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authorgVisor bot <gvisor-bot@google.com>2020-09-16 06:22:25 +0000
committergVisor bot <gvisor-bot@google.com>2020-09-16 06:22:25 +0000
commitcbc7d6a202b7e47457b3aa3daa55ebc5c1fbdb72 (patch)
tree5db961cfe01e42b712f232bd9028df2e33859a31 /pkg
parentfe3658df8a9fd634c22008533c45e7cb2a5866cc (diff)
parentdcd532e2e416aa81ca9ac42dc153731855f91418 (diff)
Merge release-20200907.0-56-gdcd532e2e (automated)
Diffstat (limited to 'pkg')
-rw-r--r--pkg/abi/linux/linux_abi_autogen_unsafe.go18
-rw-r--r--pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go8
-rw-r--r--pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go8
-rw-r--r--pkg/abi/linux/seccomp.go23
-rw-r--r--pkg/bpf/decoder.go13
-rw-r--r--pkg/bpf/program_builder.go23
-rw-r--r--pkg/seccomp/seccomp.go177
-rw-r--r--pkg/seccomp/seccomp_rules.go75
-rw-r--r--pkg/sentry/kernel/syscalls.go10
-rw-r--r--pkg/sentry/platform/ptrace/subprocess_amd64.go2
-rw-r--r--pkg/sentry/platform/ptrace/subprocess_linux.go10
-rw-r--r--pkg/sentry/platform/ring0/defs_impl_arm64.go3
12 files changed, 295 insertions, 75 deletions
diff --git a/pkg/abi/linux/linux_abi_autogen_unsafe.go b/pkg/abi/linux/linux_abi_autogen_unsafe.go
index b5c63aaa7..54c1a20c2 100644
--- a/pkg/abi/linux/linux_abi_autogen_unsafe.go
+++ b/pkg/abi/linux/linux_abi_autogen_unsafe.go
@@ -155,7 +155,7 @@ func (s *Statx) UnmarshalBytes(src []byte) {
// Packed implements marshal.Marshallable.Packed.
//go:nosplit
func (s *Statx) Packed() bool {
- return s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed()
+ return s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed()
}
// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
@@ -181,7 +181,7 @@ func (s *Statx) UnmarshalUnsafe(src []byte) {
// CopyOutN implements marshal.Marshallable.CopyOutN.
//go:nosplit
func (s *Statx) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
- if !s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() {
+ if !s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() {
// Type Statx doesn't have a packed layout in memory, fall back to MarshalBytes.
buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
s.MarshalBytes(buf) // escapes: fallback.
@@ -645,7 +645,7 @@ func (f *FUSEHeaderIn) MarshalUnsafe(dst []byte) {
// UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
func (f *FUSEHeaderIn) UnmarshalUnsafe(src []byte) {
- if f.Unique.Packed() && f.Opcode.Packed() {
+ if f.Opcode.Packed() && f.Unique.Packed() {
safecopy.CopyOut(unsafe.Pointer(f), src)
} else {
// Type FUSEHeaderIn doesn't have a packed layout in memory, fallback to UnmarshalBytes.
@@ -686,7 +686,7 @@ func (f *FUSEHeaderIn) CopyOut(task marshal.Task, addr usermem.Addr) (int, error
// CopyIn implements marshal.Marshallable.CopyIn.
//go:nosplit
func (f *FUSEHeaderIn) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
- if !f.Opcode.Packed() && f.Unique.Packed() {
+ if !f.Unique.Packed() && f.Opcode.Packed() {
// Type FUSEHeaderIn doesn't have a packed layout in memory, fall back to UnmarshalBytes.
buf := task.CopyScratchBuffer(f.SizeBytes()) // escapes: okay.
length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -2226,7 +2226,7 @@ func (i *IPTIP) MarshalUnsafe(dst []byte) {
// UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
func (i *IPTIP) UnmarshalUnsafe(src []byte) {
- if i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() {
+ if i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() {
safecopy.CopyOut(unsafe.Pointer(i), src)
} else {
// Type IPTIP doesn't have a packed layout in memory, fallback to UnmarshalBytes.
@@ -2267,7 +2267,7 @@ func (i *IPTIP) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
// CopyIn implements marshal.Marshallable.CopyIn.
//go:nosplit
func (i *IPTIP) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
- if !i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() {
+ if !i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() {
// Type IPTIP doesn't have a packed layout in memory, fall back to UnmarshalBytes.
buf := task.CopyScratchBuffer(i.SizeBytes()) // escapes: okay.
length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -2293,7 +2293,7 @@ func (i *IPTIP) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
// WriteTo implements io.WriterTo.WriteTo.
func (i *IPTIP) WriteTo(writer io.Writer) (int64, error) {
- if !i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() {
+ if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
// Type IPTIP doesn't have a packed layout in memory, fall back to MarshalBytes.
buf := make([]byte, i.SizeBytes())
i.MarshalBytes(buf)
@@ -3199,12 +3199,12 @@ func (i *IP6TIP) UnmarshalBytes(src []byte) {
// Packed implements marshal.Marshallable.Packed.
