x86: asm: instrument usercopy in get_user() and put_user()

Use hooks from instrumented.h to notify bug detection tools about usercopy
events in variations of get_user() and put_user().

Link: https://lkml.kernel.org/r/20220915150417.722975-5-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 913e593..c1b8982 100644 (file)
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -5,6 +5,7 @@
  * User space memory access functions
  */
 #include <linux/compiler.h>
+#include <linux/instrumented.h>
 #include <linux/kasan-checks.h>
 #include <linux/string.h>
 #include <asm/asm.h>
@@ -103,6 +104,7 @@ extern int __get_user_bad(void);
                     : "=a" (__ret_gu), "=r" (__val_gu),                \
                        ASM_CALL_CONSTRAINT                             \
                     : "0" (ptr), "i" (sizeof(*(ptr))));                \
+       instrument_get_user(__val_gu);                                  \
        (x) = (__force __typeof__(*(ptr))) __val_gu;                    \
        __builtin_expect(__ret_gu, 0);                                  \
 })
@@ -192,9 +194,11 @@ extern void __put_user_nocheck_8(void);
        int __ret_pu;                                                   \
        void __user *__ptr_pu;                                          \
        register __typeof__(*(ptr)) __val_pu asm("%"_ASM_AX);           \
-       __chk_user_ptr(ptr);                                            \
-       __ptr_pu = (ptr);                                               \
-       __val_pu = (x);                                                 \
+       __typeof__(*(ptr)) __x = (x); /* eval x once */                 \
+       __typeof__(ptr) __ptr = (ptr); /* eval ptr once */              \
+       __chk_user_ptr(__ptr);                                          \
+       __ptr_pu = __ptr;                                               \
+       __val_pu = __x;                                                 \
        asm volatile("call __" #fn "_%P[size]"                          \
                     : "=c" (__ret_pu),                                 \
                        ASM_CALL_CONSTRAINT                             \
@@ -202,6 +206,7 @@ extern void __put_user_nocheck_8(void);
                       "r" (__val_pu),                                  \
                       [size] "i" (sizeof(*(ptr)))                      \
                     :"ebx");                                           \
+       instrument_put_user(__x, __ptr, sizeof(*(ptr)));                \
        __builtin_expect(__ret_pu, 0);                                  \
 })
 
@@ -248,23 +253,25 @@ extern void __put_user_nocheck_8(void);
 
 #define __put_user_size(x, ptr, size, label)                           \
 do {                                                                   \
+       __typeof__(*(ptr)) __x = (x); /* eval x once */                 \
        __chk_user_ptr(ptr);                                            \
        switch (size) {                                                 \
        case 1:                                                         \
-               __put_user_goto(x, ptr, "b", "iq", label);              \
+               __put_user_goto(__x, ptr, "b", "iq", label);            \
                break;                                                  \
        case 2:                                                         \
-               __put_user_goto(x, ptr, "w", "ir", label);              \
+               __put_user_goto(__x, ptr, "w", "ir", label);            \
                break;                                                  \
        case 4:                                                         \
-               __put_user_goto(x, ptr, "l", "ir", label);              \
+               __put_user_goto(__x, ptr, "l", "ir", label);            \
                break;                                                  \
        case 8:                                                         \
-               __put_user_goto_u64(x, ptr, label);                     \
+               __put_user_goto_u64(__x, ptr, label);                   \
                break;                                                  \
        default:                                                        \
                __put_user_bad();                                       \
        }                                                               \
+       instrument_put_user(__x, ptr, size);                            \
 } while (0)
 
 #ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
@@ -305,6 +312,7 @@ do {                                                                        \
        default:                                                        \
                (x) = __get_user_bad();                                 \
        }                                                               \
+       instrument_get_user(x);                                         \
 } while (0)
 
 #define __get_user_asm(x, addr, itype, ltype, label)                   \

diff --git a/include/linux/instrumented.h b/include/linux/instrumented.h
index ee8f7d1..9f1dba8 100644 (file)
--- a/include/linux/instrumented.h
+++ b/include/linux/instrumented.h
@@ -153,4 +153,32 @@ instrument_copy_from_user_after(const void *to, const void __user *from,
 {
 }
 
+/**
+ * instrument_get_user() - add instrumentation to get_user()-like macros
+ *
+ * get_user() and friends are fragile, so it may depend on the implementation
+ * whether the instrumentation happens before or after the data is copied from
+ * the userspace.
+ *
+ * @to destination variable, may not be address-taken
+ */
+#define instrument_get_user(to)                         \
+({                                                      \
+})
+
+/**
+ * instrument_put_user() - add instrumentation to put_user()-like macros
+ *
+ * put_user() and friends are fragile, so it may depend on the implementation
+ * whether the instrumentation happens before or after the data is copied from
+ * the userspace.
+ *
+ * @from source address
+ * @ptr userspace pointer to copy to
+ * @size number of bytes to copy
+ */
+#define instrument_put_user(from, ptr, size)                    \
+({                                                              \
+})
+
 #endif /* _LINUX_INSTRUMENTED_H */