Subject: Re: [PATCH v4 12/15] smack: Remove redundant pdeath_signal clearing
To: Kees Cook <keescook@chromium.org>,
        Andrew Morton <akpm@linux-foundation.org>
Cc: David Howells <dhowells@redhat.com>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        John Johansen <john.johansen@canonical.com>,
        "Serge E. Hallyn" <serge@hallyn.com>, Paul Moore <paul@paul-moore.com>,
        Stephen Smalley <sds@tycho.nsa.gov>,
        Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
        James Morris <james.l.morris@oracle.com>,
        Andy Lutomirski <luto@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <1501545093-56634-1-git-send-email-keescook@chromium.org>
 <1501545093-56634-13-git-send-email-keescook@chromium.org>
From: Casey Schaufler <casey@schaufler-ca.com>
Message-ID: <7732a031-6603-7f9d-232c-cb8311be74e4@schaufler-ca.com>
Date: Tue, 1 Aug 2017 08:24:00 -0700
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On 7/31/2017 4:51 PM, Kees Cook wrote:
> This removes the redundant pdeath_signal clearing in Smack: the check in
> smack_bprm_committing_creds() matches the check in smack_bprm_set_creds()
> (which used to be in the now-removed smack_bprm_securexec() hook) and
> since secureexec is now being checked for clearing pdeath_signal, this
> is redundant to the common exec code.
>
> Cc: Casey Schaufler <casey@schaufler-ca.com>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> Acked-by: Serge Hallyn <serge@hallyn.com>

Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>

> ---
>  security/smack/smack_lsm.c | 15 ---------------
>  1 file changed, 15 deletions(-)
>
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index 4f1967be3d20..4e33c650b224 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -957,20 +957,6 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm)
>  	return 0;
>  }
>  
> -/**
> - * smack_bprm_committing_creds - Prepare to install the new credentials
> - * from bprm.
> - *
> - * @bprm: binprm for exec
> - */
> -static void smack_bprm_committing_creds(struct linux_binprm *bprm)
> -{
> -	struct task_smack *bsp = bprm->cred->security;
> -
> -	if (bsp->smk_task != bsp->smk_forked)
> -		current->pdeath_signal = 0;
> -}
> -
>  /*
>   * Inode hooks
>   */
> @@ -4633,7 +4619,6 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
>  	LSM_HOOK_INIT(sb_parse_opts_str, smack_parse_opts_str),
>  
>  	LSM_HOOK_INIT(bprm_set_creds, smack_bprm_set_creds),
> -	LSM_HOOK_INIT(bprm_committing_creds, smack_bprm_committing_creds),
>  
>  	LSM_HOOK_INIT(inode_alloc_security, smack_inode_alloc_security),
>  	LSM_HOOK_INIT(inode_free_security, smack_inode_free_security),