Commit 9f4ef6a9 authored by Roberto Sassu's avatar Roberto Sassu Committed by Greg Kroah-Hartman
Browse files

evm: Check size of security.evm before using it

commit 455b6c9112eff8d249e32ba165742085678a80a4 upstream.

This patch checks the size for the EVM_IMA_XATTR_DIGSIG and
EVM_XATTR_PORTABLE_DIGSIG types to ensure that the algorithm is read from
the buffer returned by vfs_getxattr_alloc().

Cc: stable@vger.kernel.org # 4.19.x
Fixes: 5feeb611

 ("evm: Allow non-SHA1 digital signatures")
Signed-off-by: default avatarRoberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: default avatarMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a42b1273
......@@ -181,6 +181,12 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
break;
case EVM_IMA_XATTR_DIGSIG:
case EVM_XATTR_PORTABLE_DIGSIG:
/* accept xattr with non-empty signature field */
if (xattr_len <= sizeof(struct signature_v2_hdr)) {
evm_status = INTEGRITY_FAIL;
goto out;
}
hdr = (struct signature_v2_hdr *)xattr_data;
digest.hdr.algo = hdr->hash_algo;
rc = evm_calc_hash(dentry, xattr_name, xattr_value,
......
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