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authorJens Axboe <jaxboe@fusionio.com>2010-11-10 14:36:25 +0100
committerJens Axboe <jaxboe@fusionio.com>2010-11-10 14:40:43 +0100
commitcb4644cac4a2797afc847e6c92736664d4b0ea34 (patch)
tree14170d74d5040be49af14b484f252d888141a99f /fs/bio.c
parentf3f63c1c28bc861a931fac283b5bc3585efb8967 (diff)
downloadlinux-cb4644cac4a2797afc847e6c92736664d4b0ea34.tar.gz
bio: take care not overflow page count when mapping/copying user data
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> Cc: stable@kernel.org Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'fs/bio.c')
-rw-r--r--fs/bio.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/fs/bio.c b/fs/bio.c
index 8317a2c106b..4bd454fa844 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -834,6 +834,12 @@ 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;
}
@@ -962,6 +968,12 @@ 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
@@ -989,7 +1001,7 @@ 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) {