* Copyright (c) 2006 Apple Computer, Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
- *
+ *
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
- *
+ *
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
- *
+ *
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
- *
+ *
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#include <sys/filedesc.h>
#include <sys/vnode_internal.h>
#include <sys/imageboot.h>
+#include <kern/assert.h>
+
+#include <sys/namei.h>
+#include <sys/fcntl.h>
+#include <sys/vnode.h>
+#include <sys/sysproto.h>
+#include <sys/csr.h>
+#include <miscfs/devfs/devfsdefs.h>
+#include <libkern/crypto/sha2.h>
+#include <libkern/crypto/rsa.h>
+#include <libkern/OSKextLibPrivate.h>
+
+#include <kern/kalloc.h>
#include <pexpert/pexpert.h>
+#include <kern/chunklist.h>
extern struct filedesc filedesc0;
extern int (*mountroot)(void);
-extern char rootdevice[];
+extern char rootdevice[DEVMAXNAMESIZE];
#define DEBUG_IMAGEBOOT 0
#define DBG_TRACE(...) do {} while(0)
#endif
-extern int di_root_image(const char *path, char devname[], dev_t *dev_p);
+extern int di_root_image(const char *path, char *devname, size_t devsz, dev_t *dev_p);
+extern int di_root_ramfile_buf(void *buf, size_t bufsz, char *devname, size_t devsz, dev_t *dev_p);
+
+static boolean_t imageboot_setup_new(void);
#define kIBFilePrefix "file://"
-int
+__private_extern__ int
+imageboot_format_is_valid(const char *root_path)
+{
+ return strncmp(root_path, kIBFilePrefix,
+ strlen(kIBFilePrefix)) == 0;
+}
+
+static void
+vnode_get_and_drop_always(vnode_t vp)
+{
+ vnode_getalways(vp);
+ vnode_rele(vp);
+ vnode_put(vp);
+}
+
+__private_extern__ int
imageboot_needed(void)
{
int result = 0;
DBG_TRACE("%s: checking for presence of root path\n", __FUNCTION__);
MALLOC_ZONE(root_path, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
- if (root_path == NULL)
+ if (root_path == NULL) {
panic("%s: M_NAMEI zone exhausted", __FUNCTION__);
+ }
- if(PE_parse_boot_argn("rp", root_path, MAXPATHLEN) == TRUE) {
- /* Got it, now verify scheme */
+ /* Check for first layer */
+ if (!(PE_parse_boot_argn("rp0", root_path, MAXPATHLEN) ||
+ PE_parse_boot_argn("rp", root_path, MAXPATHLEN) ||
+ PE_parse_boot_argn(IMAGEBOOT_ROOT_ARG, root_path, MAXPATHLEN) ||
+ PE_parse_boot_argn(IMAGEBOOT_AUTHROOT_ARG, root_path, MAXPATHLEN))) {
+ goto out;
+ }
+
+ /* Sanity-check first layer */
+ if (imageboot_format_is_valid(root_path)) {
+ DBG_TRACE("%s: Found %s\n", __FUNCTION__, root_path);
+ } else {
+ goto out;
+ }
- if (strncmp(root_path, kIBFilePrefix,
- strlen(kIBFilePrefix)) == 0) {
- DBG_TRACE("%s: Found %s\n", __FUNCTION__, root_path);
- result = 1;
+ result = 1;
+
+ /* Check for second layer */
+ if (!(PE_parse_boot_argn("rp1", root_path, MAXPATHLEN) ||
+ PE_parse_boot_argn(IMAGEBOOT_CONTAINER_ARG, root_path, MAXPATHLEN))) {
+ goto out;
+ }
+
+ /* Sanity-check second layer */
+ if (imageboot_format_is_valid(root_path)) {
+ DBG_TRACE("%s: Found %s\n", __FUNCTION__, root_path);
+ } else {
+ panic("%s: Invalid URL scheme for %s\n",
+ __FUNCTION__, root_path);
+ }
+
+out:
+ FREE_ZONE(root_path, MAXPATHLEN, M_NAMEI);
+
+ return result;
+}
+
+
+/*
+ * Swaps in new root filesystem based on image path.
+ * Current root filesystem is removed from mount list and
+ * tagged MNTK_BACKS_ROOT, MNT_ROOTFS is cleared on it, and
+ * "rootvnode" is reset. Root vnode of currentroot filesystem
+ * is returned with usecount (no iocount).
+ */
+__private_extern__ int
+imageboot_mount_image(const char *root_path, int height)
+{
+ dev_t dev;
+ int error;
+ vnode_t old_rootvnode = NULL;
+ vnode_t newdp;
+ mount_t new_rootfs;
+
+ error = di_root_image(root_path, rootdevice, DEVMAXNAMESIZE, &dev);
+ if (error) {
+ panic("%s: di_root_image failed: %d\n", __FUNCTION__, error);
+ }
+
+ rootdev = dev;
+ mountroot = NULL;
+ printf("%s: root device 0x%x\n", __FUNCTION__, rootdev);
+ error = vfs_mountroot();
+ if (error != 0) {
+ panic("vfs_mountroot() failed.\n");
+ }
+
+ /*
+ * Get the vnode for '/'.
+ * Set fdp->fd_fd.fd_cdir to reference it.
