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alts: Reduce ALTS counter overflow length from 5 to 4. #6699

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Merged
merged 1 commit into from
Oct 24, 2023
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alts: Reduce ALTS counter overflow length from 5 to 4. #6699

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2 changes: 1 addition & 1 deletion credentials/alts/internal/conn/aes128gcm.go
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Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,7 @@ import (
const (
// Overflow length n in bytes, never encrypt more than 2^(n*8) frames (in
// each direction).
overflowLenAES128GCM = 5
overflowLenAES128GCM = 4
)

// aes128gcm is the struct that holds necessary information for ALTS record.
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2 changes: 1 addition & 1 deletion credentials/alts/internal/conn/aes128gcmrekey.go
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Expand Up @@ -27,7 +27,7 @@ import (
const (
// Overflow length n in bytes, never encrypt more than 2^(n*8) frames (in
// each direction).
overflowLenAES128GCMRekey = 8
overflowLenAES128GCMRekey = 4
nonceLen = 12
aeadKeyLen = 16
kdfKeyLen = 32
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30 changes: 22 additions & 8 deletions credentials/alts/internal/conn/counter_test.go
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Expand Up @@ -52,8 +52,9 @@ func (s) TestCounterSides(t *testing.T) {

func (s) TestCounterInc(t *testing.T) {
for _, test := range []struct {
counter []byte
want []byte
counter []byte
want []byte
expectInvalid bool
}{
{
counter: []byte{0x00, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
Expand All @@ -72,19 +73,32 @@ func (s) TestCounterInc(t *testing.T) {
want: []byte{0x43, 0xff, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
},
{
counter: []byte{0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
want: []byte{0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
counter: []byte{0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
want: []byte{0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
},
{
counter: []byte{0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80},
want: []byte{0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80},
counter: []byte{0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80},
want: []byte{0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80},
},
{
counter: []byte{0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
want: []byte{},
expectInvalid: true,
},
{
counter: []byte{0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80},
want: []byte{},
expectInvalid: true,
},
} {
c := CounterFromValue(test.counter, overflowLenAES128GCM)
c.Inc()
value, _ := c.Value()
if g, w := value, test.want; !bytes.Equal(g, w) || c.invalid {
t.Errorf("counter(%v).Inc() =\n%v, want\n%v", test.counter, g, w)
if got, want := c.invalid, test.expectInvalid; got != want {
t.Errorf("counter.invalid=%t, want=%t", got, want)
}
if got, want := value, test.want; !bytes.Equal(got, want) {
t.Errorf("counter(%v).Inc() =\n%v, want\n%v", test.counter, got, want)
}
}
}
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