2022-01-25 08:41:10

by Gustavo A. R. Silva

[permalink] [raw]
Subject: [PATCH][next] apparmor: Use struct_size() helper in kmalloc()

Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows that,
in the worst scenario, could lead to heap overflows.

Also, address the following sparse warnings:
security/apparmor/lib.c:139:23: warning: using sizeof on a flexible structure

Link: https://github.com/KSPP/linux/issues/174
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
security/apparmor/lib.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/apparmor/lib.c b/security/apparmor/lib.c
index fa49b81eb54c..5eda003c0d45 100644
--- a/security/apparmor/lib.c
+++ b/security/apparmor/lib.c
@@ -136,7 +136,7 @@ __counted char *aa_str_alloc(int size, gfp_t gfp)
{
struct counted_str *str;

- str = kmalloc(sizeof(struct counted_str) + size, gfp);
+ str = kmalloc(struct_size(str, name, size), gfp);
if (!str)
return NULL;

--
2.27.0


2022-01-26 20:46:52

by John Johansen

[permalink] [raw]
Subject: Re: [PATCH][next] apparmor: Use struct_size() helper in kmalloc()

On 1/24/22 17:56, Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded version,
> in order to avoid any potential type mistakes or integer overflows that,
> in the worst scenario, could lead to heap overflows.
>
> Also, address the following sparse warnings:
> security/apparmor/lib.c:139:23: warning: using sizeof on a flexible structure
>
> Link: https://github.com/KSPP/linux/issues/174
> Signed-off-by: Gustavo A. R. Silva <[email protected]>

thanks, I have pulled this into my tree
Acked-by: John Johansen <[email protected]>

> ---
> security/apparmor/lib.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/security/apparmor/lib.c b/security/apparmor/lib.c
> index fa49b81eb54c..5eda003c0d45 100644
> --- a/security/apparmor/lib.c
> +++ b/security/apparmor/lib.c
> @@ -136,7 +136,7 @@ __counted char *aa_str_alloc(int size, gfp_t gfp)
> {
> struct counted_str *str;
>
> - str = kmalloc(sizeof(struct counted_str) + size, gfp);
> + str = kmalloc(struct_size(str, name, size), gfp);
> if (!str)
> return NULL;
>