@@ -34,7 +34,7 @@ long probe_kernel_read_strict(void *dst, const void *src, size_t size)
return __probe_kernel_read(dst, src, size);
}
-long strncpy_from_unsafe_strict(char *dst, const void *unsafe_addr, long count)
+long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count)
{
if (unlikely(invalid_probe_range((unsigned long)unsafe_addr)))
return -EFAULT;
@@ -351,8 +351,8 @@ extern long notrace probe_user_write(void __user *dst, const void *src, size_t s
extern long notrace __probe_user_write(void __user *dst, const void *src, size_t size);
extern long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count);
-extern long strncpy_from_unsafe_strict(char *dst, const void *unsafe_addr,
- long count);
+long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr,
+ long count);
extern long __strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count);
long strncpy_from_user_nofault(char *dst, const void __user *unsafe_addr,
long count);
@@ -242,7 +242,7 @@ bpf_probe_read_kernel_str_common(void *dst, u32 size, const void *unsafe_ptr,
* is returned that can be used for bpf_perf_event_output() et al.
*/
ret = compat ? strncpy_from_unsafe(dst, unsafe_ptr, size) :
- strncpy_from_unsafe_strict(dst, unsafe_ptr, size);
+ strncpy_from_kernel_nofault(dst, unsafe_ptr, size);
if (unlikely(ret < 0))
out:
memset(dst, 0, size);
@@ -414,7 +414,7 @@ BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1,
break;
#endif
case 'k':
- strncpy_from_unsafe_strict(buf, unsafe_ptr,
+ strncpy_from_kernel_nofault(buf, unsafe_ptr,
sizeof(buf));
break;
case 'u':
@@ -167,17 +167,36 @@ EXPORT_SYMBOL_GPL(probe_user_write);
* If @count is smaller than the length of the string, copies @count-1 bytes,
* sets the last byte of @dst buffer to NUL and returns @count.
*
- * strncpy_from_unsafe_strict() is the same as strncpy_from_unsafe() except
- * for the case where architectures have non-overlapping user and kernel address
- * ranges: strncpy_from_unsafe_strict() will additionally return -EFAULT for
- * probing memory on a user address range where strncpy_from_unsafe_user() is
- * supposed to be used instead.
+ * Same as strncpy_from_kernel_nofault() except that for architectures with
+ * not fully separated user and kernel address spaces this function also works
+ * for user address tanges.
+ *
+ * DO NOT USE THIS FUNCTION - it is broken on architectures with entirely
+ * separate kernel and user address spaces, and also a bad idea otherwise.
*/
long __weak strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count)
__attribute__((alias("__strncpy_from_unsafe")));
-long __weak strncpy_from_unsafe_strict(char *dst, const void *unsafe_addr,
+/**
+ * strncpy_from_kernel_nofault: - Copy a NUL terminated string from unsafe
+ * address.
+ * @dst: Destination address, in kernel space. This buffer must be at
+ * least @count bytes long.
+ * @unsafe_addr: Unsafe address.
+ * @count: Maximum number of bytes to copy, including the trailing NUL.
+ *
+ * Copies a NUL-terminated string from unsafe address to kernel buffer.
+ *
+ * On success, returns the length of the string INCLUDING the trailing NUL.
+ *
+ * If access fails, returns -EFAULT (some data may have been copied
+ * and the trailing NUL added).
+ *
+ * If @count is smaller than the length of the string, copies @count-1 bytes,
+ * sets the last byte of @dst buffer to NUL and returns @count.
+ */
+long __weak strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr,
long count)
__attribute__((alias("__strncpy_from_unsafe")));