forked from Minki/linux
[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>
This commit is contained in:
Russell King
Russell King
parent
5ec9407dd1
commit
8ec53663d2
@ -18,9 +18,32 @@ typedef elf_greg_t elf_gregset_t[ELF_NGREG];
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typedef struct user_fp elf_fpregset_t;
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#define EM_ARM 40
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#define EF_ARM_APCS26 0x08
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#define EF_ARM_SOFT_FLOAT 0x200
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#define EF_ARM_EABI_MASK 0xFF000000
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#define EF_ARM_EABI_MASK 0xff000000
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#define EF_ARM_EABI_UNKNOWN 0x00000000
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#define EF_ARM_EABI_VER1 0x01000000
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#define EF_ARM_EABI_VER2 0x02000000
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#define EF_ARM_EABI_VER3 0x03000000
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#define EF_ARM_EABI_VER4 0x04000000
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#define EF_ARM_EABI_VER5 0x05000000
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#define EF_ARM_BE8 0x00800000 /* ABI 4,5 */
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#define EF_ARM_LE8 0x00400000 /* ABI 4,5 */
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#define EF_ARM_MAVERICK_FLOAT 0x00000800 /* ABI 0 */
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#define EF_ARM_VFP_FLOAT 0x00000400 /* ABI 0 */
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#define EF_ARM_SOFT_FLOAT 0x00000200 /* ABI 0 */
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#define EF_ARM_OLD_ABI 0x00000100 /* ABI 0 */
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#define EF_ARM_NEW_ABI 0x00000080 /* ABI 0 */
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#define EF_ARM_ALIGN8 0x00000040 /* ABI 0 */
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#define EF_ARM_PIC 0x00000020 /* ABI 0 */
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#define EF_ARM_MAPSYMSFIRST 0x00000010 /* ABI 2 */
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#define EF_ARM_APCS_FLOAT 0x00000010 /* ABI 0, floats in fp regs */
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#define EF_ARM_DYNSYMSUSESEGIDX 0x00000008 /* ABI 2 */
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#define EF_ARM_APCS_26 0x00000008 /* ABI 0 */
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#define EF_ARM_SYMSARESORTED 0x00000004 /* ABI 1,2 */
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#define EF_ARM_INTERWORK 0x00000004 /* ABI 0 */
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#define EF_ARM_HASENTRY 0x00000002 /* All */
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#define EF_ARM_RELEXEC 0x00000001 /* All */
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#define R_ARM_NONE 0
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#define R_ARM_PC24 1
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@ -57,23 +80,16 @@ typedef struct user_fp elf_fpregset_t;
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extern char elf_platform[];
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struct elf32_hdr;
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/*
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* This is used to ensure we don't load something for the wrong architecture.
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*/
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#define elf_check_arch(x) ((x)->e_machine == EM_ARM && ELF_PROC_OK(x))
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extern int elf_check_arch(const struct elf32_hdr *);
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#define elf_check_arch elf_check_arch
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/*
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* 32-bit code is always OK. Some cpus can do 26-bit, some can't.
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*/
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#define ELF_PROC_OK(x) (ELF_THUMB_OK(x) && ELF_26BIT_OK(x))
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#define ELF_THUMB_OK(x) \
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((elf_hwcap & HWCAP_THUMB && ((x)->e_entry & 1) == 1) || \
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((x)->e_entry & 3) == 0)
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#define ELF_26BIT_OK(x) \
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((elf_hwcap & HWCAP_26BIT && (x)->e_flags & EF_ARM_APCS26) || \
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((x)->e_flags & EF_ARM_APCS26) == 0)
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extern int arm_elf_read_implies_exec(const struct elf32_hdr *, int);
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#define elf_read_implies_exec(ex,stk) arm_elf_read_implies_exec(&(ex), stk)
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#define USE_ELF_CORE_DUMP
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#define ELF_EXEC_PAGESIZE 4096
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@ -90,23 +106,7 @@ extern char elf_platform[];
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have no such handler. */
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#define ELF_PLAT_INIT(_r, load_addr) (_r)->ARM_r0 = 0
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/*
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* Since the FPA coprocessor uses CP1 and CP2, and iWMMXt uses CP0
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* and CP1, we only enable access to the iWMMXt coprocessor if the
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* binary is EABI or softfloat (and thus, guaranteed not to use
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* FPA instructions.)
