gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/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  	"gvisor.dev/gvisor/pkg/log"
    22  	"gvisor.dev/gvisor/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  	DirectFS         bool
    31  }
    32  
    33  // Install installs seccomp filters.
    34  func Install(opt Options) error {
    35  	s := allowedSyscalls
    36  
    37  	if opt.ProfileEnabled {
    38  		report("profile enabled: syscall filters less restrictive!")
    39  		s.Merge(profileFilters)
    40  	}
    41  
    42  	if opt.UDSOpenEnabled || opt.UDSCreateEnabled {
    43  		report("host UDS enabled: syscall filters less restrictive!")
    44  		s.Merge(udsCommonSyscalls)
    45  		if opt.UDSOpenEnabled {
    46  			s.Merge(udsOpenSyscalls)
    47  		}
    48  		if opt.UDSCreateEnabled {
    49  			s.Merge(udsCreateSyscalls)
    50  		}
    51  	}
    52  
    53  	// Set of additional filters used by -race and -msan. Returns empty
    54  	// when not enabled.
    55  	s.Merge(instrumentationFilters())
    56  
    57  	// When DirectFS is not enabled, filters for LisaFS are installed.
    58  	if !opt.DirectFS {
    59  		s.Merge(lisafsFilters)
    60  	}
    61  
    62  	return seccomp.Install(s, seccomp.DenyNewExecMappings, seccomp.DefaultProgramOptions())
    63  }
    64  
    65  // report writes a warning message to the log.
    66  func report(msg string) {
    67  	log.Warningf("*** SECCOMP WARNING: %s", msg)
    68  }