merge branch 'pr-1424'

Update Travis config to use trusty-backports libseccomp
  Add integration tests for multi-argument Seccomp filters
  Vendor updated libseccomp-golang for bugfix

LGTMs: @crosbymichael @cyphar
Closes #1424

.travis.yml

@@ -20,8 +20,9 @@ env:
     - BUILDTAGS="seccomp apparmor selinux ambient"
 
 before_install:
+  - echo "deb http://archive.ubuntu.com/ubuntu trusty-backports main restricted universe multiverse" | sudo tee -a /etc/apt/sources.list
   - sudo apt-get -qq update
-  - sudo apt-get install -y libseccomp-dev libapparmor-dev
+  - sudo apt-get install -y libapparmor-dev libseccomp-dev/trusty-backports
   - go get -u github.com/golang/lint/golint
   - go get -u github.com/vbatts/git-validation
   - env | grep TRAVIS_

libcontainer/integration/seccomp_test.go

@@ -217,3 +217,107 @@ func TestSeccompDenyWriteConditional(t *testing.T) {
 		t.Fatalf("Expected output %s but got %s\n", expected, actual)
 	}
 }
+
+func TestSeccompPermitWriteMultipleConditions(t *testing.T) {
+	if testing.Short() {
+		return
+	}
+
+	rootfs, err := newRootfs()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer remove(rootfs)
+
+	config := newTemplateConfig(rootfs)
+	config.Seccomp = &configs.Seccomp{
+		DefaultAction: configs.Allow,
+		Syscalls: []*configs.Syscall{
+			{
+				Name:   "write",
+				Action: configs.Errno,
+				Args: []*configs.Arg{
+					{
+						Index: 0,
+						Value: 2,
+						Op:    configs.EqualTo,
+					},
+					{
+						Index: 2,
+						Value: 0,
+						Op:    configs.NotEqualTo,
+					},
+				},
+			},
+		},
+	}
+
+	buffers, exitCode, err := runContainer(config, "", "ls", "/")
+	if err != nil {
+		t.Fatalf("%s: %s", buffers, err)
+	}
+	if exitCode != 0 {
+		t.Fatalf("exit code not 0. code %d buffers %s", exitCode, buffers)
+	}
+	// We don't need to verify the actual thing printed
+	// Just that something was written to stdout
+	if len(buffers.Stdout.String()) == 0 {
+		t.Fatalf("Nothing was written to stdout, write call failed!\n")
+	}
+}
+
+func TestSeccompDenyWriteMultipleConditions(t *testing.T) {
+	if testing.Short() {
+		return
+	}
+
+	// Only test if library version is v2.2.1 or higher
+	// Conditional filtering will always error in v2.2.0 and lower
+	major, minor, micro := libseccomp.GetLibraryVersion()
+	if (major == 2 && minor < 2) || (major == 2 && minor == 2 && micro < 1) {
+		return
+	}
+
+	rootfs, err := newRootfs()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer remove(rootfs)
+
+	config := newTemplateConfig(rootfs)
+	config.Seccomp = &configs.Seccomp{
+		DefaultAction: configs.Allow,
+		Syscalls: []*configs.Syscall{
+			{
+				Name:   "write",
+				Action: configs.Errno,
+				Args: []*configs.Arg{
+					{
+						Index: 0,
+						Value: 2,
+						Op:    configs.EqualTo,
+					},
+					{
+						Index: 2,
+						Value: 0,
+						Op:    configs.NotEqualTo,
+					},
+				},
+			},
+		},
+	}
+
+	buffers, exitCode, err := runContainer(config, "", "ls", "/does_not_exist")
+	if err == nil {
+		t.Fatalf("Expecting error return, instead got 0")
+	}
+	if exitCode == 0 {
+		t.Fatalf("Busybox should fail with negative exit code, instead got %d!", exitCode)
+	}
+
+	expected := ""
+	actual := strings.Trim(buffers.Stderr.String(), "\n")
+	if actual != expected {
+		t.Fatalf("Expected output %s but got %s\n", expected, actual)
+	}
+}

