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Fix off-by-one in gzip parsing #7

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Merged
jakobnissen merged 1 commit into from
Aug 31, 2025
Merged

Fix off-by-one in gzip parsing #7

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2 changes: 1 addition & 1 deletion Project.toml
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
name = "LibDeflate"
uuid = "9255714d-24a7-4b30-8ea3-d46a97f7e13b"
authors = ["Jakob Nybo Nissen <jakobnybonissen@gmail.com>"]
version = "0.4.2"
version = "0.4.3"

[deps]
libdeflate_jll = "46979653-d7f6-5232-b59e-dd310c4598de"
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2 changes: 1 addition & 1 deletion src/gzip.jl
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Expand Up @@ -185,7 +185,7 @@ function unsafe_parse_gzip_header(
extra = parse_fields!(extra_vector, ptr + index + 2, index + UInt32(2), extra_len)
extra isa LibDeflateError && return extra
index += extra_len + UInt32(2)
index > max_len && return LibDeflateErrors.gzip_extra_too_long
(index - one(index)) > max_len && return LibDeflateErrors.gzip_extra_too_long
end

filename = nothing
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11 changes: 10 additions & 1 deletion test/gzip.jl
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Expand Up @@ -81,6 +81,15 @@ end
header_data[end-2] = 0x01
@test GC.@preserve header_data unsafe_parse_gzip_header(pointer(header_data), UInt(51)) == LibDeflateErrors.gzip_string_not_null_terminated
header_data[end-2] = 0x00

minimal_data = UInt8[0x1f, 0x8b, 0x08, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00,
0xff, 0x06, 0x00, 0x42, 0x43, 0x02, 0x00, 0x10, 0x20
]
(header_len, header) = parse_gzip_header(minimal_data)
@test header_len == 18
ex = only(header.extra)
@test ex.tag == (0x42, 0x43)
@test ex.data == 17:18
end


Expand Down Expand Up @@ -154,4 +163,4 @@ complex_test_case = vcat(header_data, UInt8[
res = gzip_decompress!(decompressor, outdata, complex_test_case)
test_header_example(complex_test_case, res.header)
@test res.len == 11
end
end