coredump: add support for %d=__get_dumpable() in core name (12a2b4b2) · Commits · 戴 / test

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>

Documentation/sysctl/kernel.txt

+2 −0

Original line number	Diff line number	Diff line
		@@ -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

fs/coredump.c

+7 −3

Original line number	Diff line number	Diff line
		@@ -149,7 +149,7 @@ put_exe_file:
		* 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;

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