Merge pull request #6999 from poettering/seccomp-newgroups

add three new syscall groups, and port @privileged to make use of more existing ones

NEWS

@@ -118,8 +118,8 @@ CHANGES WITH 235:
           each time the service is restarted due to Restart=, and may be
           queried using "systemctl show -p NRestarts …".
 
-        * New system call filter groups @setuid, @memlock, @signal and
+        * New system call filter groups @aio, @sync, @chown, @setuid, @memlock,
-          @timer have been added, for usage with SystemCallFilter=
+          @signal and @timer have been added, for usage with SystemCallFilter=
           in unit files and the new --system-call-filter= command line option
           of systemd-nspawn (see above).
 

man/systemd.exec.xml

@@ -1490,10 +1490,18 @@ CapabilityBoundingSet=~CAP_B CAP_C</programlisting>
               </row>
             </thead>
             <tbody>
+              <row>
+                <entry>@aio</entry>
+                <entry>Asynchronous I/O (<citerefentry project='man-pages'><refentrytitle>io_setup</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>io_submit</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and related calls)</entry>
+              </row>
               <row>
                 <entry>@basic-io</entry>
                 <entry>System calls for basic I/O: reading, writing, seeking, file descriptor duplication and closing (<citerefentry project='man-pages'><refentrytitle>read</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>write</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and related calls)</entry>
               </row>
+              <row>
+                <entry>@chown</entry>
+                <entry>Changing file ownership (<citerefentry project='man-pages'><refentrytitle>chown</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>fchownat</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and related calls)</entry>
+              </row>
               <row>
                 <entry>@clock</entry>
                 <entry>System calls for changing the system clock (<citerefentry project='man-pages'><refentrytitle>adjtimex</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>settimeofday</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and related calls)</entry>
@@ -1574,6 +1582,10 @@ CapabilityBoundingSet=~CAP_B CAP_C</programlisting>
                 <entry>@swap</entry>
                 <entry>System calls for enabling/disabling swap devices (<citerefentry project='man-pages'><refentrytitle>swapon</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>swapoff</refentrytitle><manvolnum>2</manvolnum></citerefentry>)</entry>
               </row>
+              <row>
+                <entry>@sync</entry>
+                <entry>Synchronizing files and memory to disk: (<citerefentry project='man-pages'><refentrytitle>fsync</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>msync</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and related calls)</entry>
+              </row>
               <row>
                 <entry>@timer</entry>
                 <entry>System calls for scheduling operations by time (<citerefentry project='man-pages'><refentrytitle>alarm</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>timer_create</refentrytitle><manvolnum>2</manvolnum></citerefentry>, …)</entry>

src/nspawn/nspawn-seccomp.c

@@ -49,7 +49,9 @@ static int seccomp_add_default_syscall_filter(
                 const char* name;
         } whitelist[] = {
                 /* Let's use set names where we can */
+                { 0,                  "@aio"                   },
                 { 0,                  "@basic-io"              },
+                { 0,                  "@chown"                 },
                 { 0,                  "@default"               },
                 { 0,                  "@file-system"           },
                 { 0,                  "@io-event"              },
@@ -60,6 +62,7 @@ static int seccomp_add_default_syscall_filter(
                 { 0,                  "@resources"             },
                 { 0,                  "@setuid"                },
                 { 0,                  "@signal"                },
+                { 0,                  "@sync"                  },
                 { 0,                  "@timer"                 },
 
                 /* The following four are sets we optionally enable, in case the caps have been configured for it */
@@ -72,42 +75,25 @@ static int seccomp_add_default_syscall_filter(
                 { 0,                  "brk"                    },
                 { 0,                  "capget"                 },
                 { 0,                  "capset"                 },
-                { 0,                  "chown"                  },
-                { 0,                  "chown32"                },
                 { 0,                  "copy_file_range"        },
                 { 0,                  "fadvise64"              },
                 { 0,                  "fadvise64_64"           },
-                { 0,                  "fchown"                 },
-                { 0,                  "fchown32"               },
-                { 0,                  "fchownat"               },
-                { 0,                  "fdatasync"              },
                 { 0,                  "flock"                  },
-                { 0,                  "fsync"                  },
                 { 0,                  "get_mempolicy"          },
                 { 0,                  "getcpu"                 },
                 { 0,                  "getpriority"            },
                 { 0,                  "getrandom"              },
-                { 0,                  "io_cancel"              },
-                { 0,                  "io_destroy"             },
-                { 0,                  "io_getevents"           },
-                { 0,                  "io_setup"               },
-                { 0,                  "io_submit"              },
                 { 0,                  "ioctl"                  },
                 { 0,                  "ioprio_get"             },
                 { 0,                  "kcmp"                   },
-                { 0,                  "lchown"                 },
-                { 0,                  "lchown32"               },
                 { 0,                  "madvise"                },
                 { 0,                  "mincore"                },
                 { 0,                  "mprotect"               },
                 { 0,                  "mremap"                 },
-                { 0,                  "msync"                  },
                 { 0,                  "name_to_handle_at"      },
                 { 0,                  "oldolduname"            },
                 { 0,                  "olduname"               },
                 { 0,                  "personality"            },
-                { 0,                  "preadv2"                },
-                { 0,                  "pwritev2"               },
                 { 0,                  "readahead"              },
                 { 0,                  "readdir"                },
                 { 0,                  "remap_file_pages"       },
@@ -131,9 +117,6 @@ static int seccomp_add_default_syscall_filter(
                 { 0,                  "setpgid"                },
                 { 0,                  "setsid"                 },
                 { 0,                  "splice"                 },
-                { 0,                  "sync"                   },
-                { 0,                  "sync_file_range"        },
-                { 0,                  "syncfs"                 },
                 { 0,                  "sysinfo"                },
                 { 0,                  "tee"                    },
                 { 0,                  "umask"                  },

