From b62567bca47408e6739dee75f02a2113548af875 Mon Sep 17 00:00:00 2001 From: Tobias Gaertner Date: Sun, 29 Mar 2026 04:17:02 -0700 Subject: [PATCH] ntfs3: add buffer boundary checks to run_unpack() run_unpack() checks `run_buf < run_last` at the top of the while loop but then reads size_size and offset_size bytes via run_unpack_s64() without verifying they fit within the remaining buffer. A crafted NTFS image with truncated run data in an MFT attribute triggers an OOB heap read of up to 15 bytes when the filesystem is mounted. Add boundary checks before each run_unpack_s64() call to ensure the declared field size does not exceed the remaining buffer. Found by fuzzing with a source-patched harness (LibAFL + QEMU). Fixes: 82cae269cfa95 ("fs/ntfs3: Add initialization of super block") Cc: stable@vger.kernel.org Signed-off-by: Tobias Gaertner Signed-off-by: Konstantin Komarov --- fs/ntfs3/run.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/ntfs3/run.c b/fs/ntfs3/run.c index c0324cdc174d..29817ecb1c7d 100644 --- a/fs/ntfs3/run.c +++ b/fs/ntfs3/run.c @@ -1008,6 +1008,9 @@ int run_unpack(struct runs_tree *run, struct ntfs_sb_info *sbi, CLST ino, if (size_size > sizeof(len)) return -EINVAL; + if (run_buf + size_size > run_last) + return -EINVAL; + len = run_unpack_s64(run_buf, size_size, 0); /* Skip size_size. */ run_buf += size_size; @@ -1020,6 +1023,9 @@ int run_unpack(struct runs_tree *run, struct ntfs_sb_info *sbi, CLST ino, else if (offset_size <= sizeof(s64)) { s64 dlcn; + if (run_buf + offset_size > run_last) + return -EINVAL; + /* Initial value of dlcn is -1 or 0. */ dlcn = (run_buf[offset_size - 1] & 0x80) ? (s64)-1 : 0; dlcn = run_unpack_s64(run_buf, offset_size, dlcn); -- 2.47.3