From: Roberto Sassu <roberto.sassu@huaweicloud.com>
To: zohar@linux.ibm.com, dmitry.kasatkin@gmail.com,
paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com
Cc: linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org,
Roberto Sassu <roberto.sassu@huawei.com>,
stable@vger.kernel.org
Subject: [PATCH v2 1/2] evm: Alloc evm_digest in evm_verify_hmac() if CONFIG_VMAP_STACK=y
Date: Thu, 1 Dec 2022 11:06:24 +0100 [thread overview]
Message-ID: <20221201100625.916781-2-roberto.sassu@huaweicloud.com> (raw)
In-Reply-To: <20221201100625.916781-1-roberto.sassu@huaweicloud.com>
From: Roberto Sassu <roberto.sassu@huawei.com>
Commit ac4e97abce9b8 ("scatterlist: sg_set_buf() argument must be in linear
mapping") checks that both the signature and the digest reside in the
linear mapping area.
However, more recently commit ba14a194a434c ("fork: Add generic vmalloced
stack support"), made it possible to move the stack in the vmalloc area,
which is not contiguous, and thus not suitable for sg_set_buf() which needs
adjacent pages.
Fix this by checking if CONFIG_VMAP_STACK is enabled. If yes, allocate an
evm_digest structure, and use that instead of the in-stack counterpart.
Cc: stable@vger.kernel.org # 4.9.x
Fixes: ba14a194a434 ("fork: Add generic vmalloced stack support")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
security/integrity/evm/evm_main.c | 26 +++++++++++++++++++++-----
1 file changed, 21 insertions(+), 5 deletions(-)
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index 23d484e05e6f..7f76d6103f2e 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -174,6 +174,7 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
struct signature_v2_hdr *hdr;
enum integrity_status evm_status = INTEGRITY_PASS;
struct evm_digest digest;
+ struct evm_digest *digest_ptr = &digest;
struct inode *inode;
int rc, xattr_len, evm_immutable = 0;
@@ -231,14 +232,26 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
}
hdr = (struct signature_v2_hdr *)xattr_data;
- digest.hdr.algo = hdr->hash_algo;
+
+ if (IS_ENABLED(CONFIG_VMAP_STACK)) {
+ digest_ptr = kmalloc(sizeof(*digest_ptr), GFP_NOFS);
+ if (!digest_ptr) {
+ rc = -ENOMEM;
+ break;
+ }
+ }
+
+ digest_ptr->hdr.algo = hdr->hash_algo;
+
rc = evm_calc_hash(dentry, xattr_name, xattr_value,
- xattr_value_len, xattr_data->type, &digest);
+ xattr_value_len, xattr_data->type,
+ digest_ptr);
if (rc)
break;
rc = integrity_digsig_verify(INTEGRITY_KEYRING_EVM,
(const char *)xattr_data, xattr_len,
- digest.digest, digest.hdr.length);
+ digest_ptr->digest,
+ digest_ptr->hdr.length);
if (!rc) {
inode = d_backing_inode(dentry);
@@ -268,8 +281,11 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
else
evm_status = INTEGRITY_FAIL;
}
- pr_debug("digest: (%d) [%*phN]\n", digest.hdr.length, digest.hdr.length,
- digest.digest);
+ pr_debug("digest: (%d) [%*phN]\n", digest_ptr->hdr.length,
+ digest_ptr->hdr.length, digest_ptr->digest);
+
+ if (digest_ptr && digest_ptr != &digest)
+ kfree(digest_ptr);
out:
if (iint)
iint->evm_status = evm_status;
--
2.25.1
next prev parent reply other threads:[~2022-12-01 10:07 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-01 10:06 [PATCH v2 0/2] ima/evm: Ensure digest to verify is in linear mapping area Roberto Sassu
2022-12-01 10:06 ` Roberto Sassu [this message]
2022-12-01 18:53 ` [PATCH v2 1/2] evm: Alloc evm_digest in evm_verify_hmac() if CONFIG_VMAP_STACK=y Eric Biggers
2022-12-01 19:08 ` Mimi Zohar
2022-12-01 19:12 ` Eric Biggers
2022-12-02 7:58 ` Roberto Sassu
2022-12-02 18:49 ` Eric Biggers
2022-12-05 8:22 ` Roberto Sassu
2022-12-08 1:26 ` Mimi Zohar
2022-12-08 8:32 ` Roberto Sassu
2022-12-01 10:06 ` [PATCH v2 2/2] ima: Alloc ima_max_digest_data in xattr_verify() " Roberto Sassu
2022-12-01 18:55 ` Eric Biggers
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