Skip to content

Fix ed25519 key comparison in dkim_test_key #245

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

Open
jcastle-gh wants to merge 1 commit into
base: develop
Choose a base branch
from
Open

Fix ed25519 key comparison in dkim_test_key #245

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
35 changes: 31 additions & 4 deletions libopendkim/dkim-test.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -301,6 +301,7 @@ dkim_test_key(DKIM_LIB *lib, char *selector, char *domain,
BIO *outkey;
#endif /* USE_GNUTLS */
void *ptr;
long pubkey_bio_bytes;
struct dkim_crypto *crypto;
char buf[BUFRSZ];

Expand Down Expand Up @@ -407,7 +408,6 @@ dkim_test_key(DKIM_LIB *lib, char *selector, char *domain,
#endif /* USE_GNUTLS */

sig->sig_signature = (void *) crypto;
sig->sig_keytype = DKIM_KEYTYPE_RSA;

#ifdef USE_GNUTLS
if (err != NULL)
Expand Down Expand Up @@ -465,15 +465,42 @@ dkim_test_key(DKIM_LIB *lib, char *selector, char *domain,
(void) dkim_free(dkim);
if (err != NULL)
{
strlcpy(err, "i2d_RSA_PUBKEY_bio() failed",
strlcpy(err, "i2d_PUBKEY_bio() failed",
errlen);
}
return -1;
}

(void) BIO_get_mem_data(outkey, &ptr);
pubkey_bio_bytes = BIO_get_mem_data(outkey, &ptr);

if (BIO_number_written(outkey) == sig->sig_keylen)
/* The ed25519 pubkey in DNS doesn't have the 12-byte ASN */
/* prefix that RSA keys in DNS and the i2d_PUBKEY output do. */
/* Verify and skip over it for the comparison. */
if(EVP_PKEY_id(crypto->crypto_pkey) == EVP_PKEY_ED25519)
{
const unsigned char asnhdr[12] =
{ 0x30, 0x2a, 0x30, 0x05,
0x06, 0x03, 0x2b, 0x65,
0x70, 0x03, 0x21, 0x00 };
if(pubkey_bio_bytes != 44 ||
memcmp(ptr, asnhdr, sizeof(asnhdr)))
{
BIO_free(keybuf);
BIO_free(outkey);
(void) dkim_free(dkim);
if (err != NULL)
{
strlcpy(err,
"invalid Ed25519 PUBKEY conversion",
errlen);
}
return -1;
}
ptr += sizeof(asnhdr);
pubkey_bio_bytes -= sizeof(asnhdr);
}

if (pubkey_bio_bytes == sig->sig_keylen)
status = memcmp(ptr, sig->sig_key, sig->sig_keylen);
else
status = 1;
Expand Down