vendor.conf

@@ -5,7 +5,7 @@ github.com/opencontainers/runtime-spec v1.0.0
 # Core libcontainer functionality.
 github.com/mrunalp/fileutils ed869b029674c0e9ce4c0dfa781405c2d9946d08
 github.com/opencontainers/selinux v1.0.0-rc1
-github.com/seccomp/libseccomp-golang 32f571b70023028bd57d9288c20efbcb237f3ce0
+github.com/seccomp/libseccomp-golang 84e90a91acea0f4e51e62bc1a75de18b1fc0790f
 github.com/sirupsen/logrus a3f95b5c423586578a4e099b11a46c2479628cac
 github.com/syndtr/gocapability db04d3cc01c8b54962a58ec7e491717d06cfcc16
 github.com/vishvananda/netlink 1e2e08e8a2dcdacaae3f14ac44c5cfa31361f270

vendor/github.com/seccomp/libseccomp-golang/README

@@ -24,3 +24,28 @@ please note that a Google account is not required to subscribe to the mailing
 list.
 
 	-> https://groups.google.com/d/forum/libseccomp
+
+Documentation is also available at:
+
+	-> https://godoc.org/github.com/seccomp/libseccomp-golang
+
+* Installing the package
+
+The libseccomp-golang bindings require at least Go v1.2.1 and GCC v4.8.4;
+earlier versions may yield unpredictable results.  If you meet these
+requirements you can install this package using the command below:
+
+	$ go get github.com/seccomp/libseccomp-golang
+
+* Testing the Library
+
+A number of tests and lint related recipes are provided in the Makefile, if
+you want to run the standard regression tests, you can excute the following:
+
+	$ make check
+
+In order to execute the 'make lint' recipe the 'golint' tool is needed, it
+can be found at:
+
+	-> https://github.com/golang/lint
+

vendor/github.com/seccomp/libseccomp-golang/seccomp.go

@@ -27,6 +27,28 @@ import "C"
 
 // Exported types
 
+// VersionError denotes that the system libseccomp version is incompatible
+// with this package.
+type VersionError struct {
+	message string
+	minimum string
+}
+
+func (e VersionError) Error() string {
+	format := "Libseccomp version too low: "
+	if e.message != "" {
+		format += e.message + ": "
+	}
+	format += "minimum supported is "
+	if e.minimum != "" {
+		format += e.minimum + ": "
+	} else {
+		format += "2.2.0: "
+	}
+	format += "detected %d.%d.%d"
+	return fmt.Sprintf(format, verMajor, verMinor, verMicro)
+}
+
 // ScmpArch represents a CPU architecture. Seccomp can restrict syscalls on a
 // per-architecture basis.
 type ScmpArch uint
@@ -54,8 +76,8 @@ type ScmpSyscall int32
 
 const (
 	// Valid architectures recognized by libseccomp
-	// ARM64 and all MIPS architectures are unsupported by versions of the
+	// PowerPC and S390(x) architectures are unavailable below library version
-	// library before v2.2 and will return errors if used
+	// v2.3.0 and will returns errors if used with incompatible libraries
 
 	// ArchInvalid is a placeholder to ensure uninitialized ScmpArch
 	// variables are invalid
@@ -151,6 +173,10 @@ const (
 // GetArchFromString returns an ScmpArch constant from a string representing an
 // architecture
 func GetArchFromString(arch string) (ScmpArch, error) {
+	if err := ensureSupportedVersion(); err != nil {
+		return ArchInvalid, err
+	}
+
 	switch strings.ToLower(arch) {
 	case "x86":
 		return ArchX86, nil
@@ -298,7 +324,7 @@ func (a ScmpAction) GetReturnCode() int16 {
 // GetLibraryVersion returns the version of the library the bindings are built
 // against.
 // The version is formatted as follows: Major.Minor.Micro
-func GetLibraryVersion() (major, minor, micro int) {
+func GetLibraryVersion() (major, minor, micro uint) {
 	return verMajor, verMinor, verMicro
 }
 
@@ -338,6 +364,10 @@ func (s ScmpSyscall) GetNameByArch(arch ScmpArch) (string, error) {
 // Returns the number of the syscall, or an error if no syscall with that name
 // was found.
 func GetSyscallFromName(name string) (ScmpSyscall, error) {
+	if err := ensureSupportedVersion(); err != nil {
+		return 0, err
+	}
+
 	cString := C.CString(name)
 	defer C.free(unsafe.Pointer(cString))
 
