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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#include <errno.h>#include <fcntl.h>#include <stdint.h>#include <stdlib.h>#include <string.h>#include <sys/mman.h>#include <unistd.h>
#include "libbpf_internal.h"#include "zip.h"
#pragma GCC diagnostic push#pragma GCC diagnostic ignored "-Wpacked"#pragma GCC diagnostic ignored "-Wattributes"
/* Specification of ZIP file format can be found here: * https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT * For a high level overview of the structure of a ZIP file see * sections 4.3.1 - 4.3.6. * * Data structures appearing in ZIP files do not contain any * padding and they might be misaligned. To allow us to safely * operate on pointers to such structures and their members, we * declare the types as packed. */
#define END_OF_CD_RECORD_MAGIC 0x06054b50
/* See section 4.3.16 of the spec. */struct end_of_cd_record { /* Magic value equal to END_OF_CD_RECORD_MAGIC */ __u32 magic;
/* Number of the file containing this structure or 0xFFFF if ZIP64 archive. * Zip archive might span multiple files (disks). */ __u16 this_disk;
/* Number of the file containing the beginning of the central directory or * 0xFFFF if ZIP64 archive. */ __u16 cd_disk;
/* Number of central directory records on this disk or 0xFFFF if ZIP64 * archive. */ __u16 cd_records;
/* Number of central directory records on all disks or 0xFFFF if ZIP64 * archive. */ __u16 cd_records_total;
/* Size of the central directory record or 0xFFFFFFFF if ZIP64 archive. */ __u32 cd_size;
/* Offset of the central directory from the beginning of the archive or * 0xFFFFFFFF if ZIP64 archive. */ __u32 cd_offset;
/* Length of comment data following end of central directory record. */ __u16 comment_length;
/* Up to 64k of arbitrary bytes. */ /* uint8_t comment[comment_length] */} __attribute__((packed));
#define CD_FILE_HEADER_MAGIC 0x02014b50#define FLAG_ENCRYPTED (1 << 0)#define FLAG_HAS_DATA_DESCRIPTOR (1 << 3)
/* See section 4.3.12 of the spec. */struct cd_file_header { /* Magic value equal to CD_FILE_HEADER_MAGIC. */ __u32 magic; __u16 version; /* Minimum zip version needed to extract the file. */ __u16 min_version; __u16 flags; __u16 compression; __u16 last_modified_time; __u16 last_modified_date; __u32 crc; __u32 compressed_size; __u32 uncompressed_size; __u16 file_name_length; __u16 extra_field_length; __u16 file_comment_length; /* Number of the disk where the file starts or 0xFFFF if ZIP64 archive. */ __u16 disk; __u16 internal_attributes; __u32 external_attributes; /* Offset from the start of the disk containing the local file header to the * start of the local file header. */ __u32 offset;} __attribute__((packed));
#define LOCAL_FILE_HEADER_MAGIC 0x04034b50
/* See section 4.3.7 of the spec. */struct local_file_header { /* Magic value equal to LOCAL_FILE_HEADER_MAGIC. */ __u32 magic; /* Minimum zip version needed to extract the file. */ __u16 min_version; __u16 flags; __u16 compression; __u16 last_modified_time; __u16 last_modified_date; __u32 crc; __u32 compressed_size; __u32 uncompressed_size; __u16 file_name_length; __u16 extra_field_length;} __attribute__((packed));
#pragma GCC diagnostic pop
struct zip_archive { void *data; __u32 size; __u32 cd_offset; __u32 cd_records;};
static void *check_access(struct zip_archive *archive, __u32 offset, __u32 size){ if (offset + size > archive->size || offset > offset + size) return NULL;
return archive->data + offset;}
/* Returns 0 on success, -EINVAL on error and -ENOTSUP if the eocd indicates the * archive uses features which are not supported. */static int try_parse_end_of_cd(struct zip_archive *archive, __u32 offset){ __u16 comment_length, cd_records; struct end_of_cd_record *eocd; __u32 cd_offset, cd_size;
eocd = check_access(archive, offset, sizeof(*eocd)); if (!eocd || eocd->magic != END_OF_CD_RECORD_MAGIC) return -EINVAL;
comment_length = eocd->comment_length; if (offset + sizeof(*eocd) + comment_length != archive->size) return -EINVAL;
