* [PATCH] lkdtm: Add checks after calling kmalloc and vmalloc
@ 2022-08-31 6:53 Jiasheng Jiang
2022-08-31 7:00 ` Greg KH
0 siblings, 1 reply; 2+ messages in thread
From: Jiasheng Jiang @ 2022-08-31 6:53 UTC (permalink / raw)
To: keescook, arnd, gregkh; +Cc: linux-kernel, Jiasheng Jiang
As the potential failure of the memory allocation,
it should be better to check the return value after
calling kmalloc and vmalloc and skip the execute_location
if fails.
Fixes: cc33c537c12f ("lkdtm: add "EXEC_*" triggers")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
---
drivers/misc/lkdtm/perms.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c
index b93404d65650..9ba927d74973 100644
--- a/drivers/misc/lkdtm/perms.c
+++ b/drivers/misc/lkdtm/perms.c
@@ -180,14 +180,16 @@ static void lkdtm_EXEC_STACK(void)
static void lkdtm_EXEC_KMALLOC(void)
{
u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
- execute_location(kmalloc_area, CODE_WRITE);
+ if (kmalloc_area)
+ execute_location(kmalloc_area, CODE_WRITE);
kfree(kmalloc_area);
}
static void lkdtm_EXEC_VMALLOC(void)
{
u32 *vmalloc_area = vmalloc(EXEC_SIZE);
- execute_location(vmalloc_area, CODE_WRITE);
+ if (vmalloc_area)
+ execute_location(vmalloc_area, CODE_WRITE);
vfree(vmalloc_area);
}
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] lkdtm: Add checks after calling kmalloc and vmalloc
2022-08-31 6:53 [PATCH] lkdtm: Add checks after calling kmalloc and vmalloc Jiasheng Jiang
@ 2022-08-31 7:00 ` Greg KH
0 siblings, 0 replies; 2+ messages in thread
From: Greg KH @ 2022-08-31 7:00 UTC (permalink / raw)
To: Jiasheng Jiang; +Cc: keescook, arnd, linux-kernel
On Wed, Aug 31, 2022 at 02:53:55PM +0800, Jiasheng Jiang wrote:
> As the potential failure of the memory allocation,
> it should be better to check the return value after
> calling kmalloc and vmalloc and skip the execute_location
> if fails.
>
> Fixes: cc33c537c12f ("lkdtm: add "EXEC_*" triggers")
> Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
> ---
> drivers/misc/lkdtm/perms.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c
> index b93404d65650..9ba927d74973 100644
> --- a/drivers/misc/lkdtm/perms.c
> +++ b/drivers/misc/lkdtm/perms.c
> @@ -180,14 +180,16 @@ static void lkdtm_EXEC_STACK(void)
> static void lkdtm_EXEC_KMALLOC(void)
> {
> u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
> - execute_location(kmalloc_area, CODE_WRITE);
> + if (kmalloc_area)
How will this ever fail? Have you seen that happen?
> + execute_location(kmalloc_area, CODE_WRITE);
> kfree(kmalloc_area);
> }
>
> static void lkdtm_EXEC_VMALLOC(void)
> {
> u32 *vmalloc_area = vmalloc(EXEC_SIZE);
> - execute_location(vmalloc_area, CODE_WRITE);
> + if (vmalloc_area)
Same here, if the system really can not allocate 64 bytes, much worse
things will have happened already.
thanks,
greg k-h
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-08-31 6:53 [PATCH] lkdtm: Add checks after calling kmalloc and vmalloc Jiasheng Jiang
2022-08-31 7:00 ` Greg KH
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