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Fix PropExperimenter deserialization out-of-bounds read #66

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Fix PropExperimenter deserialization out-of-bounds read #66

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dc644eb
Fix PropExperimenter deserialization out-of-bounds read
AsGreyWolf Nov 22, 2024
d212d41
Remove unnecessary bound-check
AsGreyWolf Dec 5, 2024
a1582a8
Fix bucket boundcheck
AsGreyWolf Dec 12, 2024
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2 changes: 1 addition & 1 deletion openflow15/group.go
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Original file line number Diff line number Diff line change
Expand Up @@ -162,7 +162,7 @@ func (g *GroupMod) UnmarshalBinary(data []byte) (err error) {
g.CommandBucketId = binary.BigEndian.Uint32(data[n:])
n += 4

for n < g.Header.Length {
for n < g.BucketArrayLen+24 {
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@antoninbas antoninbas Dec 16, 2024

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this seems unrelated to the rest of the PR?

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@xelez-work xelez-work Dec 19, 2024

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Properties (including experimenter ones) are encoded after buckets. But because of n < g.Header.Length here we're trying to decode property as a bucket and fail.

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@wenyingd wenyingd Sep 4, 2025

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Not feel the change is necessary. GroupMod.Heander.Length should describe the size of this complete message including the buckets. If not, it may be some issue when marshaling the message, e.g., a bug of OVS to encoding the message, or a bug to read bytes from the OpenFlow connection.

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@xelez-work xelez-work Sep 7, 2025 •
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GroupMod.Header.Length should describe the size of this complete message including the buckets

That is true, but because there can be data after the buckets this is not correct. In current code version we're trying to decode experimental fields as buckets and it fails.

bkt := new(Bucket)
err = bkt.UnmarshalBinary(data[n:])
if err != nil {
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6 changes: 2 additions & 4 deletions openflow15/openflow15.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1509,14 +1509,12 @@ func (p *PropExperimenter) Len() uint16 {
n += 8
l := uint16(len(p.Data) * 4)
n += l
//n += uint16((8 - (l % 8)) % 8) // pad to make multiple of 8
n += uint16(8 - (l % 8)) // pad to make multiple of 8
return n
}

func (p *PropExperimenter) MarshalBinary() (data []byte, err error) {
data = make([]byte, int(p.Len()))
p.Header.Length = 8 + uint16(len(p.Data)*4)
p.Header.Length = p.Header.Len() + 8 + uint16(len(p.Data)*4)
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@wenyingd wenyingd Sep 4, 2025

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It is easier to use p.Header.Length = p.Len().

b, err := p.Header.MarshalBinary()
if err != nil {
return
Expand Down Expand Up @@ -1547,7 +1545,7 @@ func (p *PropExperimenter) UnmarshalBinary(data []byte) (err error) {
p.ExpType = binary.BigEndian.Uint32(data[n:])
n += 4

for n < p.Header.Length+p.Header.Len() {
for n < p.Header.Length {
d := binary.BigEndian.Uint32(data[n:])
p.Data = append(p.Data, d)
n += 4
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