Re: [PATCH] softmmu/physmem.c: Check return value from realpath()

[Liu, Jingqi]

On 8/12/2021 11:15 PM, Peter Maydell wrote:
> The realpath() function can return NULL on error, so we need to check
> for it to avoid crashing when we try to strstr() into it.
> This can happen if we run out of memory, or if /sys/ is not mounted,
> among other situations.
>
> Fixes: Coverity 1459913, 1460474
> Fixes: ce317be98db0 ("exec: fetch the alignment of Linux devdax pmem character 
> device nodes")
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>   softmmu/physmem.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/softmmu/physmem.c b/softmmu/physmem.c
> index c47cb6da2e4..eb0595d57c4 100644
> --- a/softmmu/physmem.c
> +++ b/softmmu/physmem.c
> @@ -1451,6 +1451,9 @@ static int64_t get_file_align(int fd)
>           path = g_strdup_printf("/sys/dev/char/%d:%d",
>                       major(st.st_rdev), minor(st.st_rdev));
>           rpath = realpath(path, NULL);
> +        if (!rpath) {
> +            return -errno;
> +        }

Good find!

Reviewed-by: Jingqi Liu <jingqi.liu@intel.com>

Thanks,
Jingqi