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x/crypto/openpgp: ReadMessage(): Panic on invalid input in math/big.nat.div() (division by zero) #11505

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marete opened this issue Jul 1, 2015 · 3 comments
Closed

x/crypto/openpgp: ReadMessage(): Panic on invalid input in math/big.nat.div() (division by zero) #11505

marete opened this issue Jul 1, 2015 · 3 comments
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@marete
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marete commented Jul 1, 2015

The following program panics:

package main

import (
    "bytes"
    "encoding/hex"
    "io"
    "log"
    "os"

    "golang.org/x/crypto/openpgp"
)

// An empty Keyring
type emptyKR struct {
}

func (kr emptyKR) KeysById(id uint64) []openpgp.Key {
    return nil
}

func (kr emptyKR) DecryptionKeys() []openpgp.Key {
    return nil
}

func (kr emptyKR) KeysByIdUsage(uint64, byte) []openpgp.Key {
    return nil
}

var data = "9c3004303030300100000011303030000000000000010130303030303030303030303030303030303030303030303030303030303030303030303030303030303030"

func main() {
    buf, err := hex.DecodeString(data)
    if err != nil {
        log.Fatalln(err)
    }

    md, err := openpgp.ReadMessage(bytes.NewBuffer(buf), emptyKR{},
        func([]openpgp.Key, bool) ([]byte, error) {
            return []byte("insecure"), nil
        }, nil)

    if err != nil {
        log.Fatalln(err)
    }

    _, err = io.Copy(os.Stdout, md.UnverifiedBody)
    if err != nil {
        log.Fatalln(err)
    }

    if md.SignatureError != nil {
        log.Fatalln("integrity check failed")
    }
}

with the trace:

panic: division by zero

goroutine 1 [running]:
math/big.nat.div(0x0, 0x0, 0x0, 0xc20803c570, 0x0, 0x5, 0x0, 0x0, 0x0, 0xc20803c570, ...)
    /opt/go/src/math/big/nat.go:503 +0xcb
math/big.(*Int).QuoRem(0xc208020320, 0xc2080200e0, 0xc2080202e0, 0xc2080202e0, 0x1, 0x5)
    /opt/go/src/math/big/int.go:224 +0xb6
math/big.(*Int).Mod(0xc2080202e0, 0xc2080200e0, 0xc2080202e0, 0xc2080202e0)
    /opt/go/src/math/big/int.go:255 +0x15c
crypto/rsa.(*PrivateKey).Precompute(0xc208068000)
    /opt/go/src/crypto/rsa/rsa.go:376 +0x1ba
golang.org/x/crypto/openpgp/packet.(*PrivateKey).parseRSAPrivateKey(0xc208040000, 0xc208066000, 0x22, 0x600, 0x0, 0x0)
    /home/marebri/devel/go/src/golang.org/x/crypto/openpgp/packet/private_key.go:266 +0x520
golang.org/x/crypto/openpgp/packet.(*PrivateKey).parsePrivateKey(0xc208040000, 0xc208066000, 0x22, 0x600, 0x0, 0x0)
    /home/marebri/devel/go/src/golang.org/x/crypto/openpgp/packet/private_key.go:234 +0x6c
golang.org/x/crypto/openpgp/packet.(*PrivateKey).parse(0xc208040000, 0x7f5e808d1bc0, 0xc208020080, 0x0, 0x0)
    /home/marebri/devel/go/src/golang.org/x/crypto/openpgp/packet/private_key.go:103 +0x3f8
golang.org/x/crypto/openpgp/packet.Read(0x7f5e808d1b60, 0xc2080120e0, 0x7f5e808d1be8, 0xc208040000, 0x0, 0x0)
    /home/marebri/devel/go/src/golang.org/x/crypto/openpgp/packet/packet.go:375 +0x152
golang.org/x/crypto/openpgp/packet.(*Reader).Next(0xc20803c330, 0x0, 0x0, 0x0, 0x0)
    /home/marebri/devel/go/src/golang.org/x/crypto/openpgp/packet/reader.go:37 +0x10c
golang.org/x/crypto/openpgp.ReadMessage(0x7f5e808d1b60, 0xc2080120e0, 0x7f5e808d1b88, 0x68c0a8, 0x5f0860, 0x0, 0xc208062000, 0x0, 0x0)
    /home/marebri/devel/go/src/golang.org/x/crypto/openpgp/read.go:101 +0x206
main.main()
    /home/marebri/devel/lab/go/crypto/openpgp/issues/50eccec52/main.go:40 +0x285

