5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Weiming Shi <redacted>
[ Upstream commit 111f8d74a19d85942ecbb3aba78f6f3c88e59391 ]
During $LogFile replay, log_replay() indexes the transaction table by the
transact_id taken from the log record header. check_log_rec() only
verifies that transact_id is non-zero and properly aligned, not its
magnitude, so a crafted image can request an arbitrarily large index.
alloc_rsttbl_from_idx() grows the table to cover that index via
extend_rsttbl(), which passes the new entry count to init_rsttbl():
rt = init_rsttbl(esize, used + add);
used + add is computed as u32 but init_rsttbl() takes a u16, and the
count is stored in struct RESTART_TABLE as a __le16. When used + add
exceeds U16_MAX it is truncated, init_rsttbl() allocates a table far
smaller than the index requires, and alloc_rsttbl_from_idx() then
dereferences and writes at the original, untruncated offset -- an
out-of-bounds access past the allocation, reachable by mounting a
crafted NTFS image.
BUG: KASAN: use-after-free in alloc_rsttbl_from_idx (fs/ntfs3/fslog.c:950)
Read of size 4 at addr ffff8880327ffff8 by task exploit
alloc_rsttbl_from_idx (fs/ntfs3/fslog.c:950)
log_replay (fs/ntfs3/fslog.c:4562)
ntfs_loadlog_and_replay (fs/ntfs3/fsntfs.c:324)
ntfs_fill_super (fs/ntfs3/super.c:1393)
get_tree_bdev_flags
vfs_get_tree
path_mount
__x64_sys_mount
A restart table is limited to U16_MAX entries by its __le16 count, so a
larger growth request is invalid input. Reject it in extend_rsttbl();
all callers already handle a NULL return.
Fixes: b46acd6a6a62 ("fs/ntfs3: Add NTFS journal")
Reported-by: Xiang Mei <redacted>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Weiming Shi <redacted>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ntfs3/fslog.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/ntfs3/fslog.c b/fs/ntfs3/fslog.c
index 192cfe0a803ef..d0f2fa1a6f91d 100644
--- a/fs/ntfs3/fslog.c
+++ b/fs/ntfs3/fslog.c
@@ -875,6 +875,9 @@ static inline struct RESTART_TABLE *extend_rsttbl(struct RESTART_TABLE *tbl,
u32 used = le16_to_cpu(tbl->used);
struct RESTART_TABLE *rt;
+ if (used + add > U16_MAX)
+ return NULL;
+
rt = init_rsttbl(esize, used + add);
if (!rt)
return NULL;
--
2.53.0