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*/
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#define SET_PERSONALITY(ex, ibcs2) \
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do { \
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if ((ex).e_flags & EF_ARM_APCS26) { \
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set_personality(PER_LINUX); \
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} else { \
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set_personality(PER_LINUX_32BIT); \
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if (elf_hwcap & HWCAP_IWMMXT && (ex).e_flags & (EF_ARM_EABI_MASK | EF_ARM_SOFT_FLOAT)) \
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set_thread_flag(TIF_USING_IWMMXT); \
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else \
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clear_thread_flag(TIF_USING_IWMMXT); \
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} \
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} while (0)
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extern void elf_set_personality(const struct elf32_hdr *);
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#define SET_PERSONALITY(ex, ibcs2) elf_set_personality(&(ex))
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#endif
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@ -184,8 +184,9 @@ typedef struct page *pgtable_t;
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#endif /* !__ASSEMBLY__ */
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#define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | VM_EXEC | \
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VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
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#define VM_DATA_DEFAULT_FLAGS \
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(((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0) | \
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VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
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/*
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* With EABI on ARMv5 and above we must have 64-bit aligned slab pointers.
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@ -197,22 +197,29 @@ extern void __pgd_error(const char *file, int line, unsigned long val);
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* shared mapping bits.
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*/
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#define _L_PTE_DEFAULT L_PTE_PRESENT | L_PTE_YOUNG
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#define _L_PTE_READ L_PTE_USER | L_PTE_EXEC
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extern pgprot_t pgprot_user;
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extern pgprot_t pgprot_kernel;
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#define PAGE_NONE pgprot_user
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#define PAGE_COPY __pgprot(pgprot_val(pgprot_user) | _L_PTE_READ)
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#define PAGE_SHARED __pgprot(pgprot_val(pgprot_user) | _L_PTE_READ | \
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L_PTE_WRITE)
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#define PAGE_READONLY __pgprot(pgprot_val(pgprot_user) | _L_PTE_READ)
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#define PAGE_KERNEL pgprot_kernel
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#define _MOD_PROT(p, b) __pgprot(pgprot_val(p) | (b))
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#define __PAGE_NONE __pgprot(_L_PTE_DEFAULT)
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#define __PAGE_COPY __pgprot(_L_PTE_DEFAULT | _L_PTE_READ)
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#define __PAGE_SHARED __pgprot(_L_PTE_DEFAULT | _L_PTE_READ | L_PTE_WRITE)
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#define __PAGE_READONLY __pgprot(_L_PTE_DEFAULT | _L_PTE_READ)
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#define PAGE_NONE pgprot_user
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#define PAGE_SHARED _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_WRITE)
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#define PAGE_SHARED_EXEC _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_WRITE | L_PTE_EXEC)
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#define PAGE_COPY _MOD_PROT(pgprot_user, L_PTE_USER)
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#define PAGE_COPY_EXEC _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_EXEC)
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#define PAGE_READONLY _MOD_PROT(pgprot_user, L_PTE_USER)
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#define PAGE_READONLY_EXEC _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_EXEC)
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#define PAGE_KERNEL pgprot_kernel
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#define PAGE_KERNEL_EXEC _MOD_PROT(pgprot_kernel, L_PTE_EXEC)
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#define __PAGE_NONE __pgprot(_L_PTE_DEFAULT)
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#define __PAGE_SHARED __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_WRITE)
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#define __PAGE_SHARED_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_WRITE | L_PTE_EXEC)
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#define __PAGE_COPY __pgprot(_L_PTE_DEFAULT | L_PTE_USER)
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#define __PAGE_COPY_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_EXEC)
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#define __PAGE_READONLY __pgprot(_L_PTE_DEFAULT | L_PTE_USER)
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#define __PAGE_READONLY_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_EXEC)
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#endif /* __ASSEMBLY__ */
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@ -228,19 +235,19 @@ extern pgprot_t pgprot_kernel;
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#define __P001 __PAGE_READONLY
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#define __P010 __PAGE_COPY
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#define __P011 __PAGE_COPY
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#define __P100 __PAGE_READONLY
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#define __P101 __PAGE_READONLY
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#define __P110 __PAGE_COPY
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#define __P111 __PAGE_COPY
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#define __P100 __PAGE_READONLY_EXEC
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#define __P101 __PAGE_READONLY_EXEC
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#define __P110 __PAGE_COPY_EXEC
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#define __P111 __PAGE_COPY_EXEC
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#define __S000 __PAGE_NONE
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#define __S001 __PAGE_READONLY
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#define __S010 __PAGE_SHARED
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#define __S011 __PAGE_SHARED
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#define __S100 __PAGE_READONLY
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#define __S101 __PAGE_READONLY
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#define __S110 __PAGE_SHARED
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#define __S111 __PAGE_SHARED
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#define __S100 __PAGE_READONLY_EXEC
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#define __S101 __PAGE_READONLY_EXEC
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#define __S110 __PAGE_SHARED_EXEC
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#define __S111 __PAGE_SHARED_EXEC
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#ifndef __ASSEMBLY__
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/*
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@ -10,7 +10,7 @@ endif
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# Object file lists.
