verifierlog

package
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 Go to latest Published: Jun 16, 2022 License: MIT Imports: 9 Imported by: 0

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Index

Constants

View Source 
const (
	StackSlotInvalid = '?'
	StackSlotSpill   = 'r'
	StackSlotMist    = 'm'
	StackSlotZero    = '0'
)

Variables

This section is empty.

Functions

This section is empty.

Types

type BackTrackInstruction 

type BackTrackInstruction struct {
	Regs        []byte
	Stack       int64
	Instruction *Instruction
}

BackTrackInstruction indicates the verifier has back tracked an instruction. Example: "regs=4 stack=0 before 25: (bf) r1 = r0"

func (*BackTrackInstruction) String 

func (bt *BackTrackInstruction) String() string

type BackTrackingHeader 

type BackTrackingHeader struct {
	Last  int
	First int
}

BackTrackingHeader indicates that the verifier is back tracking, and is followed by BackTrackInstruction and BackTrackingTrailer statements. Example: "last_idx 26 first_idx 20"

func (*BackTrackingHeader) String 

func (bt *BackTrackingHeader) String() string

type BackTrackingTrailer 

type BackTrackingTrailer struct {
	ParentMatch   bool
	Regs          []byte
	Stack         int64
	VerifierState *VerifierState
}

BackTrackingTrailer indicates the verifier is done backtracking. Example: `parent didn't have regs=4 stack=0 marks` or `parent already had regs=2a stack=0 marks`

func (*BackTrackingTrailer) String 

func (bt *BackTrackingTrailer) String() string

type BranchEvaluation 

type BranchEvaluation struct {
	From  int
	To    int
	State *VerifierState
}

BranchEvaluation means that the verifier switch state and is now evaluating another permutation. Example: "from 84 to 40: frame1: R0=invP(id=0) R6=pkt(id=0,off=38,r=38,imm=0) R7=pkt(id=0,off=0,r=38,imm=0) R8=invP18 R9=invP(id=2,umax_value=255,var_off=(0x0; 0xff)) R10=fp0 fp-8=pkt_end fp-16=mmmmmmmm"

func (*BranchEvaluation) String 

func (be *BranchEvaluation) String() string

type Comment 

type Comment struct {
	Comment string
}

A comment, usually contains the original line of the source code Example: "; if (data + nh_off > data_end)"

func (*Comment) String 

func (c *Comment) String() string

type Error 

type Error struct {
	Msg string
}

An error, something went wrong

func (*Error) Error 

func (e *Error) Error() string

func (*Error) String 

func (e *Error) String() string

type FunctionCall 

type FunctionCall struct {
	CallerState *VerifierState
	CalleeState *VerifierState
}

FunctionCall indicates the verifier is following a bpf-to-bpf function call. For example: caller: 

 frame1: R6=pkt(id=0,off=54,r=74,imm=0) R7=pkt(id=0,off=0,r=74,imm=0) R8_w=pkt(id=0,off=74,r=74,imm=0) R9=invP6 R10=fp0 fp-8=pkt_end fp-16=mmmmmmmm
callee:
 frame2: R1_w=pkt(id=0,off=54,r=74,imm=0) R2_w=invP(id=0) R10=fp0

func (*FunctionCall) String 

func (fc *FunctionCall) String() string

type Instruction 

type Instruction struct {
	InstructionNumber int
	Opcode            asm.OpCode
	Assembly          string
}

Instruction describes an instruction, is used by multiple statements. Example: "22: (85) call pc+4"

func (*Instruction) String 

func (is *Instruction) String() string

type InstructionState 

type InstructionState struct {
	Instruction
	State VerifierState
}

Instruction and verifier state. Logged when the verifier evaluates an instruction. The state is the state after the instruction was evaluated. Example: "0: (b7) r6 = 1; R6_w=invP1"

func (*InstructionState) String 

func (is *InstructionState) String() string

type Liveness 

type Liveness int

Liveness indicates the liveness of a register. 

