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pkcs7: fix slice out-of-bounds panic #24891

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Merged
fairclothjm merged 5 commits into from
Jan 17, 2024
Merged

pkcs7: fix slice out-of-bounds panic #24891

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bb9304e
pkcs7: fix slice out-of-bounds panic
fairclothjm Jan 16, 2024
3f4f1eb
changelog
fairclothjm Jan 16, 2024
bee6d35
fix tests
fairclothjm Jan 16, 2024
52775da
add test case to capture panic; found in fuzzing
fairclothjm Jan 16, 2024
8799c1b
add fuzz test
fairclothjm Jan 17, 2024
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3 changes: 3 additions & 0 deletions changelog/24891.txt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
```release-note:bug
helper/pkcs7: Fix slice out-of-bounds panic
```
8 changes: 4 additions & 4 deletions helper/pkcs7/ber.go
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Original file line number Diff line number Diff line change
Expand Up @@ -149,14 +149,14 @@ func readObject(ber []byte, offset int) (asn1Object, int, error) {
for ber[offset] >= 0x80 {
tag = tag*128 + ber[offset] - 0x80
offset++
if offset > berLen {
if offset >= berLen {
return nil, 0, errors.New("ber2der: cannot move offset forward, end of ber data reached")
}
}
// jvehent 20170227: this doesn't appear to be used anywhere...
// tag = tag*128 + ber[offset] - 0x80
offset++
if offset > berLen {
if offset >= berLen {
return nil, 0, errors.New("ber2der: cannot move offset forward, end of ber data reached")
}
}
Expand All @@ -172,7 +172,7 @@ func readObject(ber []byte, offset int) (asn1Object, int, error) {
var length int
l := ber[offset]
offset++
if offset > berLen {
if offset >= berLen {
return nil, 0, errors.New("ber2der: cannot move offset forward, end of ber data reached")
}
indefinite := false
Expand All @@ -192,7 +192,7 @@ func readObject(ber []byte, offset int) (asn1Object, int, error) {
for i := 0; i < numberOfBytes; i++ {
length = length*256 + (int)(ber[offset])
offset++
if offset > berLen {
if offset >= berLen {
return nil, 0, errors.New("ber2der: cannot move offset forward, end of ber data reached")
}
}
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5 changes: 3 additions & 2 deletions helper/pkcs7/ber_test.go
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Expand Up @@ -44,13 +44,14 @@ func TestBer2Der_Negatives(t *testing.T) {
Input []byte
ErrorContains string
}{
{[]byte{0x30, 0x85}, "tag length too long"},
{[]byte{0x30, 0x85}, "end of ber data reached"},
{[]byte{0x30, 0x84, 0x80, 0x0, 0x0, 0x0}, "length is negative"},
{[]byte{0x30, 0x82, 0x0, 0x1}, "length has leading zero"},
{[]byte{0x30, 0x80, 0x1, 0x2, 0x1, 0x2}, "Invalid BER format"},
{[]byte{0x30, 0x80, 0x1, 0x2}, "BER tag length is more than available data"},
{[]byte{0x30, 0x80, 0x1, 0x2}, "end of ber data reached"},
{[]byte{0x30, 0x03, 0x01, 0x02}, "length is more than available data"},
{[]byte{0x30}, "end of ber data reached"},
{[]byte("?0"), "end of ber data reached"},
}

for _, fixture := range fixtures {
Expand Down