On Mon, 2025-02-03 at 15:20 -0800, steven chen wrote:
> 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'.
>
> This patch includes the following changes:
> - Refactor ima_dump_measurement_list() to move the memory allocation
> to a separate function ima_alloc_kexec_file_buf() which allocates
> buffer of size 'kexec_segment_size' at kexec 'load'.
> - Make the local variable ima_kexec_file in ima_dump_measurement_list()
> a local static to the file, so that it can be accessed from
> ima_alloc_kexec_file_buf(). Compare actual memory required to ensure
> there is enough memory for the entire measurement record.
> - Copy as many measurement events as possible.
> - Make necessary changes to the function ima_add_kexec_buffer() to call
> the above two functions.
> - Compared the memory size allocated with memory size of the entire
> measurement record. If there is not enough memory, it will copy as many
> IMA measurement records as possible, and this situation will result
> in a failure of remote attestation.
>
> Author: Tushar Sugandhi <tusha...@linux.microsoft.com>
> Reviewed-by: Stefan Berger <stef...@linux.ibm.com>
> Suggested-by: Mimi Zohar <zo...@linux.ibm.com>
> Signed-off-by: Tushar Sugandhi <tusha...@linux.microsoft.com>
> Signed-off-by: steven chen <chen...@linux.microsoft.com>
> ---
> security/integrity/ima/ima.h | 1 +
> security/integrity/ima/ima_kexec.c | 105 +++++++++++++++++++++--------
> security/integrity/ima/ima_queue.c | 4 +-
> 3 files changed, 80 insertions(+), 30 deletions(-)
>
> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index 3c323ca213d4..447a6eb07c2d 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -274,6 +274,7 @@ bool ima_template_has_modsig(const struct
> ima_template_desc
> *ima_template);
> int ima_restore_measurement_entry(struct ima_template_entry *entry);
> int ima_restore_measurement_list(loff_t bufsize, void *buf);
> int ima_measurements_show(struct seq_file *m, void *v);
> +int ima_get_binary_runtime_entry_size(struct ima_template_entry *entry);
> unsigned long ima_get_binary_runtime_size(void);
> int ima_init_template(void);
> void ima_init_template_list(void);
> diff --git a/security/integrity/ima/ima_kexec.c
> b/security/integrity/ima/ima_kexec.c
> index 52e00332defe..b60a902460e2 100644
> --- a/security/integrity/ima/ima_kexec.c
> +++ b/security/integrity/ima/ima_kexec.c
> @@ -15,62 +15,99 @@
> #include "ima.h"
>
> #ifdef CONFIG_IMA_KEXEC
> +static struct seq_file ima_kexec_file;
> +
> +static void ima_reset_kexec_file(struct seq_file *sf)
> +{
> + sf->buf = NULL;
> + sf->size = 0;
> + sf->read_pos = 0;
> + sf->count = 0;
> +}
> +
> +static void ima_free_kexec_file_buf(struct seq_file *sf)
> +{
> + vfree(sf->buf);
> + ima_reset_kexec_file(sf);
> +}
> +
> +static int ima_alloc_kexec_file_buf(size_t segment_size)
> +{
> + /*
> + * kexec 'load' may be called multiple times.
> + * Free and realloc the buffer only if the segment_size is
> + * changed from the previous kexec 'load' call.
> + */
> + if (ima_kexec_file.buf &&
> + (ima_kexec_file.size == segment_size)) {
> + goto out;
> + }
Nice cleanup from v5. The line doesn't doesn't need to be split. Both the
parenthesis and the brackets can be removed.
In the future, before posting patches, please use scripts/checkpatch.pl.
CHECK: Unnecessary parentheses around 'ima_kexec_file.size == segment_size'
#82: FILE: security/integrity/ima/ima_kexec.c:41:
+ if (ima_kexec_file.buf &&
+ (ima_kexec_file.size == segment_size)) {
CHECK: Alignment should match open parenthesis
#83: FILE: security/integrity/ima/ima_kexec.c:42:
+ if (ima_kexec_file.buf &&
+ (ima_kexec_file.size == segment_size)) {
Or simply join the two lines.
thanks,
Mimi
> +
> + ima_free_kexec_file_buf(&ima_kexec_file);
> +
> + /* 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;
> +
> +out:
> + ima_kexec_file.read_pos = 0;
> + ima_kexec_file.count = sizeof(struct ima_kexec_hdr); /* reserved
> space
> */
> +
> + return 0;
> +}
>
