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authorWenwen Wang <wang6495@umn.edu>2018-05-18 22:55:35 +0300
committerHerbert Xu <herbert@gondor.apana.org.au>2018-05-26 19:12:04 +0300
commitf16b613ca8b3e4960cdc5575e9b8e1dbdd7d54d5 (patch)
tree09669bcf8732481c28af90f5b391cf34d7d76c7c /drivers/crypto/chelsio/chtls/chtls_main.c
parent01ba061d0fd769e4aa657561a2ff88e6c19e34e6 (diff)
downloadlinux-f16b613ca8b3e4960cdc5575e9b8e1dbdd7d54d5.tar.xz
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.c10
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;