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Abort on overlapping memcpy.

This commit is contained in:
Jonas 'Sortie' Termansen 2015-05-13 20:27:49 +02:00
parent 280ba8d64d
commit 9d87d76957
3 changed files with 35 additions and 1 deletions
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6
kernel/libk.cpp
View File

@ -96,6 +96,12 @@ void libk_abort(void)
Sortix::PanicF("abort()");
}
extern "C"
void libk_overlapping_memcpy(void)
{
Sortix::PanicF("Overlapping memcpy detected");
}
extern "C"
void libk_random_lock(void)
{

2
libc/include/libk.h
View File

@ -41,6 +41,8 @@ __attribute__((noreturn))
void libk_stack_chk_fail(void);
__attribute__((noreturn))
void libk_abort(void);
__attribute__((noreturn))
void libk_overlapping_memcpy(void);
void libk_random_lock(void);
void libk_random_unlock(void);
bool libk_hasentropy(size_t);

28
libc/string/memcpy.c
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2011, 2012, 2014 Jonas 'Sortie' Termansen.
* Copyright (c) 2011, 2012, 2014, 2015, 2016 Jonas 'Sortie' Termansen.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
@ -17,9 +17,15 @@
* Copy memory between non-overlapping regions.
*/
#include <scram.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#if defined(__is_sortix_libk)
#include <libk.h>
#endif
inline static
void* memcpy_slow(void* restrict dst_ptr,
const void* restrict src_ptr,
@ -36,6 +42,26 @@ void* memcpy(void* restrict dst_ptr,
const void* restrict src_ptr,
size_t size)
{
if ( dst_ptr == src_ptr || !size )
return dst_ptr;
void* dst_end = (char*) dst_ptr + size;
const void* src_end = (const const char*) src_ptr + size;
if ( (dst_ptr < src_ptr && src_ptr < dst_end) ||
(src_ptr < dst_ptr && dst_ptr < src_end) )
{
#if defined(__is_sortix_libk)
libk_overlapping_memcpy();
#else
struct scram_undefined_behavior info;
info.filename = __FILE__;
info.line = __LINE__;
info.column = 0;
info.violation = "overlapping memcpy";
scram(SCRAM_UNDEFINED_BEHAVIOR, &info);
#endif
}
#if 8 < __SIZEOF_LONG__
#warning "you should add support for your unexpectedly large unsigned long."
return memcpy_slow(dst_ptr, src_ptr, size);