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syscall: add Landlock support for execve() on Linux#77630

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syscall: add Landlock support for execve() on Linux#77630
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gnoack:landlock-exec

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@gnoack

@gnoack gnoack commented Feb 15, 2026

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  • Extend SysProcAttr on Linux to optionally store the ruleset FD and
    flag arguments for landlock_restrict_self(2).
  • Extend forkAndExecInChild1() to invoke the system call.
  • Add a flag for the prctl(PR_SET_NO_NEW_PRIVS) call as well,
    which is a prerequisite for unprivileged Landlock enforcement.
  • Define the necessary constants unexported as _PR_SET_NO_NEW_PRIVS
    and _SYS_landlock_restrict_self.
  • The test case exercises the logic and demonstrates that it works
    (provided that the host Linux system has the Landlock LSM enabled).

As it is customary in forkAndExecInChild1(), system calls need to be
invoked with RawSyscall(), and their system call numbers are defined
in the same package. (Depending on internal/syscall/unix would create
an import loop.)

The Landlock API is described in
https://docs.kernel.org/userspace-api/landlock.html

Updates landlock-lsm/go-landlock#45
Fixes #68595

@gnoack

gnoack commented Feb 15, 2026

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For a rationale on why I updated these generated files that way, please see #68595 (comment) -- the previously suggested approach to put these constants in internal/syscall/unix was not feasible, and I am under the impression that re-generation of the full files in syscall is not intended at this point either?

I'm happy to implement it either way, please let me know what you prefer.

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Message from Gopher Robot:

Patch Set 1:

(1 comment)


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Message from Günther Noack:

Patch Set 1:

(2 comments)


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Message from Günther Noack:

Patch Set 2:

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Message from Günther Noack:

Patch Set 2:

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This PR (HEAD: ed40a01) has been imported to Gerrit for code review.

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@gnoack gnoack force-pushed the landlock-exec branch 2 times, most recently from 95c53bb to 6269c26 Compare February 16, 2026 12:59
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Patch Set 2:

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Message from Günther Noack:

Patch Set 5:

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This PR (HEAD: 83e230e) has been imported to Gerrit for code review.

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Patch Set 6:

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Message from Austin Clements:

Patch Set 7:

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gnoack added 2 commits June 25, 2026 12:43
* In forkAndExecInChild1() on Linux, when SysProcAttr.NoNewPrivs is
  set, call prctl(PR_SET_NO_NEW_PRIVS).
* Define the necessary constant unexported as _PR_SET_NO_NEW_PRIVS.

When the no_new_privs flag is set, execve() does not grant additional
permissions through execve() (e.g., through the set-user-ID bit).

The no_new_privs flag is a prerequisite for enabling a Landlock policy
in an unprivileged (non-CAP_SYS_ADMIN) thread. The flag is documented
in PR_SET_NO_NEW_PRIVS(2const).

The name of the SysProcAttr.NoNewPrivs field is chosen to mirror the
naming in the Linux API.

Updates landlock-lsm/go-landlock#45
Updates golang#68595
* Extend SysProcAttr on Linux to optionally store the ruleset FD and
  flag arguments for landlock_restrict_self(2).
* Extend forkAndExecInChild1() to invoke the system call.
* The test case exercises the logic and demonstrates that it works
  (provided that the host Linux system has the Landlock LSM enabled).
* Define the necessary unexported _SYS_landlock_restrict_self constant.

As it is customary in forkAndExecInChild1(), system calls need to be
invoked with RawSyscall(), and their system call numbers are defined
in the same package. (Depending on internal/syscall/unix would create
an import loop.)

The Landlock API is described in
https://docs.kernel.org/userspace-api/landlock.html

Updates landlock-lsm/go-landlock#45
Fixes golang#68595
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Message from Günther Noack:

Patch Set 7:

(3 comments)


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This PR (HEAD: 7b6b6b1) has been imported to Gerrit for code review.

Please visit Gerrit at https://go-review.googlesource.com/c/go/+/745940.

Important tips:

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  • To change your code in response to feedback:
    • Push a new commit to the branch used by your GitHub PR.
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  • See the Sending a change via GitHub and Reviews sections of the Contribution Guide as well as the FAQ for details.

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syscall: support process sandboxing using Landlock on Linux

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