Is being able to open and stat a directory intended?

[zzjas]

Describe the bug

Wasmer is able to open and stat a directory when the flag is O_RDWR.

#include <stdio.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>

int main(int argc, char * argv[]) {
	int fd0 = open("test_dir", O_RDWR);
	printf("fd is %d\n", fd0);
	struct stat stat;
        stat.st_size = 0;
	fstat(fd0, &stat);
	printf("stat dir size %d\n", stat.st_size);
}

Steps to reproduce

Store the above into a file dir.c.
Compile with wasi-sdk-16.0 and run with wasmer.

mkdir -p test_dir
$WASI_SDK_PATH/bin/clang --sysroot=$WASI_SDK_PATH/share/wasi-sysroot dir.c -o dir.wasm
wasmer dir.wasm --dir=.

To compare:

wasmtime dir.wasm --dir=.
clang dir.c -o dir.out
./dir.out

Expected behavior

The open returns -1.

Actual behavior

open returns a file descriptor and it can be used to stat.

[fschutt]

I think this is a duplicate of #3125, which is currently being worked on in #3201.

[zzjas]

Hi, thanks for checking out the issue. I'm not sure if they are the same. #3125 was about rights for an existing file descriptor. However, here a valid file descriptor should not be returned by open in the first place.

e.g.
Here is the output from wasmer

fd is 5
stat dir size 128

and here is the output from wasmtime and native libc

fd is -1
stat dir size 0

I built wasmer on branchwasi-fs-rights commit 00ad13810869d9e07466209f4bdd686409e631a2 from #3201 with make build-wasmer. The behavior of open is still the same as described above.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

Feel free to reopen the issue if it has been closed by mistake.