel.org/stable/c/3a1230e7b043c62737b05a3e9275ca83a43ad20a ↗