* fix(golang): bound UPX decompression by what the input can justify
A UPX block's `sz_unc` was passed straight to `make([]byte, n)`, so four bytes of
attacker input spanned the full uint32 range. A ~300KB file could drive multi-GB
resident memory, which Go reports as a fatal runtime OOM that no `recover` on this
path can contain. Syft parses binaries out of arbitrary images, so that is reachable
from any scan.
Two bounds do the work, and UPX's own invariants make them exact:
- all blocks together reconstruct `p_filesize`, so a running remainder caps the sum.
Bounding only per-block would leave the total at (block count x original size), so
the remainder is the part that actually closes it
- `p_filesize` sizes the output buffer, so it is capped both absolutely and against
the size of the file on disk. The absolute cap alone left a ~60 byte header able to
claim 500MB; the ratio alone cannot work either, since LZMA encodes a run of N
equal bytes in O(log N) and a `go:embed` of 120MB of zeros legitimately packs 209x
The output buffer is also allocated on the first block that survives validation
rather than up front, so a header claiming a large size with nothing decodable behind
it costs nothing.
Alongside that, several ways the block loop could be steered off its own buffer:
- `parseELFPTLoadOffsets` bounds-checked program headers with `phStart+phentsize >
len(buf)`, which overflows for a `p_offset` near 2^64 and lets an out-of-range entry
through into a slice index. Switched to the subtraction form, and a `phentsize`
shorter than an ELF64 program header is rejected since the reads use fixed offsets
- block placement had the same overflow shape, and on failure it skipped the copy and
fell through. `outputOffset` derives from the rejected offset, so a `p_offset` at the
uint64 ceiling wrapped it to 0 and the next block landed on the reconstructed ELF
header, still returning success. Out-of-range placement now ends the block chain,
keeping the blocks already placed since those often carry `.go.buildinfo`
- the UPX 2-byte LZMA header carries `lc`/`lp` as nibbles and `pb` as three bits, so
they can hold values LZMA does not permit. Folded into the props byte they wrap
(`lc=15, lp=15, pb=7` gives 465, which truncates to 209) and the stream mis-decodes
instead of failing
- blocks decode directly into a slice of the output buffer instead of a per-block
buffer that is then copied, so one block no longer doubles peak memory
- the block count is capped: the size budget alone still allows millions of 12-byte
blocks, each spinning up an LZMA reader
Verified against the `image-small-upx` fixture, a real `upx --best --lzma` binary:
four blocks, max `sz_unc` equal to `p_blocksize` exactly, blocks summing to 0.68 of
`p_filesize`, and a 1.96x expansion against the packed file, so every bound holds with
headroom on genuine output.
Note `p_blocksize` is deliberately not used as a ceiling on `sz_unc`. It adds nothing
the remainder does not already cover, and real output sits at exactly `p_blocksize`,
so it would run with zero headroom against a value the format does not promise.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* fix(golang): report UPX binaries we cannot unpack as unknowns
A packed Go binary we fail to unpack means its packages are silently missing from the
SBOM. `getBuildInfo` checked the decompression error for nil and discarded it, so a
rejected file surfaced only the original `buildinfo.Read` error, and that one is
deliberately silenced because it is usually just "not a Go binary".
`decompressUPX` now marks the cases worth reporting with `errUPXDecompress`: it got
past the header and the method dispatch and still could not unpack the file. Everything
else stays quiet, which matters more than it sounds. `upx` defaults to NRV2B unless
`--lzma` is passed and only LZMA is implemented here, so treating any decompression
failure as reportable would attach a golang-cataloger unknown to every packed non-Go
binary in an image. Making the reportable case opt in rather than the quiet case a
growing list also means a guard added later is silent by default.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* refactor(golang): drop the vendored xcoff parser
The only thing the golang cataloger read from it was `TargetMachine`, which is the same
two magic bytes `getGOARCHFromBin` had already matched on to dispatch there. So a full
XCOFF walk (string table, symbol table, every relocation table) ran to recover a value
that was already in hand.
