coredump: add support for %d=__get_dumpable() in core name
Some coredump handlers want to create a core file in a way compatible with
standard behavior. Standard behavior with fs.suid_dumpable = 2 is to
create core file with uid=gid=0. However, there was no way for coredump
handler to know that the process being dumped was suid'ed.
This patch adds the new %d specifier for format_corename() which simply
reports __get_dumpable(mm->flags), this is compatible with
/proc/sys/fs/suid_dumpable we already have.
Addresses https://bugzilla.redhat.com/show_bug.cgi?id=787135
Developed during a discussion with Denys Vlasenko.
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: Alex Kelly <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Cong Wang <[email protected]>
Cc: Jiri Moskovcak <[email protected]>
Acked-by: Neil Horman <[email protected]>
Cc: Alan Cox <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 6d78841..2907ba6 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -181,6 +181,8 @@
%p pid
%u uid
%g gid
+ %d dump mode, matches PR_SET_DUMPABLE and
+ /proc/sys/fs/suid_dumpable
%s signal number
%t UNIX time of dump
%h hostname
diff --git a/fs/coredump.c b/fs/coredump.c
index c01aa7b..4fce06f 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -149,7 +149,7 @@
* name into corename, which must have space for at least
* CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
*/
-static int format_corename(struct core_name *cn, long signr)
+static int format_corename(struct core_name *cn, struct coredump_params *cprm)
{
const struct cred *cred = current_cred();
const char *pat_ptr = core_pattern;
@@ -194,9 +194,13 @@
case 'g':
err = cn_printf(cn, "%d", cred->gid);
break;
+ case 'd':
+ err = cn_printf(cn, "%d",
+ __get_dumpable(cprm->mm_flags));
+ break;
/* signal that caused the coredump */
case 's':
- err = cn_printf(cn, "%ld", signr);
+ err = cn_printf(cn, "%ld", cprm->signr);
break;
/* UNIX time of coredump */
case 't': {
@@ -515,7 +519,7 @@
*/
clear_thread_flag(TIF_SIGPENDING);
- ispipe = format_corename(&cn, signr);
+ ispipe = format_corename(&cn, &cprm);
if (ispipe) {
int dump_count;
