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authorPavel Begunkov <asml.silence@gmail.com>2021-03-19 13:21:19 +0300
committerJens Axboe <axboe@kernel.dk>2021-03-22 16:41:03 +0300
commitd81269fecb8ce16eb07efafc9ff5520b2a31c486 (patch)
tree7ad32ba346e62c544201ee8d4059e5c3a8af6d5d /fs/io_uring.c
parentb65c128f963df367a8adcfb08f5ecf8721052723 (diff)
downloadlinux-d81269fecb8ce16eb07efafc9ff5520b2a31c486.tar.xz
io_uring: fix provide_buffers sign extension
io_provide_buffers_prep()'s "p->len * p->nbufs" to sign extension problems. Not a huge problem as it's only used for access_ok() and increases the checked length, but better to keep typing right. Reported-by: Colin Ian King <colin.king@canonical.com> Fixes: efe68c1ca8f49 ("io_uring: validate the full range of provided buffers for access") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Colin Ian King <colin.king@canonical.com> Link: https://lore.kernel.org/r/562376a39509e260d8532186a06226e56eb1f594.1616149233.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/io_uring.c')
-rw-r--r--fs/io_uring.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index a664b44a5a94..f3ae83a2d7bc 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3977,6 +3977,7 @@ static int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags)
static int io_provide_buffers_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
+ unsigned long size;
struct io_provide_buf *p = &req->pbuf;
u64 tmp;
@@ -3990,7 +3991,8 @@ static int io_provide_buffers_prep(struct io_kiocb *req,
p->addr = READ_ONCE(sqe->addr);
p->len = READ_ONCE(sqe->len);
- if (!access_ok(u64_to_user_ptr(p->addr), (p->len * p->nbufs)))
+ size = (unsigned long)p->len * p->nbufs;
+ if (!access_ok(u64_to_user_ptr(p->addr), size))
return -EFAULT;
p->bgid = READ_ONCE(sqe->buf_group);