diff options
| -rw-r--r-- | debian/config | 5 | ||||
| -rw-r--r-- | extra/Configs/Config.in | 25 | ||||
| -rw-r--r-- | ldso/ldso/ldso.c | 45 | ||||
| -rw-r--r-- | libc/misc/internals/__uClibc_main.c | 7 | ||||
| -rw-r--r-- | libc/sysdeps/linux/common/Makefile | 3 | ||||
| -rw-r--r-- | libc/sysdeps/linux/common/ssp.c | 97 | ||||
| -rw-r--r-- | libc/sysdeps/linux/i386/Makefile | 10 | ||||
| -rw-r--r-- | libc/sysdeps/linux/i386/crt0.S | 25 |
8 files changed, 215 insertions, 2 deletions
diff --git a/debian/config b/debian/config index 487198a72..1177443ec 100644 --- a/debian/config +++ b/debian/config @@ -36,11 +36,16 @@ HAVE_DOT_CONFIG=y # # HAVE_NO_PIC is not set DOPIC=y +# HAVE_NO_SHARED is not set HAVE_SHARED=y +# ARCH_HAS_NO_LDSO is not set BUILD_UCLIBC_LDSO=y +# UCLIBC_PIE_SUPPORT is not set LDSO_LDD_SUPPORT=y UCLIBC_CTOR_DTOR=y +# UCLIBC_PROPOLICE is not set # UCLIBC_PROFILING is not set +# HAS_NO_THREADS is not set UCLIBC_HAS_THREADS=y PTHREADS_DEBUG_SUPPORT=y UCLIBC_HAS_LFS=y diff --git a/extra/Configs/Config.in b/extra/Configs/Config.in index 8f5eee439..e175a5909 100644 --- a/extra/Configs/Config.in +++ b/extra/Configs/Config.in @@ -177,6 +177,20 @@ config FORCE_SHAREABLE_TEXT_SEGMENTS little bit smaller and guarantee that no memory will be wasted by badly coded shared libraries. +config UCLIBC_PIE_SUPPORT + bool "Support ET_DYN in shared library loader" + select FORCE_SHAREABLE_TEXT_SEGMENTS + default n + help + If you answer Y here, the uClibc native shared library loader will + support ET_DYN/PIE executables. + It requires binutils-2.14.90.0.6 or later and the usage of the + -pie option. + More about ET_DYN/PIE binaries on <http://pageexec.virtualave.net/> . + WARNING: This option also enables FORCE_SHAREABLE_TEXT_SEGMENTS, so all + libraries have to be built with -fPIC or -fpic, and all assembler + functions must be written as position independent code (PIC). + config LDSO_LDD_SUPPORT bool "Native shared library loader 'ldd' support" depends on BUILD_UCLIBC_LDSO @@ -204,6 +218,17 @@ config UCLIBC_CTOR_DTOR then you definitely want to answer Y here. If you don't need ctors or dtors and want your binaries to be as small as possible, then answer N. + +config UCLIBC_PROPOLICE + bool "Support for propolice stack protection" + default n + help + Propolice stack protection. + More about it on <http://www.research.ibm.com/trl/projects/security/ssp> . + To be able to use it, you'll also need a propolice patched gcc, + supporting the -fstack-protector[-all] options. It is a specially patched + gcc version, were __guard and __stack_smash_handler are removed from libgcc. + Most people will answer N. config UCLIBC_PROFILING bool "Support gprof profiling" 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 diff --git a/libc/misc/internals/__uClibc_main.c b/libc/misc/internals/__uClibc_main.c index 5f85b5928..842e99500 100644 --- a/libc/misc/internals/__uClibc_main.c +++ b/libc/misc/internals/__uClibc_main.c @@ -15,6 +15,9 @@ #include <features.h> #include <unistd.h> #include <stdlib.h> +#ifdef __UCLIBC_PROPOLICE__ +extern void __guard_setup(void); +#endif /* @@ -139,6 +142,10 @@ __uClibc_start_main(int argc, char **argv, char **envp, } #endif +#ifdef __UCLIBC_PROPOLICE__ + __guard_setup (); +#endif + /* Note: It is possible that any