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| author | Wenwen Wang <wang6495@umn.edu> | 2018-05-18 14:55:35 -0500 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2018-05-27 00:12:04 +0800 |
| commit | f16b613ca8b3e4960cdc5575e9b8e1dbdd7d54d5 (patch) | |
| tree | 09669bcf8732481c28af90f5b391cf34d7d76c7c /drivers/crypto/chelsio/chtls/chtls_main.c | |
| parent | 01ba061d0fd769e4aa657561a2ff88e6c19e34e6 (diff) | |
| download | lwn-f16b613ca8b3e4960cdc5575e9b8e1dbdd7d54d5.tar.gz lwn-f16b613ca8b3e4960cdc5575e9b8e1dbdd7d54d5.zip | |
crypto: chtls - fix a missing-check bug
In do_chtls_setsockopt(), the tls crypto info is first copied from the
poiner 'optval' in userspace and saved to 'tmp_crypto_info'. Then the
'version' of the crypto info is checked. If the version is not as expected,
i.e., TLS_1_2_VERSION, error code -ENOTSUPP is returned to indicate that
the provided crypto info is not supported yet. Then, the 'cipher_type'
field of the 'tmp_crypto_info' is also checked to see if it is
TLS_CIPHER_AES_GCM_128. If it is, the whole struct of
tls12_crypto_info_aes_gcm_128 is copied from the pointer 'optval' and then
the function chtls_setkey() is invoked to set the key.
Given that the 'optval' pointer resides in userspace, a malicious userspace
process can race to change the data pointed by 'optval' between the two
copies. For example, a user can provide a crypto info with TLS_1_2_VERSION
and TLS_CIPHER_AES_GCM_128. After the first copy, the user can modify the
'version' and the 'cipher_type' fields to any versions and/or cipher types
that are not allowed. This way, the user can bypass the checks, inject
bad data to the kernel, cause chtls_setkey() to set a wrong key or other
issues.
This patch reuses the data copied in the first try so as to ensure these
checks will not be bypassed.
Signed-off-by: Wenwen Wang <wang6495@umn.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'drivers/crypto/chelsio/chtls/chtls_main.c')
| -rw-r--r-- | drivers/crypto/chelsio/chtls/chtls_main.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/crypto/chelsio/chtls/chtls_main.c b/drivers/crypto/chelsio/chtls/chtls_main.c index 5b9dd582aac0..53ffb00d45bf 100644 --- a/drivers/crypto/chelsio/chtls/chtls_main.c +++ b/drivers/crypto/chelsio/chtls/chtls_main.c @@ -490,9 +490,13 @@ static int do_chtls_setsockopt(struct sock *sk, int optname, switch (tmp_crypto_info.cipher_type) { case TLS_CIPHER_AES_GCM_128: { - rc = copy_from_user(crypto_info, optval, - sizeof(struct - tls12_crypto_info_aes_gcm_128)); + /* Obtain version and type from previous copy */ + crypto_info[0] = tmp_crypto_info; + /* Now copy the following data */ + rc = copy_from_user((char *)crypto_info + sizeof(*crypto_info), + optval + sizeof(*crypto_info), + sizeof(struct tls12_crypto_info_aes_gcm_128) + - sizeof(*crypto_info)); if (rc) { rc = -EFAULT; |