evm: fix writing <securityfs>/evm overflow

EVM_SETUP_COMPLETE is defined as 0x80000000, which is larger than INT_MAX. The "-fno-strict-overflow" compiler option properly prevents signaling EVM that the EVM policy setup is complete. Define and read an unsigned int. Fixes: f00d797 ("EVM: Allow userspace to signal an RSA key has been loaded") Signed-off-by: Mimi Zohar <[email protected]>
kawasaki · May 20, 2021 · 49219d9 · 49219d9
1 parent d07f6ca
commit 49219d9
Showing 1 changed file with 3 additions and 2 deletions.
diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c
@@ -66,12 +66,13 @@ static ssize_t evm_read_key(struct file *filp, char __user *buf,
 static ssize_t evm_write_key(struct file *file, const char __user *buf,
 			     size_t count, loff_t *ppos)
 {
-	int i, ret;
+	unsigned int i;
+	int ret;
 
 	if (!capable(CAP_SYS_ADMIN) || (evm_initialized & EVM_SETUP_COMPLETE))
 		return -EPERM;
 
-	ret = kstrtoint_from_user(buf, count, 0, &i);
+	ret = kstrtouint_from_user(buf, count, 0, &i);
 
 	if (ret)
 		return ret;