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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: Yin Xiujiang <yinxiujiang@kylinos.cn>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
This commit is contained in:
Yin Xiujiang 2021-12-06 10:40:45 +08:00 committed by Konstantin Komarov
parent 658015167a
commit ecfbd57cf9
No known key found for this signature in database
GPG Key ID: A9B0331F832407B6
1 changed files with 2 additions and 24 deletions
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26
fs/ntfs3/fslog.c
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@ -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));