Re: [PATCH] fs: smb: client: Reset password pointer to NULL

[Steve French]

On Thu, Jan 18, 2024 at 1:44 AM Fullway Wang <fullwaywang@xxxxxxxxxxx> wrote:
>
> ctx->password was freed but not reset to NULL, which may lead to double
> free and secrets leak issues.

But no one else could use this pointer to double free this since it is
allocated in this function, and exits a few lines after it is freed
(and its parent is freed on the next line so the pointer could not be
accessed either)


> This is similar to CVE-2023-5345, which was fixed in commit e6e43b8.
>
> Signed-off-by: Fullway Wang <fullwaywang@xxxxxxxxxxx>
> ---
>  fs/smb/client/connect.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
> index 3052a208c6ca..fb96a234b9b1 100644
> --- a/fs/smb/client/connect.c
> +++ b/fs/smb/client/connect.c
> @@ -4028,6 +4028,7 @@ cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
>  out:
>         kfree(ctx->username);
>         kfree_sensitive(ctx->password);
> +       ctx->password = NULL;
>         kfree(ctx);
>
>         return tcon;
> --
> 2.39.3 (Apple Git-145)
>
>


-- 
Thanks,

Steve