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shared: port kernel-image.c over to new common PE parser

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This commit is contained in:
Lennart Poettering
2023-08-29 11:25:52 +02:00
parent 8bc9d1aa9f
commit 5c425807bf
1 changed files with 67 additions and 186 deletions
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src/shared/kernel-image.c
+67 -186
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@@ -6,19 +6,10 @@
#include "kernel-image.h"
#include "os-util.h"
#include "parse-util.h"
#include "pe-header.h"
#include "pe-binary.h"
#include "string-table.h"
#define MAX_SECTIONS 96
static const uint8_t dos_file_magic[2] = "MZ";
static const uint8_t pe_file_magic[4] = "PE\0\0";
static const uint8_t name_osrel[8] = ".osrel";
static const uint8_t name_linux[8] = ".linux";
static const uint8_t name_initrd[8] = ".initrd";
static const uint8_t name_cmdline[8] = ".cmdline";
static const uint8_t name_uname[8] = ".uname";
#define PE_SECTION_READ_MAX (16U*1024U)
static const char * const kernel_image_type_table[_KERNEL_IMAGE_TYPE_MAX] = {
[KERNEL_IMAGE_TYPE_UNKNOWN] = "unknown",
@@ -28,172 +19,44 @@ static const char * const kernel_image_type_table[_KERNEL_IMAGE_TYPE_MAX] = {
DEFINE_STRING_TABLE_LOOKUP_TO_STRING(kernel_image_type, KernelImageType);
static int pe_sections(FILE *f, struct PeSectionHeader **ret, size_t *ret_n) {
_cleanup_free_ struct PeSectionHeader *sections = NULL;
struct DosFileHeader dos;
struct PeHeader pe;
size_t scount;
uint64_t soff, items;
assert(f);
assert(ret);
assert(ret_n);
items = fread(&dos, 1, sizeof(dos), f);
if (items < sizeof(dos.Magic))
return log_error_errno(SYNTHETIC_ERRNO(EIO), "File is smaller than DOS magic (got %"PRIu64" of %zu bytes)",
items, sizeof(dos.Magic));
if (memcmp(dos.Magic, dos_file_magic, sizeof(dos_file_magic)) != 0)
goto no_sections;
if (items != sizeof(dos))
return log_error_errno(SYNTHETIC_ERRNO(EIO), "File is smaller than DOS header (got %"PRIu64" of %zu bytes)",
items, sizeof(dos));
if (fseek(f, le32toh(dos.ExeHeader), SEEK_SET) < 0)
return log_error_errno(errno, "Failed to seek to PE header: %m");
items = fread(&pe, 1, sizeof(pe), f);
if (items != sizeof(pe))
return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to read PE header.");
if (memcmp(pe.Magic, pe_file_magic, sizeof(pe_file_magic)) != 0)
goto no_sections;
soff = le32toh(dos.ExeHeader) + sizeof(pe) + le16toh(pe.FileHeader.SizeOfOptionalHeader);
if (fseek(f, soff, SEEK_SET) < 0)
return log_error_errno(errno, "Failed to seek to PE section headers: %m");
scount = le16toh(pe.FileHeader.NumberOfSections);
if (scount > MAX_SECTIONS)
goto no_sections;
sections = new(struct PeSectionHeader, scount);
if (!sections)
return log_oom();
items = fread(sections, sizeof(*sections), scount, f);
if (items != scount)
return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to read PE section header.");
*ret = TAKE_PTR(sections);
*ret_n = scount;
return 0;
no_sections:
*ret = NULL;
*ret_n = 0;
return 0;
}
static bool find_pe_section(
struct PeSectionHeader *sections,
size_t scount,
const uint8_t *name,
size_t namelen,
size_t *ret) {
assert(sections || scount == 0);
assert(name || namelen == 0);
for (size_t s = 0; s < scount; s++)
if (memcmp_nn(sections[s].Name, sizeof(sections[s].Name), name, namelen) == 0) {
if (ret)
*ret = s;
return true;
}
return false;
}
static bool is_uki(struct PeSectionHeader *sections, size_t scount) {
assert(sections || scount == 0);
return
find_pe_section(sections, scount, name_osrel, sizeof(name_osrel), NULL) &&
find_pe_section(sections, scount, name_linux, sizeof(name_linux), NULL) &&
find_pe_section(sections, scount, name_initrd, sizeof(name_initrd), NULL);
}
static int read_pe_section(
FILE *f,
struct PeSectionHeader *sections,
size_t scount,
