Re: [PATCH 2/2] ima: Free IMA measurement buffer after kexec syscall

2021-02-03 Thread Lakshmi Ramasubramanian 

On 1/22/21 2:31 PM, Thiago Jung Bauermann wrote:


Lakshmi Ramasubramanian  writes:


IMA allocates kernel virtual memory to carry forward the measurement
list, from the current kernel to the next kernel on kexec system call,
in ima_add_kexec_buffer() function.  This buffer is not freed before
completing the kexec system call resulting in memory leak.

Add ima_buffer field in "struct kimage" to store the virtual address
of the buffer allocated for the IMA measurement list.
Free the memory allocated for the IMA measurement list in
kimage_file_post_load_cleanup() function.

Signed-off-by: Lakshmi Ramasubramanian 
Suggested-by: Tyler Hicks 
Fixes: 7b8589cc29e7 ("ima: on soft reboot, save the measurement list")


Good catch.

Reviewed-by: Thiago Jung Bauermann 



Thanks Thiago.

 -lakshmi

Re: [PATCH 2/2] ima: Free IMA measurement buffer after kexec syscall

2021-01-22 Thread Thiago Jung Bauermann 


Lakshmi Ramasubramanian  writes:

> IMA allocates kernel virtual memory to carry forward the measurement
> list, from the current kernel to the next kernel on kexec system call,
> in ima_add_kexec_buffer() function.  This buffer is not freed before
> completing the kexec system call resulting in memory leak.
>
> Add ima_buffer field in "struct kimage" to store the virtual address
> of the buffer allocated for the IMA measurement list.
> Free the memory allocated for the IMA measurement list in
> kimage_file_post_load_cleanup() function.
>
> Signed-off-by: Lakshmi Ramasubramanian 
> Suggested-by: Tyler Hicks 
> Fixes: 7b8589cc29e7 ("ima: on soft reboot, save the measurement list")

Good catch.

Reviewed-by: Thiago Jung Bauermann 

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Re: [PATCH 2/2] ima: Free IMA measurement buffer after kexec syscall

2021-01-21 Thread Tyler Hicks 
On 2021-01-21 09:30:03, Lakshmi Ramasubramanian wrote:
> IMA allocates kernel virtual memory to carry forward the measurement
> list, from the current kernel to the next kernel on kexec system call,
> in ima_add_kexec_buffer() function.  This buffer is not freed before
> completing the kexec system call resulting in memory leak.
> 
> Add ima_buffer field in "struct kimage" to store the virtual address
> of the buffer allocated for the IMA measurement list.
> Free the memory allocated for the IMA measurement list in
> kimage_file_post_load_cleanup() function.
> 
> Signed-off-by: Lakshmi Ramasubramanian 
> Suggested-by: Tyler Hicks 
> Fixes: 7b8589cc29e7 ("ima: on soft reboot, save the measurement list")

Reviewed-by: Tyler Hicks 

Tyler

> ---
>  include/linux/kexec.h  | 5 +
>  kernel/kexec_file.c| 5 +
>  security/integrity/ima/ima_kexec.c | 2 ++
>  3 files changed, 12 insertions(+)
> 
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index 9e93bef52968..5f61389f5f36 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -300,6 +300,11 @@ struct kimage {
>   /* Information for loading purgatory */
>   struct purgatory_info purgatory_info;
>  #endif
> +
> +#ifdef CONFIG_IMA_KEXEC
> + /* Virtual address of IMA measurement buffer for kexec syscall */
> + void *ima_buffer;
> +#endif
>  };
>  
>  /* kexec interface functions */
> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
> index b02086d70492..5c3447cf7ad5 100644
> --- a/kernel/kexec_file.c
> +++ b/kernel/kexec_file.c
> @@ -166,6 +166,11 @@ void kimage_file_post_load_cleanup(struct kimage *image)
>   vfree(pi->sechdrs);
>   pi->sechdrs = NULL;
>  
> +#ifdef CONFIG_IMA_KEXEC
> + vfree(image->ima_buffer);
> + image->ima_buffer = NULL;
> +#endif /* CONFIG_IMA_KEXEC */
> +
>   /* See if architecture has anything to cleanup post load */
>   arch_kimage_file_post_load_cleanup(image);
>  
> diff --git a/security/integrity/ima/ima_kexec.c 
> b/security/integrity/ima/ima_kexec.c
> index 212145008a01..8eadd0674629 100644
> --- a/security/integrity/ima/ima_kexec.c
> +++ b/security/integrity/ima/ima_kexec.c
> @@ -130,6 +130,8 @@ void ima_add_kexec_buffer(struct kimage *image)
>   return;
>   }
>  
> + image->ima_buffer = kexec_buffer;
> +
>   pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n",
>kbuf.mem);
>  }
> -- 
> 2.30.0
>

[PATCH 2/2] ima: Free IMA measurement buffer after kexec syscall

2021-01-21 Thread Lakshmi Ramasubramanian 
IMA allocates kernel virtual memory to carry forward the measurement
list, from the current kernel to the next kernel on kexec system call,
in ima_add_kexec_buffer() function.  This buffer is not freed before
completing the kexec system call resulting in memory leak.

Add ima_buffer field in "struct kimage" to store the virtual address
of the buffer allocated for the IMA measurement list.
Free the memory allocated for the IMA measurement list in
kimage_file_post_load_cleanup() function.

Signed-off-by: Lakshmi Ramasubramanian 
Suggested-by: Tyler Hicks 
Fixes: 7b8589cc29e7 ("ima: on soft reboot, save the measurement list")
---
 include/linux/kexec.h  | 5 +
 kernel/kexec_file.c| 5 +
 security/integrity/ima/ima_kexec.c | 2 ++
 3 files changed, 12 insertions(+)

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 9e93bef52968..5f61389f5f36 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -300,6 +300,11 @@ struct kimage {
/* Information for loading purgatory */
struct purgatory_info purgatory_info;
 #endif
+
+#ifdef CONFIG_IMA_KEXEC
+   /* Virtual address of IMA measurement buffer for kexec syscall */
+   void *ima_buffer;
+#endif
 };
 
 /* kexec interface functions */
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index b02086d70492..5c3447cf7ad5 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -166,6 +166,11 @@ void kimage_file_post_load_cleanup(struct kimage *image)
vfree(pi->sechdrs);
pi->sechdrs = NULL;
 
+#ifdef CONFIG_IMA_KEXEC
+   vfree(image->ima_buffer);
+   image->ima_buffer = NULL;
+#endif /* CONFIG_IMA_KEXEC */
+
/* See if architecture has anything to cleanup post load */
arch_kimage_file_post_load_cleanup(image);
 
diff --git a/security/integrity/ima/ima_kexec.c 
b/security/integrity/ima/ima_kexec.c
index 212145008a01..8eadd0674629 100644
--- a/security/integrity/ima/ima_kexec.c
+++ b/security/integrity/ima/ima_kexec.c
@@ -130,6 +130,8 @@ void ima_add_kexec_buffer(struct kimage *image)
return;
}
 
+   image->ima_buffer = kexec_buffer;
+
pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n",
 kbuf.mem);
 }
-- 
2.30.0