@@ -355,6 +385,9 @@ func GetSyscallFromName(name string) (ScmpSyscall, error) {
 // Returns the number of the syscall, or an error if an invalid architecture is
 // passed or a syscall with that name was not found.
 func GetSyscallFromNameByArch(name string, arch ScmpArch) (ScmpSyscall, error) {
+	if err := ensureSupportedVersion(); err != nil {
+		return 0, err
+	}
 	if err := sanitizeArch(arch); err != nil {
 		return 0, err
 	}
@@ -386,6 +419,10 @@ func GetSyscallFromNameByArch(name string, arch ScmpArch) (ScmpSyscall, error) {
 func MakeCondition(arg uint, comparison ScmpCompareOp, values ...uint64) (ScmpCondition, error) {
 	var condStruct ScmpCondition
 
+	if err := ensureSupportedVersion(); err != nil {
+		return condStruct, err
+	}
+
 	if comparison == CompareInvalid {
 		return condStruct, fmt.Errorf("invalid comparison operator")
 	} else if arg > 5 {
@@ -413,6 +450,10 @@ func MakeCondition(arg uint, comparison ScmpCompareOp, values ...uint64) (ScmpCo
 // GetNativeArch returns architecture token representing the native kernel
 // architecture
 func GetNativeArch() (ScmpArch, error) {
+	if err := ensureSupportedVersion(); err != nil {
+		return ArchInvalid, err
+	}
+
 	arch := C.seccomp_arch_native()
 
 	return archFromNative(arch)
@@ -435,6 +476,10 @@ type ScmpFilter struct {
 // Returns a reference to a valid filter context, or nil and an error if the
 // filter context could not be created or an invalid default action was given.
 func NewFilter(defaultAction ScmpAction) (*ScmpFilter, error) {
+	if err := ensureSupportedVersion(); err != nil {
+		return nil, err
+	}
+
 	if err := sanitizeAction(defaultAction); err != nil {
 		return nil, err
 	}
@@ -449,6 +494,13 @@ func NewFilter(defaultAction ScmpAction) (*ScmpFilter, error) {
 	filter.valid = true
 	runtime.SetFinalizer(filter, filterFinalizer)
 
+	// Enable TSync so all goroutines will receive the same rules
+	// If the kernel does not support TSYNC, allow us to continue without error
+	if err := filter.setFilterAttr(filterAttrTsync, 0x1); err != nil && err != syscall.ENOTSUP {
+		filter.Release()
+		return nil, fmt.Errorf("could not create filter - error setting tsync bit: %v", err)
+	}
+
 	return filter, nil
 }
 
@@ -505,7 +557,7 @@ func (f *ScmpFilter) Release() {
 // The source filter src will be released as part of the process, and will no
 // longer be usable or valid after this call.
 // To be merged, filters must NOT share any architectures, and all their
-// attributes (Default Action, Bad Arch Action, No New Privs and TSync bools)
+// attributes (Default Action, Bad Arch Action, and No New Privs bools)
 // must match.
 // The filter src will be merged into the filter this is called on.
 // The architectures of the src filter not present in the destination, and all
@@ -678,30 +730,6 @@ func (f *ScmpFilter) GetNoNewPrivsBit() (bool, error) {
 	return true, nil
 }
 
-// GetTsyncBit returns whether Thread Synchronization will be enabled on the
-// filter being loaded, or an error if an issue was encountered retrieving the
-// value.
-// Thread Sync ensures that all members of the thread group of the calling
-// process will share the same Seccomp filter set.
-// Tsync is a fairly recent addition to the Linux kernel and older kernels
-// lack support. If the running kernel does not support Tsync and it is
-// requested in a filter, Libseccomp will not enable TSync support and will
-// proceed as normal.
-// This function is unavailable before v2.2 of libseccomp and will return an
-// error.
-func (f *ScmpFilter) GetTsyncBit() (bool, error) {
-	tSync, err := f.getFilterAttr(filterAttrTsync)
-	if err != nil {
-		return false, err
-	}
-
-	if tSync == 0 {
-		return false, nil
-	}
-
-	return true, nil
-}
-
 // SetBadArchAction sets the default action taken on a syscall for an
 // architecture not in the filter, or an error if an issue was encountered
 // setting the value.
@@ -728,27 +756,6 @@ func (f *ScmpFilter) SetNoNewPrivsBit(state bool) error {
 	return f.setFilterAttr(filterAttrNNP, toSet)
 }
 
