From d635711daa98be86d4c7fd01499c34f566b54ccb Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Fri, 10 Jun 2016 05:30:17 -0300 Subject: Linux-libre 4.6.2-gnu --- arch/arm64/include/asm/uaccess.h | 82 +++++++++++++++++++++++++--------------- 1 file changed, 52 insertions(+), 30 deletions(-) (limited to 'arch/arm64/include/asm/uaccess.h') diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index b2ede967f..0685d7457 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -36,11 +36,11 @@ #define VERIFY_WRITE 1 /* - * The exception table consists of pairs of addresses: the first is the - * address of an instruction that is allowed to fault, and the second is - * the address at which the program should continue. No registers are - * modified, so it is entirely up to the continuation code to figure out - * what to do. + * The exception table consists of pairs of relative offsets: the first + * is the relative offset to an instruction that is allowed to fault, + * and the second is the relative offset at which the program should + * continue. No registers are modified, so it is entirely up to the + * continuation code to figure out what to do. * * All the routines below use bits of fixup code that are out of line * with the main instruction path. This means when everything is well, @@ -50,9 +50,11 @@ struct exception_table_entry { - unsigned long insn, fixup; + int insn, fixup; }; +#define ARCH_HAS_RELATIVE_EXTABLE + extern int fixup_exception(struct pt_regs *regs); #define KERNEL_DS (-1UL) @@ -64,6 +66,16 @@ extern int fixup_exception(struct pt_regs *regs); static inline void set_fs(mm_segment_t fs) { current_thread_info()->addr_limit = fs; + + /* + * Enable/disable UAO so that copy_to_user() etc can access + * kernel memory with the unprivileged instructions. + */ + if (IS_ENABLED(CONFIG_ARM64_UAO) && fs == KERNEL_DS) + asm(ALTERNATIVE("nop", SET_PSTATE_UAO(1), ARM64_HAS_UAO)); + else + asm(ALTERNATIVE("nop", SET_PSTATE_UAO(0), ARM64_HAS_UAO, + CONFIG_ARM64_UAO)); } #define segment_eq(a, b) ((a) == (b)) @@ -105,6 +117,12 @@ static inline void set_fs(mm_segment_t fs) #define access_ok(type, addr, size) __range_ok(addr, size) #define user_addr_max get_fs +#define _ASM_EXTABLE(from, to) \ + " .pushsection __ex_table, \"a\"\n" \ + " .align 3\n" \ + " .long (" #from " - .), (" #to " - .)\n" \ + " .popsection\n" + /* * The "__xxx" versions of the user access functions do not verify the address * space - it must have been done previously with a separate "access_ok()" @@ -113,9 +131,10 @@ static inline void set_fs(mm_segment_t fs) * The "__xxx_error" versions set the third argument to -EFAULT if an error * occurs, and leave it unchanged on success. */ -#define __get_user_asm(instr, reg, x, addr, err) \ +#define __get_user_asm(instr, alt_instr, reg, x, addr, err, feature) \ asm volatile( \ - "1: " instr " " reg "1, [%2]\n" \ + "1:"ALTERNATIVE(instr " " reg "1, [%2]\n", \ + alt_instr " " reg "1, [%2]\n", feature) \ "2:\n" \ " .section .fixup, \"ax\"\n" \ " .align 2\n" \ @@ -123,10 +142,7 @@ static inline void set_fs(mm_segment_t fs) " mov %1, #0\n" \ " b 2b\n" \ " .previous\n" \ - " .section __ex_table,\"a\"\n" \ - " .align 3\n" \ - " .quad 1b, 3b\n" \ - " .previous" \ + _ASM_EXTABLE(1b, 3b) \ : "+r" (err), "=&r" (x) \ : "r" (addr), "i" (-EFAULT)) @@ -134,26 +150,30 @@ static inline void set_fs(mm_segment_t fs) do { \ unsigned long __gu_val; \ __chk_user_ptr(ptr); \ - asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, \ + asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_ALT_PAN_NOT_UAO,\ CONFIG_ARM64_PAN)); \ switch (sizeof(*(ptr))) { \ case 1: \ - __get_user_asm("ldrb", "%w", __gu_val, (ptr), (err)); \ + __get_user_asm("ldrb", "ldtrb", "%w", __gu_val, (ptr), \ + (err), ARM64_HAS_UAO); \ break; \ case 2: \ - __get_user_asm("ldrh", "%w", __gu_val, (ptr), (err)); \ + __get_user_asm("ldrh", "ldtrh", "%w", __gu_val, (ptr), \ + (err), ARM64_HAS_UAO); \ break; \ case 4: \ - __get_user_asm("ldr", "%w", __gu_val, (ptr), (err)); \ + __get_user_asm("ldr", "ldtr", "%w", __gu_val, (ptr), \ + (err), ARM64_HAS_UAO); \ break; \ case 8: \ - __get_user_asm("ldr", "%", __gu_val, (ptr), (err)); \ + __get_user_asm("ldr", "ldtr", "%", __gu_val, (ptr), \ + (err), ARM64_HAS_UAO); \ break; \ default: \ BUILD_BUG(); \ } \ (x) = (__force __typeof__(*(ptr)))__gu_val; \ - asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, \ + asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_ALT_PAN_NOT_UAO,\ CONFIG_ARM64_PAN)); \ } while (0) @@ -181,19 +201,17 @@ do { \ ((x) = 0, -EFAULT); \ }) -#define __put_user_asm(instr, reg, x, addr, err) \ +#define __put_user_asm(instr, alt_instr, reg, x, addr, err, feature) \ asm volatile( \ - "1: " instr " " reg "1, [%2]\n" \ + "1:"ALTERNATIVE(instr " " reg "1, [%2]\n", \ + alt_instr " " reg "1, [%2]\n", feature) \ "2:\n" \ " .section .fixup,\"ax\"\n" \ " .align 2\n" \ "3: mov %w0, %3\n" \ " b 2b\n" \ " .previous\n" \ - " .section __ex_table,\"a\"\n" \ - " .align 3\n" \ - " .quad 1b, 3b\n" \ - " .previous" \ + _ASM_EXTABLE(1b, 3b) \ : "+r" (err) \ : "r" (x), "r" (addr), "i" (-EFAULT)) @@ -201,25 +219,29 @@ do { \ do { \ __typeof__(*(ptr)) __pu_val = (x); \ __chk_user_ptr(ptr); \ - asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, \ + asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_ALT_PAN_NOT_UAO,\ CONFIG_ARM64_PAN)); \ switch (sizeof(*(ptr))) { \ case 1: \ - __put_user_asm("strb", "%w", __pu_val, (ptr), (err)); \ + __put_user_asm("strb", "sttrb", "%w", __pu_val, (ptr), \ + (err), ARM64_HAS_UAO); \ break; \ case 2: \ - __put_user_asm("strh", "%w", __pu_val, (ptr), (err)); \ + __put_user_asm("strh", "sttrh", "%w", __pu_val, (ptr), \ + (err), ARM64_HAS_UAO); \ break; \ case 4: \ - __put_user_asm("str", "%w", __pu_val, (ptr), (err)); \ + __put_user_asm("str", "sttr", "%w", __pu_val, (ptr), \ + (err), ARM64_HAS_UAO); \ break; \ case 8: \ - __put_user_asm("str", "%", __pu_val, (ptr), (err)); \ + __put_user_asm("str", "sttr", "%", __pu_val, (ptr), \ + (err), ARM64_HAS_UAO); \ break; \ default: \ BUILD_BUG(); \ } \ - asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, \ + asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_ALT_PAN_NOT_UAO,\ CONFIG_ARM64_PAN)); \ } while (0) -- cgit v1.2.3-54-g00ecf