Unverified Commit ecfbd57c authored by Yin Xiujiang's avatar Yin Xiujiang Committed by Konstantin Komarov
Browse files

fs/ntfs3: Fix slab-out-of-bounds in r_page 



When PAGE_SIZE is 64K, if read_log_page is called by log_read_rst for
the first time, the size of *buffer would be equal to
DefaultLogPageSize(4K).But for *buffer operations like memcpy,
if the memory area size(n) which being assigned to buffer is larger
than 4K (log->page_size(64K) or bytes(64K-page_off)), it will cause
an out of boundary error.
 Call trace:
  [...]
  kasan_report+0x44/0x130
  check_memory_region+0xf8/0x1a0
  memcpy+0xc8/0x100
  ntfs_read_run_nb+0x20c/0x460
  read_log_page+0xd0/0x1f4
  log_read_rst+0x110/0x75c
  log_replay+0x1e8/0x4aa0
  ntfs_loadlog_and_replay+0x290/0x2d0
  ntfs_fill_super+0x508/0xec0
  get_tree_bdev+0x1fc/0x34c
  [...]

Fix this by setting variable r_page to NULL in log_read_rst.

Signed-off-by: default avatarYin Xiujiang <yinxiujiang@kylinos.cn>
Signed-off-by: default avatarKonstantin Komarov <almaz.alexandrovich@paragon-software.com>
parent 65801516

fs/ntfs3/fslog.c

+2 −24
Original line number Diff line number Diff line
@@ -1132,7 +1132,7 @@ static int read_log_page(struct ntfs_log *log, u32 vbo, 
		return -EINVAL;



	if (!*buffer) {

		to_free = kmalloc(bytes, GFP_NOFS);

		to_free = kmalloc(log->page_size, GFP_NOFS);

		if (!to_free)

			return -ENOMEM;

		*buffer = to_free;
@@ -1180,10 +1180,7 @@ static int log_read_rst(struct ntfs_log *log, u32 l_size, bool first, 
			struct restart_info *info)

{

	u32 skip, vbo;

	struct RESTART_HDR *r_page = kmalloc(DefaultLogPageSize, GFP_NOFS);



	if (!r_page)

		return -ENOMEM;

	struct RESTART_HDR *r_page = NULL;



	/* Determine which restart area we are looking for. */

	if (first) {
@@ -1197,7 +1194,6 @@ static int log_read_rst(struct ntfs_log *log, u32 l_size, bool first, 
	/* Loop continuously until we succeed. */

	for (; vbo < l_size; vbo = 2 * vbo + skip, skip = 0) {

		bool usa_error;

		u32 sys_page_size;

		bool brst, bchk;

		struct RESTART_AREA *ra;
@@ -1251,24 +1247,6 @@ static int log_read_rst(struct ntfs_log *log, u32 l_size, bool first, 
			goto check_result;

		}



		/* Read the entire restart area. */

		sys_page_size = le32_to_cpu(r_page->sys_page_size);

		if (DefaultLogPageSize != sys_page_size) {

			kfree(r_page);

			r_page = kzalloc(sys_page_size, GFP_NOFS);

			if (!r_page)

				return -ENOMEM;



			if (read_log_page(log, vbo,

					  (struct RECORD_PAGE_HDR **)&r_page,

					  &usa_error)) {

				/* Ignore any errors. */

				kfree(r_page);

				r_page = NULL;

				continue;

			}

		}



		if (is_client_area_valid(r_page, usa_error)) {

			info->valid_page = true;

			ra = Add2Ptr(r_page, le16_to_cpu(r_page->ra_off));