diff options
| author | David Howells <dhowells@redhat.com> | 2026-05-16 00:05:13 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-05-20 16:36:45 -0700 |
| commit | 2b50aceafe6606ea52ed42aadd1b4d44a188aade (patch) | |
| tree | 0613b29044f8b780928f6d1237a45f064539dff1 /crypto | |
| parent | b1a736f8bcb1b0ec4ce657f6fa9afc1f698f8f7a (diff) | |
| download | linux-next-history-2b50aceafe6606ea52ed42aadd1b4d44a188aade.tar.gz | |
crypto/krb5, rxrpc: Fix lack of pre-decrypt/pre-verify length checks
Change the krb5 crypto library to provide facilities to precheck the length
of the message about to be decrypted or verified.
Fix AF_RXRPC to make use of this to validate DATA packets secured with
RxGK.
Fixes: 9d1d2b59341f ("rxrpc: rxgk: Implement the yfs-rxgk security class (GSSAPI)")
Closes: https://sashiko.dev/#/patchset/20260511160753.607296-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Herbert Xu <herbert@gondor.apana.org.au>
cc: Simon Horman <horms@kernel.org>
cc: Chuck Lever <chuck.lever@oracle.com>
cc: linux-afs@lists.infradead.org
Reviewed-by: Jeffrey Altman <jaltman@auristor.com>
Tested-by: Marc Dionne <marc.dionne@auristor.com>
Link: https://patch.msgid.link/20260515230516.2718212-2-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/krb5/krb5_api.c | 54 |
1 files changed, 48 insertions, 6 deletions
diff --git a/crypto/krb5/krb5_api.c b/crypto/krb5/krb5_api.c index 23026d4206c82..c7ea40f900a77 100644 --- a/crypto/krb5/krb5_api.c +++ b/crypto/krb5/krb5_api.c @@ -134,27 +134,69 @@ EXPORT_SYMBOL(crypto_krb5_how_much_data); * Find the offset and size of the data in a secure message so that this * information can be used in the metadata buffer which will get added to the * digest by crypto_krb5_verify_mic(). + * + * Return: 0 if successful, -EBADMSG if the message is too short or -EINVAL if + * the mode is unsupported. */ -void crypto_krb5_where_is_the_data(const struct krb5_enctype *krb5, - enum krb5_crypto_mode mode, - size_t *_offset, size_t *_len) +int crypto_krb5_where_is_the_data(const struct krb5_enctype *krb5, + enum krb5_crypto_mode mode, + size_t *_offset, size_t *_len) { switch (mode) { case KRB5_CHECKSUM_MODE: + if (*_len < krb5->cksum_len) + return -EBADMSG; *_offset += krb5->cksum_len; *_len -= krb5->cksum_len; - return; + return 0; case KRB5_ENCRYPT_MODE: + if (*_len < krb5->conf_len + krb5->cksum_len) + return -EBADMSG; *_offset += krb5->conf_len; *_len -= krb5->conf_len + krb5->cksum_len; - return; + return 0; default: WARN_ON_ONCE(1); - return; + return -EINVAL; } } EXPORT_SYMBOL(crypto_krb5_where_is_the_data); +/** + * crypto_krb5_check_data_len - Check a message is big enough + * @krb5: The encoding to use. + * @mode: Mode of operation. + * @len: The length of the secure blob. + * @min_content: Minimum length of the content inside the blob. + * + * Check that a message is large enough to hold whatever bits the encryption + * type wants to glue on (nonce, checksum) plus a minimum amount of content. + * + * Return: 0 if successful, -EBADMSG if the message is too short or -EINVAL if + * the mode is unsupported. + */ +int crypto_krb5_check_data_len(const struct krb5_enctype *krb5, + enum krb5_crypto_mode mode, + size_t len, size_t min_content) +{ + switch (mode) { + case KRB5_CHECKSUM_MODE: + if (len < krb5->cksum_len || + len - krb5->cksum_len < min_content) + return -EBADMSG; + return 0; + case KRB5_ENCRYPT_MODE: + if (len < krb5->conf_len + krb5->cksum_len || + len - (krb5->conf_len + krb5->cksum_len) < min_content) + return -EBADMSG; + return 0; + default: + WARN_ON_ONCE(1); + return -EINVAL; + } +} +EXPORT_SYMBOL(crypto_krb5_check_data_len); + /* * Prepare the encryption with derived key data. */ |