Merge pull request #4340 from smitsohu/kcmp

augment seccomp lists in firejail.config

1 files changed, 33 insertions, 20 deletions

diff --git a/src/man/firejail.txt b/src/man/firejail.txt
index d18811316..0462705c0 100644
--- a/src/man/firejail.txt
+++ b/src/man/firejail.txt
@@ -2178,7 +2178,7 @@ $ firejail \-\-net=eth0 \-\-scan
 .TP
 \fB\-\-seccomp
 Enable seccomp filter and blacklist the syscalls in the default list,
-which is  @default-nodebuggers unless allow-debuggers is specified,
+which is  @default-nodebuggers unless \-\-allow-debuggers is specified,
 then it is @default.
 
 .br
@@ -2189,18 +2189,13 @@ system call groups are defined: @aio, @basic-io, @chown, @clock,
 @network-io, @obsolete, @privileged, @process, @raw-io, @reboot,
 @resources, @setuid, @swap, @sync, @system-service and @timer.
 More information about groups can be found in /usr/share/doc/firejail/syscalls.txt
-
-In addition, a system call can be specified by its number instead of
-name with prefix $, so for example $165 would be equal to mount on i386.
-Exceptions can be allowed with prefix !.
+.br
 
 .br
 System architecture is strictly imposed only if flag
 \-\-seccomp.block-secondary is used. The filter is applied at run time
 only if the correct architecture was detected. For the case of I386
-and AMD64 both 32-bit and 64-bit filters are installed. On a 64 bit
-architecture, an additional filter for 32 bit system calls can be
-installed with \-\-seccomp.32.
+and AMD64 both 32-bit and 64-bit filters are installed.
 .br
 
 .br
@@ -2211,11 +2206,18 @@ Firejail will print seccomp violations to the audit log if the kernel was compil
 Example:
 .br
 $ firejail \-\-seccomp
+.br
+
+.br
+The default list can be customized, see \-\-seccomp= for a description. It can be customized
+also globally in /etc/firejail/firejail.config file.
+
 .TP
 \fB\-\-seccomp=syscall,@group,!syscall2
-Enable seccomp filter, whitelist "syscall2", but blacklist the default
-list and the syscalls or syscall groups specified by the
-command.
+Enable seccomp filter, blacklist the default list and the syscalls or syscall groups
+specified by the command, but don't blacklist "syscall2". On a 64 bit
+architecture, an additional filter for 32 bit system calls can be
+installed with \-\-seccomp.32.
 .br
 
 .br
@@ -2225,6 +2227,13 @@ $ firejail \-\-seccomp=utime,utimensat,utimes firefox
 .br
 $ firejail \-\-seccomp=@clock,mkdir,unlinkat transmission-gtk
 .br
+$ firejail '\-\-seccomp=@ipc,!pipe,!pipe2' audacious
+.br
+
+.br
+Syscalls can be specified by their number if prefix $ is added,
+so for example $165 would be equal to mount on i386.
+.br
 
 .br
 Instead of dropping the syscall by returning EPERM, another error
@@ -2237,6 +2246,7 @@ by using \fBsyscall:kill\fR syntax, or the attempt may be logged with
 
 .br
 Example:
+.br
 $ firejail \-\-seccomp=unlinkat:ENOENT,utimensat,utimes
 .br
 Parent pid 10662, child pid 10663
@@ -2245,9 +2255,13 @@ Child process initialized
 .br
 $ touch testfile
 .br
+$ ls testfile
+.br
+testfile
+.br
 $ rm testfile
 .br
-rm: cannot remove `testfile': Operation not permitted
+rm: cannot remove `testfile': No such file or directory
 .br
 
 .br
@@ -2260,7 +2274,7 @@ filters.
 .br
 Example:
 .br
-$ firejail \-\-noprofile \-\-shell=none \-\-seccomp=execve bash
+$ firejail \-\-noprofile \-\-shell=none \-\-seccomp=execve sh
 .br
 Parent pid 32751, child pid 32752
 .br
@@ -2272,8 +2286,7 @@ Child process initialized in 46.44 ms
 .br
 $ ls
 .br
-Bad system call
-.br
+Operation not permitted
 
 .TP
 \fB\-\-seccomp.block-secondary
@@ -2317,15 +2330,15 @@ Child process initialized
 .br
 $ touch testfile
 .br
+$ ls testfile
+.br
+testfile
+.br
 $ rm testfile
 .br
-rm: cannot remove `testfile': Operation not permitted
+rm: cannot remove `testfile': No such file or directory
 .br
 
-
-
-
-
 .TP
 \fB\-\-seccomp.keep=syscall,@group,!syscall2
 Enable seccomp filter, blacklist all syscall not listed and "syscall2".