1 files changed, 77 insertions, 0 deletions

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index d2a4fd2fd8c1..f94a56915e69 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -148,6 +148,83 @@ DEFINE_BASIC_FETCH_FUNCS(stack)
 #define fetch_stack_string      NULL
 #define fetch_stack_string_size NULL
 
+#define DEFINE_FETCH_memory(type)                                       \
+static __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,\
+                                          void *addr, void *dest)       \
+{                                                                       \
+        type retval;                                                    \
+        if (probe_kernel_address(addr, retval))                         \
+                *(type *)dest = 0;                                      \
+        else                                                            \
+                *(type *)dest = retval;                                 \
+}
+DEFINE_BASIC_FETCH_FUNCS(memory)
+/*
+ * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
+ * length and relative data location.
+ */
+static __kprobes void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
+                                                      void *addr, void *dest)
+{
+        long ret;
+        int maxlen = get_rloc_len(*(u32 *)dest);
+        u8 *dst = get_rloc_data(dest);
+        u8 *src = addr;
+        mm_segment_t old_fs = get_fs();
+
+        if (!maxlen)
+                return;
+
+        /*
+         * Try to get string again, since the string can be changed while
+         * probing.
+         */
+        set_fs(KERNEL_DS);
+        pagefault_disable();
+
+        do
+                ret = __copy_from_user_inatomic(dst++, src++, 1);
+        while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen);
+
+        dst[-1] = '\0';
+        pagefault_enable();
+        set_fs(old_fs);
+
+        if (ret < 0) {  /* Failed to fetch string */
+                ((u8 *)get_rloc_data(dest))[0] = '\0';
+                *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
+        } else {
+                *(u32 *)dest = make_data_rloc(src - (u8 *)addr,
+                                              get_rloc_offs(*(u32 *)dest));
+        }
+}
+
+/* Return the length of string -- including null terminal byte */
+static __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
+                                                        void *addr, void *dest)
+{
+        mm_segment_t old_fs;
+        int ret, len = 0;
+        u8 c;
+
+        old_fs = get_fs();
+        set_fs(KERNEL_DS);
+        pagefault_disable();
+
+        do {
+                ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
+                len++;
+        } while (c && ret == 0 && len < MAX_STRING_SIZE);
+
+        pagefault_enable();
+        set_fs(old_fs);
+
+        if (ret < 0)    /* Failed to check the length */
+                *(u32 *)dest = 0;
+        else
+                *(u32 *)dest = len;
+}
+
 #define DEFINE_FETCH_symbol(type)                                       \
 __kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs,      \
                                           void *data, void *dest)       \