From d0405298b24db0e2a6b2abfdc8c7e5ebbe49d1a0 Mon Sep 17 00:00:00 2001 From: Hrutvik Kanabar Date: Tue, 25 Oct 2022 10:13:51 +0000 Subject: prog, pkg/compiler: add `BufferCompressed` buffer type & `compressed_image` builtin Create the `BufferCompressed` kind of `BufferType`, which will be used to represent compressed data. Create the corresponding `compressed_image` syzlang builtin, which is backed by `BufferCompressed`. For now, no syscalls use this feature - this will be introduced in future commits. We have to be careful to decompress the data before mutating, and re-compress before storing. We make sure that any deserialised `BufferCompressed` data is valid too. `BufferCompressed` arguments are mutated using a generic heatmap. In future, we could add variants of `BufferCompressed` or populate the `BufferType` sub-kind, using it to choose different kinds of heatmap for different uncompressed data formats. Various operations on compressed data must be forbidden, so we check for `BufferCompressed` in key places. We also have to ensure `compressed_image` can only be used in syscalls that are marked `no_{generate,minimize}`. Therefore, we add a generic compiler check which allows type descriptions to require attributes on the syscalls which use them. --- prog/encoding.go | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'prog/encoding.go') diff --git a/prog/encoding.go b/prog/encoding.go index 92b7f2be3..82c93273a 100644 --- a/prog/encoding.go +++ b/prog/encoding.go @@ -597,6 +597,15 @@ func (p *parser) parseArgString(t Type, dir Dir) (Arg, error) { if err != nil { return nil, err } + // Check compressed data for validity. + if typ.IsCompressed() { + _, err = Decompress(data) + if err != nil { + p.strictFailf("invalid compressed data in arg: %v", err) + // In non-strict mode, empty the data slice. + data = Compress([]byte{}) + } + } size := ^uint64(0) if p.Char() == '/' { p.Parse('/') -- cgit mrf-deployment