[RFC PATCH v3 9/9] mkeficapsule: Add support for generating empty capsules
Sughosh Ganu
sughosh.ganu at linaro.org
Fri Jan 21 07:48:38 CET 2022
hi Takahiro,
On Thu, 20 Jan 2022 at 07:43, AKASHI Takahiro
<takahiro.akashi at linaro.org> wrote:
>
> Hi Sughosh,
>
> From user's point of view,
>
> On Thu, Jan 20, 2022 at 12:25:48AM +0530, Sughosh Ganu wrote:
> > The Dependable Boot specification describes the structure of the
>
> May we have a pointer or reference to it?
Okay.
>
> > firmware accept and revert capsules. These are empty capsules which
> > are used for signalling the acceptance or rejection of the updated
> > firmware by the OS. Add support for generating these empty capsules.
> >
> > Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
> > ---
> >
> > Changes since V2:
> > * New patch for generating empty capsules
> >
> > tools/eficapsule.h | 8 ++++
> > tools/mkeficapsule.c | 102 ++++++++++++++++++++++++++++++++++++++-----
> > 2 files changed, 100 insertions(+), 10 deletions(-)
> >
> > diff --git a/tools/eficapsule.h b/tools/eficapsule.h
> > index 8c1560bb06..6001952bdc 100644
> > --- a/tools/eficapsule.h
> > +++ b/tools/eficapsule.h
> > @@ -50,6 +50,14 @@ typedef struct {
> > EFI_GUID(0x4aafd29d, 0x68df, 0x49ee, 0x8a, 0xa9, \
> > 0x34, 0x7d, 0x37, 0x56, 0x65, 0xa7)
> >
> > +#define FW_ACCEPT_OS_GUID \
> > + EFI_GUID(0x0c996046, 0xbcc0, 0x4d04, 0x85, 0xec, \
> > + 0xe1, 0xfc, 0xed, 0xf1, 0xc6, 0xf8)
> > +
> > +#define FW_REVERT_OS_GUID \
> > + EFI_GUID(0xacd58b4b, 0xc0e8, 0x475f, 0x99, 0xb5, \
> > + 0x6b, 0x3f, 0x7e, 0x07, 0xaa, 0xf0)
> > +
> > /* flags */
> > #define CAPSULE_FLAGS_PERSIST_ACROSS_RESET 0x00010000
> >
> > diff --git a/tools/mkeficapsule.c b/tools/mkeficapsule.c
> > index 161affdd15..643da3849d 100644
> > --- a/tools/mkeficapsule.c
> > +++ b/tools/mkeficapsule.c
> > @@ -29,6 +29,7 @@
> > #include "eficapsule.h"
> >
> > static const char *tool_name = "mkeficapsule";
> > +static unsigned char empty_capsule;
> >
> > efi_guid_t efi_guid_fm_capsule = EFI_FIRMWARE_MANAGEMENT_CAPSULE_ID_GUID;
> > efi_guid_t efi_guid_image_type_uboot_fit =
> > @@ -38,9 +39,9 @@ efi_guid_t efi_guid_image_type_uboot_raw =
> > efi_guid_t efi_guid_cert_type_pkcs7 = EFI_CERT_TYPE_PKCS7_GUID;
> >
> > #ifdef CONFIG_TOOLS_LIBCRYPTO
> > -static const char *opts_short = "frg:i:I:v:p:c:m:dh";
> > +static const char *opts_short = "frg:i:I:v:p:c:m:dhAR";
> > #else
> > -static const char *opts_short = "frg:i:I:v:h";
> > +static const char *opts_short = "frg:i:I:v:hAR";
> > #endif
> >
> > static struct option options[] = {
> > @@ -55,15 +56,23 @@ static struct option options[] = {
> > {"monotonic-count", required_argument, NULL, 'm'},
> > {"dump-sig", no_argument, NULL, 'd'},
> > #endif
> > + {"fw-accept", no_argument, NULL, 'A'},
> > + {"fw-revert", no_argument, NULL, 'R'},
> > {"help", no_argument, NULL, 'h'},
> > {NULL, 0, NULL, 0},
> > };
> >
> > static void print_usage(void)
> > {
> > - fprintf(stderr, "Usage: %s [options] <image blob> <output file>\n"
> > - "Options:\n"
> > + if (empty_capsule) {
> > + fprintf(stderr, "Usage: %s [options] <output file>\n",
> > + tool_name);
> > + } else {
> > + fprintf(stderr, "Usage: %s [options] <image blob> <output file>\n",
> > + tool_name);
> > + }
>
> We should always show both cases regardless of "empty_capsule".
>
> Or if you have any restrictions on a combination of options,
> you'd better describe them more specifically in help message.
Yes, there are restrictions on the combination of options. I will call
a separate function, like empty_capsule_usage for these.
>
> I'd also like to encourage you to update the man page as well as uefi.rst.