//go:nosplit
func (i *IP6TIP) Packed() bool {
- return i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed()
+ return i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed()
}
// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
func (i *IP6TIP) MarshalUnsafe(dst []byte) {
- if i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() {
+ if i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() {
safecopy.CopyIn(dst, unsafe.Pointer(i))
} else {
// Type IP6TIP doesn't have a packed layout in memory, fallback to MarshalBytes.
diff --git a/pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go b/pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go
index 4c8706edc..3826f6b95 100644
--- a/pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go
+++ b/pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go
@@ -293,7 +293,7 @@ func (s *Stat) Packed() bool {
// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
func (s *Stat) MarshalUnsafe(dst []byte) {
- if s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
+ if s.CTime.Packed() && s.ATime.Packed() && s.MTime.Packed() {
safecopy.CopyIn(dst, unsafe.Pointer(s))
} else {
// Type Stat doesn't have a packed layout in memory, fallback to MarshalBytes.
@@ -303,7 +303,7 @@ func (s *Stat) MarshalUnsafe(dst []byte) {
// UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
func (s *Stat) UnmarshalUnsafe(src []byte) {
- if s.MTime.Packed() && s.CTime.Packed() && s.ATime.Packed() {
+ if s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
safecopy.CopyOut(unsafe.Pointer(s), src)
} else {
// Type Stat doesn't have a packed layout in memory, fallback to UnmarshalBytes.
@@ -344,7 +344,7 @@ func (s *Stat) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
// CopyIn implements marshal.Marshallable.CopyIn.
//go:nosplit
func (s *Stat) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
- if !s.CTime.Packed() && s.ATime.Packed() && s.MTime.Packed() {
+ if !s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
// Type Stat doesn't have a packed layout in memory, fall back to UnmarshalBytes.
buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -370,7 +370,7 @@ func (s *Stat) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
// WriteTo implements io.WriterTo.WriteTo.
func (s *Stat) WriteTo(writer io.Writer) (int64, error) {
- if !s.CTime.Packed() && s.ATime.Packed() && s.MTime.Packed() {
+ if !s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
// Type Stat doesn't have a packed layout in memory, fall back to MarshalBytes.
buf := make([]byte, s.SizeBytes())
s.MarshalBytes(buf)
diff --git a/pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go b/pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go
index f74f9a6ab..4c0fb6baa 100644
--- a/pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go
+++ b/pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go
@@ -295,7 +295,7 @@ func (s *Stat) UnmarshalBytes(src []byte) {
// Packed implements marshal.Marshallable.Packed.
//go:nosplit
func (s *Stat) Packed() bool {
- return s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed()
+ return s.MTime.Packed() && s.CTime.Packed() && s.ATime.Packed()
}
// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
@@ -321,7 +321,7 @@ func (s *Stat) UnmarshalUnsafe(src []byte) {
// CopyOutN implements marshal.Marshallable.CopyOutN.
//go:nosplit
func (s *Stat) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
- if !s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
+ if !s.CTime.Packed() && s.ATime.Packed() && s.MTime.Packed() {
// Type Stat doesn't have a packed layout in memory, fall back to MarshalBytes.
buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
s.MarshalBytes(buf) // escapes: fallback.
@@ -351,7 +351,7 @@ func (s *Stat) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
// CopyIn implements marshal.Marshallable.CopyIn.
//go:nosplit
func (s *Stat) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
- if !s.CTime.Packed() && s.ATime.Packed() && s.MTime.Packed() {
+ if !s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
// Type Stat doesn't have a packed layout in memory, fall back to UnmarshalBytes.
buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -377,7 +377,7 @@ func (s *Stat) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
// WriteTo implements io.WriterTo.WriteTo.
func (s *Stat) WriteTo(writer io.Writer) (int64, error) {
- if !s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
+ if !s.MTime.Packed() && s.CTime.Packed() && s.ATime.Packed() {
// Type Stat doesn't have a packed layout in memory, fall back to MarshalBytes.
