6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
commit 6f7b9dbdc1b7520206abce0049bdd143eb536e75 upstream.
The copy_lcns loop and the redo shorten loop index page_lcns[] at j + i,
where i runs up to the log record's lcns_follow. That count is checked only
against the record's own length, not the target entry, so check_dp_table()
(which validates the entry's lcns_follow) does not cover it: the copy_lcns
entry may even be freshly allocated after that check, and find_dp() bounds j
but not i. A crafted record thus overflows page_lcns[] of an otherwise valid
entry.
Add dp_range_ok() and reject, before each loop, any record whose run does
not fit the entry. These are the only two page_lcns[] accesses indexed by
the record rather than the entry, so together with the entry validation
every access is now bounded.
Fixes: b46acd6a6a62 ("fs/ntfs3: Add NTFS journal")
Cc: <redacted>
Reported-by: Weiming Shi <redacted>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Xiang Mei <redacted>
[almaz.alexandrovich@paragon-software.com: original patch contained changes to the problem already handled, applied partly]
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/ntfs3/fslog.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
--- a/fs/ntfs3/fslog.c
+++ b/fs/ntfs3/fslog.c
@@ -648,6 +648,14 @@ static inline void *enum_rstbl(struct RE
}
/*
+ * dp_range_ok - true if [j, j + count) fits in a page_lcns[cap] array.
+ */
+static inline bool dp_range_ok(size_t j, u32 count, u32 cap)
+{
+ return j < cap && count <= cap - j;
+}
+
+/*
* find_dp - Search for a @vcn in Dirty Page Table.
*/
static inline struct DIR_PAGE_ENTRY *find_dp(struct RESTART_TABLE *dptbl,@@ -5078,6 +5086,13 @@ find_dirty_page:
/* Shorten length by any Lcns which were deleted. */
saved_len = dlen;
+ if (!dp_range_ok(le64_to_cpu(lrh->target_vcn) - le64_to_cpu(dp->vcn),
+ le16_to_cpu(lrh->lcns_follow),
+ le32_to_cpu(dp->lcns_follow))) {
+ err = -EINVAL;
+ goto out;
+ }
+
for (i = le16_to_cpu(lrh->lcns_follow); i; i--) {
size_t j;
u32 alen, voff;