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Re: [Qemu-devel] [PATCH v1 1/3] memfd: fix possible usage of the uniniti
From: |
Marc-André Lureau |
Subject: |
Re: [Qemu-devel] [PATCH v1 1/3] memfd: fix possible usage of the uninitialized file descriptor |
Date: |
Sat, 9 Jun 2018 12:17:39 +0200 |
On Sat, Jun 9, 2018 at 9:52 AM, Dima Stepanov <address@hidden> wrote:
> The qemu_memfd_alloc_check() routine allocates the fd variable on stack.
> This variable is initialized inside the qemu_memfd_alloc() function.
> There are several cases when *fd will be left unintialized which can
> lead to the unexpected close() in the qemu_memfd_free() call.
>
> Set file descriptor to -1 before calling the qemu_memfd_alloc routine.
>
> Signed-off-by: Dima Stepanov <address@hidden>
Reviewed-by: Marc-André Lureau <address@hidden>
> ---
> util/memfd.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/util/memfd.c b/util/memfd.c
> index d248a53..6287946 100644
> --- a/util/memfd.c
> +++ b/util/memfd.c
> @@ -187,6 +187,7 @@ bool qemu_memfd_alloc_check(void)
> int fd;
> void *ptr;
>
> + fd = -1;
> ptr = qemu_memfd_alloc("test", 4096, 0, &fd, NULL);
> memfd_check = ptr ? MEMFD_OK : MEMFD_KO;
> qemu_memfd_free(ptr, 4096, fd);
> --
> 2.7.4
>
>
--
Marc-André Lureau