src/shared/seccomp-util.c

@@ -317,6 +317,16 @@ const SyscallFilterSet syscall_filter_sets[_SYSCALL_FILTER_SET_MAX] = {
                 "time\0"
                 "ugetrlimit\0"
         },
+        [SYSCALL_FILTER_SET_AIO] = {
+                .name = "@aio",
+                .help = "Asynchronous IO",
+                .value =
+                "io_cancel\0"
+                "io_destroy\0"
+                "io_getevents\0"
+                "io_setup\0"
+                "io_submit\0"
+        },
         [SYSCALL_FILTER_SET_BASIC_IO] = {
                 .name = "@basic-io",
                 .help = "Basic IO",
@@ -329,13 +339,27 @@ const SyscallFilterSet syscall_filter_sets[_SYSCALL_FILTER_SET_MAX] = {
                 "lseek\0"
                 "pread64\0"
                 "preadv\0"
+                "preadv2\0"
                 "pwrite64\0"
                 "pwritev\0"
+                "pwritev2\0"
                 "read\0"
                 "readv\0"
                 "write\0"
                 "writev\0"
         },
+        [SYSCALL_FILTER_SET_CHOWN] = {
+                .name = "@chown",
+                .help = "Change ownership of files and directories",
+                .value =
+                "chown\0"
+                "chown32\0"
+                "fchown\0"
+                "fchown32\0"
+                "fchownat\0"
+                "lchown\0"
+                "lchown32\0"
+        },
         [SYSCALL_FILTER_SET_CLOCK] = {
                 .name = "@clock",
                 .help = "Change the system time",
@@ -600,27 +624,20 @@ const SyscallFilterSet syscall_filter_sets[_SYSCALL_FILTER_SET_MAX] = {
                 .name = "@privileged",
                 .help = "All system calls which need super-user capabilities",
                 .value =
+                "@chown\0"
                 "@clock\0"
                 "@module\0"
                 "@raw-io\0"
+                "@reboot\0"
+                "@swap\0"
                 "_sysctl\0"
                 "acct\0"
                 "bpf\0"
                 "capset\0"
-                "chown\0"
-                "chown32\0"
                 "chroot\0"
-                "fchown\0"
-                "fchown32\0"
-                "fchownat\0"
-                "kexec_file_load\0"
-                "kexec_load\0"
-                "lchown\0"
-                "lchown32\0"
                 "nfsservctl\0"
                 "pivot_root\0"
                 "quotactl\0"
-                "reboot\0"
                 "setdomainname\0"
                 "setfsuid\0"
                 "setfsuid32\0"
@@ -633,8 +650,6 @@ const SyscallFilterSet syscall_filter_sets[_SYSCALL_FILTER_SET_MAX] = {
                 "setreuid32\0"
                 "setuid\0"
                 "setuid32\0"
-                "swapoff\0"
-                "swapon\0"
                 "vhangup\0"
         },
         [SYSCALL_FILTER_SET_PROCESS] = {
@@ -681,8 +696,8 @@ const SyscallFilterSet syscall_filter_sets[_SYSCALL_FILTER_SET_MAX] = {
                 .name = "@reboot",
                 .help = "Reboot and reboot preparation/kexec",
                 .value =
-                "kexec\0"
                 "kexec_file_load\0"
+                "kexec_load\0"
                 "reboot\0"
         },
         [SYSCALL_FILTER_SET_RESOURCES] = {
@@ -746,6 +761,17 @@ const SyscallFilterSet syscall_filter_sets[_SYSCALL_FILTER_SET_MAX] = {
                 "swapoff\0"
                 "swapon\0"
         },
+        [SYSCALL_FILTER_SET_SYNC] = {
+                .name = "@sync",
+                .help = "Synchronize files and memory to storage",
+                .value =
+                "fdatasync\0"
+                "fsync\0"
+                "msync\0"
+                "sync\0"
+                "sync_file_range\0"
+                "syncfs\0"
+        },
         [SYSCALL_FILTER_SET_TIMER] = {
                 .name = "@timer",
                 .help = "Schedule operations by time",

src/shared/seccomp-util.h

@@ -41,7 +41,9 @@ typedef struct SyscallFilterSet {
 enum {
         /* Please leave DEFAULT first, but sort the rest alphabetically */
         SYSCALL_FILTER_SET_DEFAULT,
+        SYSCALL_FILTER_SET_AIO,
         SYSCALL_FILTER_SET_BASIC_IO,
+        SYSCALL_FILTER_SET_CHOWN,
         SYSCALL_FILTER_SET_CLOCK,
         SYSCALL_FILTER_SET_CPU_EMULATION,
         SYSCALL_FILTER_SET_DEBUG,
@@ -62,6 +64,7 @@ enum {
         SYSCALL_FILTER_SET_SETUID,
         SYSCALL_FILTER_SET_SIGNAL,
         SYSCALL_FILTER_SET_SWAP,
+        SYSCALL_FILTER_SET_SYNC,
         SYSCALL_FILTER_SET_TIMER,
         _SYSCALL_FILTER_SET_MAX
 };