coredump: use from_kuid/kgid when formatting corename
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.
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/coredump.c b/fs/coredump.c
index bbbe139..833a57b 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -209,11 +209,15 @@
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",