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From: Johannes Sixt <j6t@kdbg.org>
To: "İsmail Dönmez" <ismail@i10z.com>,
	"Johannes Schindelin" <johannes.schindelin@gmx.de>
Cc: "İsmail Dönmez via GitGitGadget" <gitgitgadget@gmail.com>,
	git@vger.kernel.org, "Junio C Hamano" <gitster@pobox.com>
Subject: Re: [PATCH 2/2] mingw: enable DEP and ASLR
Date: Tue, 30 Apr 2019 08:26:26 +0200	[thread overview]
Message-ID: <8e59dbf6-a339-74f3-4e60-e56b3817aea5@kdbg.org> (raw)
In-Reply-To: <e142c1396ec3541486317819e885cf42be24af34.1556575015.git.gitgitgadget@gmail.com>

[had to add Dscho as recipient manually, mind you]

Am 29.04.19 um 23:56 schrieb İsmail Dönmez via GitGitGadget:
> From: =?UTF-8?q?=C4=B0smail=20D=C3=B6nmez?= <ismail@i10z.com>
> 
> Enable DEP (Data Execution Prevention) and ASLR (Address Space Layout
> Randomization) support. This applies to both 32bit and 64bit builds
> and makes it substantially harder to exploit security holes in Git by
> offering a much more unpredictable attack surface.
> 
> ASLR interferes with GDB's ability to set breakpoints. A similar issue
> holds true when compiling with -O2 (in which case single-stepping is
> messed up because GDB cannot map the code back to the original source
> code properly). Therefore we simply enable ASLR only when an
> optimization flag is present in the CFLAGS, using it as an indicator
> that the developer does not want to debug in GDB anyway.
> 
> Signed-off-by: İsmail Dönmez <ismail@i10z.com>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
>  config.mak.uname | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/config.mak.uname b/config.mak.uname
> index e7c7d14e5f..a9edcc5f0b 100644
> --- a/config.mak.uname
> +++ b/config.mak.uname
> @@ -570,6 +570,12 @@ else
>  	ifeq ($(shell expr "$(uname_R)" : '2\.'),2)
>  		# MSys2
>  		prefix = /usr/
> +		# Enable DEP
> +		BASIC_LDFLAGS += -Wl,--nxcompat
> +		# Enable ASLR (unless debugging)
> +		ifneq (,$(findstring -O,$(CFLAGS)))
> +			BASIC_LDFLAGS += -Wl,--dynamicbase
> +		endif
>  		ifeq (MINGW32,$(MSYSTEM))
>  			prefix = /mingw32
>  			HOST_CPU = i686
> 

I'm a bit concerned that this breaks my debug sessions where I use -O0.
But I'll test without -O0 before I really complain.

-- Hannes

  reply	other threads:[~2019-04-30  6:26 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-29 21:56 [PATCH 0/2] Enable Data Execution Protection and Address Space Layout Randomization on Windows Johannes Schindelin via GitGitGadget
2019-04-29 21:56 ` [PATCH 1/2] mingw: do not let ld strip relocations İsmail Dönmez via GitGitGadget
2019-04-29 21:56 ` [PATCH 2/2] mingw: enable DEP and ASLR İsmail Dönmez via GitGitGadget
2019-04-30  6:26   ` Johannes Sixt [this message]
2019-04-30 22:41     ` Johannes Schindelin
2019-04-30 22:59       ` Johannes Sixt
2019-05-01 18:39       ` Alban Gruin
2019-05-01 23:36         ` brian m. carlson
2019-05-08 11:33           ` Johannes Schindelin
2019-05-08 11:33         ` Johannes Schindelin
2019-05-01 20:46       ` Jeff King
2019-05-01 22:02         ` Jonathan Nieder
2019-05-08 11:27           ` Johannes Schindelin
2019-05-08 11:30 ` [PATCH v2 0/2] Enable Data Execution Protection and Address Space Layout Randomization on Windows Johannes Schindelin via GitGitGadget
2019-05-08 11:30   ` [PATCH v2 1/2] mingw: do not let ld strip relocations İsmail Dönmez via GitGitGadget
2019-05-08 11:30   ` [PATCH v2 2/2] mingw: enable DEP and ASLR İsmail Dönmez via GitGitGadget

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