buf := make([]byte, s.SizeBytes())
s.MarshalBytes(buf)
diff --git a/pkg/abi/linux/seccomp.go b/pkg/abi/linux/seccomp.go
index d0607e256..b07cafe12 100644
--- a/pkg/abi/linux/seccomp.go
+++ b/pkg/abi/linux/seccomp.go
@@ -34,11 +34,11 @@ type BPFAction uint32
const (
SECCOMP_RET_KILL_PROCESS BPFAction = 0x80000000
- SECCOMP_RET_KILL_THREAD = 0x00000000
- SECCOMP_RET_TRAP = 0x00030000
- SECCOMP_RET_ERRNO = 0x00050000
- SECCOMP_RET_TRACE = 0x7ff00000
- SECCOMP_RET_ALLOW = 0x7fff0000
+ SECCOMP_RET_KILL_THREAD BPFAction = 0x00000000
+ SECCOMP_RET_TRAP BPFAction = 0x00030000
+ SECCOMP_RET_ERRNO BPFAction = 0x00050000
+ SECCOMP_RET_TRACE BPFAction = 0x7ff00000
+ SECCOMP_RET_ALLOW BPFAction = 0x7fff0000
)
func (a BPFAction) String() string {
@@ -64,6 +64,19 @@ func (a BPFAction) Data() uint16 {
return uint16(a & SECCOMP_RET_DATA)
}
+// WithReturnCode sets the lower 16 bits of the SECCOMP_RET_ERRNO or
+// SECCOMP_RET_TRACE actions to the provided return code, overwriting the previous
+// action, and returns a new BPFAction. If not SECCOMP_RET_ERRNO or
+// SECCOMP_RET_TRACE then this panics.
+func (a BPFAction) WithReturnCode(code uint16) BPFAction {
+ // mask out the previous return value
+ baseAction := a & SECCOMP_RET_ACTION_FULL
+ if baseAction == SECCOMP_RET_ERRNO || baseAction == SECCOMP_RET_TRACE {
+ return BPFAction(uint32(baseAction) | uint32(code))
+ }
+ panic("WithReturnCode only valid for SECCOMP_RET_ERRNO and SECCOMP_RET_TRACE")
+}
+
// SockFprog is sock_fprog taken from <linux/filter.h>.
type SockFprog struct {
Len uint16
diff --git a/pkg/bpf/decoder.go b/pkg/bpf/decoder.go
index c8ee0c3b1..069d0395d 100644
--- a/pkg/bpf/decoder.go
+++ b/pkg/bpf/decoder.go
@@ -21,10 +21,15 @@ import (
"gvisor.dev/gvisor/pkg/abi/linux"
)
-// DecodeProgram translates an array of BPF instructions into text format.
-func DecodeProgram(program []linux.BPFInstruction) (string, error) {
+// DecodeProgram translates a compiled BPF program into text format.
+func DecodeProgram(p Program) (string, error) {
+ return DecodeInstructions(p.instructions)
+}
+
+// DecodeInstructions translates an array of BPF instructions into text format.
+func DecodeInstructions(instns []linux.BPFInstruction) (string, error) {
var ret bytes.Buffer
- for line, s := range program {
+ for line, s := range instns {
ret.WriteString(fmt.Sprintf("%v: ", line))
if err := decode(s, line, &ret); err != nil {
return "", err
@@ -34,7 +39,7 @@ func DecodeProgram(program []linux.BPFInstruction) (string, error) {
return ret.String(), nil
}
-// Decode translates BPF instruction into text format.
+// Decode translates a single BPF instruction into text format.
func Decode(inst linux.BPFInstruction) (string, error) {
var ret bytes.Buffer
err := decode(inst, -1, &ret)
diff --git a/pkg/bpf/program_builder.go b/pkg/bpf/program_builder.go
index 7992044d0..caaf99c83 100644
--- a/pkg/bpf/program_builder.go
+++ b/pkg/bpf/program_builder.go
@@ -32,13 +32,21 @@ type ProgramBuilder struct {
// Maps label names to label objects.
labels map[string]*label
+ // unusableLabels are labels that are added before being referenced in a
+ // jump. Any labels added this way cannot be referenced later in order to
+ // avoid backwards references.
+ unusableLabels map[string]bool
+
// Array of BPF instructions that makes up the program.
instructions []linux.BPFInstruction
}
// NewProgramBuilder creates a new ProgramBuilder instance.
func NewProgramBuilder() *ProgramBuilder {
- return &ProgramBuilder{labels: map[string]*label{}}
+ return &ProgramBuilder{
+ labels: map[string]*label{},
+ unusableLabels: map[string]bool{},
+ }
}
// label contains information to resolve a label to an offset.
@@ -108,9 +116,12 @@ func (b *ProgramBuilder) AddJumpLabels(code uint16, k uint32, jtLabel, jfLabel s
func (b *ProgramBuilder) AddLabel(name string) error {
l, ok := b.labels[name]
if !ok {
- // This is done to catch jump backwards cases, but it's not strictly wrong
- // to have unused labels.
- return fmt.Errorf("Adding a label that hasn't been used is not allowed: %v", name)
+ if _, ok = b.unusableLabels[name]; ok {
+ return fmt.Errorf("label %q already set", name)
+ }
+ // Mark the label as unusable. This is done to catch backwards jumps.
