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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Huaxin Lu <luhuaxin1@huawei.com>,
        Mimi Zohar <zohar@linux.ibm.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 041/167] ima: Fix a potential integer overflow in ima_appraise_measurement
Date:   Tue, 19 Jul 2022 13:52:53 +0200
Message-Id: <20220719114700.650088221@linuxfoundation.org>
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From: Huaxin Lu <luhuaxin1@huawei.com>

[ Upstream commit d2ee2cfc4aa85ff6a2a3b198a3a524ec54e3d999 ]

When the ima-modsig is enabled, the rc passed to evm_verifyxattr() may be
negative, which may cause the integer overflow problem.

Fixes: 39b07096364a ("ima: Implement support for module-style appended signatures")
Signed-off-by: Huaxin Lu <luhuaxin1@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 security/integrity/ima/ima_appraise.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index dbba51583e7c..ed04bb7c7512 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -408,7 +408,8 @@ int ima_appraise_measurement(enum ima_hooks func,
 		goto out;
 	}
 
-	status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, rc, iint);
+	status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value,
+				 rc < 0 ? 0 : rc, iint);
 	switch (status) {
 	case INTEGRITY_PASS:
 	case INTEGRITY_PASS_IMMUTABLE:
-- 
2.35.1