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Diffstat (limited to 'arch/arm64/include/asm/uaccess.h')
-rw-r--r--arch/arm64/include/asm/uaccess.h111
1 files changed, 74 insertions, 37 deletions
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index b2ede967fe7d..c3d445b42351 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)
@@ -247,24 +269,39 @@ do { \
-EFAULT; \
})
-extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
-extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
+extern unsigned long __must_check __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
+extern unsigned long __must_check __arch_copy_to_user(void __user *to, const void *from, unsigned long n);
extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n);
extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
+static inline unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+ check_object_size(to, n, false);
+ return __arch_copy_from_user(to, from, n);
+}
+
+static inline unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+ check_object_size(from, n, true);
+ return __arch_copy_to_user(to, from, n);
+}
+
static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
{
- if (access_ok(VERIFY_READ, from, n))
- n = __copy_from_user(to, from, n);
- else /* security hole - plug it */
+ if (access_ok(VERIFY_READ, from, n)) {
+ check_object_size(to, n, false);
+ n = __arch_copy_from_user(to, from, n);
+ } else /* security hole - plug it */
memset(to, 0, n);
return n;
}
static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
{
- if (access_ok(VERIFY_WRITE, to, n))
- n = __copy_to_user(to, from, n);
+ if (access_ok(VERIFY_WRITE, to, n)) {
+ check_object_size(from, n, true);
+ n = __arch_copy_to_user(to, from, n);
+ }
return n;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-26 09:52:54 +0000