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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 /ldso
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 'ldso')
-rw-r--r--ldso/ldso/ldso.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/ldso/ldso/ldso.c b/ldso/ldso/ldso.c
index 768ff241c..0f89d70e8 100644
--- a/ldso/ldso/ldso.c
+++ b/ldso/ldso/ldso.c
@@ -371,6 +371,28 @@ LD_BOOT(unsigned long args)
app_tpnt = LD_MALLOC(sizeof(struct elf_resolve));
_dl_memset(app_tpnt, 0, sizeof(struct elf_resolve));
+#ifdef __UCLIBC_PIE_SUPPORT__
+ /* Find the runtime load address of the main executable, this may be
+ * different from what the ELF header says for ET_DYN/PIE executables.
+ */
+ {
+ ElfW(Phdr) *ppnt;
+ int i;
+
+ ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_ptr;
+ for (i = 0; i < auxvt[AT_PHNUM].a_un.a_val; i++, ppnt++)
+ if (ppnt->p_type == PT_PHDR) {
+ app_tpnt->loadaddr = (ElfW(Addr)) (auxvt[AT_PHDR].a_un.a_val - ppnt->p_vaddr);
+ break;
+ }
+ }
+
+#ifdef __SUPPORT_LD_DEBUG_EARLY__
+ SEND_STDERR("app_tpnt->loadaddr=");
+ SEND_ADDRESS_STDERR(app_tpnt->loadaddr, 1);
+#endif
+#endif
+
/*
* This is used by gdb to locate the chain of shared libraries that are currently loaded.
*/
@@ -407,7 +429,11 @@ LD_BOOT(unsigned long args)
ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_ptr;
for (i = 0; i < auxvt[AT_PHNUM].a_un.a_val; i++, ppnt++)
if (ppnt->p_type == PT_DYNAMIC) {
+#ifndef __UCLIBC_PIE_SUPPORT__
dpnt = (Elf32_Dyn *) ppnt->p_vaddr;
+#else
+ dpnt = (Elf32_Dyn *) (ppnt->p_vaddr + app_tpnt->loadaddr);
+#endif
while (dpnt->d_tag) {
#if defined(__mips__)
if (dpnt->d_tag == DT_MIPS_GOTSYM)
@@ -501,8 +527,13 @@ LD_BOOT(unsigned long args)
ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_ptr;
for (i = 0; i < auxvt[AT_PHNUM].a_un.a_val; i++, ppnt++) {
if (ppnt->p_type == PT_LOAD && !(ppnt->p_flags & PF_W))
+#ifndef __UCLIBC_PIE_SUPPORT__
_dl_mprotect((void *) (ppnt->p_vaddr & PAGE_ALIGN),
(ppnt->p_vaddr & ADDR_ALIGN) +
+#else
+ _dl_mprotect((void *) ((ppnt->p_vaddr + app_tpnt->loadaddr) & PAGE_ALIGN),
+ ((ppnt->p_vaddr + app_tpnt->loadaddr) & ADDR_ALIGN) +
+#endif
(unsigned long) ppnt->p_filesz,
PROT_READ | PROT_WRITE | PROT_EXEC);
}
@@ -717,8 +748,13 @@ static void _dl_get_ready_to_run(struct elf_resolve *tpnt, struct elf_resolve *a
ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_ptr;
for (i = 0; i < auxvt[AT_PHNUM].a_un.a_val; i++, ppnt++) {
if (ppnt->p_type == PT_LOAD) {
+#ifndef __UCLIBC_PIE_SUPPORT__
if (ppnt->p_vaddr + ppnt->p_memsz > brk_addr)
brk_addr = ppnt->p_vaddr + ppnt->p_memsz;
+#else
+ if (ppnt->p_vaddr + app_tpnt->loadaddr + ppnt->p_memsz > brk_addr)
+ brk_addr = ppnt->p_vaddr + app_tpnt->loadaddr + ppnt->p_memsz;
+#endif
}
if (ppnt->p_type == PT_DYNAMIC) {
#ifndef ALLOW_ZERO_PLTGOT
@@ -727,8 +763,13 @@ static void _dl_get_ready_to_run(struct elf_resolve *tpnt, struct elf_resolve *a
continue;
#endif
/* OK, we have what we need - slip this one into the list. */
+#ifndef __UCLIBC_PIE_SUPPORT__
app_tpnt = _dl_add_elf_hash_table("", 0,
app_tpnt->dynamic_info, ppnt->p_vaddr, ppnt->p_filesz);
+#else
+ app_tpnt = _dl_add_elf_hash_table("", (char *)app_tpnt->loadaddr,
+ app_tpnt->dynamic_info, ppnt->p_vaddr + app_tpnt->loadaddr, ppnt->p_filesz);
+#endif
_dl_loaded_modules->libtype = elf_executable;
_dl_loaded_modules->ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_ptr;
_dl_loaded_modules->n_phent = auxvt[AT_PHNUM].a_un.a_val;
@@ -737,7 +778,11 @@ static void _dl_get_ready_to_run(struct elf_resolve *tpnt, struct elf_resolve *a
rpnt->dyn = _dl_loaded_modules;
app_tpnt->usage_count++;
app_tpnt->symbol_scope = _dl_symbol_tables;
+#ifndef __UCLIBC_PIE_SUPPORT__
lpnt = (unsigned long *) (app_tpnt->dynamic_info[DT_PLTGOT]);
+#else
+ lpnt = (unsigned long *) (app_tpnt->dynamic_info[DT_PLTGOT] + app_tpnt->loadaddr);
+#endif
#ifdef ALLOW_ZERO_PLTGOT
if (lpnt)
#endif