#include <linux/uaccess.h>
#include <linux/module.h>
+#include <wrapper/uaccess.h>
#include <probes/lttng-probe-user.h>
+#define LTTNG_MAX_USER_STRING_LEN 1048576 /* 1MB */
+
/*
* Calculate string length. Include final null terminating character if there is
* one, or ends at first fault. Disabling page faults ensures that we can safely
long lttng_strlen_user_inatomic(const char *addr)
{
long count = 0;
- mm_segment_t old_fs;
if (!addr)
return 0;
- old_fs = get_fs();
- set_fs(KERNEL_DS);
pagefault_disable();
for (;;) {
char v;
unsigned long ret;
- if (unlikely(!access_ok(VERIFY_READ,
+ if (unlikely(!lttng_access_ok(VERIFY_READ,
(__force const char __user *) addr,
sizeof(v))))
break;
if (unlikely(ret > 0))
break;
count++;
+ if (unlikely(count > LTTNG_MAX_USER_STRING_LEN))
+ break;
if (unlikely(!v))
break;
addr++;
}
pagefault_enable();
- set_fs(old_fs);
return count;
}
EXPORT_SYMBOL_GPL(lttng_strlen_user_inatomic);