[PATCH] evm: zero-initialize the evm_xattrs read buffer

[Pengpeng Hou]

evm_read_xattrs() allocates size + 1 bytes, fills them from the list of
enabled xattrs and then passes strlen(temp) to simple_read_from_buffer().
When no configured xattrs are enabled, the fill loop stores nothing and
temp[0] remains uninitialized, so strlen() reads beyond initialized
memory.

Use kzalloc() so the empty-list case stays a valid empty C string.

Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
---
 security/integrity/evm/evm_secfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c
index acd840461902..03d376fa36c2 100644
--- a/security/integrity/evm/evm_secfs.c
+++ b/security/integrity/evm/evm_secfs.c
@@ -145,7 +145,7 @@ static ssize_t evm_read_xattrs(struct file *filp, char __user *buf,
 		size += strlen(xattr->name) + 1;
 	}
 
-	temp = kmalloc(size + 1, GFP_KERNEL);
+	temp = kzalloc(size + 1, GFP_KERNEL);
 	if (!temp) {
 		mutex_unlock(&xattr_list_mutex);
 		return -ENOMEM;
-- 
2.50.1 (Apple Git-155)