From aeec5efab58adb2c8fe02ab4f6f8864b07905e7e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= <cgzones@googlemail.com>
Date: Thu, 28 Nov 2019 12:17:48 +0100
Subject: [PATCH] copy: add flag COPY_MAC_CREATE to create with correct label

Useful for MAC aware file creation like in systemd-tmpfiles.
---
 src/basic/copy.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++--
 src/basic/copy.h |  1 +
 2 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/src/basic/copy.c b/src/basic/copy.c
index 9028868f69..97d566c5b9 100644
--- a/src/basic/copy.c
+++ b/src/basic/copy.c
@@ -21,6 +21,7 @@
 #include "missing_syscall.h"
 #include "mountpoint-util.h"
 #include "nulstr-util.h"
+#include "selinux-util.h"
 #include "stat-util.h"
 #include "string-util.h"
 #include "strv.h"
@@ -372,7 +373,15 @@ static int fd_copy_symlink(
         if (r < 0)
                 return r;
 
-        if (symlinkat(target, dt, to) < 0)
+        if (copy_flags & COPY_MAC_CREATE) {
+                r = mac_selinux_create_file_prepare_at(dt, to, S_IFLNK);
+                if (r < 0)
+                        return r;
+        }
+        r = symlinkat(target, dt, to);
+        if (copy_flags & COPY_MAC_CREATE)
+                mac_selinux_create_file_clear();
+        if (r < 0)
                 return -errno;
 
         if (fchownat(dt, to,
@@ -408,7 +417,14 @@ static int fd_copy_regular(
         if (fdf < 0)
                 return -errno;
 
+        if (copy_flags & COPY_MAC_CREATE) {
+                r = mac_selinux_create_file_prepare_at(dt, to, S_IFREG);
+                if (r < 0)
+                        return r;
+        }
         fdt = openat(dt, to, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW, st->st_mode & 07777);
+        if (copy_flags & COPY_MAC_CREATE)
+                mac_selinux_create_file_clear();
         if (fdt < 0)
                 return -errno;
 
@@ -457,7 +473,14 @@ static int fd_copy_fifo(
         assert(st);
         assert(to);
 
+        if (copy_flags & COPY_MAC_CREATE) {
+                r = mac_selinux_create_file_prepare_at(dt, to, S_IFIFO);
+                if (r < 0)
+                        return r;
+        }
         r = mkfifoat(dt, to, st->st_mode & 07777);
+        if (copy_flags & COPY_MAC_CREATE)
+                mac_selinux_create_file_clear();
         if (r < 0)
                 return -errno;
 
@@ -488,7 +511,14 @@ static int fd_copy_node(
         assert(st);
         assert(to);
 
+        if (copy_flags & COPY_MAC_CREATE) {
+                r = mac_selinux_create_file_prepare_at(dt, to, st->st_mode & S_IFMT);
+                if (r < 0)
+                        return r;
+        }
         r = mknodat(dt, to, st->st_mode, st->st_rdev);
+        if (copy_flags & COPY_MAC_CREATE)
+                mac_selinux_create_file_clear();
         if (r < 0)
                 return -errno;
 
@@ -556,7 +586,10 @@ static int fd_copy_directory(
         if (exists)
                 created = false;
         else {
-                r = mkdirat(dt, to, st->st_mode & 07777);
+                if (copy_flags & COPY_MAC_CREATE)
+                        r = mkdirat_label(dt, to, st->st_mode & 07777);
+                else
+                        r = mkdirat(dt, to, st->st_mode & 07777);
                 if (r >= 0)
                         created = true;
                 else if (errno == EEXIST && (copy_flags & COPY_MERGE))
@@ -796,7 +829,14 @@ int copy_file_full(
         assert(to);
 
         RUN_WITH_UMASK(0000) {
+                if (copy_flags & COPY_MAC_CREATE) {
+                        r = mac_selinux_create_file_prepare(to, S_IFREG);
+                        if (r < 0)
+                                return r;
+                }
                 fdt = open(to, flags|O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY, mode);
+                if (copy_flags & COPY_MAC_CREATE)
+                        mac_selinux_create_file_clear();
                 if (fdt < 0)
                         return -errno;
         }
@@ -850,13 +890,29 @@ int copy_file_atomic_full(
                 if (r < 0)
                         return r;
 
+                if (copy_flags & COPY_MAC_CREATE) {
+                        r = mac_selinux_create_file_prepare(to, S_IFREG);
+                        if (r < 0) {
+                                t = mfree(t);
+                                return r;
+                        }
+                }
                 fdt = open(t, O_CREAT|O_EXCL|O_NOFOLLOW|O_NOCTTY|O_WRONLY|O_CLOEXEC, 0600);
+                if (copy_flags & COPY_MAC_CREATE)
+                        mac_selinux_create_file_clear();
                 if (fdt < 0) {
                         t = mfree(t);
                         return -errno;
                 }
         } else {
+                if (copy_flags & COPY_MAC_CREATE) {
+                        r = mac_selinux_create_file_prepare(to, S_IFREG);
+                        if (r < 0)
+                                return r;
+                }
                 fdt = open_tmpfile_linkable(to, O_WRONLY|O_CLOEXEC, &t);
+                if (copy_flags & COPY_MAC_CREATE)
+                        mac_selinux_create_file_clear();
                 if (fdt < 0)
                         return fdt;
         }
diff --git a/src/basic/copy.h b/src/basic/copy.h
index 906c6f70ae..af8e88af04 100644
--- a/src/basic/copy.h
+++ b/src/basic/copy.h
@@ -16,6 +16,7 @@ typedef enum CopyFlags {
         COPY_MERGE_EMPTY = 1 << 4, /* Merge an existing, empty directory with our new tree to copy */
         COPY_CRTIME      = 1 << 5, /* Generate a user.crtime_usec xattr off the source crtime if there is one, on copying */
         COPY_SIGINT      = 1 << 6, /* Check for SIGINT regularly and return EINTR if seen (caller needs to block SIGINT) */
+        COPY_MAC_CREATE  = 1 << 7, /* Create files with the correct MAC label (currently SELinux only) */
 } CopyFlags;
 
 typedef int (*copy_progress_bytes_t)(uint64_t n_bytes, void *userdata);