Revert "Change /dev to be mounted by default with /noexec"

This reverts commit 09d837b.

Mounting /dev with 'noexec' option triggers problems when
containers try to create Intel SGX enclaves:

...
ioctl(4, SGX_IOC_ENCLAVE_ADD_PAGES, 0x7ffd38e7bf90) = 0
mmap(0x7f36d9002000, 139264, PROT_READ|PROT_EXEC, MAP_SHARED|MAP_FIXED, 4, 0) = -1 EPERM (Operation not permitted)
close(4)
...

The issue where a device node is mmap()'d with PROT_EXEC has been
discussed in length on Linux development mailing lists and with
udev/systemd maintainers [1].

As a result of this conversation, systemd changed its defaults
to mount /dev with 'exec' [2] and added ExecPaths= and
NoExecPaths= [3] to let users to control the behavior.

Change runtime-tools to follow the systemd default and to get
the runtime behavior fixed for Intel SGX based confidential
compute.

[1] https://lore.kernel.org/linux-sgx/CALCETrWM2rGPRudtaQ=mn9MRsrbQqFfZDkOGsBbVMsk6mMw_+A@mail.gmail.com/
[2] systemd/systemd#17940
[3] systemd/systemd#17942

Signed-off-by: Mikko Ylinen <[email protected]>

Author: mythi

generate/generate.go

@@ -182,7 +182,7 @@ func New(os string) (generator Generator, err error) {
 				Destination: "/dev",
 				Type:        "tmpfs",
 				Source:      "tmpfs",
-				Options:     []string{"nosuid", "noexec", "strictatime", "mode=755", "size=65536k"},
+				Options:     []string{"nosuid", "strictatime", "mode=755", "size=65536k"},
 			},
 			{
 				Destination: "/dev/pts",