Skip to content

Avoid more instances of the DRBG in GCable RAM by reseeding rather than regenerating. #146

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
sgmiller merged 1 commit into from
Feb 4, 2025
Merged

Avoid more instances of the DRBG in GCable RAM by reseeding rather than regenerating. #146

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
15 changes: 10 additions & 5 deletions cryptoutil/rsa.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -41,17 +41,22 @@ func GenerateRSAKeyWithHMACDRBG(rand io.Reader, bits int) (*rsa.PrivateKey, erro
}
}()

if _, err := rand.Read(seed); err != nil {
return nil, err
}
drbg := hmacdrbg.NewHmacDrbg(256, seed, []byte("generate-key-with-hmac-drbg"))
reader := hmacdrbg.NewHmacDrbgReader(drbg)

// Pretty unlikely to need even one reseed, but better to avoid an infinite loop.
for i := 0; i < maxReseeds; i++ {
if _, err := rand.Read(seed); err != nil {
return nil, err
}
drbg := hmacdrbg.NewHmacDrbg(256, seed, []byte("generate-key-with-hmac-drbg"))
reader := hmacdrbg.NewHmacDrbgReader(drbg)
key, err := rsa.GenerateKey(reader, bits)
if err != nil {
if err.Error() == "MUST_RESEED" {
// Oops, ran out of bytes (pretty unlikely but just in case)
if _, err := rand.Read(seed); err != nil {
return nil, err
}
drbg.Reseed(seed)
continue
}
return nil, err
Expand Down