From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolas Iooss Subject: [PATCH 1/2] coredump: use from_kuid/kgid_munged when formatting corename Date: Sun, 3 May 2015 18:34:05 +0800 Message-ID: <1430649246-32726-1-git-send-email-nicolas.iooss_linux@m4x.org> References: <1429181404.2850.44.camel@perches.com> Cc: Andrew Morton , linux-kernel@vger.kernel.org, Nicolas Iooss To: Alexander Viro , linux-fsdevel@vger.kernel.org Return-path: Received: from mx1.polytechnique.org ([129.104.30.34]:49391 "EHLO mx1.polytechnique.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751359AbbECKgp (ORCPT ); Sun, 3 May 2015 06:36:45 -0400 In-Reply-To: <1429181404.2850.44.camel@perches.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: When adding __printf attribute to cn_printf, gcc reports some issues: fs/coredump.c:213:5: warning: format '%d' expects argument of type 'int', but argument 3 has type 'kuid_t' [-Wformat=] err = cn_printf(cn, "%d", cred->uid); ^ fs/coredump.c:217:5: warning: format '%d' expects argument of type 'int', but argument 3 has type 'kgid_t' [-Wformat=] err = cn_printf(cn, "%d", cred->gid); ^ These warnings come from the fact that the value of uid/gid needs to be extracted from the kuid_t/kgid_t structure before being used as an integer. More precisely, cred->uid and cred->gid need to be converted to either user-namespace uid/gid or to init_user_ns uid/gid. As Documentation/sysctl/kernel.txt does not specify which user namespace is used to translate %u and %g in core_pattern, but lowercase %p and %i are used to format pid/tid in the current process namespace, it seems intuitive that lowercase %u and %g use the current user namespace. While at it, format uid and gid values with %u instead of %d because uid_t/__kernel_uid32_t and gid_t/__kernel_gid32_t are unsigned int. Signed-off-by: Nicolas Iooss --- fs/coredump.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/coredump.c b/fs/coredump.c index bbbe139ab280..99c8af640c5a 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -209,11 +209,15 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm) break; /* uid */ case 'u': - err = cn_printf(cn, "%d", cred->uid); + err = cn_printf(cn, "%u", + from_kuid_munged(cred->user_ns, + cred->uid)); break; /* gid */ case 'g': - err = cn_printf(cn, "%d", cred->gid); + err = cn_printf(cn, "%u", + from_kgid_munged(cred->user_ns, + cred->gid)); break; case 'd': err = cn_printf(cn, "%d", -- 2.3.6