diff options
Diffstat (limited to 'vendor/gopkg.in/yaml.v2/decode.go')
| -rw-r--r-- | vendor/gopkg.in/yaml.v2/decode.go | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/vendor/gopkg.in/yaml.v2/decode.go b/vendor/gopkg.in/yaml.v2/decode.go index e4e56e28..53108765 100644 --- a/vendor/gopkg.in/yaml.v2/decode.go +++ b/vendor/gopkg.in/yaml.v2/decode.go @@ -229,6 +229,10 @@ type decoder struct { mapType reflect.Type terrors []string strict bool + + decodeCount int + aliasCount int + aliasDepth int } var ( @@ -314,7 +318,39 @@ func (d *decoder) prepare(n *node, out reflect.Value) (newout reflect.Value, unm return out, false, false } +const ( + // 400,000 decode operations is ~500kb of dense object declarations, or ~5kb of dense object declarations with 10000% alias expansion + alias_ratio_range_low = 400000 + // 4,000,000 decode operations is ~5MB of dense object declarations, or ~4.5MB of dense object declarations with 10% alias expansion + alias_ratio_range_high = 4000000 + // alias_ratio_range is the range over which we scale allowed alias ratios + alias_ratio_range = float64(alias_ratio_range_high - alias_ratio_range_low) +) + +func allowedAliasRatio(decodeCount int) float64 { + switch { + case decodeCount <= alias_ratio_range_low: + // allow 99% to come from alias expansion for small-to-medium documents + return 0.99 + case decodeCount >= alias_ratio_range_high: + // allow 10% to come from alias expansion for very large documents + return 0.10 + default: + // scale smoothly from 99% down to 10% over the range. + // this maps to 396,000 - 400,000 allowed alias-driven decodes over the range. + // 400,000 decode operations is ~100MB of allocations in worst-case scenarios (single-item maps). + return 0.99 - 0.89*(float64(decodeCount-alias_ratio_range_low)/alias_ratio_range) + } +} + func (d *decoder) unmarshal(n *node, out reflect.Value) (good bool) { + d.decodeCount++ + if d.aliasDepth > 0 { + d.aliasCount++ + } + if d.aliasCount > 100 && d.decodeCount > 1000 && float64(d.aliasCount)/float64(d.decodeCount) > allowedAliasRatio(d.decodeCount) { + failf("document contains excessive aliasing") + } switch n.kind { case documentNode: return d.document(n, out) @@ -353,7 +389,9 @@ func (d *decoder) alias(n *node, out reflect.Value) (good bool) { failf("anchor '%s' value contains itself", n.value) } d.aliases[n] = true + d.aliasDepth++ good = d.unmarshal(n.alias, out) + d.aliasDepth-- delete(d.aliases, n) return good } |