diff options
| -rw-r--r-- | arch/x86/include/asm/uaccess.h | 78 | ||||
| -rw-r--r-- | arch/x86/include/asm/uaccess_64.h | 94 | ||||
| -rw-r--r-- | include/linux/uaccess.h | 7 | ||||
| -rw-r--r-- | lib/strncpy_from_user.c | 11 | ||||
| -rw-r--r-- | lib/strnlen_user.c | 18 |
5 files changed, 155 insertions, 53 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 660458af425d..a4a30e4b2d34 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -134,6 +134,9 @@ extern int __get_user_4(void); extern int __get_user_8(void); extern int __get_user_bad(void); +#define __uaccess_begin() stac() +#define __uaccess_end() clac() + /* * This is a type: either unsigned long, if the argument fits into * that type, or otherwise unsigned long long. @@ -193,10 +196,10 @@ __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) #ifdef CONFIG_X86_32 #define __put_user_asm_u64(x, addr, err, errret) \ - asm volatile(ASM_STAC "\n" \ + asm volatile("\n" \ "1: movl %%eax,0(%2)\n" \ "2: movl %%edx,4(%2)\n" \ - "3: " ASM_CLAC "\n" \ + "3:" \ ".section .fixup,\"ax\"\n" \ "4: movl %3,%0\n" \ " jmp 3b\n" \ @@ -207,10 +210,10 @@ __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) : "A" (x), "r" (addr), "i" (errret), "0" (err)) #define __put_user_asm_ex_u64(x, addr) \ - asm volatile(ASM_STAC "\n" \ + asm volatile("\n" \ "1: movl %%eax,0(%1)\n" \ "2: movl %%edx,4(%1)\n" \ - "3: " ASM_CLAC "\n" \ + "3:" \ _ASM_EXTABLE_EX(1b, 2b) \ _ASM_EXTABLE_EX(2b, 3b) \ : : "A" (x), "r" (addr)) @@ -304,6 +307,10 @@ do { \ } \ } while (0) +/* + * This doesn't do __uaccess_begin/end - the exception handling + * around it must do that. + */ #define __put_user_size_ex(x, ptr, size) \ do { \ __chk_user_ptr(ptr); \ @@ -358,9 +365,9 @@ do { \ } while (0) #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \ - asm volatile(ASM_STAC "\n" \ + asm volatile("\n" \ "1: mov"itype" %2,%"rtype"1\n" \ - "2: " ASM_CLAC "\n" \ + "2:\n" \ ".section .fixup,\"ax\"\n" \ "3: mov %3,%0\n" \ " xor"itype" %"rtype"1,%"rtype"1\n" \ @@ -370,6 +377,10 @@ do { \ : "=r" (err), ltype(x) \ : "m" (__m(addr)), "i" (errret), "0" (err)) +/* + * This doesn't do __uaccess_begin/end - the exception handling + * around it must do that. + */ #define __get_user_size_ex(x, ptr, size) \ do { \ __chk_user_ptr(ptr); \ @@ -400,7 +411,9 @@ do { \ #define __put_user_nocheck(x, ptr, size) \ ({ \ int __pu_err; \ + __uaccess_begin(); \ __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \ + __uaccess_end(); \ __builtin_expect(__pu_err, 0); \ }) @@ -408,7 +421,9 @@ do { \ ({ \ int __gu_err; \ unsigned long __gu_val; \ + __uaccess_begin(); \ __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \ + __uaccess_end(); \ (x) = (__force __typeof__(*(ptr)))__gu_val; \ __builtin_expect(__gu_err, 0); \ }) @@ -423,9 +438,9 @@ struct __large_struct { unsigned long buf[100]; }; * aliasing issues. */ #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \ - asm volatile(ASM_STAC "\n" \ + asm volatile("\n" \ "1: mov"itype" %"rtype"1,%2\n" \ - "2: " ASM_CLAC "\n" \ + "2:\n" \ ".section .fixup,\"ax\"\n" \ "3: mov %3,%0\n" \ " jmp 2b\n" \ @@ -445,11 +460,11 @@ struct __large_struct { unsigned long buf[100]; }; */ #define uaccess_try do { \ current_thread_info()->uaccess_err = 0; \ - stac(); \ + __uaccess_begin(); \ barrier(); #define uaccess_catch(err) \ - clac(); \ + __uaccess_end(); \ (err) |= (current_thread_info()->uaccess_err ? -EFAULT : 0); \ } while (0) @@ -547,12 +562,13 @@ extern void __cmpxchg_wrong_size(void) __typeof__(ptr) __uval = (uval); \ __typeof__(*(ptr)) __old = (old); \ __typeof__(*(ptr)) __new = (new); \ + __uaccess_begin(); \ switch (size) { \ case 1: \ { \ - asm volatile("\t" ASM_STAC "\n" \ + asm volatile("\n" \ "1:\t" LOCK_PREFIX "cmpxchgb %4, %2\n" \ - "2:\t" ASM_CLAC "\n" \ + "2:\n" \ "\t.section .fixup, \"ax\"\n" \ "3:\tmov %3, %0\n" \ "\tjmp 2b\n" \ @@ -566,9 +582,9 @@ extern void __cmpxchg_wrong_size(void) } \ case 2: \ { \ - asm volatile("\t" ASM_STAC "\n" \ + asm volatile("\n" \ "1:\t" LOCK_PREFIX "cmpxchgw %4, %2\n" \ - "2:\t" ASM_CLAC "\n" \ + "2:\n" \ "\t.section .fixup, \"ax\"\n" \ "3:\tmov %3, %0\n" \ "\tjmp 2b\n" \ @@ -582,9 +598,9 @@ extern void __cmpxchg_wrong_size(void) } \ case 4: \ { \ - asm volatile("\t" ASM_STAC "\n" \ + asm volatile("\n" \ "1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n" \ - "2:\t" ASM_CLAC "\n" \ + "2:\n" \ "\t.section .fixup, \"ax\"\n" \ "3:\tmov %3, %0\n" \ "\tjmp 2b\n" \ @@ -601,9 +617,9 @@ extern void __cmpxchg_wrong_size(void) if (!IS_ENABLED(CONFIG_X86_64)) \ __cmpxchg_wrong_size(); \ \ - asm volatile("\t" ASM_STAC "\n" \ + asm volatile("\n" \ "1:\t" LOCK_PREFIX "cmpxchgq %4, %2\n" \ - "2:\t" ASM_CLAC "\n" \ + "2:\n" \ "\t.section .fixup, \"ax\"\n" \ "3:\tmov %3, %0\n" \ "\tjmp 2b\n" \ @@ -618,6 +634,7 @@ extern void __cmpxchg_wrong_size(void) default: \ __cmpxchg_wrong_size(); \ } \ + __uaccess_end(); \ *__uval = __old; \ __ret; \ }) @@ -754,5 +771,30 @@ copy_to_user(void __user *to, const void *from, unsigned long n) */ #define __copy_from_user_nmi __copy_from_user_inatomic +/* + * The "unsafe" user accesses aren't really "unsafe", but the naming + * is a big fat warning: you have to not only do the access_ok() + * checking before using them, but you have to surround them with the + * user_access_begin/end() pair. + */ +#define user_access_begin() __uaccess_begin() +#define user_access_end() __uaccess_end() + +#define unsafe_put_user(x, ptr) \ +({ \ + int __pu_err; \ + __put_user_size((x), (ptr), sizeof(*(ptr)), __pu_err, -EFAULT); \ + __builtin_expect(__pu_err, 0); \ +}) + +#define unsafe_get_user(x, ptr) \ +({ \ + int __gu_err; \ + unsigned long __gu_val; \ + __get_user_size(__gu_val, (ptr), sizeof(*(ptr)), __gu_err, -EFAULT); \ + (x) = (__force __typeof__(*(ptr)))__gu_val; \ + __builtin_expect(__gu_err, 0); \ +}) + #endif /* _ASM_X86_UACCESS_H */ diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h index f2f9b39b274a..b89c34c4019b 100644 --- a/arch/x86/include/asm/uaccess_64.h +++ b/arch/x86/include/asm/uaccess_64.h @@ -56,35 +56,49 @@ int __copy_from_user_nocheck(void *dst, const void __user *src, unsigned size) if (!__builtin_constant_p(size)) return copy_user_generic(dst, (__force void *)src, size); switch (size) { - case 1:__get_user_asm(*(u8 *)dst, (u8 __user *)src, + case 1: + __uaccess_begin(); + __get_user_asm(*(u8 *)dst, (u8 __user *)src, ret, "b", "b", "=q", 1); + __uaccess_end(); return ret; - case 2:__get_user_asm(*(u16 *)dst, (u16 __user *)src, + case 2: + __uaccess_begin(); + __get_user_asm(*(u16 *)dst, (u16 __user *)src, ret, "w", "w", "=r", 2); + __uaccess_end(); return ret; - case 4:__get_user_asm(*(u32 *)dst, (u32 __user *)src, + case 4: + __uaccess_begin(); + __get_user_asm(*(u32 *)dst, (u32 __user *)src, ret, "l", "k", "=r", 4); + __uaccess_end(); return ret; - case 8:__get_user_asm(*(u64 *)dst, (u64 __user *)src, + case 8: + __uaccess_begin(); + __get_user_asm(*(u64 *)dst, (u64 __user *)src, ret, "q", "", "=r", 