const (
	LivenessNone Liveness = iota
	LivenessRead
	LivenessWritten
	LivenessDone
)

type PropagatePrecision 

type PropagatePrecision struct {
	Register *asm.Register
	Offset   int
}

PropagatePrecision indicates that the verifier is propagating the precision of a register or stack slot to another state. Example: "propagating r6"

func (*PropagatePrecision) String 

func (pp *PropagatePrecision) String() string

type RecapState 

type RecapState struct {
	InstructionNumber int
	State             VerifierState
}

A recap of the current state of the verifier and its location, without indicating it evaluated an expression. This happens when the verifier switches state to evaluate another permutation. Example: "0: R1=ctx(id=0,off=0,imm=0) R10=fp0"

func (*RecapState) String 

func (is *RecapState) String() string

type RegType 

type RegType int

RegType indicates the data type contained in a register 

const (
	RegTypeNotInit RegType = iota
	RegTypeScalarValue
	RegTypePtrToCtx
	RegTypeConstPtrToMap
	RegTypeMapValue
	RegTypePtrToStack
	RegTypePtrToPacket
	RegTypePtrToPacketMeta
	RegTypePtrToPacketEnd
	RegTypePtrToFlowKeys
	RegTypePtrToSock
	RegTypePtrToSockCommon
	RegTypePtrToTCPSock
	RegTypePtrToTPBuf
	RegTypePtrToXDPSock
	RegTypePtrToBTFID
	RegTypePtrToMem
	RegTypePtrToBuf
	RegTypePtrToFunc
	RegTypePtrToMapKey
)
const (
	RegTypeBaseType RegType = 0xFF

	RegTypePtrMaybeNull RegType = 1 << (8 + iota)
	RegTypeMemReadonly
	RegTypeMemAlloc
	RegTypeMemUser
	RegTypeMemPreCPU
)

func (RegType) String 

func (rt RegType) String() string

type RegisterState 

type RegisterState struct {
	Register asm.Register
	Liveness Liveness
	Value    RegisterValue
}

RegisterState describes a single register and its state. Example: "R1_w=invP(id=2,umax_value=255,var_off=(0x0; 0xff))"

func (RegisterState) String 

func (r RegisterState) String() string

type RegisterValue 

type RegisterValue struct {
	Type      RegType
	Off       int32
	ID        int
	RefObjID  int
	Range     int
	KeySize   int
	ValueSize int
	// if (!precise && SCALAR_VALUE) min/max/tnum don't affect safety
	Precise bool
	/* For scalar types (SCALAR_VALUE), this represents our knowledge of
	 * the actual value.
	 * For pointer types, this represents the variable part of the offset
	 * from the pointed-to object, and is shared with all bpf_reg_states
	 * with the same id as us.
	 */
	VarOff TNum
	/* Used to determine if any memory access using this register will
	 * result in a bad access.
	 * These refer to the same value as var_off, not necessarily the actual
	 * contents of the register.
	 */
	SMinValue   int64  /* minimum possible (s64)value */
	SMaxValue   int64  /* maximum possible (s64)value */
	UMinValue   uint64 /* minimum possible (u64)value */
	UMaxValue   uint64 /* maximum possible (u64)value */
	S32MinValue int32  /* minimum possible (s32)value */
	S32MaxValue int32  /* maximum possible (s32)value */
	U32MinValue uint32 /* minimum possible (u32)value */
	U32MaxValue uint32 /* maximum possible (u32)value */

	BTFName string
}

RegisterValue is the value part of the register state, the part after the = Example: "invP(id=2,umax_value=255,var_off=(0x0; 0xff))"

func (RegisterValue) String 

func (rv RegisterValue) String() string

type ReturnFunctionCall 

type ReturnFunctionCall struct {
	CallerState *VerifierState
	CallSite    int
	CalleeState *VerifierState
}