`getGOARCHFromBin` reads those two bytes directly now. That is also strictly more
correct: `xcoff.NewFile` bailed with "no symbol table" when `symptr == 0`, so a stripped
XCOFF binary reported no arch at all.
Fixtures move to `testdata/xcoff/`, since they are no longer a package's own testdata.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* feat(internal/file): report a reader's real size behind one helper
Bounds get written as "does this claim exceed what the reader actually holds", and the
subtlety is that a reader's own answer cannot be trusted: an `io.SectionReader` reports
the nominal length it was built with, so one constructed with `1<<63-1` will happily
claim to hold 8EB. Confirming the last byte is readable is what separates a real size
from a nominal one.
Returns `(int64, bool)` rather than a bare size, since there are five ways to not know
and collapsing them to 0 makes every caller reinvent "0 means stop bounding".
The doc also names the wrapper trap: a type embedding `io.ReaderAt` as an interface
promotes only `ReadAt`, so it answers no size at all however large the reader beneath it
is, and a bound written against it silently does nothing.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* fix(golang): bound every section a reader can expand, not just the name table
`CheckSectionNameTable` bounds the one section `elf.NewFile` expands while parsing, which
is enough for a caller that only parses. It is not enough for one that goes on to read
sections: those are expanded lazily, so a 260KB ELF declaring a compressed `.symtab`
drove 1.3GB of allocation through `goversion`, which opens the file with `debug/elf`
inside its own package and cannot be routed through `elfutil.NewFile`.
`CheckAllSections` is that gate, and is deliberately named as the superset so the
relationship to the narrow one is structural rather than documented.
Also exports `ErrDeclaredSizeExceeded`. A refusal here costs the SBOM a package, so
callers report it as an unknown, and matching on an error string to decide that is not
something to build a reporting policy on.
A ruleguard rule now flags `buildinfo.Read` and `version.ReadExeFromReader` outside
`scan_binary.go`. Both open `debug/elf` internally and are only bounded there by the
wrappers that gate the reader first, which the existing rule on `elf.NewFile` could not
see through.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* feat(internal/spillbuf): sparse offset-addressed buffer that spills to disk
For output that arrives out of order, at offsets the input itself declares: a
decompressor placing extents, an archive rebuilding a file from chunks. A plain `[]byte`
cannot do that without either pre-sizing to a length the input claims or growing to the
furthest offset it names, and both hand a hostile input an allocation knob.
The load-bearing property is that it reports only what it actually stored. `Size` is the
contiguous run written from offset zero and a read past it is `io.EOF`, never the zeros
an unwritten region would hand back for free. Sparse storage serving holes as real
content is what lets a write offset stand in for output nothing produced, so anything
sizing an allocation against this reader (`saferio` in `debug/elf` does exactly that)
stays bounded by work actually done.
`FirstGap` answers where the next write fits, so callers filling holes do not need the
extent bookkeeping and cannot re-derive that rule wrongly, and it only reports gaps
lying entirely inside `[0, within)`. The extent type is unexported for the same reason.
The rest of the contract worth stating: reads and writes after `Close` fail with
`os.ErrClosed` rather than looking like an empty buffer, and a write that fails leaves
the buffer unchanged.
Memory is bounded by the limit rather than by how much is written: filling 1MB and
filling 64MB cost about the same. What lands on disk past that limit is the caller's
bound to set, not this package's. Growth is geometric and capped, because sizing the
tier to exactly what each write needs is quadratic once a caller streams through it in
small chunks.
The golang cataloger is the only consumer today, and nothing else in the tree has this
shape.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* fix(golang): rebuild UPX binaries through spillbuf and read the reconstruction everywhere
Two amplification paths were still reachable. A 128 byte input allocated 16MB by
trusting `sz_cpr` before weighing it against the bytes the file actually holds, and the
reconstruction was assembled in a `[]byte` sized from the header's declared original
size, so a 301KB input allocated 300MB.
The reconstruction is a `spillbuf.Buffer` now, which is what makes the second one go
away: blocks are placed at the offsets the file declares, nothing is pre-sized from a
claim, and the reader's length is the contiguous run actually rebuilt. That last part is
the invariant everything downstream leans on. A reader reporting the declared size would
serve the holes between placed blocks as zeros it never stored, and a 64 byte block
parked at `p_filesize-64` then made a 300KB input hand out a 64MB reader: measured, that
drove 269MB through `getBuildInfo` and returned nothing, silently.
