[ARM] Improve non-executable support
Add support for detecting non-executable stack binaries, and adjust
permissions to prevent execution from data and stack areas. Also,
ensure that READ_IMPLIES_EXEC is enabled for older CPUs where that
is true, and for any executable-stack binary.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/include/asm/elf.h b/arch/arm/include/asm/elf.h
index 7ea302c..5be0169 100644
--- a/arch/arm/include/asm/elf.h
+++ b/arch/arm/include/asm/elf.h
@@ -18,9 +18,32 @@
typedef struct user_fp elf_fpregset_t;
#define EM_ARM 40
-#define EF_ARM_APCS26 0x08
-#define EF_ARM_SOFT_FLOAT 0x200
-#define EF_ARM_EABI_MASK 0xFF000000
+
+#define EF_ARM_EABI_MASK 0xff000000
+#define EF_ARM_EABI_UNKNOWN 0x00000000
+#define EF_ARM_EABI_VER1 0x01000000
+#define EF_ARM_EABI_VER2 0x02000000
+#define EF_ARM_EABI_VER3 0x03000000
+#define EF_ARM_EABI_VER4 0x04000000
+#define EF_ARM_EABI_VER5 0x05000000
+
+#define EF_ARM_BE8 0x00800000 /* ABI 4,5 */
+#define EF_ARM_LE8 0x00400000 /* ABI 4,5 */
+#define EF_ARM_MAVERICK_FLOAT 0x00000800 /* ABI 0 */
+#define EF_ARM_VFP_FLOAT 0x00000400 /* ABI 0 */
+#define EF_ARM_SOFT_FLOAT 0x00000200 /* ABI 0 */
+#define EF_ARM_OLD_ABI 0x00000100 /* ABI 0 */
+#define EF_ARM_NEW_ABI 0x00000080 /* ABI 0 */
+#define EF_ARM_ALIGN8 0x00000040 /* ABI 0 */
+#define EF_ARM_PIC 0x00000020 /* ABI 0 */
+#define EF_ARM_MAPSYMSFIRST 0x00000010 /* ABI 2 */
+#define EF_ARM_APCS_FLOAT 0x00000010 /* ABI 0, floats in fp regs */
+#define EF_ARM_DYNSYMSUSESEGIDX 0x00000008 /* ABI 2 */
+#define EF_ARM_APCS_26 0x00000008 /* ABI 0 */
+#define EF_ARM_SYMSARESORTED 0x00000004 /* ABI 1,2 */
+#define EF_ARM_INTERWORK 0x00000004 /* ABI 0 */
+#define EF_ARM_HASENTRY 0x00000002 /* All */
+#define EF_ARM_RELEXEC 0x00000001 /* All */
#define R_ARM_NONE 0
#define R_ARM_PC24 1
@@ -57,23 +80,16 @@
extern char elf_platform[];
+struct elf32_hdr;
+
/*
* This is used to ensure we don't load something for the wrong architecture.
*/
-#define elf_check_arch(x) ((x)->e_machine == EM_ARM && ELF_PROC_OK(x))
+extern int elf_check_arch(const struct elf32_hdr *);
+#define elf_check_arch elf_check_arch
-/*
- * 32-bit code is always OK. Some cpus can do 26-bit, some can't.
- */
-#define ELF_PROC_OK(x) (ELF_THUMB_OK(x) && ELF_26BIT_OK(x))
-
-#define ELF_THUMB_OK(x) \
- ((elf_hwcap & HWCAP_THUMB && ((x)->e_entry & 1) == 1) || \
- ((x)->e_entry & 3) == 0)
-
-#define ELF_26BIT_OK(x) \
- ((elf_hwcap & HWCAP_26BIT && (x)->e_flags & EF_ARM_APCS26) || \
- ((x)->e_flags & EF_ARM_APCS26) == 0)
+extern int arm_elf_read_implies_exec(const struct elf32_hdr *, int);
+#define elf_read_implies_exec(ex,stk) arm_elf_read_implies_exec(&(ex), stk)
#define USE_ELF_CORE_DUMP
#define ELF_EXEC_PAGESIZE 4096
@@ -90,23 +106,7 @@
have no such handler. */
#define ELF_PLAT_INIT(_r, load_addr) (_r)->ARM_r0 = 0
-/*
- * Since the FPA coprocessor uses CP1 and CP2, and iWMMXt uses CP0
- * and CP1, we only enable access to the iWMMXt coprocessor if the
- * binary is EABI or softfloat (and thus, guaranteed not to use
- * FPA instructions.)
- */
-#define SET_PERSONALITY(ex, ibcs2) \
- do { \
- if ((ex).e_flags & EF_ARM_APCS26) { \
- set_personality(PER_LINUX); \
- } else { \
- set_personality(PER_LINUX_32BIT); \
- if (elf_hwcap & HWCAP_IWMMXT && (ex).e_flags & (EF_ARM_EABI_MASK | EF_ARM_SOFT_FLOAT)) \
- set_thread_flag(TIF_USING_IWMMXT); \
- else \
- clear_thread_flag(TIF_USING_IWMMXT); \
- } \
- } while (0)
+extern void elf_set_personality(const struct elf32_hdr *);
+#define SET_PERSONALITY(ex, ibcs2) elf_set_personality(&(ex))
#endif