ReturnFunctionCall indicates the verifier is evaluating returning from a function call. Example: returning from callee: 

frame2: R0=map_value(id=0,off=0,ks=1,vs=16,imm=0) R1_w=invP(id=0) R6=invP(id=31) R10=fp0 fp-8=m???????

to caller at 156: 

frame1: R0=map_value(id=0,off=0,ks=1,vs=16,imm=0) R6=pkt(id=0,off=54,r=54,imm=0) R7=pkt(id=0,off=0,r=54,imm=0) R8=invP14 R9=invP(id=30,umax_value=255,var_off=(0x0; 0xff)) R10=fp0 fp-8=pkt_end fp-16=mmmmmmmm

func (*ReturnFunctionCall) String 

func (rfc *ReturnFunctionCall) String() string

type StackSlot 

type StackSlot byte

StackSlot describes the contents of a single byte within a stack slot

type StackState 

type StackState struct {
	Offset            int
	Liveness          Liveness
	SpilledRegister   RegisterValue
	Slots             [8]StackSlot
	AcquiredRefs      []string
	InCallbackFn      bool
	InAsyncCallbackFn bool
}

StackState describes the state of a single stack slot. Example: `fp-8=m???????`

func (*StackState) String 

func (ss *StackState) String() string

type StatePruned 

type StatePruned struct {
	From int
	To   int
}

StatePruned means that the verifier considers a specific permutation to be safe and will prune the state from memory. Example: "25: safe" or "from 42 to 57: safe"

func (*StatePruned) String 

func (sp *StatePruned) String() string

type SubProgLocation 

type SubProgLocation struct {
	ProgID           int
	StartInstruction int
}

SubProgLocation states the location of a sub program. Example: "func#3 @85"

func (*SubProgLocation) String 

func (spl *SubProgLocation) String() string

type TNum 

type TNum struct {
	Value int64
	Mask  int64
}

TNum is a tracked (or tristate) number. Relevant parts ported from linux kernel. https://elixir.bootlin.com/linux/v5.18.3/source/include/linux/tnum.h https://elixir.bootlin.com/linux/v5.18.3/source/kernel/bpf/tnum.c

type Unknown 

type Unknown struct {
	Log string
}

For when we have no clue what a line is or means

func (*Unknown) String 

func (u *Unknown) String() string

type VerifierDone 

type VerifierDone struct {
	InstructionsProcessed int
	InstructionLimit      int
	MaxStatesPerInst      int
	TotalStates           int
	PeakStates            int
	MarkRead              int
}

VerifierDone indicates the verifier is done and has failed or succeeded. Example: "processed 520 insns (limit 1000000) max_states_per_insn 1 total_states 46 peak_states 46 mark_read 7"

func (*VerifierDone) String 

func (ls *VerifierDone) String() string

type VerifierState 

type VerifierState struct {
	FrameNumber int
	Registers   []RegisterState
	Stack       []StackState
}

VerifierState contains a description of the state of the verifier at a certain point. Used by a number of statements. Example: "frame1: R2_w=invP(id=0) R10=fp0 fp-16_w=mmmmmmmm"

func MergedPerInstruction 

func MergedPerInstruction(log string) []VerifierState

MergedPerInstruction takes and parses the verifier log. It then merges the observed register and stack states seen for each permutation the verifier considers. The resulting state isn't useful for its values, just to see which registers are never used and which stack slots/offsets are never used.

func (*VerifierState) String 

func (is *VerifierState) String() string

type VerifierStatement 

type VerifierStatement interface {
	fmt.Stringer
	// contains filtered or unexported methods
}

VerifierStatement is often a single line of the log.

func ParseVerifierLog 

func ParseVerifierLog(log string) []VerifierStatement

ParseVerifierLog parses the verbose output of the kernel eBPF verifier. It simply returns all statements in the order they appeared in the verifier output.

Source Files

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