-// SetTsync sets whether Thread Synchronization will be enabled on the filter
-// being loaded. Returns an error if setting Tsync failed, or the filter is
-// invalid.
-// Thread Sync ensures that all members of the thread group of the calling
-// process will share the same Seccomp filter set.
-// Tsync is a fairly recent addition to the Linux kernel and older kernels
-// lack support. If the running kernel does not support Tsync and it is
-// requested in a filter, Libseccomp will not enable TSync support and will
-// proceed as normal.
-// This function is unavailable before v2.2 of libseccomp and will return an
-// error.
-func (f *ScmpFilter) SetTsync(enable bool) error {
-	var toSet C.uint32_t = 0x0
-
-	if enable {
-		toSet = 0x1
-	}
-
-	return f.setFilterAttr(filterAttrTsync, toSet)
-}
-
 // SetSyscallPriority sets a syscall's priority.
 // This provides a hint to the filter generator in libseccomp about the
 // importance of this syscall. High-priority syscalls are placed

vendor/github.com/seccomp/libseccomp-golang/seccomp_internal.go

@@ -7,7 +7,6 @@ package seccomp
 
 import (
 	"fmt"
-	"os"
 	"syscall"
 )
 
@@ -21,43 +20,15 @@ import (
 #include <seccomp.h>
 
 #if SCMP_VER_MAJOR < 2
-#error Minimum supported version of Libseccomp is v2.1.0
+#error Minimum supported version of Libseccomp is v2.2.0
-#elif SCMP_VER_MAJOR == 2 && SCMP_VER_MINOR < 1
+#elif SCMP_VER_MAJOR == 2 && SCMP_VER_MINOR < 2
-#error Minimum supported version of Libseccomp is v2.1.0
+#error Minimum supported version of Libseccomp is v2.2.0
 #endif
 
 #define ARCH_BAD ~0
 
 const uint32_t C_ARCH_BAD = ARCH_BAD;
 
-#ifndef SCMP_ARCH_AARCH64
-#define SCMP_ARCH_AARCH64 ARCH_BAD
-#endif
-
-#ifndef SCMP_ARCH_MIPS
-#define SCMP_ARCH_MIPS ARCH_BAD
-#endif
-
-#ifndef SCMP_ARCH_MIPS64
-#define SCMP_ARCH_MIPS64 ARCH_BAD
-#endif
-
-#ifndef SCMP_ARCH_MIPS64N32
-#define SCMP_ARCH_MIPS64N32 ARCH_BAD
-#endif
-
-#ifndef SCMP_ARCH_MIPSEL
-#define SCMP_ARCH_MIPSEL ARCH_BAD
-#endif
-
-#ifndef SCMP_ARCH_MIPSEL64
-#define SCMP_ARCH_MIPSEL64 ARCH_BAD
-#endif
-
-#ifndef SCMP_ARCH_MIPSEL64N32
-#define SCMP_ARCH_MIPSEL64N32 ARCH_BAD
-#endif
-
 #ifndef SCMP_ARCH_PPC
 #define SCMP_ARCH_PPC ARCH_BAD
 #endif
@@ -102,12 +73,6 @@ const uint32_t C_ACT_ERRNO         = SCMP_ACT_ERRNO(0);
 const uint32_t C_ACT_TRACE         = SCMP_ACT_TRACE(0);
 const uint32_t C_ACT_ALLOW         = SCMP_ACT_ALLOW;
 
