1 files changed, 178 insertions, 0 deletions
diff --git a/src/shared/kernel-image.c b/src/shared/kernel-image.c
new file mode 100644
index 0000000..7dc9e01
--- /dev/null
+++ b/src/shared/kernel-image.c
@@ -0,0 +1,178 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "fd-util.h"
+#include "fileio.h"
+#include "env-file.h"
+#include "kernel-image.h"
+#include "os-util.h"
+#include "parse-util.h"
+#include "pe-binary.h"
+#include "string-table.h"
+
+#define PE_SECTION_READ_MAX (16U*1024U)
+
+static const char * const kernel_image_type_table[_KERNEL_IMAGE_TYPE_MAX] = {
+        [KERNEL_IMAGE_TYPE_UNKNOWN] = "unknown",
+        [KERNEL_IMAGE_TYPE_UKI]     = "uki",
+        [KERNEL_IMAGE_TYPE_PE]      = "pe",
+};
+
+DEFINE_STRING_TABLE_LOOKUP_TO_STRING(kernel_image_type, KernelImageType);
+
+static int uki_read_pretty_name(
+                int fd,
+                const PeHeader *pe_header,
+                const IMAGE_SECTION_HEADER *sections,
+                char **ret) {
+
+        _cleanup_free_ char *pname = NULL, *name = NULL;
+        _cleanup_fclose_ FILE *f = NULL;
+        _cleanup_free_ void *osrel = NULL;
+        size_t osrel_size;
+        int r;
+
+        assert(fd >= 0);
+        assert(pe_header);
+        assert(sections || le16toh(pe_header->pe.NumberOfSections) == 0);
+        assert(ret);
+
+        r = pe_read_section_data(
+                        fd,
+                        pe_header,
+                        sections,
+                        ".osrel",
+                        /* max_size=*/ PE_SECTION_READ_MAX,
+                        &osrel,
+                        &osrel_size);
+        if (r == -ENXIO) { /* Section not found */
+                *ret = NULL;
+                return 0;
+        }
+
+        f = fmemopen(osrel, osrel_size, "r");
+        if (!f)
+                return log_error_errno(errno, "Failed to open embedded os-release file: %m");
+
+        r = parse_env_file(
+                        f, NULL,
+                        "PRETTY_NAME", &pname,
+                        "NAME",        &name);
+        if (r < 0)
+                return log_error_errno(r, "Failed to parse embedded os-release file: %m");
+
+        /* follow the same logic as os_release_pretty_name() */
+        if (!isempty(pname))
+                *ret = TAKE_PTR(pname);
+        else if (!isempty(name))
+                *ret = TAKE_PTR(name);
+        else {
+                char *n = strdup("Linux");
+                if (!n)
+                        return log_oom();
+
+                *ret = n;
+        }
+
+        return 0;
+}
+
+static int inspect_uki(
+                int fd,
+                const PeHeader *pe_header,
+                const IMAGE_SECTION_HEADER *sections,
+                char **ret_cmdline,
+                char **ret_uname,
+                char **ret_pretty_name) {
+
+        _cleanup_free_ char *cmdline = NULL, *uname = NULL, *pname = NULL;
+        int r;
+
+        assert(fd >= 0);
+        assert(sections || le16toh(pe_header->pe.NumberOfSections) == 0);
+
+        if (ret_cmdline) {
+                r = pe_read_section_data(fd, pe_header, sections, ".cmdline", PE_SECTION_READ_MAX, (void**) &cmdline, NULL);
+                if (r < 0 && r != -ENXIO) /* If the section doesn't exist, that's fine */
+                        return r;
+        }
+
+        if (ret_uname) {
+                r = pe_read_section_data(fd, pe_header, sections, ".uname", PE_SECTION_READ_MAX, (void**) &uname, NULL);
+                if (r < 0 && r != -ENXIO) /* If the section doesn't exist, that's fine */
+                        return r;
+        }
+
+        if (ret_pretty_name) {
+                r = uki_read_pretty_name(fd, pe_header, sections, &pname);
+                if (r < 0)
+                        return r;
+        }
+
+        if (ret_cmdline)
+                *ret_cmdline = TAKE_PTR(cmdline);
+        if (ret_uname)
+                *ret_uname = TAKE_PTR(uname);
+        if (ret_pretty_name)
+                *ret_pretty_name = TAKE_PTR(pname);
+
+        return 0;
+}
+
+int inspect_kernel(
+                int dir_fd,
+                const char *filename,
+                KernelImageType *ret_type,
+                char **ret_cmdline,
+                char **ret_uname,
+                char **ret_pretty_name) {
+
+        _cleanup_free_ IMAGE_SECTION_HEADER *sections = NULL;
+        _cleanup_free_ IMAGE_DOS_HEADER *dos_header = NULL;
+        KernelImageType t = KERNEL_IMAGE_TYPE_UNKNOWN;
+        _cleanup_free_ PeHeader *pe_header = NULL;
+        _cleanup_close_ int fd = -EBADF;
+        int r;
+
+        assert(dir_fd >= 0 || dir_fd == AT_FDCWD);
+        assert(filename);
+
+        fd = openat(dir_fd, filename, O_RDONLY|O_CLOEXEC);
+        if (fd < 0)
+                return log_error_errno(errno, "Failed to open kernel image file '%s': %m", filename);
+
+        r = pe_load_headers(fd, &dos_header, &pe_header);
+        if (r == -EBADMSG) /* not a valid PE file */
+                goto not_uki;
+        if (r < 0)
+                return log_error_errno(r, "Failed to parse kernel image file '%s': %m", filename);
+
+        r = pe_load_sections(fd, dos_header, pe_header, &sections);
+        if (r == -EBADMSG) /* not a valid PE file */
+                goto not_uki;
+        if (r < 0)
+                return log_error_errno(r, "Failed to load PE sections from kernel image file '%s': %m", filename);
+
+        if (pe_is_uki(pe_header, sections)) {
+                r = inspect_uki(fd, pe_header, sections, ret_cmdline, ret_uname, ret_pretty_name);
+                if (r < 0)
+                        return r;
+
+                t = KERNEL_IMAGE_TYPE_UKI;
+                goto done;
+        } else
+                t = KERNEL_IMAGE_TYPE_PE;
+
+not_uki:
+        if (ret_cmdline)
+                *ret_cmdline = NULL;
+        if (ret_uname)
+                *ret_uname = NULL;
+        if (ret_pretty_name)
+                *ret_pretty_name = NULL;
+
+done:
+        if (ret_type)
+                *ret_type = t;
+
+        return 0;
+}