+ b.unusableLabels[name] = true
+ return nil
}
if l.target != -1 {
return fmt.Errorf("label %q target already set: %v", name, l.target)
@@ -141,6 +152,10 @@ func (b *ProgramBuilder) addLabelSource(labelName string, t jmpType) {
func (b *ProgramBuilder) resolveLabels() error {
for key, v := range b.labels {
+ if _, ok := b.unusableLabels[key]; ok {
+ return fmt.Errorf("backwards reference detected for label: %q", key)
+ }
+
if v.target == -1 {
return fmt.Errorf("label target not set: %v", key)
}
diff --git a/pkg/seccomp/seccomp.go b/pkg/seccomp/seccomp.go
index 55fd6967e..752e2dc32 100644
--- a/pkg/seccomp/seccomp.go
+++ b/pkg/seccomp/seccomp.go
@@ -12,7 +12,8 @@
// See the License for the specific language governing permissions and
// limitations under the License.
-// Package seccomp provides basic seccomp filters for x86_64 (little endian).
+// Package seccomp provides generation of basic seccomp filters. Currently,
+// only little endian systems are supported.
package seccomp
import (
@@ -64,9 +65,9 @@ func Install(rules SyscallRules) error {
Rules: rules,
Action: linux.SECCOMP_RET_ALLOW,
},
- }, defaultAction)
+ }, defaultAction, defaultAction)
if log.IsLogging(log.Debug) {
- programStr, errDecode := bpf.DecodeProgram(instrs)
+ programStr, errDecode := bpf.DecodeInstructions(instrs)
if errDecode != nil {
programStr = fmt.Sprintf("Error: %v\n%s", errDecode, programStr)
}
@@ -117,7 +118,7 @@ var SyscallName = func(sysno uintptr) string {
// BuildProgram builds a BPF program from the given map of actions to matching
// SyscallRules. The single generated program covers all provided RuleSets.
-func BuildProgram(rules []RuleSet, defaultAction linux.BPFAction) ([]linux.BPFInstruction, error) {
+func BuildProgram(rules []RuleSet, defaultAction, badArchAction linux.BPFAction) ([]linux.BPFInstruction, error) {
program := bpf.NewProgramBuilder()
// Be paranoid and check that syscall is done in the expected architecture.
@@ -128,7 +129,7 @@ func BuildProgram(rules []RuleSet, defaultAction linux.BPFAction) ([]linux.BPFIn
// defaultLabel is at the bottom of the program. The size of program
// may exceeds 255 lines, which is the limit of a condition jump.
program.AddJump(bpf.Jmp|bpf.Jeq|bpf.K, LINUX_AUDIT_ARCH, skipOneInst, 0)
- program.AddDirectJumpLabel(defaultLabel)
+ program.AddStmt(bpf.Ret|bpf.K, uint32(badArchAction))
if err := buildIndex(rules, program); err != nil {
return nil, err
}
@@ -144,6 +145,11 @@ func BuildProgram(rules []RuleSet, defaultAction linux.BPFAction) ([]linux.BPFIn
// buildIndex builds a BST to quickly search through all syscalls.
func buildIndex(rules []RuleSet, program *bpf.ProgramBuilder) error {
+ // Do nothing if rules is empty.
+ if len(rules) == 0 {
+ return nil
+ }
+
// Build a list of all application system calls, across all given rule
// sets. We have a simple BST, but may dispatch individual matchers
// with different actions. The matchers are evaluated linearly.
@@ -216,42 +222,163 @@ func addSyscallArgsCheck(p *bpf.ProgramBuilder, rules []Rule, action linux.BPFAc
labelled := false
for i, arg := range rule {
if arg != nil {
+ // Break out early if using MatchAny since no further
+ // instructions are required.
+ if _, ok := arg.(MatchAny); ok {
+ continue
+ }
+
+ // Determine the data offset for low and high bits of input.
+ dataOffsetLow := seccompDataOffsetArgLow(i)
+ dataOffsetHigh := seccompDataOffsetArgHigh(i)
+ if i == RuleIP {
+ dataOffsetLow = seccompDataOffsetIPLow
+ dataOffsetHigh = seccompDataOffsetIPHigh
+ }
+
+ // Add the conditional operation. Input values to the BPF
+ // program are 64bit values. However, comparisons in BPF can
+ // only be done on 32bit values. This means that we need to do
+ // multiple BPF comparisons in order to do one logical 64bit
+ // comparison.
switch a := arg.(type) {
- case AllowAny:
- case AllowValue:
- dataOffsetLow := seccompDataOffsetArgLow(i)
- dataOffsetHigh := seccompDataOffsetArgHigh(i)
- if i == RuleIP {
- dataOffsetLow = seccompDataOffsetIPLow
- dataOffsetHigh = seccompDataOffsetIPHigh
- }
+ case EqualTo:
+ // EqualTo checks that both the higher and lower 32bits are equal.
high, low := uint32(a>>32), uint32(a)
- // assert arg_low == low
+
+ // Assert that the lower 32bits are equal.
