From: Mark Wielaard <mark@klomp.org>
Date: Sun, 26 Apr 2020 00:10:41 +0000 (+0200)
Subject: libdwfl: Fix double free on failure path in gzip.c.
X-Git-Tag: elfutils-0.180~16
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a894c63dba7019ceb8f6aa2c3cdcef519c65c92d;p=thirdparty%2Felfutils.git

libdwfl: Fix double free on failure path in gzip.c.

GCC10 -fanalyzer found a double free when openstream failed. When
openstream fails __libdw_gunzip will call fail, which frees the
state->buffer. But openstream can call zlib_fail, which will also
call fail. Instead of calling zlib_fail, just return the error
that zlib_fail would have returned.

Signed-off-by: Mark Wielaard <mark@klomp.org>
---

diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index 4ddc9ad47..daedaed8f 100644
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -1,3 +1,8 @@
+2020-04-25  Mark Wielaard  <mark@klomp.org>
+
+	* gzip.c (open_stream): Return DWFL_E_NOMEM instead of calling
+	zlib_fail.
+
 2020-04-16  Mark Wielaard  <mark@klomp.org>
 
 	* find-debuginfo.c (dwfl_standard_find_debuginfo): Initialize bits
diff --git a/libdwfl/gzip.c b/libdwfl/gzip.c
index 043d0b6ed..e9988cc2b 100644
--- a/libdwfl/gzip.c
+++ b/libdwfl/gzip.c
@@ -153,7 +153,7 @@ open_stream (int fd, off_t start_offset, struct unzip_state *state)
     if (unlikely (state->zf == NULL))
       {
 	close (d);
-	return zlib_fail (state, Z (MEM_ERROR));
+	return DWFL_E_NOMEM;
       }
 
     /* From here on, zlib will close D.  */