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Add additional checks in chunking functionality #671

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Merged
merged 4 commits into from
May 9, 2024
Merged

Add additional checks in chunking functionality #671

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6c8d2a2
Add additional checks in chunking functionality
dhurley May 9, 2024
902e5f8
Clean up
dhurley May 9, 2024
32cd885
Clean up
dhurley May 9, 2024
5275787
Clean up
dhurley May 9, 2024
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15 changes: 14 additions & 1 deletion sdk/checksum/checksum.go
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Original file line number Diff line number Diff line change
Expand Up @@ -26,13 +26,26 @@ func HexChecksum(b []byte) string {
// Chunk - split bytes to chunk limits
func Chunk(buf []byte, lim int) [][]byte {
var chunk []byte
chunks := make([][]byte, 0, len(buf)/lim+1)
bufSize := len(buf)

if bufSize == 0 {
return [][]byte{}
}

if bufSize <= lim {
return [][]byte{buf}
}

chunks := make([][]byte, 0)
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Why do we no longer set the capacity for chunks?

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Donal answered here at the office, so the reason was that the tool was complaining about our capacity potentially overflowing.

FWIW, I did the math on this one. The capacity was len(buf)/lim+1 meaning the only way we exceed the maximum length of an integer (i.e. overflow) is if the buffer (=buf) had 2^63 elements in it (so 9,223,372,036,854,775,807 elements) on a 64-bit system. Since buf is a byte slice, that means you would have 2^63 bytes, which translates to ~9,223 petabytes, meaning you definitely would have run into problem far earlier than when entering this.


for len(buf) >= lim {
chunk, buf = buf[:lim], buf[lim:]
chunks = append(chunks, chunk)
}

if len(buf) > 0 {
chunks = append(chunks, buf[:])
}

return chunks
}
1 change: 1 addition & 0 deletions sdk/checksum/checksum_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -87,6 +87,7 @@ func TestHexChunk(t *testing.T) {
expected: [][]byte{},
},
}

for _, test := range tests {
result := Chunk(test.input, test.limit)
assert.Equal(t, test.expected, result)
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15 changes: 14 additions & 1 deletion test/integration/vendor/github.com/nginx/agent/sdk/v2/checksum/checksum.go
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15 changes: 14 additions & 1 deletion test/performance/vendor/github.com/nginx/agent/sdk/v2/checksum/checksum.go
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15 changes: 14 additions & 1 deletion vendor/github.com/nginx/agent/sdk/v2/checksum/checksum.go
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