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-rw-r--r--tools/lib/bpf/zip.c333
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diff --git a/tools/lib/bpf/zip.c b/tools/lib/bpf/zip.c
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+++ b/tools/lib/bpf/zip.c
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+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/*
+ * Routines for dealing with .zip archives.
+ *
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ */
+
+#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;
+}