Placement and storage are separate concerns. `upx.go` places blocks at the offsets the
file declares and asks the buffer how much was rebuilt and where the next gap is; it
knows nothing about temp files or memory limits.
The remaining bounds are ratios against the input wherever they can be, since an
absolute ceiling only ever drops a large legitimate binary. The one absolute left is on
`p_filesize`, because padding an input is nearly free, and the LZMA dictionary is paid
for in its own block's `sz_cpr`.
Interface change: `scanFile` takes a context and hands back the reconstruction for each
binary that turned out to be packed, and the caller owns it. Everything after the build
info read (crypto settings, arch, symbols, the version scan) reads it, so a packed
binary no longer reports its packages with no symbols at all.
Also narrows what gets reported. This cataloger runs on every executable in an image, so
reporting every `getBuildInfo` error attached an unknown to every corrupt ELF, odd PE and
non-Go Mach-O slice in it. Now only four gaps, the ones that cost the SBOM something
syft could have had: a packed file we could not decode (`errUPXDecompress`), a header
the size bounds refused (`errUPXSizeRefused`), a reconstruction that came up short
(`errUPXPartial`), and an ELF expansion `elfutil` declined
(`ErrDeclaredSizeExceeded`). An unimplemented UPX method stays quiet on purpose: `upx`
defaults to NRV2B and only LZMA is implemented here, so reporting it would attach an
unknown to most packed non-Go binaries in an image.
That filtering is a new pattern. No other cataloger picks which of its errors become
unknowns, and the reason this one does is that it runs on every executable in an image
rather than on files a glob already selected.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* chore: ignore local spec/ planning notes
`/specs` was already ignored; `/spec` is the same thing under the singular name and was
not, so working notes landed in commits.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* refactor(golang): name what the unpack hands back, not where it stores it
the scan's signatures said `*spillbuf.Buffer` all the way down, which told
every reader below the scan that it cares whether the reconstruction lives in
memory or on disk. it does not. two interfaces instead, each naming only what
its side actually uses:
- `unpackedContents` for the consumers: `ReaderAt`, `Closer`, and a `Size` that
is the contiguous run rebuilt from zero
- `blockSink` for the decoder, which additionally needs `WriterAt` and
`FirstGap` to place blocks
this costs one thing worth flagging. `Close` on a nil `*spillbuf.Buffer` was
nil-safe, so callers just deferred it; widened into an interface, a nil pointer
becomes a non-nil interface and the same call panics. `closeUnpacked` absorbs
that, and it is now the only way an owner releases contents. `readerFor`,
`seekerFor` and `closeUnpacked` are the three places that resolve the nil.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* docs(elfutil): say that CheckAllSections is the decompression-bomb gate
the doc led with "bounds every section syft can drive debug/elf into
decompressing", which describes the mechanism without ever naming what it is
defending against. a reader landing on the call site could not tell that this
is the decompression-bomb check.
state the attack instead: a compressed section header declares its own
decompressed size, debug/elf believes that number and allocates it on open, and
nothing forces it to match what the compressed bytes actually yield. the 260KB
ELF that drove 1.3GB of allocation now lives in the doc rather than only at the
one call site that happened to mention it.
comments only.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* docs(golang): move the overflow note onto the bounds test it describes
the "subtraction form" note sat above the phStart assignment with ten lines of
wrap analysis between it and the `if` it was talking about, so the subtraction
it names reads as missing. it is `hdrLen-phStart < phentsize`.
move it onto that test and name the form it is avoiding (`phStart+phentsize >
hdrLen`, which can overflow past the buffer end) so the referent is not several
paragraphs away.
comments only.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* chore(golang): drop the internal/ README left over from xcoff
that README existed to record where the vendored xcoff package came from and
that Go keeps it internal, which is a provenance note worth having while
third-party code sat there. dropping xcoff took the reason with it, and
repurposing it to point at gotestdata just made it redundant: gotestdata has
its own README covering why it is under internal/, why it is not testdata/, and
what belongs in each.
internal/ now holds one self-documenting directory.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
---------
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* fix(elf): bound compressed ELF section reads
`debug/elf` takes a section's decompressed size from that section's own
compression header, and a highly compressible stream really does deliver the
bytes that header promises, so `internal/saferio` does not help: it faithfully
allocates every one of them. A 2MB input file drives `elf.NewFile` to allocate
over 10GB and return no error, which is a fatal OOM rather than a recoverable
panic.
