github.com/nicocha30/gvisor-ligolo@v0.0.0-20230726075806-989fa2c0a413/runsc/fsgofer/filter/filter.go (about)

     1  // Copyright 2018 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // Package filter defines all syscalls the gofer is allowed to make, and
    16  // installs seccomp filters to prevent prohibited syscalls in case it's
    17  // compromised.
    18  package filter
    19  
    20  import (
    21  	"github.com/nicocha30/gvisor-ligolo/pkg/log"
    22  	"github.com/nicocha30/gvisor-ligolo/pkg/seccomp"
    23  )
    24  
    25  // Options are seccomp filter related options.
    26  type Options struct {
    27  	UDSOpenEnabled   bool
    28  	UDSCreateEnabled bool
    29  	ProfileEnabled   bool
    30  }
    31  
    32  // Install installs seccomp filters.
    33  func Install(opt Options) error {
    34  	s := allowedSyscalls
    35  
    36  	if opt.ProfileEnabled {
    37  		report("profile enabled: syscall filters less restrictive!")
    38  		s.Merge(profileFilters)
    39  	}
    40  
    41  	if opt.UDSOpenEnabled || opt.UDSCreateEnabled {
    42  		report("host UDS enabled: syscall filters less restrictive!")
    43  		s.Merge(udsCommonSyscalls)
    44  		if opt.UDSOpenEnabled {
    45  			s.Merge(udsOpenSyscalls)
    46  		}
    47  		if opt.UDSCreateEnabled {
    48  			s.Merge(udsCreateSyscalls)
    49  		}
    50  	}
    51  
    52  	// Set of additional filters used by -race and -msan. Returns empty
    53  	// when not enabled.
    54  	s.Merge(instrumentationFilters())
    55  
    56  	return seccomp.Install(s, seccomp.DenyNewExecMappings)
    57  }
    58  
    59  // report writes a warning message to the log.
    60  func report(msg string) {
    61  	log.Warningf("*** SECCOMP WARNING: %s", msg)
    62  }