On Wed, 2025-04-02 at 05:47 -0700, steven chen wrote:
> In the current implementation, the ima_dump_measurement_list() API is
> called during the kexec "load" phase, where a buffer is allocated and
> the measurement records are copied. Due to this, new events added after
> kexec load but before kexec execute are not carried over to the new kernel
> during kexec operation
Repeating this here is unnecessary.
>
> To allow the buffer allocation and population to be separated into distinct
> steps, make the function local seq_file "ima_kexec_file" to a file variable.
This change was already made in [PATCH v11 1/9] ima: rename variable the
set_file "file" to "ima_kexec_file". Please remove.
>
> Carrying the IMA measurement list across kexec requires allocating a
> buffer and copying the measurement records. Separate allocating the
> buffer and copying the measurement records into separate functions in
> order to allocate the buffer at kexec 'load' and copy the measurements
> at kexec 'execute'.
>
> Signed-off-by: Tushar Sugandhi <tusha...@linux.microsoft.com>
> Signed-off-by: steven chen <chen...@linux.microsoft.com>
> ---
> security/integrity/ima/ima_kexec.c | 46 +++++++++++++++++++++++-------
> 1 file changed, 35 insertions(+), 11 deletions(-)
>
> diff --git a/security/integrity/ima/ima_kexec.c
> b/security/integrity/ima/ima_kexec.c
> index 650beb74346c..b12ac3619b8f 100644
> --- a/security/integrity/ima/ima_kexec.c
> +++ b/security/integrity/ima/ima_kexec.c
> @@ -15,26 +15,46 @@
> #include "ima.h"
>
> #ifdef CONFIG_IMA_KEXEC
> +static struct seq_file ima_kexec_file;
> +
> +static void ima_free_kexec_file_buf(struct seq_file *sf)
> +{
> + vfree(sf->buf);
> + sf->buf = NULL;
> + sf->size = 0;
> + sf->read_pos = 0;
> + sf->count = 0;
> +}
> +
> +static int ima_alloc_kexec_file_buf(size_t segment_size)
> +{
> + ima_free_kexec_file_buf(&ima_kexec_file);
After moving the vfree() here at this stage in the patch set, the IMA
measurement list fails to verify when doing two consecutive "kexec -s -l"
with/without a "kexec -s -u" in between. Only after "ima: kexec: move IMA log
copy from kexec load to execute" the IMA measurement list verifies properly with
the vfree() here.
> +
> + /* segment size can't change between kexec load and execute */
> + ima_kexec_file.buf = vmalloc(segment_size);
> + if (!ima_kexec_file.buf)
> + return -ENOMEM;
> +
> + ima_kexec_file.size = segment_size;
> + ima_kexec_file.read_pos = 0;
> + ima_kexec_file.count = sizeof(struct ima_kexec_hdr); /* reserved
> space */
> +
> + return 0;
> +}
> +
