[dm-devel] [PATCH] libmultipath: check if adopt_path() really added current path

[Benjamin Marzinski]

On Tue, Feb 02, 2021 at 08:57:44PM +0100, mwilck at suse.com wrote:
> From: Martin Wilck <mwilck at suse.com>
> 
> The description of 2d32d6f ("libmultipath: adopt_paths(): don't bail out on
> single path failure") said "we need to check after successful call to
> adopt_paths() if that specific path had been actually added, and fail in the
> caller otherwise". But the commit failed to actually implement this check.
> Instead, it just checked if the path was member of the pathvec, which will
> almost always be the case.
> 
> Fix it by checking what actually needs to be checked, membership of the
> path to be added in mpp->paths.
> 
> Fixes: 2d32d6f ("libmultipath: adopt_paths(): don't bail out on single path failure")
> Signed-off-by: Martin Wilck <mwilck at suse.com>
Reviewed-by: Benjamin Marzinski <bmarzins at redhat.com>
> ---
> 
> @lixiaokeng, I believe that this fixes the issue you mentioned in your
> post "libmultipath: fix NULL dereference in get_be64".
> 
> ---
>  libmultipath/structs_vec.c | 4 ++--
>  multipathd/main.c          | 4 ++--
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/libmultipath/structs_vec.c b/libmultipath/structs_vec.c
> index f7f45f1..47b1d03 100644
> --- a/libmultipath/structs_vec.c
> +++ b/libmultipath/structs_vec.c
> @@ -707,8 +707,8 @@ struct multipath *add_map_with_path(struct vectors *vecs, struct path *pp,
>  		goto out;
>  	mpp->size = pp->size;
>  
> -	if (adopt_paths(vecs->pathvec, mpp) ||
> -	    find_slot(vecs->pathvec, pp) == -1)
> +	if (adopt_paths(vecs->pathvec, mpp) || pp->mpp != mpp ||
> +	    find_slot(mpp->paths, pp) == -1)
>  		goto out;
>  
>  	if (add_vec) {
> diff --git a/multipathd/main.c b/multipathd/main.c
> index 134185f..425492a 100644
> --- a/multipathd/main.c
> +++ b/multipathd/main.c
> @@ -1008,8 +1008,8 @@ rescan:
>  	if (mpp) {
>  		condlog(4,"%s: adopting all paths for path %s",
>  			mpp->alias, pp->dev);
> -		if (adopt_paths(vecs->pathvec, mpp) ||
> -		    find_slot(vecs->pathvec, pp) == -1)
> +		if (adopt_paths(vecs->pathvec, mpp) || pp->mpp != mpp ||
> +		    find_slot(mpp->paths, pp) == -1)
>  			goto fail; /* leave path added to pathvec */
>  
>  		verify_paths(mpp);
> -- 
> 2.29.2