initialization done above could * have resulted in errno being set nonzero, so set it to 0 before * we call main. diff --git a/libc/sysdeps/linux/common/Makefile b/libc/sysdeps/linux/common/Makefile index cfd95300f..5b5034095 100644 --- a/libc/sysdeps/linux/common/Makefile +++ b/libc/sysdeps/linux/common/Makefile @@ -33,6 +33,9 @@ endif ifeq ($(strip $(UCLIBC_PROFILING)),y) CSRC+=gmon.c endif +ifeq ($(strip $(UCLIBC_PROPOLICE)),y) +CSRC+=ssp.c +endif COBJS=$(patsubst %.c,%.o, $(CSRC)) MSRC=syscalls.c diff --git a/libc/sysdeps/linux/common/ssp.c b/libc/sysdeps/linux/common/ssp.c new file mode 100644 index 000000000..135892c37 --- /dev/null +++ b/libc/sysdeps/linux/common/ssp.c @@ -0,0 +1,97 @@ +#include <stdio.h> +#include <string.h> +#include <fcntl.h> +#include <unistd.h> + +#ifdef _POSIX_SOURCE +#include <signal.h> +#endif + +#if defined(HAVE_SYSLOG) +#include <sys/types.h> +#include <sys/socket.h> +#include <sys/un.h> + +#include <sys/syslog.h> +#ifndef _PATH_LOG +#define _PATH_LOG "/dev/log" +#endif +#endif + +long __guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; + +void __guard_setup (void) +{ + int fd; + if (__guard[0]!=0) return; + fd = open ("/dev/urandom", 0); + if (fd != -1) { + ssize_t size = read (fd, (char*)&__guard, sizeof(__guard)); + close (fd) ; + if (size == sizeof(__guard)) return; + } + /* If a random generator can't be used, the protector switches the guard + to the "terminator canary" */ + ((char*)__guard)[0] = 0; ((char*)__guard)[1] = 0; + ((char*)__guard)[2] = '\n'; ((char*)__guard)[3] = 255; +} + +void __stack_smash_handler (char func[], int damaged) +{ +#if defined (__GNU_LIBRARY__) + extern char * __progname; +#endif + const char message[] = ": stack smashing attack in function "; + int bufsz = 512, len; + char buf[bufsz]; +#if defined(HAVE_SYSLOG) + int LogFile; + struct sockaddr_un SyslogAddr; /* AF_UNIX address of local logger */ +#endif +#ifdef _POSIX_SOURCE + { + sigset_t mask; + sigfillset(&mask); + sigdelset(&mask, SIGABRT); /* Block all signal handlers */ + sigprocmask(SIG_BLOCK, &mask, NULL); /* except SIGABRT */ + } +#endif + + strcpy(buf, "<2>"); len=3; /* send LOG_CRIT */ +#if defined (__GNU_LIBRARY__) + strncat(buf, __progname, bufsz-len-1); len = strlen(buf); +#endif + if (bufsz>len) {strncat(buf, message, bufsz-len-1); len = strlen(buf);} + if (bufsz>len) {strncat(buf, func, bufsz-len-1); len = strlen(buf);} + /* print error message */ + write (STDERR_FILENO, buf+3, len-3); +#if defined(HAVE_SYSLOG) + if ((LogFile = socket(AF_UNIX, SOCK_DGRAM, 0)) != -1) { + + /* + * Send "found" message to the "/dev/log" path + */ + SyslogAddr.sun_family = AF_UNIX; + (void)strncpy(SyslogAddr.sun_path, _PATH_LOG, + sizeof(SyslogAddr.sun_path) - 1); + SyslogAddr.sun_path[sizeof(SyslogAddr.sun_path) - 1] = '\0'; + sendto(LogFile, buf, len, 0, (struct sockaddr *)&SyslogAddr, + sizeof(SyslogAddr)); + } +#endif + +#ifdef _POSIX_SOURCE + { /* Make sure the default handler is associated with SIGABRT */ + struct sigaction sa; + + memset(&sa, 0, sizeof(struct sigaction)); + sigfillset(&sa.sa_mask); /* Block all signals */ + sa.sa_flags = 0; + sa.sa_handler = SIG_DFL; + sigaction(SIGABRT, &sa, NULL); + (void)kill(getpid(), SIGABRT); + } +#endif + _exit(127); +} + 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 |