7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ibrahim Hashimov [ Upstream commit e2fcb0040b0b4097b2e97f3fbe77d3b66df9e816 ] find_log_rec() validates the on-disk LFS_RECORD_HDR.client_data_len field (`len`, a raw u32 read straight from a mounted $LogFile page) against the log's total available space: len = le32_to_cpu(rh->client_data_len); rec_len = len + log->record_header_len; if (rec_len >= log->total_avail) return -EINVAL; The addition is unchecked. For len in [0xffffffd0, 0xffffffff] (i.e. log->record_header_len away from UINT_MAX), `rec_len` wraps to a small u32 value that trivially clears the `rec_len >= log->total_avail` guard, so a record whose declared length is actually ~4 GiB is reported as valid and in-page. Because find_log_rec() wrongly accepts the record, its caller read_log_rec_lcb() hands it back to log_replay() as good. On the transaction-table replay leg, log_replay() re-derives the record length directly from the same raw, still-unclamped client_data_len field and uses it to size the restart-table blob: rec_len = le32_to_cpu(frh->client_data_len); /* ~0xffffffff */ ... t16 = le16_to_cpu(lrh->redo_off); rt = Add2Ptr(lrh, t16); t32 = rec_len - t16; /* still ~4 GiB */ if (!check_rstbl(rt, t32)) return -EINVAL; check_rstbl()'s own `bytes < ts` bounds guard is defeated because the caller-supplied `bytes` (t32) is itself the poisoned ~4 GiB value, so the guard can never trigger. The subsequent entry-validation loop then walks `rt->used` (also attacker-controlled) entries of sizeof(struct RESTART_TABLE) == 0x18 bytes each straight past the end of the kmalloc(log->page_size) log-page buffer allocated in read_log_page(), producing an out-of-bounds read that is reachable simply by mounting a crafted $LogFile (no genuine dirty-page / crash-recovery state is required). Confirmed via KASAN as a slab-out-of-bounds read in check_rstbl(), called from log_replay() -> ntfs_loadlog_and_replay() -> ntfs_fill_super() -> mount(2). Fix the root cause instead of hardening every downstream consumer of the poisoned length: make the addition in find_log_rec() overflow-safe with check_add_overflow(), mirroring the pattern fs/ntfs3/run.c already uses to validate other attacker-controlled on-disk length/offset arithmetic decoded from MAPPING_PAIRS runs, e.g.: if (check_add_overflow(vcn64, len, &next_vcn)) return -EINVAL; ... if (check_add_overflow(lcn, len, &lcn_end)) return -EINVAL; (fs/ntfs3/run.c, run_unpack()). With the overflow rejected instead of silently wrapped, `rec_len` is only ever a true, non-wrapped sum, so the existing `rec_len >= log->total_avail` check now correctly rejects any oversized record up front. log_replay()'s transaction-table leg then never gets a chance to re-read the poisoned client_data_len, and check_rstbl() is never invoked with an attacker-inflated `bytes` for this path. Verified on a v6.19 KASAN build: mounting a crafted $LogFile whose client_data_len overflows trips a KASAN slab-out-of-bounds-read report in check_rstbl() before this fix; with check_add_overflow() applied, the same image is cleanly rejected during log replay and no KASAN report fires. Fixes: b46acd6a6a62 ("fs/ntfs3: Add NTFS journal") Cc: stable@vger.kernel.org Signed-off-by: Ibrahim Hashimov Assisted-by: AuditCode-AI:2026.07 Signed-off-by: Konstantin Komarov Signed-off-by: Sasha Levin --- fs/ntfs3/fslog.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/ntfs3/fslog.c b/fs/ntfs3/fslog.c index ed50c1d0c23e3..9a44b322ad60e 100644 --- a/fs/ntfs3/fslog.c +++ b/fs/ntfs3/fslog.c @@ -7,6 +7,7 @@ #include #include +#include #include #include @@ -2457,7 +2458,8 @@ static int find_log_rec(struct ntfs_log *log, u64 lsn, struct lcb *lcb) * Check that the length field isn't greater than the total * available space the log file. */ - rec_len = len + log->record_header_len; + if (check_add_overflow(len, log->record_header_len, &rec_len)) + return -EINVAL; if (rec_len >= log->total_avail) return -EINVAL; -- 2.53.0