Commit 455b6c91 authored Sep 04, 2020 by Roberto Sassu Committed by Mimi Zohar Sep 15, 2020

evm: Check size of security.evm before using it



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: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

parent 4be92db3

security/integrity/evm/evm_main.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -184,6 +184,12 @@ 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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