+ // arg_low == low ? continue : violation
p.AddStmt(bpf.Ld|bpf.Abs|bpf.W, dataOffsetLow)
p.AddJumpFalseLabel(bpf.Jmp|bpf.Jeq|bpf.K, low, 0, ruleViolationLabel(ruleSetIdx, sysno, ruleidx))
- // assert arg_high == high
+
+ // Assert that the lower 32bits are also equal.
+ // arg_high == high ? continue/success : violation
p.AddStmt(bpf.Ld|bpf.Abs|bpf.W, dataOffsetHigh)
p.AddJumpFalseLabel(bpf.Jmp|bpf.Jeq|bpf.K, high, 0, ruleViolationLabel(ruleSetIdx, sysno, ruleidx))
labelled = true
+ case NotEqual:
+ // NotEqual checks that either the higher or lower 32bits
+ // are *not* equal.
+ high, low := uint32(a>>32), uint32(a)
+ labelGood := fmt.Sprintf("ne%v", i)
+
+ // Check if the higher 32bits are (not) equal.
+ // arg_low == low ? continue : success
+ p.AddStmt(bpf.Ld|bpf.Abs|bpf.W, dataOffsetLow)
+ p.AddJumpFalseLabel(bpf.Jmp|bpf.Jeq|bpf.K, low, 0, ruleLabel(ruleSetIdx, sysno, ruleidx, labelGood))
+
+ // Assert that the lower 32bits are not equal (assuming
+ // higher bits are equal).
+ // arg_high == high ? violation : continue/success
+ p.AddStmt(bpf.Ld|bpf.Abs|bpf.W, dataOffsetHigh)
+ p.AddJumpTrueLabel(bpf.Jmp|bpf.Jeq|bpf.K, high, ruleViolationLabel(ruleSetIdx, sysno, ruleidx), 0)
+ p.AddLabel(ruleLabel(ruleSetIdx, sysno, ruleidx, labelGood))
+ labelled = true
case GreaterThan:
- dataOffsetLow := seccompDataOffsetArgLow(i)
- dataOffsetHigh := seccompDataOffsetArgHigh(i)
- if i == RuleIP {
- dataOffsetLow = seccompDataOffsetIPLow
- dataOffsetHigh = seccompDataOffsetIPHigh
- }
- labelGood := fmt.Sprintf("gt%v", i)
+ // GreaterThan checks that the higher 32bits is greater
+ // *or* that the higher 32bits are equal and the lower
+ // 32bits are greater.
high, low := uint32(a>>32), uint32(a)
- // assert arg_high < high
+ labelGood := fmt.Sprintf("gt%v", i)
+
+ // Assert the higher 32bits are greater than or equal.
+ // arg_high >= high ? continue : violation (arg_high < high)
p.AddStmt(bpf.Ld|bpf.Abs|bpf.W, dataOffsetHigh)
p.AddJumpFalseLabel(bpf.Jmp|bpf.Jge|bpf.K, high, 0, ruleViolationLabel(ruleSetIdx, sysno, ruleidx))
- // arg_high > high
+
+ // Assert that the lower 32bits are greater.
+ // arg_high == high ? continue : success (arg_high > high)
p.AddJumpFalseLabel(bpf.Jmp|bpf.Jeq|bpf.K, high, 0, ruleLabel(ruleSetIdx, sysno, ruleidx, labelGood))
- // arg_low < low
+ // arg_low > low ? continue/success : violation (arg_high == high and arg_low <= low)
p.AddStmt(bpf.Ld|bpf.Abs|bpf.W, dataOffsetLow)
p.AddJumpFalseLabel(bpf.Jmp|bpf.Jgt|bpf.K, low, 0, ruleViolationLabel(ruleSetIdx, sysno, ruleidx))
p.AddLabel(ruleLabel(ruleSetIdx, sysno, ruleidx, labelGood))
labelled = true
+ case GreaterThanOrEqual:
+ // GreaterThanOrEqual checks that the higher 32bits is
+ // greater *or* that the higher 32bits are equal and the
+ // lower 32bits are greater than or equal.
+ high, low := uint32(a>>32), uint32(a)
+ labelGood := fmt.Sprintf("ge%v", i)
+
+ // Assert the higher 32bits are greater than or equal.
