| Message ID | 20190516161257.6640-1-roberto.sassu@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/4] evm: check hash algorithm passed to init_desc() | expand |
On Thu, 2019-05-16 at 18:12 +0200, Roberto Sassu wrote: > This patch prevents memory access beyond the evm_tfm array by checking the > validity of the index (hash algorithm) passed to init_desc(). The hash > algorithm can be arbitrarily set if the security.ima xattr type is not > EVM_XATTR_HMAC. > > Fixes: 5feeb61183dde ("evm: Allow non-SHA1 digital signatures") > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > Cc: stable@vger.kernel.org Thanks! > --- > security/integrity/evm/evm_crypto.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c > index e11564eb645b..82a38e801ee4 100644 > --- a/security/integrity/evm/evm_crypto.c > +++ b/security/integrity/evm/evm_crypto.c > @@ -89,6 +89,9 @@ static struct shash_desc *init_desc(char type, uint8_t hash_algo) > tfm = &hmac_tfm; > algo = evm_hmac; > } else { > + if (hash_algo >= HASH_ALGO__LAST) > + return ERR_PTR(-EINVAL); > + > tfm = &evm_tfm[hash_algo]; > algo = hash_algo_name[hash_algo]; > }
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c index e11564eb645b..82a38e801ee4 100644 --- a/security/integrity/evm/evm_crypto.c +++ b/security/integrity/evm/evm_crypto.c @@ -89,6 +89,9 @@ static struct shash_desc *init_desc(char type, uint8_t hash_algo) tfm = &hmac_tfm; algo = evm_hmac; } else { + if (hash_algo >= HASH_ALGO__LAST) + return ERR_PTR(-EINVAL); + tfm = &evm_tfm[hash_algo]; algo = hash_algo_name[hash_algo]; }
This patch prevents memory access beyond the evm_tfm array by checking the validity of the index (hash algorithm) passed to init_desc(). The hash algorithm can be arbitrarily set if the security.ima xattr type is not EVM_XATTR_HMAC. Fixes: 5feeb61183dde ("evm: Allow non-SHA1 digital signatures") Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Cc: stable@vger.kernel.org --- security/integrity/evm/evm_crypto.c | 3 +++ 1 file changed, 3 insertions(+)