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List:       linux-stable-commits
Subject:    Patch "evm: Check size of security.evm before using it" has been added to the 5.9-stable tree
From:       <gregkh () linuxfoundation ! org>
Date:       2020-10-31 10:24:53
Message-ID: 1604139893209133 () kroah ! com
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This is a note to let you know that I've just added the patch titled

    evm: Check size of security.evm before using it

to the 5.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     evm-check-size-of-security.evm-before-using-it.patch
and it can be found in the queue-5.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From 455b6c9112eff8d249e32ba165742085678a80a4 Mon Sep 17 00:00:00 2001
From: Roberto Sassu <roberto.sassu@huawei.com>
Date: Fri, 4 Sep 2020 11:23:30 +0200
Subject: evm: Check size of security.evm before using it

From: Roberto Sassu <roberto.sassu@huawei.com>

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: 5feeb61183dde ("evm: Allow non-SHA1 digital signatures")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 security/integrity/evm/evm_main.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -181,6 +181,12 @@ static enum integrity_status evm_verify_
 		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,


Patches currently in stable-queue which might be from roberto.sassu@huawei.com are

queue-5.9/evm-check-size-of-security.evm-before-using-it.patch
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