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coredump: add support for %d=__get_dumpable() in core name

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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 <oleg@redhat.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Alex Kelly <alex.page.kelly@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Cong Wang <amwang@redhat.com>
Cc: Jiri Moskovcak <jmoskovc@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2012-10-04 17:15:25 -07:00 committed by Linus Torvalds
parent 179899fd5d
commit 12a2b4b224
2 changed files with 9 additions and 3 deletions
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2
Documentation/sysctl/kernel.txt
View file

@ -181,6 +181,8 @@ core_pattern is used to specify a core dumpfile pattern name.
%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

10
fs/coredump.c
View file

@ -149,7 +149,7 @@ static int cn_print_exe_file(struct core_name *cn)
* 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 @@ static int format_corename(struct core_name *cn, long signr)
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 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
*/
clear_thread_flag(TIF_SIGPENDING);
ispipe = format_corename(&cn, signr);
ispipe = format_corename(&cn, &cprm);
if (ispipe) {
int dump_count;