Okay
>
> > + fprintf(stderr, "Options:\n"
> > "\t-f, --fit FIT image type\n"
> > "\t-r, --raw raw image type\n"
> > "\t-g, --guid <guid string> guid for image blob type\n"
> > @@ -75,8 +84,9 @@ static void print_usage(void)
> > "\t-m, --monotonic-count <count> monotonic count\n"
> > "\t-d, --dump_sig dump signature (*.p7)\n"
> > #endif
> > - "\t-h, --help print a help message\n",
> > - tool_name);
> > + "\t-A, --fw-accept firmware accept capsule\n"
> > + "\t-R, --fw-revert firmware revert capsule\n"
> > + "\t-h, --help print a help message\n");
> > }
> >
> > /**
> > @@ -598,6 +608,59 @@ void convert_uuid_to_guid(unsigned char *buf)
> > buf[7] = c;
> > }
> >
> > +static int create_empty_capsule(char *path, efi_guid_t *guid, bool fw_accept)
> > +{
> > + struct efi_capsule_header header;
> > + FILE *f;
> > + int ret;
> > + efi_guid_t fw_accept_guid = FW_ACCEPT_OS_GUID;
> > + efi_guid_t fw_revert_guid = FW_REVERT_OS_GUID;
> > + efi_guid_t payload, capsule_guid;
> > +
> > + f = NULL;
> > + ret = -1;
> > +
> > + f = fopen(path, "w");
> > + if (!f) {
> > + printf("cannot open %s\n", path);
>
> To stderr as Heinrich has requested.
I thought I saw an email from Heinrich in which he said that he did
not want a fprintf call, and was going to revert those hunks from your
patch. I will recheck this bit.
>
> > + goto err;
> > + }
> > +
> > + if (fw_accept)
> > + capsule_guid = fw_accept_guid;
> > + else
> > + capsule_guid = fw_revert_guid;
> > +
> > + memcpy(&header.capsule_guid, &capsule_guid, sizeof(efi_guid_t));
> > + header.header_size = sizeof(header);
> > + header.flags = 0;
> > +
> > + if (fw_accept) {
> > + header.capsule_image_size = sizeof(header) + sizeof(efi_guid_t);
> > + } else {
> > + header.capsule_image_size = sizeof(header);
> > + }
>
> I wonder why we don't need GUID in revert case (and why need GUID
> in fw case. Since we want to add A/B update, there seems to be
> no ambiguity.
The revert capsule is used not as a rejection of a specific individual
image, but for reverting the platform to the other bank. Which does
not require a image specific GUID.
>
> > + if (write_capsule_file(f, &header, sizeof(header),
> > + "Capsule header"))
> > + goto err;
> > +
> > + if (fw_accept) {
> > + memcpy(&payload, guid, sizeof(efi_guid_t));
> > + if (write_capsule_file(f, &payload, sizeof(payload),
> > + "FW Accept Capsule Payload"))
> > + goto err;
> > + }
> > +
> > + ret = 0;
> > +
> > +err:
> > + if (f)
> > + fclose(f);
> > +
> > + return ret;
> > +}
> > +
> > /**
> > * main - main entry function of mkeficapsule
> > * @argc: Number of arguments
> > @@ -616,6 +679,7 @@ int main(int argc, char **argv)
> > unsigned char uuid_buf[16];
> > unsigned long index, instance;
> > uint64_t mcount;
> > + unsigned char accept_fw_capsule, revert_fw_capsule;
> > char *privkey_file, *cert_file;
> > int c, idx;
> >
> > @@ -625,6 +689,8 @@ int main(int argc, char **argv)
> > mcount = 0;
> > privkey_file = NULL;
> > cert_file = NULL;
> > + accept_fw_capsule = 0;
> > + revert_fw_capsule = 0;
> > dump_sig = 0;
> > for (;;) {
> > c = getopt_long(argc, argv, opts_short, options, &idx);
> > @@ -691,22 +757,38 @@ int main(int argc, char **argv)
> > dump_sig = 1;
> > break;
> > #endif /* CONFIG_TOOLS_LIBCRYPTO */
> > + case 'A':
> > + accept_fw_capsule = 1;
> > + break;
> > + case 'R':
> > + revert_fw_capsule = 1;
> > + break;
> > case 'h':
> > print_usage();
> > exit(EXIT_SUCCESS);
> > }
> > }
> >
> > + empty_capsule = (accept_fw_capsule || revert_fw_capsule);
>
> Please check that two options are exclusive here.
Okay
>
> > /* check necessary parameters */
> > - if ((argc != optind + 2) || !guid ||
> > - ((privkey_file && !cert_file) ||
> > + if ((!empty_capsule && argc != optind + 2) ||
> > + (empty_capsule && argc != optind + 1) ||
> > + (!revert_fw_capsule && !guid) || ((privkey_file && !cert_file) ||
> > (!privkey_file && cert_file))) {
> > print_usage();
> > exit(EXIT_FAILURE);
> > }
> >
> > - if (create_fwbin(argv[argc - 1], argv[argc - 2], guid, index, instance,
> > - mcount, privkey_file, cert_file) < 0) {
> > + if (empty_capsule) {
> > + if (create_empty_capsule(argv[argc - 1], guid,
> > + accept_fw_capsule ? 1 : 0) < 0) {
> > + printf("Creating empty capsule failed\n");
>
> To stderr
Okay, will check.
-sughosh
>
> -Takahiro Akashi
>
> > + exit(EXIT_FAILURE);
> > + }
> > + } else if (create_fwbin(argv[argc - 1], argv[argc - 2], guid,
> > + index, instance, mcount, privkey_file,
> > + cert_file) < 0) {
> > fprintf(stderr, "Creating firmware capsule failed\n");
> > exit(EXIT_FAILURE);
> > }
> > --
> > 2.17.1
> >
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