Which sections get read is not up to the caller. `elf.NewFile` always reads the
section-name string table, and `File.Symbols` reads `.symtab` plus whatever
section its `Link` field points at, so being selective about sections is not
enough to avoid it.
New `elfutil.NewFile` is a drop-in for `elf.NewFile` that rejects a declared
decompressed size over 128MB. Every production call site goes through it, and a
ruleguard rule keeps the next one from going direct.
The check runs in two parts, since `debug/elf` expands sections at two different
times. The section-name string table is the only one `elf.NewFile` expands
itself, so it is checked against the raw bytes before the call; everything else
is expanded lazily by `(*Section).Open` and is checked after the parse, where
names, types and decompressed sizes are already resolved.
Only the sections syft can actually reach are bounded, which keeps the guard
from costing real binaries. DWARF is excluded since nothing calls `File.DWARF`,
so a large compressed `.debug_info` no longer skips the whole file, and sections
`debug/elf` will not decompress anyway (`SHF_ALLOC`, `SHT_NOBITS`) are left
alone. The legacy `.zdebug` form is matched on the section name the way
`debug/elf` gates it rather than on the `ZLIB` magic, so an ordinary section
starting with those four bytes is not mistaken for a compressed one.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* fix(elf): gate debug/buildinfo behind the compressed-section check
`debug/buildinfo.Read` opens ELF files with `debug/elf` itself, and `elf.NewFile`
expands the section-name string table as it parses, so the golang cataloger was
still reachable by the same bomb `elfutil` exists to stop. A 261KB fixture drove
1.4GB of allocation through `buildinfo.Read` and returned no error.
`elfutil.CheckSectionNameTable` is now exported for that case: callers that cannot
use `NewFile` because the `debug/elf` call is made for them inside another package.
Both `buildinfo.Read` call sites go through it, including the UPX-decompressed one.
Also corrects claims that did not hold up:
- the package doc's 2MB-to-10GB figure is not reachable with zlib (~1000:1), so it
now carries the measured 510KB-to-2.6GB, and names zstd's 32767:1 since that is
what makes the small inputs possible
- `.go.buildinfo` was listed as a hot-path section elfutil covers, but it is read
through `debug/buildinfo` and never touches `Section.Data`
- the graalvm comment claimed routing size rejections away from `*elf.FormatError`
improved reporting; both branches are skipped by the caller and only the
FormatError branch logs, so it did the opposite
- `sharedLibraries` logged short and truncated files as real ELF failures, since
`debug/elf` returns a bare `io.EOF` rather than an `*elf.FormatError` for those
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* added test comments around the negative cases
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* additional tests
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* better decomposition and comments
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* use a less brittle constant for error detection
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
---------
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* feat(golang): add extended-stdlib scope and include patterns for symbol capture
`golang.capture-symbols` decides how much symbol data lands in the SBOM for grype's reachability analysis. It's `none`, `stdlib`, or `all` today, and the useful middle is missing: `stdlib` stops at the standard library, `all` multiplies SBOM size.
A new `extended-stdlib` configurable covers stdlib plus everything under `golang.org/x/`:
```yaml
golang:
capture-symbols: extended-stdlib
```
Also, a new `capture-symbols-include` configurable for modules that are noisy in your binaries but not everyone's. It's unioned with whatever the scope selects, so it only ever widens:
```yaml
golang:
capture-symbols: extended-stdlib
capture-symbols-include:
- github.com/klauspost/**
```
Patterns are standard doublestar globs, which matters because module paths carry `/v2`-style suffixes:
```yaml
golang:
capture-symbols-include:
- github.com/klauspost/* # compress, but not compress/v2
- github.com/klauspost/** # both
- k8s.io/client-go # exact match only
```
Ordering is `none` < `stdlib` < `extended-stdlib` < `all`. The existing three values
and the `none` default are unchanged, and the include list is inert under `none`.
