54 lines
1.9 KiB
Diff
54 lines
1.9 KiB
Diff
From f8b1f860c0038613c31b800ff0466fc1c4e25823 Mon Sep 17 00:00:00 2001
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From: Enrico Scholz <enrico.scholz@informatik.tu-chemnitz.de>
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Date: Sat, 19 Apr 2008 17:56:07 +0200
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Subject: [PATCH] Enhanced __stack_chk_fail
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* modified __stack_chk_fail() to trigger a segfault by accessing
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address 0x0. Every system with an MMU known by me, segfaults
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by dereferencing a NULL pointer.
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* added hack to compile stack_smash_handler2 with
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'--fno-omit-frame-pointer'.
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---
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Makefile | 3 ++-
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lib/stack_smash_handler2.c | 10 +++++++++-
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2 files changed, 11 insertions(+), 2 deletions(-)
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diff --git a/Makefile b/Makefile
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index adc2779..0cd0105 100644
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--- a/Makefile
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+++ b/Makefile
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@@ -172,9 +172,10 @@ $(OBJDIR)/%.o: %.S $(ARCH)/syscalls.h
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$(OBJDIR)/pthread_%.o: libpthread/pthread_%.c
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$(CROSS)$(CC) $(INC) $(CFLAGS) -c $< -o $@
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$(COMMENT) -$(CROSS)strip -x -R .comment -R .note $@
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+$(OBJDIR)/stack_smash_handler2.o: XCFLAGS:=-fno-omit-frame-pointer
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$(OBJDIR)/%.o: %.c
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- $(CROSS)$(CC) $(INC) $(CFLAGS) -c $< -o $@ -D__dietlibc__
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+ $(CROSS)$(CC) $(INC) $(CFLAGS) $(XCFLAGS) -c $< -o $@ -D__dietlibc__
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$(COMMENT) -$(CROSS)strip -x -R .comment -R .note $@
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endif
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diff --git a/lib/stack_smash_handler2.c b/lib/stack_smash_handler2.c
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index 9e85099..ecefeb8 100644
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--- a/lib/stack_smash_handler2.c
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+++ b/lib/stack_smash_handler2.c
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@@ -8,5 +8,13 @@ void __stack_chk_fail(void);
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* diagnostics. No more. :-( */
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void __stack_chk_fail(void) {
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__write2("smashed stack detected, program terminated.\n");
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- _exit(127);
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+
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+ /* trigger a segfault which can be inspected within a debugger (inclusive
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+ * stack-trace). 'abort(3)' at this place would be too heavy weighted.
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+ *
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+ * TODO: limit this to systems which are known to have an MMU (resp. is
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+ * dietlibc with stack-protector used on systems without an MMU?)
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+ */
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+ while (1)
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+ *(char *)0 = 0;
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}
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--
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1.6.0.6
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