Module: Homebrew::Vulns::OsvExport Private

Defined in:
vulns/osv_export.rb

Overview

This module is part of a private API. This module may only be used in the Homebrew/brew repository. Third parties should avoid using this module if possible, as it may be removed or changed without warning.

Emits OSV-schema records for the Homebrew ecosystem describing CVEs that homebrew-core formulae resolve via shipped patches.

One record is written per (formula, vulnerability id) pair found in serialized_patches[].resolves. The record states that the formula was affected up to (but not including) the currently shipped version+revision; this is a "fixed at or before what we ship today" approximation, since the precise fix boundary requires homebrew-core git archaeology.

Record shape follows the OSV 1.7 schema and mirrors the Debian DSA layout (upstream listing the source CVE, affected[].ranges of type ECOSYSTEM, ecosystem_specific carrying the resolving patch detail).

See DevCmd::GenerateVulnsAdvisories for the entry point and https://github.com/Homebrew/advisory-database for the published feed.

Constant Summary collapse

SCHEMA_VERSION =

This constant is part of a private API. This constant may only be used in the Homebrew/brew repository. Third parties should avoid using this constant if possible, as it may be removed or changed without warning.

https://ossf.github.io/osv-schema/ — value of the emitted schema_version field, pinning the OSV schema release these records target. Homebrew and BREW were registered in that schema in ossf/osv-schema#576.

"1.7.3"
ECOSYSTEM =

This constant is part of a private API. This constant may only be used in the Homebrew/brew repository. Third parties should avoid using this constant if possible, as it may be removed or changed without warning. 

"Homebrew"
ID_PREFIX =

This constant is part of a private API. This constant may only be used in the Homebrew/brew repository. Third parties should avoid using this constant if possible, as it may be removed or changed without warning. 

"BREW"
PatchRef =

This constant is part of a private API. This constant may only be used in the Homebrew/brew repository. Third parties should avoid using this constant if possible, as it may be removed or changed without warning. 

T.type_alias { T::Hash[Symbol, T.any(String, T::Array[String])] }

Class Method Summary collapse

Class Method Details

.affected_entry(formula, vuln_id, patches, fixed) ⇒ Hash{Symbol => T.untyped}

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Parameters:

Returns:



235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
 
# File 'vulns/osv_export.rb', line 235

def self.affected_entry(formula, vuln_id, patches, fixed)
  {
    package:            {
      ecosystem: ECOSYSTEM,
      name:      formula.name,
      purl:      purl(formula.name),
    },
    ranges:             [
      {
        type:   "ECOSYSTEM",
        events: [{ introduced: "0" }, { fixed: }],
      },
    ],
    ecosystem_specific: {
      fix:     "patch",
      patches: patches_resolving(patches, vuln_id).filter_map { |p| patch_ref(p) },
    },
  }
end

.fetch_upstream(vuln_id) ⇒ Hash{String => T.untyped}, Symbol

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Returns :failed (not nil) on error so callers can distinguish a transient outage from a successful fetch that returned no enrichment.

Parameters:

Returns:



293
294
295
296
297
 
# File 'vulns/osv_export.rb', line 293

def self.fetch_upstream(vuln_id)
  OSV.vulnerability(vuln_id)
rescue OSV::Error
  :failed
end

.merge_existing(path, record, close_open_ranges: false) ⇒ Hash{Symbol => T.untyped}?

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

If a record already exists at path, carry forward its published timestamp and affected[].ranges (so a terminal boundary does not drift to today's pkg_version), and skip the write entirely when nothing else has changed. close_open_ranges lets the matcher append a newly discovered fixed event to an existing open range while preserving its reviewed introduction events. Records for annotations no longer in core are simply not visited, so they persist.

Parameters:

  • path (String)
  • record (Hash{Symbol => T.untyped})
  • close_open_ranges (Boolean) (defaults to: false)

Returns:



95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
 
# File 'vulns/osv_export.rb', line 95

def self.merge_existing(path, record, close_open_ranges: false)
  return record unless File.file?(path)

  existing = JSON.parse(File.read(path))
  # Records written before `published` was introduced only have
  # `modified`; use it as the migration value so `published` does not
  # jump forward to today on first rewrite.
  if (existing_published = existing["published"] || existing["modified"])
    record[:published] = existing_published
  end
  Array(record[:affected]).each_with_index do |affected, index|
    existing_ranges = existing.dig("affected", index, "ranges")
    next unless existing_ranges

    affected[:ranges] = if close_open_ranges
      merge_open_ranges(existing_ranges, affected[:ranges])
    else
      existing_ranges
    end
  end

  # Compare as parsed structures so key ordering (which JSON does not
  # define but Ruby serialisation preserves) does not cause spurious
  # rewrites of a hand-formatted or differently-serialised existing file.
  return if JSON.parse(JSON.generate(record)).except("modified") == existing.except("modified")

  record
rescue JSON::ParserError
  record
end

.patch_ref(patch) ⇒ PatchRef?

