[PATCH 5.4 23/71] ima: Fix a potential integer overflow in ima_appraise_measurement

Greg Kroah-Hartman
2022-07-19T12:10:59Z

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 23b04c6521b2..9368688449b0 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -352,7 +352,8 @@ 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