drivers: virt: acrn: hsm: Use kzalloc to avoid info leak in pmcmd_ioctl

In the "pmcmd_ioctl" function, three memory objects allocated by
kmalloc are initialized by "hcall_get_cpu_state", which are then
copied to user space. The initializer is indeed implemented in
"acrn_hypercall2" (arch/x86/include/asm/acrn.h). There is a risk of
information leakage due to uninitialized bytes.

Fixes: 3d679d5 ("virt: acrn: Introduce interfaces to query C-states and P-states allowed by hypervisor")
Signed-off-by: Haoyu Li <lihaoyu499@gmail.com>
Cc: stable <stable@kernel.org>
Acked-by: Fei Li <fei1.li@intel.com>
Link: https://lore.kernel.org/r/20250130115811.92424-1-lihaoyu499@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/virt/acrn/hsm.c

@@ -49,7 +49,7 @@ static int pmcmd_ioctl(u64 cmd, void __user *uptr)
 	switch (cmd & PMCMD_TYPE_MASK) {
 	case ACRN_PMCMD_GET_PX_CNT:
 	case ACRN_PMCMD_GET_CX_CNT:
-		pm_info = kmalloc(sizeof(u64), GFP_KERNEL);
+		pm_info = kzalloc(sizeof(u64), GFP_KERNEL);
 		if (!pm_info)
 			return -ENOMEM;
 
@@ -64,7 +64,7 @@ static int pmcmd_ioctl(u64 cmd, void __user *uptr)
 		kfree(pm_info);
 		break;
 	case ACRN_PMCMD_GET_PX_DATA:
-		px_data = kmalloc(sizeof(*px_data), GFP_KERNEL);
+		px_data = kzalloc(sizeof(*px_data), GFP_KERNEL);
 		if (!px_data)
 			return -ENOMEM;
 
@@ -79,7 +79,7 @@ static int pmcmd_ioctl(u64 cmd, void __user *uptr)
 		kfree(px_data);
 		break;
 	case ACRN_PMCMD_GET_CX_DATA:
-		cx_data = kmalloc(sizeof(*cx_data), GFP_KERNEL);
+		cx_data = kzalloc(sizeof(*cx_data), GFP_KERNEL);
 		if (!cx_data)
 			return -ENOMEM;