goroutine 2 [runnable]:
runtime.forcegchelper()
    /opt/go/src/runtime/proc.go:90
runtime.goexit()
    /opt/go/src/runtime/asm_amd64.s:2232 +0x1

goroutine 3 [runnable]:
runtime.bgsweep()
    /opt/go/src/runtime/mgc0.go:82
runtime.goexit()
    /opt/go/src/runtime/asm_amd64.s:2232 +0x1

goroutine 4 [runnable]:
runtime.runfinq()
    /opt/go/src/runtime/malloc.go:712
runtime.goexit()
    /opt/go/src/runtime/asm_amd64.s:2232 +0x1

Found using gofuzz. You may assign this issue to me.
@bradfitz
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bradfitz commented Jul 2, 2015

What version of Go?

@marete
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marete commented Jul 2, 2015

go version go1.4.2 linux/amd64

@ianlancetaylor ianlancetaylor added this to the Unreleased milestone Jul 10, 2015
@gopherbot
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CL https://golang.org/cl/12356 mentions this issue.

benburkert pushed a commit to benburkert/openpgp that referenced this issue Feb 29, 2016
@ebfe @agl
x/crypto/openpgp/packet: validate parsed rsa private keys
6e60921 
parseRSAPrivateKey calls rsa.PrivateKey.Precompute which triggers
divide-by-zero panic if either p or q is 1. Sanity check the parsed
values by calling rsa.PrivateKey.Validate.

Fixes golang/go#11505

Change-Id: Ia6c9eccca0cfa49aaa58716e708c557a788bb204
Reviewed-on: https://go-review.googlesource.com/12356
Reviewed-by: Adam Langley <agl@golang.org>
@golang golang locked and limited conversation to collaborators Aug 5, 2016
c-expert-zigbee pushed a commit to c-expert-zigbee/crypto_go that referenced this issue Mar 28, 2022
@ebfe @agl
x/crypto/openpgp/packet: validate parsed rsa private keys
7c3d3bd 
parseRSAPrivateKey calls rsa.PrivateKey.Precompute which triggers
divide-by-zero panic if either p or q is 1. Sanity check the parsed
values by calling rsa.PrivateKey.Validate.

Fixes golang/go#11505

Change-Id: Ia6c9eccca0cfa49aaa58716e708c557a788bb204
Reviewed-on: https://go-review.googlesource.com/12356
Reviewed-by: Adam Langley <agl@golang.org>
c-expert-zigbee pushed a commit to c-expert-zigbee/crypto_go that referenced this issue Mar 29, 2022
@ebfe @c-expert-zigbee
x/crypto/openpgp/packet: validate parsed rsa private keys
4307ec8 
parseRSAPrivateKey calls rsa.PrivateKey.Precompute which triggers
divide-by-zero panic if either p or q is 1. Sanity check the parsed
values by calling rsa.PrivateKey.Validate.

Fixes golang/go#11505

Change-Id: Ia6c9eccca0cfa49aaa58716e708c557a788bb204
Reviewed-on: https://go-review.googlesource.com/12356
Reviewed-by: Adam Langley <agl@golang.org>
@rsc rsc unassigned marete Jun 23, 2022
BiiChris pushed a commit to BiiChris/crypto that referenced this issue Sep 15, 2023
@ebfe @agl
x/crypto/openpgp/packet: validate parsed rsa private keys
13f5946 
parseRSAPrivateKey calls rsa.PrivateKey.Precompute which triggers
divide-by-zero panic if either p or q is 1. Sanity check the parsed
values by calling rsa.PrivateKey.Validate.

Fixes golang/go#11505

Change-Id: Ia6c9eccca0cfa49aaa58716e708c557a788bb204
Reviewed-on: https://go-review.googlesource.com/12356
Reviewed-by: Adam Langley <agl@golang.org>
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