From 5f5cda9706aae968c06ae6db343d8227da9a0dde Mon Sep 17 00:00:00 2001
From: Colin <colin@uninsane.org>
Date: Fri, 30 Aug 2024 13:17:24 +0000
Subject: [PATCH] refactor: bunpen: namespace: swallow /proc/self/*_map errors
 instead of aborting

---
 pkgs/additional/bunpen/errors/ext/check.ha   |  4 +++-
 pkgs/additional/bunpen/restrict/namespace.ha | 24 ++++++++++++++------
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/pkgs/additional/bunpen/errors/ext/check.ha b/pkgs/additional/bunpen/errors/ext/check.ha
index 4cdeab84f..70a87d83a 100644
--- a/pkgs/additional/bunpen/errors/ext/check.ha
+++ b/pkgs/additional/bunpen/errors/ext/check.ha
@@ -1,4 +1,5 @@
 // vim: set shiftwidth=2 :
+use io;
 use fmt;
 use fs;
 use log;
@@ -6,12 +7,13 @@ use os::exec;
 use path;
 use rt;
 
-export type error = (fs::error | os::exec::error | path::error | rt::errno);
+export type error = (io::error | fs::error | os::exec::error | path::error | rt::errno);
 
 // stringify an error. return value is statically allocated, no need to free.
 export fn maybe_strerror(what: (void | ...error)) (void | str) = {
   let errorbuf: [4096]u8 = [0...];
   return match (what) {
+    case let e: io::error => yield io::strerror(e);
     case let e: fs::error => yield fs::strerror(e);
     case let e: os::exec::error => yield os::exec::strerror(e);
     case let e: path::error => yield path::strerror(e);
diff --git a/pkgs/additional/bunpen/restrict/namespace.ha b/pkgs/additional/bunpen/restrict/namespace.ha
index b133b127a..1e54f0312 100644
--- a/pkgs/additional/bunpen/restrict/namespace.ha
+++ b/pkgs/additional/bunpen/restrict/namespace.ha
@@ -45,7 +45,7 @@ export fn namespace_restrict(what: *resources) void = {
   // and `mkdir` will return EOVERFLOW.
   // all this does is make it so that namespace operations under uid 1000 are
   // mapped to non-ns ops by the same user, and vice-versa
-  write_uid_map(uid, gid);
+  write_id_maps(uid, gid);
 
   if (!what.pid) {
     // fork and become:
@@ -282,17 +282,27 @@ fn pivot_into(new_root: str, stash_old_root: (str|void) = void) void = {
   errors::ext::check("[namespace] cd /", os::chdir("/"));
 };
 
-fn write_uid_map(uid: unix::uid, gid: unix::gid) void = {
-  let uid_fd = rt::open("/proc/self/uid_map", rt::O_RDWR | rt::O_CLOEXEC, 0)!;
+fn write_id_maps(uid: unix::uid, gid: unix::gid) void = {
+  errors::ext::swallow("[namespace] write /proc/self/uid_map", write_uid_map(uid));
+  errors::ext::swallow("[namespace] write /proc/self/setgroups", write_setgroups());
+  errors::ext::swallow("[namespace] write /proc/self/gid_map", write_gid_map(gid));
+};
+
+fn write_uid_map(uid: unix::uid) (void | rt::errno | io::error) = {
+  let uid_fd = rt::open("/proc/self/uid_map", rt::O_RDWR | rt::O_CLOEXEC, 0)?;
   let uid_buf: [4096]u8 = [0...];
   let uid_str = fmt::bsprintf(uid_buf, "{0} {0} 1\n", uid: uint);
-  io::write(uid_fd, strings::toutf8(uid_str))!;
+  io::write(uid_fd, strings::toutf8(uid_str))?;
+};
 
-  let setgroups_fd = rt::open("/proc/self/setgroups", rt::O_RDWR | rt::O_CLOEXEC, 0)!;
-  io::write(setgroups_fd, &['d': u8, 'e', 'n', 'y', '\n', 0])!;
+fn write_setgroups() (void | rt::errno | io::error) = {
+  let setgroups_fd = rt::open("/proc/self/setgroups", rt::O_RDWR | rt::O_CLOEXEC, 0)?;
+  io::write(setgroups_fd, &['d': u8, 'e', 'n', 'y', '\n', 0])?;
+};
 
+fn write_gid_map(gid: unix::gid) (void | rt::errno | io::error) = {
   let gid_fd = rt::open("/proc/self/gid_map", rt::O_RDWR | rt::O_CLOEXEC, 0)!;
   let gid_buf: [4096]u8 = [0...];
   let gid_str = fmt::bsprintf(gid_buf, "{0} {0} 1\n", gid: uint);
-  io::write(gid_fd, strings::toutf8(gid_str))!;
+  io::write(gid_fd, strings::toutf8(gid_str))?;
 };