Zach Brown <z...@redhat.com> writes:
> Commit 7572777eef78ebdee1ecb7c258c0ef94d35bad16 attempted to verify that
> the total iovec from the client doesn't overflow iov_length() but it
> only checked the first element. The iovec could still overflow by
> starting with a small element. The obvious fix is to check all the
> elements.
>
> The overflow case doesn't look dangerous to the kernel as the copy is
> limited by the length after the overflow. This fix restores the
> intention of returning an error instead of successfully copying less
> than the iovec represented.
>
> I found this by code inspection. I built it but don't have a test case.
> I'm cc:ing stable because the initial commit did as well.
Thanks! Applied.
Miklos
>
> Signed-off-by: Zach Brown <z...@redhat.com>
> CC: <sta...@kernel.org> [2.6.37+]
> ---
> fs/fuse/file.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/fs/fuse/file.c b/fs/fuse/file.c
> index b321a68..514f12a 100644
> --- a/fs/fuse/file.c
> +++ b/fs/fuse/file.c
> @@ -1700,7 +1700,7 @@ static int fuse_verify_ioctl_iov(struct iovec *iov,
> size_t count)
> size_t n;
> u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT;
>
> - for (n = 0; n < count; n++) {
> + for (n = 0; n < count; n++, iov++) {
> if (iov->iov_len > (size_t) max)
> return -ENOMEM;
> max -= iov->iov_len;
--
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