From: Lennart Poettering <lennart@poettering.net>
Date: Thu, 25 Aug 2022 14:54:03 +0000 (+0200)
Subject: cpio: add helper for packing cpios of literally specified data blobs
X-Git-Tag: v252-rc1~217^2~7
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e139565b01429ccd0373366d1cfd96274ccf7e31;p=thirdparty%2Fsystemd.git

cpio: add helper for packing cpios of literally specified data blobs

Let's add simple helpers for passing data blobs from the stub into the
booted kernel as initrds that are generated on-the-fly.

(Note used yet, a later commit will make use of this)
---

diff --git a/src/boot/efi/cpio.c b/src/boot/efi/cpio.c
index b21cf53b465..c71c218e4fb 100644
--- a/src/boot/efi/cpio.c
+++ b/src/boot/efi/cpio.c
@@ -487,3 +487,60 @@ nothing:
 
         return EFI_SUCCESS;
 }
+
+EFI_STATUS pack_cpio_literal(
+                const void *data,
+                size_t data_size,
+                const char *target_dir_prefix,
+                const char16_t *target_filename,
+                uint32_t dir_mode,
+                uint32_t access_mode,
+                const uint32_t tpm_pcr[],
+                UINTN n_tpm_pcr,
+                const char16_t *tpm_description,
+                void **ret_buffer,
+                UINTN *ret_buffer_size,
+                bool *ret_measured) {
+
+        uint32_t inode = 1; /* inode counter, so that each item gets a new inode */
+        _cleanup_free_ void *buffer = NULL;
+        UINTN buffer_size;
+        EFI_STATUS err;
+
+        assert(data || data_size == 0);
+        assert(target_dir_prefix);
+        assert(target_filename);
+        assert(tpm_pcr || n_tpm_pcr == 0);
+        assert(ret_buffer);
+        assert(ret_buffer_size);
+
+        /* Generate the leading directory inodes right before adding the first files, to the
+         * archive. Otherwise the cpio archive cannot be unpacked, since the leading dirs won't exist. */
+
+        err = pack_cpio_prefix(target_dir_prefix, dir_mode, &inode, &buffer, &buffer_size);
+        if (err != EFI_SUCCESS)
+                return log_error_status_stall(err, L"Failed to pack cpio prefix: %r", err);
+
+        err = pack_cpio_one(
+                        target_filename,
+                        data, data_size,
+                        target_dir_prefix,
+                        access_mode,
+                        &inode,
+                        &buffer, &buffer_size);
+        if (err != EFI_SUCCESS)
+                return log_error_status_stall(err, L"Failed to pack cpio file %s: %r", target_filename, err);
+
+        err = pack_cpio_trailer(&buffer, &buffer_size);
+        if (err != EFI_SUCCESS)
+                return log_error_status_stall(err, L"Failed to pack cpio trailer: %r");
+
+        err = measure_cpio(buffer, buffer_size, tpm_pcr, n_tpm_pcr, tpm_description, ret_measured);
+        if (err != EFI_SUCCESS)
+                return err;
+
+        *ret_buffer = TAKE_PTR(buffer);
+        *ret_buffer_size = buffer_size;
+
+        return EFI_SUCCESS;
+}
diff --git a/src/boot/efi/cpio.h b/src/boot/efi/cpio.h
index 672a751825f..beebef3d8b0 100644
--- a/src/boot/efi/cpio.h
+++ b/src/boot/efi/cpio.h
@@ -18,3 +18,17 @@ EFI_STATUS pack_cpio(
                 void **ret_buffer,
                 UINTN *ret_buffer_size,
                 bool *ret_measured);
+
+EFI_STATUS pack_cpio_literal(
+                const void *data,
+                size_t data_size,
+                const char *target_dir_prefix,
+                const char16_t *target_filename,
+                uint32_t dir_mode,
+                uint32_t access_mode,
+                const uint32_t tpm_pcr[],
+                UINTN n_tpm_pcr,
+                const char16_t *tpm_description,
+                void **ret_buffer,
+                UINTN *ret_buffer_size,
+                bool *ret_measured);