8); + __uaccess_end(); return ret; case 10: + __uaccess_begin(); __get_user_asm(*(u64 *)dst, (u64 __user *)src, ret, "q", "", "=r", 10); - if (unlikely(ret)) - return ret; - __get_user_asm(*(u16 *)(8 + (char *)dst), - (u16 __user *)(8 + (char __user *)src), - ret, "w", "w", "=r", 2); + if (likely(!ret)) + __get_user_asm(*(u16 *)(8 + (char *)dst), + (u16 __user *)(8 + (char __user *)src), + ret, "w", "w", "=r", 2); + __uaccess_end(); return ret; case 16: + __uaccess_begin(); __get_user_asm(*(u64 *)dst, (u64 __user *)src, ret, "q", "", "=r", 16); - if (unlikely(ret)) - return ret; - __get_user_asm(*(u64 *)(8 + (char *)dst), - (u64 __user *)(8 + (char __user *)src), - ret, "q", "", "=r", 8); + if (likely(!ret)) + __get_user_asm(*(u64 *)(8 + (char *)dst), + (u64 __user *)(8 + (char __user *)src), + ret, "q", "", "=r", 8); + __uaccess_end(); return ret; default: return copy_user_generic(dst, (__force void *)src, size); @@ -106,35 +120,51 @@ int __copy_to_user_nocheck(void __user *dst, const void *src, unsigned size) if (!__builtin_constant_p(size)) return copy_user_generic((__force void *)dst, src, size); switch (size) { - case 1:__put_user_asm(*(u8 *)src, (u8 __user *)dst, + case 1: + __uaccess_begin(); + __put_user_asm(*(u8 *)src, (u8 __user *)dst, ret, "b", "b", "iq", 1); + __uaccess_end(); return ret; - case 2:__put_user_asm(*(u16 *)src, (u16 __user *)dst, + case 2: + __uaccess_begin(); + __put_user_asm(*(u16 *)src, (u16 __user *)dst, ret, "w", "w", "ir", 2); + __uaccess_end(); return ret; - case 4:__put_user_asm(*(u32 *)src, (u32 __user *)dst, + case 4: + __uaccess_begin(); + __put_user_asm(*(u32 *)src, (u32 __user *)dst, ret, "l", "k", "ir", 4); + __uaccess_end(); return ret; - case 8:__put_user_asm(*(u64 *)src, (u64 __user *)dst, + case 8: + __uaccess_begin(); + __put_user_asm(*(u64 *)src, (u64 __user *)dst, ret, "q", "", "er", 8); + __uaccess_end(); return ret; case 10: + __uaccess_begin(); __put_user_asm(*(u64 *)src, (u64 __user *)dst, ret, "q", "", "er", 10); - if (unlikely(ret)) - return ret; - asm("":::"memory"); - __put_user_asm(4[(u16 *)src], 4 + (u16 __user *)dst, - ret, "w", "w", "ir", 2); + if (likely(!ret)) { + asm("":::"memory"); + __put_user_asm(4[(u16 *)src], 4 + (u16 __user *)dst, + ret, "w", "w", "ir", 2); + } + __uaccess_end(); return ret; case 16: + __uaccess_begin(); __put_user_asm(*(u64 *)src, (u64 __user *)dst, ret, "q", "", "er", 16); - if (unlikely(ret)) - return ret; - asm("":::"memory"); - __put_user_asm(1[(u64 *)src], 1 + (u64 __user *)dst, - ret, "q", "", "er", 8); + if (likely(!ret)) { + asm("":::"memory"); + __put_user_asm(1[(u64 *)src], 1 + (u64 __user *)dst, + ret, "q", "", "er", 8); + } + __uaccess_end(); return ret; default: return copy_user_generic((__force void *)dst, src, size); @@ -160,39 +190,47 @@ int __copy_in_user(void __user *dst, const void __user *src, unsigned size) switch (size) { case 1: { u8 tmp; + __uaccess_begin(); __get_user_asm(tmp, (u8 __user *)src, ret, "b", "b", "=q", 1); if (likely(!ret)) __put_user_asm(tmp, (u8 __user *)dst, ret, "b", "b", "iq", 1); + __uaccess_end(); return ret; } case 2: { u16 tmp; + __uaccess_begin(); __get_user_asm(tmp, (u16 __user *)src, ret, "w", "w", "=r", 2); if (likely(!ret)) __put_user_asm(tmp, (u16 __user *)dst, ret, "w", "w", "ir", 2); + __uaccess_end(); return ret; } case 4: { u32 tmp; + __uaccess_begin(); __get_user_asm(tmp, (u32 __user *)src, ret, "l", "k", "=r", 4); if (likely(!ret)) __put_user_asm(tmp, (u32 __user *)dst, ret, "l", "k", "ir", 