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Add more safety checks for Unpacker

This commit is contained in:
Alexander Neumann 2016-08-23 22:21:29 +02:00
parent 9fd941f6fc
commit e07ae7631c
1 changed files with 12 additions and 2 deletions
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14
src/restic/pack/pack.go
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@ -235,7 +235,10 @@ type Unpacker struct {
k *crypto.Key k *crypto.Key
} }
const preloadHeaderSize = 2048 const (
preloadHeaderSize = 2048
maxHeaderSize = 16 * 1024 * 1024
)
// NewUnpacker returns a pointer to Unpacker which can be used to read // NewUnpacker returns a pointer to Unpacker which can be used to read
// individual Blobs from a pack. // individual Blobs from a pack.
@ -264,6 +267,10 @@ func NewUnpacker(k *crypto.Key, ldr Loader) (*Unpacker, error) {
length := int(binary.LittleEndian.Uint32(buf[p : p+bs])) length := int(binary.LittleEndian.Uint32(buf[p : p+bs]))
buf = buf[:p] buf = buf[:p]
if length > maxHeaderSize {
return nil, fmt.Errorf("header too large (%d bytes)", length)
}
// if the header is longer than the preloaded buffer, call the loader again. // if the header is longer than the preloaded buffer, call the loader again.
if length > len(buf) { if length > len(buf) {
buf = make([]byte, length) buf = make([]byte, length)
@ -271,7 +278,10 @@ func NewUnpacker(k *crypto.Key, ldr Loader) (*Unpacker, error) {
if err != nil { if err != nil {
return nil, fmt.Errorf("Load at -%d failed: %v", len(buf), err) return nil, fmt.Errorf("Load at -%d failed: %v", len(buf), err)
} }
buf = buf[:n]
if n != len(buf) {
return nil, fmt.Errorf("not enough header bytes read: wanted %v, got %v", len(buf), n)
}
} }
buf = buf[len(buf)-length:] buf = buf[len(buf)-length:]