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obj-y := compat.o entry-armv.o entry-common.o irq.o \
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obj-y := compat.o elf.o entry-armv.o entry-common.o irq.o \
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process.o ptrace.o setup.o signal.o \
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sys_arm.o stacktrace.o time.o traps.o
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79
arch/arm/kernel/elf.c
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79
arch/arm/kernel/elf.c
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@ -0,0 +1,79 @@
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/personality.h>
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#include <linux/binfmts.h>
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#include <linux/elf.h>
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int elf_check_arch(const struct elf32_hdr *x)
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{
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unsigned int eflags;
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/* Make sure it's an ARM executable */
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if (x->e_machine != EM_ARM)
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return 0;
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/* Make sure the entry address is reasonable */
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if (x->e_entry & 1) {
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if (!(elf_hwcap & HWCAP_THUMB))
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return 0;
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} else if (x->e_entry & 3)
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return 0;
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eflags = x->e_flags;
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if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN) {
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/* APCS26 is only allowed if the CPU supports it */
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if ((eflags & EF_ARM_APCS_26) && !(elf_hwcap & HWCAP_26BIT))
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return 0;
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/* VFP requires the supporting code */
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if ((eflags & EF_ARM_VFP_FLOAT) && !(elf_hwcap & HWCAP_VFP))
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return 0;
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}
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return 1;
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}
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EXPORT_SYMBOL(elf_check_arch);
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void elf_set_personality(const struct elf32_hdr *x)
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{
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unsigned int eflags = x->e_flags;
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unsigned int personality = PER_LINUX_32BIT;
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/*
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* APCS-26 is only valid for OABI executables
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*/
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if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN) {
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if (eflags & EF_ARM_APCS_26)
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personality = PER_LINUX;
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}
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set_personality(personality);
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/*
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* Since the FPA coprocessor uses CP1 and CP2, and iWMMXt uses CP0
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* and CP1, we only enable access to the iWMMXt coprocessor if the
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* binary is EABI or softfloat (and thus, guaranteed not to use
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* FPA instructions.)
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*/
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if (elf_hwcap & HWCAP_IWMMXT &&
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eflags & (EF_ARM_EABI_MASK | EF_ARM_SOFT_FLOAT)) {
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set_thread_flag(TIF_USING_IWMMXT);
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} else {
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clear_thread_flag(TIF_USING_IWMMXT);
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}
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}
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EXPORT_SYMBOL(elf_set_personality);
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/*
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* Set READ_IMPLIES_EXEC if:
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* - the binary requires an executable stack
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* - we're running on a CPU which doesn't support NX.
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*/
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int arm_elf_read_implies_exec(const struct elf32_hdr *x, int executable_stack)
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{
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if (executable_stack != EXSTACK_ENABLE_X)
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return 1;
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if (cpu_architecture() <= CPU_ARCH_ARMv6)
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return 1;
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return 0;
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}
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EXPORT_SYMBOL(arm_elf_read_implies_exec);
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@ -47,7 +47,7 @@ void *module_alloc(unsigned long size)
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if (!area)
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return NULL;
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return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL);
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return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL_EXEC);
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}
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#else /* CONFIG_MMU */
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void *module_alloc(unsigned long size)
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