+ // arg_high >= high ? continue : violation (arg_high < high)
+ p.AddStmt(bpf.Ld|bpf.Abs|bpf.W, dataOffsetHigh)
+ p.AddJumpFalseLabel(bpf.Jmp|bpf.Jge|bpf.K, high, 0, ruleViolationLabel(ruleSetIdx, sysno, ruleidx))
+ // arg_high == high ? continue : success (arg_high > high)
+ p.AddJumpFalseLabel(bpf.Jmp|bpf.Jeq|bpf.K, high, 0, ruleLabel(ruleSetIdx, sysno, ruleidx, labelGood))
+
+ // Assert that the lower 32bits are greater (assuming the
+ // higher bits are equal).
+ // arg_low >= low ? continue/success : violation (arg_high == high and arg_low < low)
+ p.AddStmt(bpf.Ld|bpf.Abs|bpf.W, dataOffsetLow)
+ p.AddJumpFalseLabel(bpf.Jmp|bpf.Jge|bpf.K, low, 0, ruleViolationLabel(ruleSetIdx, sysno, ruleidx))
+ p.AddLabel(ruleLabel(ruleSetIdx, sysno, ruleidx, labelGood))
+ labelled = true
+ case LessThan:
+ // LessThan checks that the higher 32bits is less *or* that
+ // the higher 32bits are equal and the lower 32bits are
+ // less.
+ high, low := uint32(a>>32), uint32(a)
+ labelGood := fmt.Sprintf("lt%v", i)
+
+ // Assert the higher 32bits are less than or equal.
+ // arg_high > high ? violation : continue
+ p.AddStmt(bpf.Ld|bpf.Abs|bpf.W, dataOffsetHigh)
+ p.AddJumpTrueLabel(bpf.Jmp|bpf.Jgt|bpf.K, high, ruleViolationLabel(ruleSetIdx, sysno, ruleidx), 0)
+ // arg_high == high ? continue : success (arg_high < high)
+ p.AddJumpFalseLabel(bpf.Jmp|bpf.Jeq|bpf.K, high, 0, ruleLabel(ruleSetIdx, sysno, ruleidx, labelGood))
+
+ // Assert that the lower 32bits are less (assuming the
+ // higher bits are equal).
+ // arg_low >= low ? violation : continue
+ p.AddStmt(bpf.Ld|bpf.Abs|bpf.W, dataOffsetLow)
+ p.AddJumpTrueLabel(bpf.Jmp|bpf.Jge|bpf.K, low, ruleViolationLabel(ruleSetIdx, sysno, ruleidx), 0)
+ p.AddLabel(ruleLabel(ruleSetIdx, sysno, ruleidx, labelGood))
+ labelled = true
+ case LessThanOrEqual:
+ // LessThan checks that the higher 32bits is less *or* that
+ // the higher 32bits are equal and the lower 32bits are
+ // less than or equal.
+ high, low := uint32(a>>32), uint32(a)
+ labelGood := fmt.Sprintf("le%v", i)
+
+ // Assert the higher 32bits are less than or equal.
+ // assert arg_high > high ? violation : continue
+ p.AddStmt(bpf.Ld|bpf.Abs|bpf.W, dataOffsetHigh)
+ p.AddJumpTrueLabel(bpf.Jmp|bpf.Jgt|bpf.K, high, ruleViolationLabel(ruleSetIdx, sysno, ruleidx), 0)
+ // arg_high == high ? continue : success
+ p.AddJumpFalseLabel(bpf.Jmp|bpf.Jeq|bpf.K, high, 0, ruleLabel(ruleSetIdx, sysno, ruleidx, labelGood))
+
+ // Assert the lower bits are less than or equal (assuming
+ // the higher bits are equal).
+ // arg_low > low ? violation : success
+ p.AddStmt(bpf.Ld|bpf.Abs|bpf.W, dataOffsetLow)
+ p.AddJumpTrueLabel(bpf.Jmp|bpf.Jgt|bpf.K, low, ruleViolationLabel(ruleSetIdx, sysno, ruleidx), 0)
+ p.AddLabel(ruleLabel(ruleSetIdx, sysno, ruleidx, labelGood))
+ labelled = true
+ case maskedEqual:
+ // MaskedEqual checks that the bitwise AND of the value and
+ // mask are equal for both the higher and lower 32bits.
+ high, low := uint32(a.value>>32), uint32(a.value)
+ maskHigh, maskLow := uint32(a.mask>>32), uint32(a.mask)
+
+ // Assert that the lower 32bits are equal when masked.
+ // A <- arg_low.
+ p.AddStmt(bpf.Ld|bpf.Abs|bpf.W, dataOffsetLow)
+ // A <- arg_low & maskLow
+ p.AddStmt(bpf.Alu|bpf.And|bpf.K, maskLow)
+ // Assert that arg_low & maskLow == low.
+ p.AddJumpFalseLabel(bpf.Jmp|bpf.Jeq|bpf.K, low, 0, ruleViolationLabel(ruleSetIdx, sysno, ruleidx))
+
+ // Assert that the higher 32bits are equal when masked.