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Parameters:

Returns:



281
282
283
284
285
286
287
288
 
# File 'vulns/osv_export.rb', line 281

def self.patch_ref(patch)
  ref = T.let({}, PatchRef)
  ref[:type] = patch["type"] if patch["type"]
  ref[:url] = patch["url"] if patch["url"]
  ref[:file] = patch["file"] if patch["file"]
  ref[:apply] = patch["apply"] if patch["apply"]
  ref.presence
end

.patches_resolving(serialized_patches, vuln_id) ⇒ Array<Hash{String => T.untyped}>

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Parameters:

Returns:



271
272
273
274
275
276
 
# File 'vulns/osv_export.rb', line 271

def self.patches_resolving(serialized_patches, vuln_id)
  target = vuln_id.upcase
  serialized_patches.select do |p|
    Array(p["resolves"]).any? { |r| r.is_a?(Hash) && r["type"] == "security" && r["id"].to_s.upcase == target }
  end
end

.purl(name) ⇒ String

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Parameters:

Returns:



263
264
265
 
# File 'vulns/osv_export.rb', line 263

def self.purl(name)
  "pkg:brew/#{name.gsub(/[@+]/, PURL_NAME_ENCODE)}"
end

.ranges_terminal?(ranges) ⇒ Boolean

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

True only when every range has a terminal fixed, last_affected, or limit event. Invalid/empty ranges deliberately return false so the selective matcher repairs them instead of treating them as reviewed.

Parameters:

  • ranges (T.untyped)

Returns:

  • (Boolean) 


130
131
132
133
134
135
 
# File 'vulns/osv_export.rb', line 130

def self.ranges_terminal?(ranges)
  return false unless ranges.is_a?(Array)
  return false if ranges.empty?

  !!ranges.all? { |range| range_state(range) == :terminal }
end

.record_for(formula, vuln_id, patches: formula.serialized_patches, fixed: formula.pkg_version.to_s, upstream: nil, now: Time.now.utc) ⇒ Hash{Symbol => T.untyped}

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Parameters:

  • formula (Formula)
  • vuln_id (String)
  • patches (Array<Hash{String => T.untyped}>) (defaults to: formula.serialized_patches)
  • fixed (String) (defaults to: formula.pkg_version.to_s)
  • upstream (Hash{String => T.untyped}, nil) (defaults to: nil)
  • now (Time) (defaults to: Time.now.utc)

Returns:



194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
 
# File 'vulns/osv_export.rb', line 194

def self.record_for(formula, vuln_id, patches: formula.serialized_patches,
                    fixed: formula.pkg_version.to_s, upstream: nil, now: Time.now.utc)
  timestamp = now.strftime("%Y-%m-%dT%H:%M:%SZ")
  record = T.let({
    schema_version:    SCHEMA_VERSION,
    id:                record_id(formula, vuln_id),
    published:         timestamp,
    modified:          timestamp,
    upstream:          [vuln_id],
    affected:          [affected_entry(formula, vuln_id, patches, fixed)],
    database_specific: { source: "generated" },
  }, T::Hash[Symbol, T.untyped])

  if upstream
    record[:summary] = upstream["summary"] if upstream["summary"]
    record[:details] = upstream["details"] if upstream["details"]
    record[:severity] = upstream["severity"] if upstream["severity"]
    record[:upstream] = ([vuln_id] + Array(upstream["aliases"])).uniq
    if (refs = upstream["references"])
      # OSV.dev merges NVD and cve.org reference lists without normalising
      # percent-encoding, so the same URL can appear twice (e.g. `%40` vs
      # `@`). Collapse those while keeping the same URL under distinct
      # `type` values, which the schema allows and which carries meaning.
      record[:references] = refs.uniq do |r|
        [r["type"], URI::RFC2396_PARSER.unescape(r["url"].to_s)]
      end
    end
  end

  record
end

.record_id(formula, vuln_id) ⇒ String

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Parameters:

Returns:



227
228
229
 
# File 'vulns/osv_export.rb', line 227

def self.record_id(formula, vuln_id)
  "#{ID_PREFIX}-#{formula.name}-#{vuln_id}"
end

.run(annotated, dir, first_fixed: nil, now: Time.now.utc) ⇒ Array<String>

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

annotated is a list of [formula, serialized_patches] pairs. The patches are passed in rather than read from the formula so callers can supply the union across OS/architecture variations (a patch inside an on_linux/on_intel block only appears in Formula#serialized_patches under the matching SimulateSystem).

first_fixed, when given, is called (formula, vuln_id) -> String? for records with no existing file to derive an accurate fixed boundary (e.g. via FormulaVersions git history); existing records preserve their on-disk ranges regardless.

Parameters:

Returns:



56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
 
# File 'vulns/osv_export.rb', line 56

def self.run(annotated, dir, first_fixed: nil, now: Time.now.utc)
  FileUtils.mkdir_p(dir)
  written = []
  upstream_cache = T.let({}, T::Hash[String, T.any(T::Hash[String, T.untyped], Symbol)])

  annotated.each do |formula, patches|
    Scanner.resolved_ids(patches).each do |vuln_id|
      upstream = upstream_cache.fetch(vuln_id) { upstream_cache[vuln_id] = fetch_upstream(vuln_id) }
      path = File.join(dir, "#{record_id(formula, vuln_id)}.json")
      existing = File.file?(path)
      # A transient OSV outage would otherwise strip summary/severity/etc.
      # from an existing enriched record; leave it untouched instead.
      next if upstream == :failed && existing

      fixed = (first_fixed&.call(formula, vuln_id) unless existing) || formula.pkg_version.to_s
      record = record_for(formula, vuln_id, patches:, fixed:,
                          upstream: upstream.is_a?(Hash) ? upstream : nil, now:)
      merged = merge_existing(path, record)
      next if merged.nil?

      File.write(path, "#{JSON.pretty_generate(merged)}\n")
      written << path
    end
  end

  written
end