diff options
| -rw-r--r-- | arch/arm64/include/asm/uaccess.h | 8 | ||||
| -rw-r--r-- | arch/arm64/kernel/traps.c | 27 |
2 files changed, 23 insertions, 12 deletions
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index bcaf6fba1b65..55d0adbf6509 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -21,6 +21,7 @@ /* * User space memory access functions */ +#include <linux/bitops.h> #include <linux/kasan-checks.h> #include <linux/string.h> #include <linux/thread_info.h> @@ -102,6 +103,13 @@ static inline void set_fs(mm_segment_t fs) flag; \ }) +/* + * When dealing with data aborts or instruction traps we may end up with + * a tagged userland pointer. Clear the tag to get a sane pointer to pass + * on to access_ok(), for instance. + */ +#define untagged_addr(addr) sign_extend64(addr, 55) + #define access_ok(type, addr, size) __range_ok(addr, size) #define user_addr_max get_fs diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 5ff020f8fb7f..7255c9d6cfb7 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -434,18 +434,21 @@ void cpu_enable_cache_maint_trap(void *__unused) } #define __user_cache_maint(insn, address, res) \ - asm volatile ( \ - "1: " insn ", %1\n" \ - " mov %w0, #0\n" \ - "2:\n" \ - " .pushsection .fixup,\"ax\"\n" \ - " .align 2\n" \ - "3: mov %w0, %w2\n" \ - " b 2b\n" \ - " .popsection\n" \ - _ASM_EXTABLE(1b, 3b) \ - : "=r" (res) \ - : "r" (address), "i" (-EFAULT) ) + if (untagged_addr(address) >= user_addr_max()) \ + res = -EFAULT; \ + else \ + asm volatile ( \ + "1: " insn ", %1\n" \ + " mov %w0, #0\n" \ + "2:\n" \ + " .pushsection .fixup,\"ax\"\n" \ + " .align 2\n" \ + "3: mov %w0, %w2\n" \ + " b 2b\n" \ + " .popsection\n" \ + _ASM_EXTABLE(1b, 3b) \ + : "=r" (res) \ + : "r" (address), "i" (-EFAULT) ) static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs) { |