-// If TSync is not supported, make sure it doesn't map to a supported filter attribute
-// Don't worry about major version < 2, the minimum version checks should catch that case
-#if SCMP_VER_MAJOR == 2 && SCMP_VER_MINOR < 2
-#define SCMP_FLTATR_CTL_TSYNC _SCMP_CMP_MIN
-#endif
-
 const uint32_t C_ATTRIBUTE_DEFAULT = (uint32_t)SCMP_FLTATR_ACT_DEFAULT;
 const uint32_t C_ATTRIBUTE_BADARCH = (uint32_t)SCMP_FLTATR_ACT_BADARCH;
 const uint32_t C_ATTRIBUTE_NNP     = (uint32_t)SCMP_FLTATR_CTL_NNP;
@@ -125,25 +90,61 @@ const int      C_VERSION_MAJOR     = SCMP_VER_MAJOR;
 const int      C_VERSION_MINOR     = SCMP_VER_MINOR;
 const int      C_VERSION_MICRO     = SCMP_VER_MICRO;
 
+#if SCMP_VER_MAJOR == 2 && SCMP_VER_MINOR >= 3
+unsigned int get_major_version()
+{
+        return seccomp_version()->major;
+}
+
+unsigned int get_minor_version()
+{
+        return seccomp_version()->minor;
+}
+
+unsigned int get_micro_version()
+{
+        return seccomp_version()->micro;
+}
+#else
+unsigned int get_major_version()
+{
+        return (unsigned int)C_VERSION_MAJOR;
+}
+
+unsigned int get_minor_version()
+{
+        return (unsigned int)C_VERSION_MINOR;
+}
+
+unsigned int get_micro_version()
+{
+        return (unsigned int)C_VERSION_MICRO;
+}
+#endif
+
 typedef struct scmp_arg_cmp* scmp_cast_t;
 
-// Wrapper to create an scmp_arg_cmp struct
+void* make_arg_cmp_array(unsigned int length)
-void*
-make_struct_arg_cmp(
-                    unsigned int arg,
-                    int compare,
-                    uint64_t a,
-                    uint64_t b
-                   )
 {
-	struct scmp_arg_cmp *s = malloc(sizeof(struct scmp_arg_cmp));
+        return calloc(length, sizeof(struct scmp_arg_cmp));
+}
 
-	s->arg = arg;
+// Wrapper to add an scmp_arg_cmp struct to an existing arg_cmp array
-	s->op = compare;
+void add_struct_arg_cmp(
-	s->datum_a = a;
+                        struct scmp_arg_cmp* arr,
-	s->datum_b = b;
+                        unsigned int pos,
+                        unsigned int arg,
+                        int compare,
+                        uint64_t a,
+                        uint64_t b
+                       )
+{
+        arr[pos].arg = arg;
+        arr[pos].op = compare;
+        arr[pos].datum_a = a;
+        arr[pos].datum_b = b;
 
-	return s;
+        return;
 }
 */
 import "C"
@@ -178,26 +179,26 @@ var (
 	// Error thrown on bad filter context
 	errBadFilter = fmt.Errorf("filter is invalid or uninitialized")
 	// Constants representing library major, minor, and micro versions
-	verMajor = int(C.C_VERSION_MAJOR)
+	verMajor = uint(C.get_major_version())
-	verMinor = int(C.C_VERSION_MINOR)
+	verMinor = uint(C.get_minor_version())
-	verMicro = int(C.C_VERSION_MICRO)
+	verMicro = uint(C.get_micro_version())
 )
 
 // Nonexported functions
 
 // Check if library version is greater than or equal to the given one
-func checkVersionAbove(major, minor, micro int) bool {
+func checkVersionAbove(major, minor, micro uint) bool {
 	return (verMajor > major) ||
 		(verMajor == major && verMinor > minor) ||
 		(verMajor == major && verMinor == minor && verMicro >= micro)
 }
 
-// Init function: Verify library version is appropriate
+// Ensure that the library is supported, i.e. >= 2.2.0.
-func init() {
+func ensureSupportedVersion() error {
-	if !checkVersionAbove(2, 1, 0) {
+	if !checkVersionAbove(2, 2, 0) {
-		fmt.Fprintf(os.Stderr, "Libseccomp version too low: minimum supported is 2.1.0, detected %d.%d.%d", C.C_VERSION_MAJOR, C.C_VERSION_MINOR, C.C_VERSION_MICRO)
+		return VersionError{}
-		os.Exit(-1)
 	}
+	return nil
 }
 
 // Filter helpers
@@ -216,10 +217,6 @@ func (f *ScmpFilter) getFilterAttr(attr scmpFilterAttr) (C.uint32_t, error) {
 		return 0x0, errBadFilter
 	}
 
