From 006cb7713dec10368e699abc4367e5faa334c9a5 Mon Sep 17 00:00:00 2001 From: Xiang Mei Date: Wed, 17 Jun 2026 16:13:42 -0700 Subject: [PATCH] fs/ntfs3: validate dirty page table on log replay Each DIR_PAGE_ENTRY ends in a page_lcns[] array whose length is the on-disk lcns_follow field. check_rstbl() validates the table bookkeeping but never checks that this array fits in the entry, so a crafted lcns_follow lets the v0->v1 conversion memmove and later replay passes run off the entry. Add check_dp_table() to reject, right after check_rstbl(), any entry larger than its size claims via struct_size() (the same expression used to allocate these entries, so the check is overflow-safe by construction). All consumers can then trust lcns_follow as the real capacity. This covers every page_lcns[] access whose index is bounded by the entry itself (the conversion memmove, the HotFix store via find_dp(), and the self-bounded scan loops). Accesses whose index comes from the log record need a separate bound and are handled in a follow-up patch. Fixes: b46acd6a6a62 ("fs/ntfs3: Add NTFS journal") Cc: stable@vger.kernel.org Reported-by: Weiming Shi Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Xiang Mei Signed-off-by: Konstantin Komarov --- fs/ntfs3/fslog.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/fs/ntfs3/fslog.c b/fs/ntfs3/fslog.c index ab210c33f770..db5eec0aab61 100644 --- a/fs/ntfs3/fslog.c +++ b/fs/ntfs3/fslog.c @@ -789,6 +789,20 @@ static bool check_rstbl(const struct RESTART_TABLE *rt, size_t bytes) return true; } +static bool check_dp_table(const struct RESTART_TABLE *dptbl) +{ + u32 rsize = le16_to_cpu(dptbl->size); + struct DIR_PAGE_ENTRY *dp = NULL; + + while ((dp = enum_rstbl((struct RESTART_TABLE *)dptbl, dp))) { + if (struct_size(dp, page_lcns, le32_to_cpu(dp->lcns_follow)) > + rsize) + return false; + } + + return true; +} + /* * free_rsttbl_idx - Free a previously allocated index a Restart Table. */ @@ -4293,6 +4307,11 @@ int log_replay(struct ntfs_inode *ni, bool *initialized) goto out; } + if (!check_dp_table(rt)) { + err = -EINVAL; + goto out; + } + dptbl = kmemdup(rt, t32, GFP_NOFS); if (!dptbl) { err = -ENOMEM;