Messages in this thread Patch in this message | | | From | Yin Xiujiang <> | Subject | [PATCH] Fix slab-out-of-bounds in r_page | Date | Fri, 17 Dec 2021 16:40:45 +0800 |
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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> --- fs/ntfs3/fslog.c | 24 +----------------------- 1 file changed, 1 insertion(+), 23 deletions(-)
diff --git a/fs/ntfs3/fslog.c b/fs/ntfs3/fslog.c index 06492f088d60..4fdb5bdfc2ee 100644 --- a/fs/ntfs3/fslog.c +++ b/fs/ntfs3/fslog.c @@ -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; memset(info, 0, sizeof(struct restart_info)); @@ -1199,7 +1196,6 @@ 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; @@ -1253,24 +1249,6 @@ 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)); -- 2.30.0
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