const uint8_t *name,
size_t name_len,
void **ret,
size_t *ret_n) {
struct PeSectionHeader *section;
_cleanup_free_ void *data = NULL;
uint32_t size, bytes;
uint64_t soff;
size_t idx;
assert(f);
assert(sections || scount == 0);
assert(ret);
if (!find_pe_section(sections, scount, name, name_len, &idx)) {
*ret = NULL;
if (ret_n)
*ret_n = 0;
return 0;
}
section = sections + idx;
soff = le32toh(section->PointerToRawData);
size = le32toh(section->VirtualSize);
if (size > 16 * 1024)
return log_error_errno(SYNTHETIC_ERRNO(E2BIG), "PE section too big.");
if (fseek(f, soff, SEEK_SET) < 0)
return log_error_errno(errno, "Failed to seek to PE section: %m");
data = malloc(size+1);
if (!data)
return log_oom();
((uint8_t*) data)[size] = 0; /* safety NUL byte */
bytes = fread(data, 1, size, f);
if (bytes != size)
return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to read PE section.");
*ret = TAKE_PTR(data);
if (ret_n)
*ret_n = size;
return 1;
}
static int uki_read_pretty_name(
FILE *f,
struct PeSectionHeader *sections,
size_t scount,
int fd,
const PeHeader *pe_header,
const IMAGE_SECTION_HEADER *sections,
char **ret) {
_cleanup_free_ char *pname = NULL, *name = NULL;
_cleanup_fclose_ FILE *s = NULL;
_cleanup_fclose_ FILE *f = NULL;
_cleanup_free_ void *osrel = NULL;
size_t osrel_size = 0;
size_t osrel_size;
int r;
assert(f);
assert(sections || scount == 0);
assert(fd >= 0);
assert(pe_header);
assert(sections || le16toh(pe_header->pe.NumberOfSections) == 0);
assert(ret);
r = read_pe_section(f, sections, scount, name_osrel, sizeof(name_osrel), &osrel, &osrel_size);
if (r < 0)
return r;
if (r == 0) {
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;
}
s = fmemopen(osrel, osrel_size, "r");
if (!s)
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(s, NULL,
"PRETTY_NAME", &pname,
"NAME", &name);
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");
@@ -214,9 +77,9 @@ static int uki_read_pretty_name(
}
static int inspect_uki(
FILE *f,
struct PeSectionHeader *sections,
size_t scount,
int fd,
const PeHeader *pe_header,
const IMAGE_SECTION_HEADER *sections,
char **ret_cmdline,
char **ret_uname,
char **ret_pretty_name) {
@@ -224,23 +87,23 @@ static int inspect_uki(
_cleanup_free_ char *cmdline = NULL, *uname = NULL, *pname = NULL;
int r;
assert(f);
assert(sections || scount == 0);
assert(fd >= 0);
assert(sections || le16toh(pe_header->pe.NumberOfSections) == 0);
if (ret_cmdline) {
r = read_pe_section(f, sections, scount, name_cmdline, sizeof(name_cmdline), (void**) &cmdline, NULL);
if (r < 0)
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 = read_pe_section(f, sections, scount, name_uname, sizeof(name_uname), (void**) &uname, NULL);
if (r < 0)
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(f, sections, scount, &pname);
r = uki_read_pretty_name(fd, pe_header, sections, &pname);
if (r < 0)
return r;
}
@@ -263,33 +126,51 @@ int inspect_kernel(
char **ret_uname,
char **ret_pretty_name) {
_cleanup_fclose_ FILE *f = NULL;
_cleanup_free_ struct PeSectionHeader *sections = NULL;
size_t scount;
KernelImageType t;
_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);
r = xfopenat(dir_fd, filename, "re", 0, &f);
if (r < 0)
return log_error_errno(r, "Failed to open kernel image file '%s': %m", 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_sections(f, &sections, &scount);
r = pe_load_headers(fd, &dos_header, &pe_header);
if (r == -EBADMSG) /* not a valid PE file */
goto not_uki;
if (r < 0)
return r;
return log_error_errno(r, "Failed to parse kernel image file '%s': %m", filename);
if (!sections)
t = KERNEL_IMAGE_TYPE_UNKNOWN;
else if (is_uki(sections, scount)) {
t = KERNEL_IMAGE_TYPE_UKI;
r = inspect_uki(f, sections, scount, ret_cmdline, ret_uname, ret_pretty_name);
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;