From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman) To: Nicolas Iooss <nicolas.iooss_linux-oWGTIYur0i8@public.gmane.org> Cc: linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Linux Containers <containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Alexander Viro <viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Subject: Re: [PATCH v2 1/2] coredump: use from_kuid/kgid when formatting corename Date: Fri, 15 May 2015 09:52:59 -0500 [thread overview] Message-ID: <87d221yjsk.fsf@x220.int.ebiederm.org> (raw) In-Reply-To: <1431656975-3563-1-git-send-email-nicolas.iooss_linux-oWGTIYur0i8@public.gmane.org> (Nicolas Iooss's message of "Fri, 15 May 2015 10:29:34 +0800") Nicolas Iooss <nicolas.iooss_linux-oWGTIYur0i8@public.gmane.org> writes: > 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. > > Use init_user_ns in order not to break existing ABI, and document this > in Documentation/sysctl/kernel.txt. > > 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. Acked-by: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org> > Signed-off-by: Nicolas Iooss <nicolas.iooss_linux-oWGTIYur0i8@public.gmane.org> > --- > Documentation/sysctl/kernel.txt | 4 ++-- > fs/coredump.c | 8 ++++++-- > 2 files changed, 8 insertions(+), 4 deletions(-) > > diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt > index c831001c45f1..e1913f78f21e 100644 > --- a/Documentation/sysctl/kernel.txt > +++ b/Documentation/sysctl/kernel.txt > @@ -197,8 +197,8 @@ core_pattern is used to specify a core dumpfile pattern name. > %P global pid (init PID namespace) > %i tid > %I global tid (init PID namespace) > - %u uid > - %g gid > + %u uid (in initial user namespace) > + %g gid (in initial user namespace) > %d dump mode, matches PR_SET_DUMPABLE and > /proc/sys/fs/suid_dumpable > %s signal number > diff --git a/fs/coredump.c b/fs/coredump.c > index bbbe139ab280..833a57bc856c 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(&init_user_ns, > + cred->uid)); > break; > /* gid */ > case 'g': > - err = cn_printf(cn, "%d", cred->gid); > + err = cn_printf(cn, "%u", > + from_kgid(&init_user_ns, > + cred->gid)); > break; > case 'd': > err = cn_printf(cn, "%d",
WARNING: multiple messages have this Message-ID (diff)
From: ebiederm@xmission.com (Eric W. Biederman) To: Nicolas Iooss <nicolas.iooss_linux@m4x.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk>, linux-fsdevel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org, Linux Containers <containers@lists.linux-foundation.org> Subject: Re: [PATCH v2 1/2] coredump: use from_kuid/kgid when formatting corename Date: Fri, 15 May 2015 09:52:59 -0500 [thread overview] Message-ID: <87d221yjsk.fsf@x220.int.ebiederm.org> (raw) In-Reply-To: <1431656975-3563-1-git-send-email-nicolas.iooss_linux@m4x.org> (Nicolas Iooss's message of "Fri, 15 May 2015 10:29:34 +0800") Nicolas Iooss <nicolas.iooss_linux@m4x.org> writes: > 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. > > Use init_user_ns in order not to break existing ABI, and document this > in Documentation/sysctl/kernel.txt. > > 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. Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> > Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org> > --- > Documentation/sysctl/kernel.txt | 4 ++-- > fs/coredump.c | 8 ++++++-- > 2 files changed, 8 insertions(+), 4 deletions(-) > > diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt > index c831001c45f1..e1913f78f21e 100644 > --- a/Documentation/sysctl/kernel.txt > +++ b/Documentation/sysctl/kernel.txt > @@ -197,8 +197,8 @@ core_pattern is used to specify a core dumpfile pattern name. > %P global pid (init PID namespace) > %i tid > %I global tid (init PID namespace) > - %u uid > - %g gid > + %u uid (in initial user namespace) > + %g gid (in initial user namespace) > %d dump mode, matches PR_SET_DUMPABLE and > /proc/sys/fs/suid_dumpable > %s signal number > diff --git a/fs/coredump.c b/fs/coredump.c > index bbbe139ab280..833a57bc856c 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(&init_user_ns, > + cred->uid)); > break; > /* gid */ > case 'g': > - err = cn_printf(cn, "%d", cred->gid); > + err = cn_printf(cn, "%u", > + from_kgid(&init_user_ns, > + cred->gid)); > break; > case 'd': > err = cn_printf(cn, "%d",
next prev parent reply other threads:[~2015-05-15 14:52 UTC|newest] Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-04-16 10:28 [PATCH RESENT] coredump: fix cn_printf formatting warnings Nicolas Iooss 2015-04-16 10:50 ` Joe Perches 2015-05-03 10:34 ` [PATCH 1/2] coredump: use from_kuid/kgid_munged when formatting corename Nicolas Iooss 2015-05-03 10:34 ` [PATCH 2/2] coredump: add __printf attribute to cn_*printf functions Nicolas Iooss [not found] ` <1430649246-32726-1-git-send-email-nicolas.iooss_linux-oWGTIYur0i8@public.gmane.org> 2015-05-05 19:13 ` [PATCH 1/2] coredump: use from_kuid/kgid_munged when formatting corename Eric W. Biederman 2015-05-05 19:13 ` Eric W. Biederman [not found] ` <87bnhyhm7f.fsf-JOvCrm2gF+uungPnsOpG7nhyD016LWXt@public.gmane.org> 2015-05-06 12:18 ` Nicolas Iooss 2015-05-06 12:18 ` Nicolas Iooss [not found] ` <554A0684.2000400-oWGTIYur0i8@public.gmane.org> 2015-05-15 2:29 ` [PATCH v2 1/2] coredump: use from_kuid/kgid " Nicolas Iooss 2015-05-15 2:29 ` Nicolas Iooss 2015-05-15 2:29 ` [PATCH v2 2/2] coredump: add __printf attribute to cn_*printf functions Nicolas Iooss [not found] ` <1431656975-3563-2-git-send-email-nicolas.iooss_linux-oWGTIYur0i8@public.gmane.org> 2015-05-15 14:54 ` Eric W. Biederman 2015-05-15 14:54 ` Eric W. Biederman [not found] ` <1431656975-3563-1-git-send-email-nicolas.iooss_linux-oWGTIYur0i8@public.gmane.org> 2015-05-15 2:29 ` Nicolas Iooss 2015-05-15 14:52 ` Eric W. Biederman [this message] 2015-05-15 14:52 ` [PATCH v2 1/2] coredump: use from_kuid/kgid when formatting corename Eric W. Biederman
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