4); + __uaccess_end(); return ret; } case 8: { u64 tmp; + __uaccess_begin(); __get_user_asm(tmp, (u64 __user *)src, ret, "q", "", "=r", 8); if (likely(!ret)) __put_user_asm(tmp, (u64 __user *)dst, ret, "q", "", "er", 8); + __uaccess_end(); return ret; } default: diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index 558129af828a..349557825428 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -111,4 +111,11 @@ extern long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count); #define probe_kernel_address(addr, retval) \ probe_kernel_read(&retval, addr, sizeof(retval)) +#ifndef user_access_begin +#define user_access_begin() do { } while (0) +#define user_access_end() do { } while (0) +#define unsafe_get_user(x, ptr) __get_user(x, ptr) +#define unsafe_put_user(x, ptr) __put_user(x, ptr) +#endif + #endif /* __LINUX_UACCESS_H__ */ diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c index e0af6ff73d14..33840324138c 100644 --- a/lib/strncpy_from_user.c +++ b/lib/strncpy_from_user.c @@ -39,7 +39,7 @@ static inline long do_strncpy_from_user(char *dst, const char __user *src, long unsigned long c, data; /* Fall back to byte-at-a-time if we get a page fault */ - if (unlikely(__get_user(c,(unsigned long __user *)(src+res)))) + if (unlikely(unsafe_get_user(c,(unsigned long __user *)(src+res)))) break; *(unsigned long *)(dst+res) = c; if (has_zero(c, &data, &constants)) { @@ -55,7 +55,7 @@ byte_at_a_time: while (max) { char c; - if (unlikely(__get_user(c,src+res))) + if (unlikely(unsafe_get_user(c,src+res))) return -EFAULT; dst[res] = c; if (!c) @@ -107,7 +107,12 @@ long strncpy_from_user(char *dst, const char __user *src, long count) src_addr = (unsigned long)src; if (likely(src_addr < max_addr)) { unsigned long max = max_addr - src_addr; - return do_strncpy_from_user(dst, src, count, max); + long retval; + + user_access_begin(); + retval = do_strncpy_from_user(dst, src, count, max); + user_access_end(); + return retval; } return -EFAULT; } diff --git a/lib/strnlen_user.c b/lib/strnlen_user.c index 3a5f2b366d84..2625943625d7 100644 --- a/lib/strnlen_user.c +++ b/lib/strnlen_user.c @@ -45,7 +45,7 @@ static inline long do_strnlen_user(const char __user *src, unsigned long count, src -= align; max += align; - if (unlikely(__get_user(c,(unsigned long __user *)src))) + if (unlikely(unsafe_get_user(c,(unsigned long __user *)src))) return 0; c |= aligned_byte_mask(align); @@ -61,7 +61,7 @@ static inline long do_strnlen_user(const char __user *src, unsigned long count, if (unlikely(max <= sizeof(unsigned long))) break; max -= sizeof(unsigned long); - if (unlikely(__get_user(c,(unsigned long __user *)(src+res)))) + if (unlikely(unsafe_get_user(c,(unsigned long __user *)(src+res)))) return 0; } res -= align; @@ -112,7 +112,12 @@ long strnlen_user(const char __user *str, long count) src_addr = (unsigned long)str; if (likely(src_addr < max_addr)) { unsigned long max = max_addr - src_addr; - return do_strnlen_user(str, count, max); + long retval; + + user_access_begin(); + retval = do_strnlen_user(str, count, max); + user_access_end(); + return retval; } return 0; } @@ -141,7 +146,12 @@ long strlen_user(const char __user *str) src_addr = (unsigned long)str; if (likely(src_addr < max_addr)) { unsigned long max = max_addr - src_addr; - return do_strnlen_user(str, ~0ul, max); + long retval; + + user_access_begin(); + retval = do_strnlen_user(str, ~0ul, max); + user_access_end(); + return retval; } return 0; } |