diff options
| author | Jens Axboe <jaxboe@fusionio.com> | 2010-11-10 14:36:25 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-12-09 13:26:52 -0800 |
| commit | cbe7684480e2b379eeae1317b6aa7fab413501a8 (patch) | |
| tree | b1d9309f6715ca81e73185a2da66fdad57000cca | |
| parent | a7c486e4d247d5a076b6f94937ac402f4ac9c70b (diff) | |
bio: take care not overflow page count when mapping/copying user data
commit cb4644cac4a2797afc847e6c92736664d4b0ea34 upstream.
If the iovec is being set up in a way that causes uaddr + PAGE_SIZE
to overflow, we could end up attempting to map a huge number of
pages. Check for this invalid input type.
Reported-by: Dan Rosenberg <drosenberg@vsecurity.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | fs/bio.c | 14 |
1 files changed, 13 insertions, 1 deletions
@@ -838,6 +838,12 @@ struct bio *bio_copy_user_iov(struct request_queue *q, end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT; start = uaddr >> PAGE_SHIFT; + /* + * Overflow, abort + */ + if (end < start) + return ERR_PTR(-EINVAL); + nr_pages += end - start; len += iov[i].iov_len; } @@ -965,6 +971,12 @@ static struct bio *__bio_map_user_iov(struct request_queue *q, unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; unsigned long start = uaddr >> PAGE_SHIFT; + /* + * Overflow, abort + */ + if (end < start) + return ERR_PTR(-EINVAL); + nr_pages += end - start; /* * buffer must be aligned to at least hardsector size for now @@ -992,7 +1004,7 @@ static struct bio *__bio_map_user_iov(struct request_queue *q, unsigned long start = uaddr >> PAGE_SHIFT; const int local_nr_pages = end - start; const int page_limit = cur_page + local_nr_pages; - + ret = get_user_pages_fast(uaddr, local_nr_pages, write_to_vm, &pages[cur_page]); if (ret < local_nr_pages) { |