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

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

[Haoyu Li]

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: 3d679d5aec64 ("virt: acrn: Introduce interfaces to query C-states and P-states allowed by hypervisor")
Signed-off-by: Haoyu Li <lihaoyu499@gmail.com>
Cc: stable@vger.kernel.org
---
 drivers/virt/acrn/hsm.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/virt/acrn/hsm.c b/drivers/virt/acrn/hsm.c
index c24036c4e51e..e4e196abdaac 100644
--- a/drivers/virt/acrn/hsm.c
+++ b/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;
 
-- 
2.34.1

RE: [PATCH] drivers: virt: acrn: hsm: Use kzalloc to avoid info leak in pmcmd_ioctl

[Li, Fei1]

> -----Original Message-----
> From: Haoyu Li <lihaoyu499@gmail.com>
> Sent: Thursday, January 30, 2025 7:58 PM
> To: Li, Fei1 <fei1.li@intel.com>; Shuo Liu <shuo.a.liu@intel.com>; Chatre,
> Reinette <reinette.chatre@intel.com>; Zhi Wang <zhi.a.wang@intel.com>;
> Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: linux-kernel@vger.kernel.org; chenyuan0y@gmail.com; Haoyu Li
> <lihaoyu499@gmail.com>; stable@vger.kernel.org
> Subject: [PATCH] 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: 3d679d5aec64 ("virt: acrn: Introduce interfaces to query C-states and P-
> states allowed by hypervisor")
> Signed-off-by: Haoyu Li <lihaoyu499@gmail.com>
Acked-by: Fei Li <fei1.li@intel.com>
Thanks.
> Cc: stable@vger.kernel.org
> ---
>  drivers/virt/acrn/hsm.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/virt/acrn/hsm.c b/drivers/virt/acrn/hsm.c index
> c24036c4e51e..e4e196abdaac 100644
> --- a/drivers/virt/acrn/hsm.c
> +++ b/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;
> 
> --
> 2.34.1