Hi Johannes, Le 01/05/2019 à 00:41, Johannes Schindelin a écrit : > Hi Hannes, > > On Tue, 30 Apr 2019, Johannes Sixt wrote: > >> [had to add Dscho as recipient manually, mind you] > > I usually pick up responses to GitGitGadget patch series even if I am not > on explicit Cc: (but it might take a couple of days when I am too busy > elsewhere to read the Git mailing list). > >> Am 29.04.19 um 23:56 schrieb İsmail Dönmez via GitGitGadget: >>> From: =?UTF-8?q?=C4=B0smail=20D=C3=B6nmez?= <ismail@xxxxxxxx> >>> >>> 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 I don’t know if it stands true when combined with something like -ggdb3, but I may be very wrong. Feel free to correct me. >>> 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@xxxxxxxx> >>> Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx> >>> --- >>> 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,$(MSYSTEM)) >>> prefix = /mingw32 >>> HOST_CPU = i686 >>> >> >> I'm a bit concerned that this breaks my debug sessions where I use -O0. >> But I'll test without -O0 before I really complain. > > Weird. Jameson Miller also mentioned this very concern in an internal > review. > > I guess I'll do something like > > ifneq (,$(findstring -O,$(filter-out -O0,$(CFLAGS)))) > -Og also exists to debug[0], even if it’s far less known. Perhaps it’s better to check for -g (and its variants[1]) as the user clearly states their intent to debug the resulting binary, rather than checking for special cases. > Does that work for you? > > Ciao, > Dscho > [0] https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-Og [1] https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html Cheers, Alban