+ // A <- arg_high
+ p.AddStmt(bpf.Ld|bpf.Abs|bpf.W, dataOffsetHigh)
+ // A <- arg_high & maskHigh
+ p.AddStmt(bpf.Alu|bpf.And|bpf.K, maskHigh)
+ // Assert that arg_high & maskHigh == high.
+ p.AddJumpFalseLabel(bpf.Jmp|bpf.Jeq|bpf.K, high, 0, ruleViolationLabel(ruleSetIdx, sysno, ruleidx))
+ labelled = true
default:
return fmt.Errorf("unknown syscall rule type: %v", reflect.TypeOf(a))
}
diff --git a/pkg/seccomp/seccomp_rules.go b/pkg/seccomp/seccomp_rules.go
index a52dc1b4e..daf165bbf 100644
--- a/pkg/seccomp/seccomp_rules.go
+++ b/pkg/seccomp/seccomp_rules.go
@@ -39,28 +39,79 @@ func seccompDataOffsetArgHigh(i int) uint32 {
return seccompDataOffsetArgLow(i) + 4
}
-// AllowAny is marker to indicate any value will be accepted.
-type AllowAny struct{}
+// MatchAny is marker to indicate any value will be accepted.
+type MatchAny struct{}
-func (a AllowAny) String() (s string) {
+func (a MatchAny) String() (s string) {
return "*"
}
-// AllowValue specifies a value that needs to be strictly matched.
-type AllowValue uintptr
+// EqualTo specifies a value that needs to be strictly matched.
+type EqualTo uintptr
+
+func (a EqualTo) String() (s string) {
+ return fmt.Sprintf("== %#x", uintptr(a))
+}
+
+// NotEqual specifies a value that is strictly not equal.
+type NotEqual uintptr
+
+func (a NotEqual) String() (s string) {
+ return fmt.Sprintf("!= %#x", uintptr(a))
+}
// GreaterThan specifies a value that needs to be strictly smaller.
type GreaterThan uintptr
-func (a AllowValue) String() (s string) {
- return fmt.Sprintf("%#x ", uintptr(a))
+func (a GreaterThan) String() (s string) {
+ return fmt.Sprintf("> %#x", uintptr(a))
+}
+
+// GreaterThanOrEqual specifies a value that needs to be smaller or equal.
+type GreaterThanOrEqual uintptr
+
+func (a GreaterThanOrEqual) String() (s string) {
+ return fmt.Sprintf(">= %#x", uintptr(a))
+}
+
+// LessThan specifies a value that needs to be strictly greater.
+type LessThan uintptr
+
+func (a LessThan) String() (s string) {
+ return fmt.Sprintf("< %#x", uintptr(a))
+}
+
+// LessThanOrEqual specifies a value that needs to be greater or equal.
+type LessThanOrEqual uintptr
+
+func (a LessThanOrEqual) String() (s string) {
+ return fmt.Sprintf("<= %#x", uintptr(a))
+}
+
+type maskedEqual struct {
+ mask uintptr
+ value uintptr
+}
+
+func (a maskedEqual) String() (s string) {
+ return fmt.Sprintf("& %#x == %#x", a.mask, a.value)
+}
+
+// MaskedEqual specifies a value that matches the input after the input is
+// masked (bitwise &) against the given mask. Can be used to verify that input
+// only includes certain approved flags.
+func MaskedEqual(mask, value uintptr) interface{} {
+ return maskedEqual{
+ mask: mask,
+ value: value,
+ }
}
// Rule stores the allowed syscall arguments.
//
// For example:
// rule := Rule {
-// AllowValue(linux.ARCH_GET_FS | linux.ARCH_SET_FS), // arg0
+// EqualTo(linux.ARCH_GET_FS | linux.ARCH_SET_FS), // arg0
// }
type Rule [7]interface{} // 6 arguments + RIP
@@ -89,12 +140,12 @@ func (r Rule) String() (s string) {
// rules := SyscallRules{
// syscall.SYS_FUTEX: []Rule{
// {
-// AllowAny{},
-// AllowValue(linux.FUTEX_WAIT | linux.FUTEX_PRIVATE_FLAG),
+// MatchAny{},
+// EqualTo(linux.FUTEX_WAIT | linux.FUTEX_PRIVATE_FLAG),
// }, // OR
// {
-// AllowAny{},
-// AllowValue(linux.FUTEX_WAKE | linux.FUTEX_PRIVATE_FLAG),
+// MatchAny{},
+// EqualTo(linux.FUTEX_WAKE | linux.FUTEX_PRIVATE_FLAG),
// },
// },
// syscall.SYS_GETPID: []Rule{},
diff --git a/pkg/sentry/kernel/syscalls.go b/pkg/sentry/kernel/syscalls.go
index 413111faf..332bdb8e8 100644
--- a/pkg/sentry/kernel/syscalls.go
+++ b/pkg/sentry/kernel/syscalls.go
@@ -348,6 +348,16 @@ func (s *SyscallTable) LookupName(sysno uintptr) string {
return fmt.Sprintf("sys_%d", sysno) // Unlikely.
