linux-kernel - [PATCH 4.20 075/127] kconfig: fix memory leak when EOF is encountered in quotation

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Message-Id: <20190124190215.341629806@linuxfoundation.org>
Date:   Thu, 24 Jan 2019 20:20:21 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.20 075/127] kconfig: fix memory leak when EOF is encountered in quotation

4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit fbac5977d81cb2b2b7e37b11c459055d9585273c ]

An unterminated string literal followed by new line is passed to the
parser (with "multi-line strings not supported" warning shown), then
handled properly there.

On the other hand, an unterminated string literal at end of file is
never passed to the parser, then results in memory leak.

[Test Code]

  ----------(Kconfig begin)----------
  source "Kconfig.inc"

  config A
          bool "a"
  -----------(Kconfig end)-----------

  --------(Kconfig.inc begin)--------
  config B
          bool "b\No new line at end of file
  ---------(Kconfig.inc end)---------

[Summary from Valgrind]

  Before the fix:

    LEAK SUMMARY:
       definitely lost: 16 bytes in 1 blocks
       ...

  After the fix:

    LEAK SUMMARY:
       definitely lost: 0 bytes in 0 blocks
       ...

Eliminate the memory leak path by handling this case. Of course, such
a Kconfig file is wrong already, so I will add an error message later.

Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 scripts/kconfig/zconf.l | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/scripts/kconfig/zconf.l b/scripts/kconfig/zconf.l
index eeac64ccc730..c2f577d71964 100644
--- a/scripts/kconfig/zconf.l
+++ b/scripts/kconfig/zconf.l
@@ -221,6 +221,8 @@ n	[A-Za-z0-9_-]
 	}
 	<<EOF>>	{
 		BEGIN(INITIAL);
+		yylval.string = text;
+		return T_WORD_QUOTE;
 	}
 }
 
-- 
2.19.1