[PATCH] mdadm/Monitor:triggers core dump when stat2devnm return NULL

[PATCH] mdadm/Monitor:triggers core dump when stat2devnm return NULL

[Zhilong Liu]

Monitor: ensure that the device should be a block
device when uses --wait parameter, such as the 'f'
and 'd' type file would be triggered core dumped.
such as: ./mdadm --wait /dev/md/

Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Zhilong Liu <zlliu@suse.com>
---
 Monitor.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/Monitor.c b/Monitor.c
index 802a9d9..f8850d3 100644
--- a/Monitor.c
+++ b/Monitor.c
@@ -1002,7 +1002,12 @@ int Wait(char *dev)
 			strerror(errno));
 		return 2;
 	}
-	strcpy(devnm, stat2devnm(&stb));
+	char *tmp = stat2devnm(&stb);
+	if (!tmp) {
+		pr_err("%s is not a block device.\n", dev);
+		return 2;
+	}
+	strcpy(devnm, tmp);
 
 	while(1) {
 		struct mdstat_ent *ms = mdstat_read(1, 0);
-- 
2.6.6

Re: [PATCH] mdadm/Monitor:triggers core dump when stat2devnm return NULL

[jes.sorensen]

Zhilong Liu <zlliu@suse.com> writes:
> Monitor: ensure that the device should be a block
> device when uses --wait parameter, such as the 'f'
> and 'd' type file would be triggered core dumped.
> such as: ./mdadm --wait /dev/md/

I modified the patch description here to make it easier to read.

> Reviewed-by: NeilBrown <neilb@suse.com>
> Signed-off-by: Zhilong Liu <zlliu@suse.com>
> ---
>  Monitor.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/Monitor.c b/Monitor.c
> index 802a9d9..f8850d3 100644
> --- a/Monitor.c
> +++ b/Monitor.c
> @@ -1002,7 +1002,12 @@ int Wait(char *dev)
>  			strerror(errno));
>  		return 2;
>  	}
> -	strcpy(devnm, stat2devnm(&stb));
> +	char *tmp = stat2devnm(&stb);

Please do not declare variables in the middle of the codeflow, that is
extremely bad programming practice.

I fixed this up and applied the patch.

Thanks,
Jes