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authorSeth Forshee <seth.forshee@canonical.com>2016-08-01 08:19:10 -0500
committerMimi Zohar <zohar@linux.vnet.ibm.com>2016-11-13 22:50:11 -0500
commitb4bfec7f4a86424b114f94f41c4e1841ec102df3 (patch)
tree9f4a668c3d28ef3de0743d3dda285829b38a85a3 /security
parent5465d02a4970990d8ec692c7539af5fdde95e613 (diff)
downloadlinux-stericsson-b4bfec7f4a86424b114f94f41c4e1841ec102df3.tar.gz
security/integrity: Harden against malformed xattrs
In general the handling of IMA/EVM xattrs is good, but I found a few locations where either the xattr size or the value of the type field in the xattr are not checked. Add a few simple checks to these locations to prevent malformed or malicious xattrs from causing problems. Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Diffstat (limited to 'security')
-rw-r--r--security/integrity/digsig.c2
-rw-r--r--security/integrity/evm/evm_main.c4
-rw-r--r--security/integrity/ima/ima_appraise.c5
3 files changed, 9 insertions, 2 deletions
diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index 4304372b323f..106e855e2d9d 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -51,7 +51,7 @@ static bool init_keyring __initdata;
int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
const char *digest, int digestlen)
{
- if (id >= INTEGRITY_KEYRING_MAX)
+ if (id >= INTEGRITY_KEYRING_MAX || siglen < 2)
return -EINVAL;
if (!keyring[id]) {
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index ba8615576d4d..e2ed498c0f5f 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -145,6 +145,10 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
/* check value type */
switch (xattr_data->type) {
case EVM_XATTR_HMAC:
+ if (xattr_len != sizeof(struct evm_ima_xattr_data)) {
+ evm_status = INTEGRITY_FAIL;
+ goto out;
+ }
rc = evm_calc_hmac(dentry, xattr_name, xattr_value,
xattr_value_len, calc.digest);
if (rc)
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index a705598ced5f..1fd9539a969d 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -130,6 +130,7 @@ enum hash_algo ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value,
int xattr_len)
{
struct signature_v2_hdr *sig;
+ enum hash_algo ret;
if (!xattr_value || xattr_len < 2)
/* return default hash algo */
@@ -143,7 +144,9 @@ enum hash_algo ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value,
return sig->hash_algo;
break;
case IMA_XATTR_DIGEST_NG:
- return xattr_value->digest[0];
+ ret = xattr_value->digest[0];
+ if (ret < HASH_ALGO__LAST)
+ return ret;
break;
case IMA_XATTR_DIGEST:
/* this is for backward compatibility */