cd_records = eocd->cd_records; if (eocd->this_disk != 0 || eocd->cd_disk != 0 || eocd->cd_records_total != cd_records) /* This is a valid eocd, but we only support single-file non-ZIP64 archives. */ return -ENOTSUP;
cd_offset = eocd->cd_offset; cd_size = eocd->cd_size; if (!check_access(archive, cd_offset, cd_size)) return -EINVAL;
archive->cd_offset = cd_offset; archive->cd_records = cd_records; return 0;}
static int find_cd(struct zip_archive *archive){ int64_t limit, offset; int rc = -EINVAL;
if (archive->size <= sizeof(struct end_of_cd_record)) return -EINVAL;
/* Because the end of central directory ends with a variable length array of * up to 0xFFFF bytes we can't know exactly where it starts and need to * search for it at the end of the file, scanning the (limit, offset] range. */ offset = archive->size - sizeof(struct end_of_cd_record); limit = (int64_t)offset - (1 << 16);
for (; offset >= 0 && offset > limit && rc != 0; offset--) { rc = try_parse_end_of_cd(archive, offset); if (rc == -ENOTSUP) break; } return rc;}
struct zip_archive *zip_archive_open(const char *path){ struct zip_archive *archive; int err, fd; off_t size; void *data;
fd = open(path, O_RDONLY | O_CLOEXEC); if (fd < 0) return ERR_PTR(-errno);
size = lseek(fd, 0, SEEK_END); if (size == (off_t)-1 || size > UINT32_MAX) { close(fd); return ERR_PTR(-EINVAL); }
data = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0); err = -errno; close(fd);
if (data == MAP_FAILED) return ERR_PTR(err);
archive = malloc(sizeof(*archive)); if (!archive) { munmap(data, size); return ERR_PTR(-ENOMEM); }
archive->data = data; archive->size = size;
err = find_cd(archive); if (err) { munmap(data, size); free(archive); return ERR_PTR(err); }
return archive;}
void zip_archive_close(struct zip_archive *archive){ munmap(archive->data, archive->size); free(archive);}
static struct local_file_header *local_file_header_at_offset(struct zip_archive *archive, __u32 offset){ struct local_file_header *lfh;
lfh = check_access(archive, offset, sizeof(*lfh)); if (!lfh || lfh->magic != LOCAL_FILE_HEADER_MAGIC) return NULL;
return lfh;}
static int get_entry_at_offset(struct zip_archive *archive, __u32 offset, struct zip_entry *out){ struct local_file_header *lfh; __u32 compressed_size; const char *name; void *data;
lfh = local_file_header_at_offset(archive, offset); if (!lfh) return -EINVAL;
offset += sizeof(*lfh); if ((lfh->flags & FLAG_ENCRYPTED) || (lfh->flags & FLAG_HAS_DATA_DESCRIPTOR)) return -EINVAL;
name = check_access(archive, offset, lfh->file_name_length); if (!name) return -EINVAL;
offset += lfh->file_name_length; if (!check_access(archive, offset, lfh->extra_field_length)) return -EINVAL;
offset += lfh->extra_field_length; compressed_size = lfh->compressed_size; data = check_access(archive, offset, compressed_size); if (!data) return -EINVAL;
out->compression = lfh->compression; out->name_length = lfh->file_name_length; out->name = name; out->data = data; out->data_length = compressed_size; out->data_offset = offset;
return 0;}
int zip_archive_find_entry(struct zip_archive *archive, const char *file_name, struct zip_entry *out){ size_t file_name_length = strlen(file_name); __u32 i, offset = archive->cd_offset;
for (i = 0; i < archive->cd_records; ++i) { __u16 cdfh_name_length, cdfh_flags; struct cd_file_header *cdfh; const char *cdfh_name;
cdfh = check_access(archive, offset, sizeof(*cdfh)); if (!cdfh || cdfh->magic != CD_FILE_HEADER_MAGIC) return -EINVAL;
offset += sizeof(*cdfh); cdfh_name_length = cdfh->file_name_length; cdfh_name = check_access(archive, offset, cdfh_name_length); if (!cdfh_name) return -EINVAL;
cdfh_flags = cdfh->flags; if ((cdfh_flags & FLAG_ENCRYPTED) == 0 && (cdfh_flags & FLAG_HAS_DATA_DESCRIPTOR) == 0 && file_name_length == cdfh_name_length && memcmp(file_name, archive->data + offset, file_name_length) == 0) { return get_entry_at_offset(archive, cdfh->offset, out); }
offset += cdfh_name_length; offset += cdfh->extra_field_length; offset += cdfh->file_comment_length; }
return -ENOENT;}