[BUG REPORT] Integer overflow in page_align_up

[Marsman1996]

描述错误/Describe the bug
There is an integer overflow in page_align_up() at kernel/src/libs/align.rs:135 when program calls memory related syscall (i.e., mmap, munmap, and mprotect) with large len.

DragonOS/kernel/src/libs/align.rs

Lines 133 to 136 in 72423f9

	pub const fn page_align_up(addr: usize) -> usize {
	let page_size = MMArch::PAGE_SIZE;
	return (addr + page_size - 1) & (!(page_size - 1));
	}

请填写您的电脑的信息/Environment

• OS Version：Debian GNU/Linux 11
• DragonOS Version：72423f9
• DADK Version：dadk 0.2.0
• Rust Version：rustc 1.84.0-nightly (fbab78289 2024-11-04)

重现步骤/To Reproduce

1. Compile a program which calls system call munmap with large len

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <unistd.h>

int main() {
  void *addr = mmap(NULL, 0x1000, 0x3, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  munmap(addr, 0xffffffffffffffff);
  perror("mmap error");

  return EXIT_SUCCESS;
}

2. Run the compiled program

期望行为/Expected behavior
DragonOS should check the add behavior first and not overflow here.

屏幕截图/Log
I add log before and after the alignment:

root@DragonOS:/$ /bin/overflow
[ WARN ] (src/syscall/mod.rs:626)        len before align: 0xffffffffffffffff
[ WARN ] (src/syscall/mod.rs:628)        len after align: 0x0
mmap error: Invalid argument

[Marsman1996]

I'm trying to add check for overflow in kernel/Cargo.toml, but after adding the check I cannot enter the DragonOS.

我尝试在 kernel/Cargo.toml 中增加对 overflow 的检查，但是这样编译后无法正常进入系统:

# The release profile, used for `cargo build --release`
[profile.release]
debug = false
overflow-checks = true

[fslongjin]

cc @MemoryShore @Jomocool
麻烦看看~

[fslongjin]

但是这个貌似也是正常？Linux上面传入过大的len的话，会返回什么？ @Marsman1996

[Marsman1996]

但是这个貌似也是正常？Linux上面传入过大的len的话，会返回什么？ @Marsman1996

以 munmap 为例，会返回 EINVAL
https://elixir.bootlin.com/linux/v6.10.5/source/mm/mmap.c#L2738

但是在 Rust 程序中，这样的溢出在 debug 模式下会导致 panic。
不过 DragonOS 似乎写死了就以 release 编译👀
kernel/src/Makefile

kernel_rust:
	RUSTFLAGS="$(RUSTFLAGS)" cargo +nightly-2024-11-05 $(CARGO_ZBUILD) build --release --target $(TARGET_JSON)

[fslongjin]

这里可以考虑在内核里面加个判断啥的，实现行为上跟Linux一致？ 你方便发个pr吗 @Marsman1996

[Marsman1996]

这里可以考虑在内核里面加个判断啥的，实现行为上跟Linux一致？ 你方便发个pr吗 @Marsman1996

👌