From 979ae704ddc9e6f19d8dbf7a83bea155065ef3cc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= <ppisar@redhat.com>
Date: Mon, 6 Feb 2017 15:26:09 +0100
Subject: [PATCH] prevent leak of class name from retrieve_hook() on an
 exception
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Ported from perl:

commit da1ec2b1b9abdfd956d9c539abf39d908d046304
Author: Tony Cook <tony@develop-help.com>
Date:   Mon Feb 6 11:38:10 2017 +1100

    prevent leak of class name from retrieve_hook() on an exception

    If supplied with a large class name, retrieve_hook() allocates
    buffer for the class name and Safefree()s it on exit path.

    Unfortunately this memory leaks if load_module() (or a couple of other
    code paths) throw an exception.

    So use SAVEFREEPV() to release the memory instead.

    ==20183== 193 bytes in 1 blocks are definitely lost in loss record 4 of 6
    ==20183==    at 0x4C28C20: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
    ==20183==    by 0x55F85D: Perl_safesysmalloc (util.c:153)
    ==20183==    by 0x6ACA046: retrieve_hook (Storable.xs:4265)
    ==20183==    by 0x6AD6D19: retrieve (Storable.xs:6217)
    ==20183==    by 0x6AD8144: do_retrieve (Storable.xs:6401)
    ==20183==    by 0x6AD85B7: pretrieve (Storable.xs:6506)
    ==20183==    by 0x6AD8E14: XS_Storable_pretrieve (Storable.xs:6718)
    ==20183==    by 0x5C176D: Perl_pp_entersub (pp_hot.c:4227)
    ==20183==    by 0x55E1C6: Perl_runops_debug (dump.c:2450)
    ==20183==    by 0x461B79: S_run_body (perl.c:2528)
    ==20183==    by 0x46115C: perl_run (perl.c:2451)
    ==20183==    by 0x41F1CD: main (perlmain.c:123)

Signed-off-by: Petr Písař <ppisar@redhat.com>
---
 Storable.xs | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/Storable.xs b/Storable.xs
index 3cce3ed..75ce3df 100644
--- a/Storable.xs
+++ b/Storable.xs
@@ -4249,6 +4249,11 @@ static SV *retrieve_hook(pTHX_ stcxt_t *cxt, const char *cname)
 
 	TRACEME(("class name: %s", classname));
 
+	if (!(flags & SHF_IDX_CLASSNAME) && classname != buf) {
+                /* some execution paths can throw an exception */
+		SAVEFREEPV(classname);
+        }
+
 	/*
 	 * Decode user-frozen string length and read it in an SV.
 	 *
@@ -4367,8 +4372,6 @@ static SV *retrieve_hook(pTHX_ stcxt_t *cxt, const char *cname)
 		SEEN0(sv, 0);
 		SvRV_set(attached, NULL);
 		SvREFCNT_dec(attached);
-		if (!(flags & SHF_IDX_CLASSNAME) && classname != buf)
-		    Safefree(classname);
 		return sv;
 	    }
 	    CROAK(("STORABLE_attach did not return a %s object", classname));
@@ -4449,8 +4452,6 @@ static SV *retrieve_hook(pTHX_ stcxt_t *cxt, const char *cname)
 	SvREFCNT_dec(frozen);
 	av_undef(av);
 	sv_free((SV *) av);
-	if (!(flags & SHF_IDX_CLASSNAME) && classname != buf)
-		Safefree(classname);
 
 	/*
 	 * If we had an <extra> type, then the object was not as simple, and
-- 
2.7.4