Re: [PATCH v2] Carry forward IMA measurement log on kexec on x86_64

Mimi Zohar
2022-04-29T21:30:48Z

> diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
> index 13753136f03f..419c50cfe6b9 100644
> --- a/security/integrity/ima/ima_kexec.c
> +++ b/security/integrity/ima/ima_kexec.c
> @@ -10,6 +10,7 @@
> #include <linux/seq_file.h>
> #include <linux/vmalloc.h>
> #include <linux/kexec.h>
> +#include <linux/memblock.h>
> #include <linux/of.h>
> #include <linux/ima.h>
> #include "ima.h"
> @@ -134,10 +135,66 @@ void ima_add_kexec_buffer(struct kimage *image)
> }
> #endif /* IMA_KEXEC */
>
> +#ifndef CONFIG_OF
> +static phys_addr_t ima_early_kexec_buffer_phys;
> +static size_t ima_early_kexec_buffer_size;
> +
> +void __init ima_set_kexec_buffer(phys_addr_t phys_addr, size_t size)
> +{
> + if (size == 0)
> + return;
> +
> + ima_early_kexec_buffer_phys = phys_addr;
> + ima_early_kexec_buffer_size = size;
> +}
> +
> +int __init ima_free_kexec_buffer(void)
> +{
> + int rc;
> +
> + if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC))
> + return -ENOTSUPP;
> +
> + if (ima_early_kexec_buffer_size == 0)
> + return -ENOENT;
> +
> + rc = memblock_phys_free(ima_early_kexec_buffer_phys,
> + ima_early_kexec_buffer_size);
> + if (rc)
> + return rc;
> +
> + ima_early_kexec_buffer_phys = 0;
> + ima_early_kexec_buffer_size = 0;
> +
> + return 0;
> +}
> +
> +int __init ima_get_kexec_buffer(void **addr, size_t *size)
> +{
> + if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC))
> + return -ENOTSUPP;
> +
> + if (ima_early_kexec_buffer_size == 0)
> + return -ENOENT;
> +
> + *addr = __va(ima_early_kexec_buffer_phys);
> + *size = ima_early_kexec_buffer_size;
> +
> + return 0;
> +}
> +

Originally both ima_get_kexec_buffer() and ima_free_kexec_buffer() were
architecture specific. Refer to commit 467d27824920 ("powerpc: ima:
get the kexec buffer passed by the previous kernel"). Is there any
need for defining them here behind an "#ifndef CONFIG_OF"?

> +#else
> +
> +void __init ima_set_kexec_buffer(phys_addr_t phys_addr, size_t size)
> +{
> + pr_warn("CONFIG_OF enabled, ignoring call to set buffer details.\n");
> +}
> +#endif /* CONFIG_OF */
> +

Only when "HAVE_IMA_KEXEC" is defined is this file included. Why is
this warning needed?

thanks,

Mimi

> /*
> * Restore the measurement list from the previous kernel.
> */
> -void ima_load_kexec_buffer(void)
> +void __init ima_load_kexec_buffer(void)
> {
> void *kexec_buffer = NULL;
> size_t kexec_buffer_size = 0;