-	if !checkVersionAbove(2, 2, 0) && attr == filterAttrTsync {
-		return 0x0, fmt.Errorf("the thread synchronization attribute is not supported in this version of the library")
-	}
-
 	var attribute C.uint32_t
 
 	retCode := C.seccomp_attr_get(f.filterCtx, attr.toNative(), &attribute)
@@ -239,10 +236,6 @@ func (f *ScmpFilter) setFilterAttr(attr scmpFilterAttr, value C.uint32_t) error
 		return errBadFilter
 	}
 
-	if !checkVersionAbove(2, 2, 0) && attr == filterAttrTsync {
-		return fmt.Errorf("the thread synchronization attribute is not supported in this version of the library")
-	}
-
 	retCode := C.seccomp_attr_set(f.filterCtx, attr.toNative(), value)
 	if retCode != 0 {
 		return syscall.Errno(-1 * retCode)
@@ -254,12 +247,9 @@ func (f *ScmpFilter) setFilterAttr(attr scmpFilterAttr, value C.uint32_t) error
 // DOES NOT LOCK OR CHECK VALIDITY
 // Assumes caller has already done this
 // Wrapper for seccomp_rule_add_... functions
-func (f *ScmpFilter) addRuleWrapper(call ScmpSyscall, action ScmpAction, exact bool, cond C.scmp_cast_t) error {
+func (f *ScmpFilter) addRuleWrapper(call ScmpSyscall, action ScmpAction, exact bool, length C.uint, cond C.scmp_cast_t) error {
-	var length C.uint
+	if length != 0 && cond == nil {
-	if cond != nil {
+		return fmt.Errorf("null conditions list, but length is nonzero")
-		length = 1
-	} else {
-		length = 0
 	}
 
 	var retCode C.int
@@ -273,6 +263,8 @@ func (f *ScmpFilter) addRuleWrapper(call ScmpSyscall, action ScmpAction, exact b
 		return fmt.Errorf("unrecognized syscall")
 	} else if syscall.Errno(-1*retCode) == syscall.EPERM {
 		return fmt.Errorf("requested action matches default action of filter")
+	} else if syscall.Errno(-1*retCode) == syscall.EINVAL {
+		return fmt.Errorf("two checks on same syscall argument")
 	} else if retCode != 0 {
 		return syscall.Errno(-1 * retCode)
 	}
@@ -290,22 +282,32 @@ func (f *ScmpFilter) addRuleGeneric(call ScmpSyscall, action ScmpAction, exact b
 	}
 
 	if len(conds) == 0 {
-		if err := f.addRuleWrapper(call, action, exact, nil); err != nil {
+		if err := f.addRuleWrapper(call, action, exact, 0, nil); err != nil {
 			return err
 		}
 	} else {
 		// We don't support conditional filtering in library version v2.1
 		if !checkVersionAbove(2, 2, 1) {
-			return fmt.Errorf("conditional filtering requires libseccomp version >= 2.2.1")
+			return VersionError{
+				message: "conditional filtering is not supported",
+				minimum: "2.2.1",
+			}
 		}
 
-		for _, cond := range conds {
+		argsArr := C.make_arg_cmp_array(C.uint(len(conds)))
-			cmpStruct := C.make_struct_arg_cmp(C.uint(cond.Argument), cond.Op.toNative(), C.uint64_t(cond.Operand1), C.uint64_t(cond.Operand2))
+		if argsArr == nil {
-			defer C.free(cmpStruct)
+			return fmt.Errorf("error allocating memory for conditions")
+		}
+		defer C.free(argsArr)
 
-			if err := f.addRuleWrapper(call, action, exact, C.scmp_cast_t(cmpStruct)); err != nil {
+		for i, cond := range conds {
-				return err
+			C.add_struct_arg_cmp(C.scmp_cast_t(argsArr), C.uint(i),
-			}
+				C.uint(cond.Argument), cond.Op.toNative(),
+				C.uint64_t(cond.Operand1), C.uint64_t(cond.Operand2))
+		}
+
+		if err := f.addRuleWrapper(call, action, exact, C.uint(len(conds)), C.scmp_cast_t(argsArr)); err != nil {
+			return err
 		}
 	}