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authorEric Andersen <andersen@codepoet.org>2004-01-02 23:34:13 +0000
committerEric Andersen <andersen@codepoet.org>2004-01-02 23:34:13 +0000
commitfb84603f8c45fdafdaa750490785fc1b15541386 (patch)
tree257c50f56dfb4d90e775b83a915ae21d9f39bb04 /libc/sysdeps/linux/i386
parentcadff3f10e8f20f8db0e2878abf90fb16eba797a (diff)
Peter S. Mazinger writes:
Hello Erik! I have made some cosmetical changes to the files, removed the added SCRT=-fPIC option from building the crt0.S file (but it is a requirement to build them with -fPIC), and changed some comments. I have left the ldso.c patch with PIE_SUPPORT ifdefs, but consider applying it w/o them (see some earlier comment from PaX Team on this issue, as it is considered a bug). To have it work correctly, you'll also need removing COMPLETELY_PIC. One thing is missing: PIE_SUPPORT should be usable only for i386 (for now). Also added the support for propolice protection (that works for me and catches memcpy/strcpy attacks (but needs a special gcc version). Thanks, Peter
Diffstat (limited to 'libc/sysdeps/linux/i386')
-rw-r--r--libc/sysdeps/linux/i386/Makefile10
-rw-r--r--libc/sysdeps/linux/i386/crt0.S25
2 files changed, 33 insertions, 2 deletions
diff --git a/libc/sysdeps/linux/i386/Makefile b/libc/sysdeps/linux/i386/Makefile
index 9ba60f59e..c7f88b681 100644
--- a/libc/sysdeps/linux/i386/Makefile
+++ b/libc/sysdeps/linux/i386/Makefile
@@ -22,6 +22,9 @@ ASFLAGS=$(CFLAGS)
CRT0_SRC = crt0.S
CRT0_OBJ = crt0.o crt1.o gcrt1.o
+ifeq ($(strip $(UCLIBC_PIE_SUPPORT)),y)
+CRT0_OBJ += Scrt0.o Scrt1.o
+endif
CRT0_DEPS=gmon-start.S
CTOR_TARGETS=$(TOPDIR)lib/crti.o $(TOPDIR)lib/crtn.o
@@ -44,6 +47,13 @@ $(LIBC): ar-target
ar-target: $(OBJS) $(CRT0_OBJ) $(CTOR_TARGETS)
$(AR) $(ARFLAGS) $(LIBC) $(OBJS)
cp $(CRT0_OBJ) $(TOPDIR)lib/
+ifeq ($(strip $(UCLIBC_PIE_SUPPORT)),y)
+ifeq ($(strip $(UCLIBC_CTOR_DTOR)),y)
+ $(RM) $(TOPDIR)lib/Scrt0.o
+else
+ mv $(TOPDIR)lib/Scrt0.o $(TOPDIR)lib/Scrt1.o
+endif
+endif
$(CRT0_OBJ): $(CRT0_SRC)
$(CC) $(CFLAGS) -DL_$* $< -c -o $*.o
diff --git a/libc/sysdeps/linux/i386/crt0.S b/libc/sysdeps/linux/i386/crt0.S
index a488d6508..e7df6992b 100644
--- a/libc/sysdeps/linux/i386/crt0.S
+++ b/libc/sysdeps/linux/i386/crt0.S
@@ -18,6 +18,7 @@ Cambridge, MA 02139, USA. */
/* Based on the code from GNU libc, but hacked up by John Beppu and Erik Andersen */
+/* adapted by PaX Team for ET_DYN/PIE binaries */
/*
When we enter this piece of code, the program stack looks like this:
@@ -37,7 +38,7 @@ Cambridge, MA 02139, USA. */
.global _start
.type _start,%function
-#if defined L_crt0 || ! defined __UCLIBC_CTOR_DTOR__
+#if defined L_crt0 || defined L_Scrt0 || ! defined __UCLIBC_CTOR_DTOR__
.type __uClibc_main,%function
#else
.weak _init
@@ -74,10 +75,22 @@ _start:
pushl %ebp /* callers %ebp (frame pointer) */
movl %esp,%ebp /* mark callers stack frame as invalid */
-#if (defined L_crt1 || defined L_gcrt1 ) && defined __UCLIBC_CTOR_DTOR__
+#if defined L_Scrt0 || defined L_Scrt1
+ call .L0
+.L0:
+ pop %edx
+ addl $_GLOBAL_OFFSET_TABLE_+[.-.L0],%edx
+#endif
+
+#if (defined L_crt1 || defined L_Scrt1 || defined L_gcrt1 ) && defined __UCLIBC_CTOR_DTOR__
/* Push .init and .fini arguments to __uClibc_start_main() on the stack */
+#ifdef L_Scrt1
+ pushl _fini@GOT(%edx)
+ pushl _init@GOT(%edx)
+#else
pushl $_fini
pushl $_init
+#endif
/* Push envp, argc, and argc arguments to __uClibc_start_main() on the stack */
pushl %eax /* Environment pointer */
@@ -85,15 +98,23 @@ _start:
pushl %ecx /* And the argument count */
/* Ok, now run uClibc's main() -- shouldn't return */
+#ifdef L_Scrt1
+ call *__uClibc_start_main@GOT(%edx)
+#else
call __uClibc_start_main
+#endif
#else
/* Push envp, argc, and argc arguments to __uClibc_start_main() on the stack */
pushl %eax /* Environment pointer */
pushl %ebx /* Argument pointer */
pushl %ecx /* And the argument count */
+#ifdef L_Scrt0
+ call *__uClibc_main@GOT(%edx)
+#else
call __uClibc_main
#endif
+#endif
/* Crash if somehow `exit' returns anyways. */
hlt