Presets compile into glob lists internally, so a single matcher answers "does this
module get symbols" instead of a preset branch sitting next to a separate glob branch.
An unrecognized `capture-symbols` value still falls back to `none`, but warns now
instead of doing it silently. A malformed include pattern warns and gets skipped.
One thing worth a look beyond the feature: the `Symbols` field description in the JSON
schema was wrong after this (it claimed only `all` and `stdlib` populate anything), and
that description lives in the already-published `16.1.10`. Rather than bump a version for
a sentence, `16.1.10` is amended in place and `schema/json/README.md` grows an explicit
exception for description-only changes: descriptions only, no shape change of any kind,
`$id` unchanged. Anything else still needs a bump. Happy to split that into its own PR if
you'd rather review the policy separately.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* refactor(golang): rename capture-symbols-include to capture-symbols-modules
The key's entries are go module paths, and `-include` sitting next to `capture-symbols` reads as plausibly taking symbol or package names instead. Those spellings parse and match nothing, which is quieter than the confusion `-include` was picked to avoid, so the name now says what the list holds.
`golang.CatalogerConfig.CaptureSymbolsModules` and `WithCaptureSymbolsModules` rename with it. Nothing behavioral changes; the key is new in this PR so there is no compatibility surface.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
* feat(golang): match capture-symbols-modules across major version suffixes
`github.com/anchore/*` covered `github.com/anchore/syft` and silently stopped covering it the day it became `github.com/anchore/syft/v2`. The config keeps parsing, nothing warns, and symbols quietly go missing from the SBOM. Exact paths had the same hole: `github.com/klauspost/compress` did not cover `compress/v2` either, so no spelling short of `**` survived a major bump.
A major version suffix is part of a module's path but not part of its identity, so patterns are now matched against the module path both with and without it, using `module.SplitPathVersion` from `golang.org/x/mod` (already a direct dep, already used in this package for `PseudoVersion`).
```yaml
golang:
capture-symbols-modules:
- github.com/klauspost/* # compress and compress/v2
- github.com/klauspost/compress # same module at every major version
- github.com/klauspost/compress/v2 # v2 alone
```
Only a trailing suffix is a version, which is Go's own rule. In `github.com/anchore/syft/v2/thing` the `v2` is an ordinary path element naming a major subdirectory a nested module lives in, so it stays literal and `github.com/anchore/**/thing` is how you reach it. `/v0` and `/v1` are not valid suffixes and are left alone.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
---------
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
Improves the go cataloger semver extraction logic to include getting the
release version of traefik. This is based off of the regex pattern that
already existed in the traefik binary classifier.
Signed-off-by: Weston Steimel <commits@weston.slmail.me>
adds a unique synthetic package to the SBOM output that represents the go compiler when it is detected as a part of a package discovered by the go binary cataloger.
When using an SBOM generated by syft - downstream vulnerability scanners now have the opportunity to detect/report on the PURL/CPEs attached to the new stdlib package.
---------
Signed-off-by: Christopher Phillips <christopher.phillips@anchore.com>
If crypto settings or arch cannot be determined, still attempt to catalog packages from
the build info, rather than panicking.
Signed-off-by: Will Murphy <will.murphy@anchore.com>
The original fix b125ea83ba didn't catch
all the excessive warnings, it seems like getArches can also be called
on binaries that aren't neccessarily go binaries, so the messages from
this should also be Trace instead of Warn.
Signed-off-by: Justin Chadwell <me@jedevc.com>
Alex Goodman
Christopher Angelo PhillipsandAlex Goodman
VictorHuu
anchore-actions-token-generator[bot]andspiffcs
Keith Zantow
Weston Steimel
Laurent Goderre
Jon JohnsonandWill Murphy
Sirish Bathina
Avi Deitcher
Justin Chadwell