Nicolas Iooss <nicolas.iooss_linux@xxxxxxx> 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@xxxxxxxxxxxx> > Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@xxxxxxx> > --- > 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", _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
