diff options
| author | Jérémy Jean <Jeremy.Jean@oss.cyber.gouv.fr> | 2026-08-21 19:25:03 +0000 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2026-09-23 18:35:32 +1000 |
| commit | 2618f76b277cef3df8ebdff403b05705f5f8a36d (patch) | |
| tree | 9f0fc0a1409968e65ea0587d94af52a9c4dea5fb /crypto | |
| parent | a9a2152d292fd0bc73814eb4a127278ee7dd3f6a (diff) | |
crypto: asymmetric_keys/x509 - copy X.509 TBS for data signature algorithms
For signature algorithms operating on a message rather than a digest,
x509_get_sig_params() points sig->m directly into cert->tbs.
cert->tbs is the preparsed add_key() payload. The syscall wipes and frees
it on return, while the instantiated key retains public_key_signature.
A later KEYCTL_LINK into an asymmetric restricted keyring therefore passes
a dangling message pointer to ML-DSA. KASAN reports a slab-use-after-free
in mldsa_verify(), with allocation and free provenance both leading to
__do_sys_add_key(). Reuse is also an integrity issue: bytes occupying the
freed object become the authenticated message instead of the certificate's
own TBSCertificate.
Give the signature object its own copy of the TBS, as is already done for
a precomputed digest, and release it through the existing m_free contract.
Fixes: f3eccecd782d ("pkcs7: Allow the signing algo to do whatever digestion it wants itself")
Signed-off-by: Jérémy Jean <Jeremy.Jean@oss.cyber.gouv.fr>
Assisted-by: Codex:gpt-5
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/asymmetric_keys/x509_public_key.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c index 25cf8ac7f257..5c9165a83f91 100644 --- a/crypto/asymmetric_keys/x509_public_key.c +++ b/crypto/asymmetric_keys/x509_public_key.c @@ -53,9 +53,11 @@ int x509_get_sig_params(struct x509_certificate *cert) if (sig->algo_takes_data) { /* The signature algorithm does whatever passes for hashing. */ - sig->m = (u8 *)cert->tbs; + sig->m = kmemdup(cert->tbs, cert->tbs_size, GFP_KERNEL); + if (!sig->m) + return -ENOMEM; sig->m_size = cert->tbs_size; - sig->m_free = false; + sig->m_free = true; goto out; } |