}
+// LookupNo looks up a syscall number by name.
+func (s *SyscallTable) LookupNo(name string) (uintptr, error) {
+ for i, syscall := range s.Table {
+ if syscall.Name == name {
+ return uintptr(i), nil
+ }
+ }
+ return 0, fmt.Errorf("syscall %q not found", name)
+}
+
// LookupEmulate looks up an emulation syscall number.
func (s *SyscallTable) LookupEmulate(addr usermem.Addr) (uintptr, bool) {
sysno, ok := s.Emulate[addr]
diff --git a/pkg/sentry/platform/ptrace/subprocess_amd64.go b/pkg/sentry/platform/ptrace/subprocess_amd64.go
index 84b699f0d..020bbda79 100644
--- a/pkg/sentry/platform/ptrace/subprocess_amd64.go
+++ b/pkg/sentry/platform/ptrace/subprocess_amd64.go
@@ -201,7 +201,7 @@ func appendArchSeccompRules(rules []seccomp.RuleSet, defaultAction linux.BPFActi
seccomp.RuleSet{
Rules: seccomp.SyscallRules{
syscall.SYS_ARCH_PRCTL: []seccomp.Rule{
- {seccomp.AllowValue(linux.ARCH_SET_CPUID), seccomp.AllowValue(0)},
+ {seccomp.EqualTo(linux.ARCH_SET_CPUID), seccomp.EqualTo(0)},
},
},
Action: linux.SECCOMP_RET_ALLOW,
diff --git a/pkg/sentry/platform/ptrace/subprocess_linux.go b/pkg/sentry/platform/ptrace/subprocess_linux.go
index 2ce528601..8548853da 100644
--- a/pkg/sentry/platform/ptrace/subprocess_linux.go
+++ b/pkg/sentry/platform/ptrace/subprocess_linux.go
@@ -80,9 +80,9 @@ func attachedThread(flags uintptr, defaultAction linux.BPFAction) (*thread, erro
Rules: seccomp.SyscallRules{
syscall.SYS_CLONE: []seccomp.Rule{
// Allow creation of new subprocesses (used by the master).
- {seccomp.AllowValue(syscall.CLONE_FILES | syscall.SIGKILL)},
+ {seccomp.EqualTo(syscall.CLONE_FILES | syscall.SIGKILL)},
// Allow creation of new threads within a single address space (used by addresss spaces).
- {seccomp.AllowValue(
+ {seccomp.EqualTo(
syscall.CLONE_FILES |
syscall.CLONE_FS |
syscall.CLONE_SIGHAND |
@@ -97,14 +97,14 @@ func attachedThread(flags uintptr, defaultAction linux.BPFAction) (*thread, erro
// For the stub prctl dance (all).
syscall.SYS_PRCTL: []seccomp.Rule{
- {seccomp.AllowValue(syscall.PR_SET_PDEATHSIG), seccomp.AllowValue(syscall.SIGKILL)},
+ {seccomp.EqualTo(syscall.PR_SET_PDEATHSIG), seccomp.EqualTo(syscall.SIGKILL)},
},
syscall.SYS_GETPPID: {},
// For the stub to stop itself (all).
syscall.SYS_GETPID: {},
syscall.SYS_KILL: []seccomp.Rule{
- {seccomp.AllowAny{}, seccomp.AllowValue(syscall.SIGSTOP)},
+ {seccomp.MatchAny{}, seccomp.EqualTo(syscall.SIGSTOP)},
},
// Injected to support the address space operations.
@@ -115,7 +115,7 @@ func attachedThread(flags uintptr, defaultAction linux.BPFAction) (*thread, erro
})
}
rules = appendArchSeccompRules(rules, defaultAction)
- instrs, err := seccomp.BuildProgram(rules, defaultAction)
+ instrs, err := seccomp.BuildProgram(rules, defaultAction, defaultAction)
if err != nil {
return nil, err
}
diff --git a/pkg/sentry/platform/ring0/defs_impl_arm64.go b/pkg/sentry/platform/ring0/defs_impl_arm64.go
index 8ebfbfdb6..9fb351879 100644
--- a/pkg/sentry/platform/ring0/defs_impl_arm64.go
+++ b/pkg/sentry/platform/ring0/defs_impl_arm64.go
@@ -1,10 +1,9 @@
package ring0
import (
- "gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
-
"fmt"
"gvisor.dev/gvisor/pkg/sentry/arch"
+ "gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
"gvisor.dev/gvisor/pkg/usermem"
"io"
"reflect"