+ */
+ if (VFS_ROOT(TAILQ_LAST(&mountlist, mntlist), &newdp, vfs_context_kernel())) {
+ panic("%s: cannot find root vnode", __FUNCTION__);
+ }
+
+ if (rootvnode != NULL) {
+ /* remember the old rootvnode, but remove it from mountlist */
+ mount_t old_rootfs;
+
+ old_rootvnode = rootvnode;
+ old_rootfs = rootvnode->v_mount;
+
+ mount_list_remove(old_rootfs);
+
+ mount_lock(old_rootfs);
+#ifdef CONFIG_IMGSRC_ACCESS
+ old_rootfs->mnt_kern_flag |= MNTK_BACKS_ROOT;
+#endif /* CONFIG_IMGSRC_ACCESS */
+ old_rootfs->mnt_flag &= ~MNT_ROOTFS;
+ mount_unlock(old_rootfs);
+ }
+
+ /* switch to the new rootvnode */
+ rootvnode = newdp;
+
+ new_rootfs = rootvnode->v_mount;
+ mount_lock(new_rootfs);
+ new_rootfs->mnt_flag |= MNT_ROOTFS;
+ mount_unlock(new_rootfs);
+
+ vnode_ref(newdp);
+ vnode_put(newdp);
+ filedesc0.fd_cdir = newdp;
+ DBG_TRACE("%s: root switched\n", __FUNCTION__);
+
+ if (old_rootvnode != NULL) {
+#ifdef CONFIG_IMGSRC_ACCESS
+ if (height >= 0 && PE_imgsrc_mount_supported()) {
+ imgsrc_rootvnodes[height] = old_rootvnode;
} else {
- DBG_TRACE("%s: Invalid URL scheme for %s\n",
- __FUNCTION__, root_path);
+ vnode_get_and_drop_always(old_rootvnode);
}
+#else
+ height = 0; /* keep the compiler from complaining */
+ vnode_get_and_drop_always(old_rootvnode);
+#endif /* CONFIG_IMGSRC_ACCESS */
+ }
+ return 0;
+}
+
+
+/*
+ * Authenticated root-dmg support
+ */
+
+#define AUTHDBG(fmt, args...) do { printf("%s: " fmt "\n", __func__, ##args); } while (0)
+#define AUTHPRNT(fmt, args...) do { printf("%s: " fmt "\n", __func__, ##args); } while (0)
+
+#define kfree_safe(x) do { if ((x)) { kfree_addr((x)); (x) = NULL; } } while (0)
+
+enum {
+ MISSING_SIG = -1,
+ INVALID_SIG = -2
+};
+
+static void
+key_byteswap(void *_dst, const void *_src, size_t len)
+{
+ uint32_t *dst __attribute__((align_value(1))) = _dst;
+ const uint32_t *src __attribute__((align_value(1))) = _src;
+
+ assert(len % sizeof(uint32_t) == 0);
+
+ len = len / sizeof(uint32_t);
+ for (size_t i = 0; i < len; i++) {
+ dst[len - i - 1] = OSSwapInt32(src[i]);
+ }
+}
+
+static int
+read_file(const char *path, void **bufp, size_t *bufszp)
+{
+ int err = 0;
+ struct nameidata ndp = {};
+ struct vnode *vp = NULL;
+ off_t fsize = 0;
+ int resid = 0;
+ char *buf = NULL;
+ bool doclose = false;
+
+ vfs_context_t ctx = vfs_context_kernel();
+ proc_t p = vfs_context_proc(ctx);
+ kauth_cred_t kerncred = vfs_context_ucred(ctx);
+
+ NDINIT(&ndp, LOOKUP, OP_OPEN, LOCKLEAF, UIO_SYSSPACE, CAST_USER_ADDR_T(path), ctx);
+ if ((err = namei(&ndp)) != 0) {
+ AUTHPRNT("namei failed (%s)", path);
+ goto out;
+ }
+ nameidone(&ndp);
+ vp = ndp.ni_vp;
+
+ if ((err = vnode_size(vp, &fsize, ctx)) != 0) {
+ AUTHPRNT("failed to get vnode size");
+ goto out;
+ }
+ if (fsize < 0) {
+ panic("negative file size");
+ }
+
+ if ((err = VNOP_OPEN(vp, FREAD, ctx)) != 0) {
+ AUTHPRNT("failed to open vnode");
+ goto out;
+ }
+ doclose = true;
+
+ /* if bufsz is non-zero, cap the read at bufsz bytes */
+ if (*bufszp && *bufszp < (size_t)fsize) {
+ fsize = *bufszp;
+ }
+
+ buf = kalloc(fsize);
+ if (buf == NULL) {
+ err = ENOMEM;
+ goto out;
+ }
+
+ if ((err = vn_rdwr(UIO_READ, vp, (caddr_t)buf, fsize, 0, UIO_SYSSPACE, IO_NODELOCKED, kerncred, &resid, p)) != 0) {
+ AUTHPRNT("vn_rdwr() failed");
+ goto out;
+ }
+
+ if (resid) {
+ /* didnt get everything we wanted */
+ AUTHPRNT("vn_rdwr resid = %d", resid);
+ err = EINVAL;
+ goto out;
+ }
+
+out:
+ if (doclose) {
+ VNOP_CLOSE(vp, FREAD, ctx);
+ }
+ if (vp) {
+ vnode_put(vp);
+ vp = NULL;
}
- FREE_ZONE(root_path, MAXPATHLEN, M_NAMEI);
- return (result);
+ if (err) {
+ kfree_safe(buf);
+ } else {
+ *bufp = buf;
+ *bufszp = fsize;
+ }
+
+ return err;
}
+static int
+validate_signature(const uint8_t *key_msb, size_t keylen, uint8_t *sig_msb, size_t siglen, uint8_t *digest)
+{
+ int err = 0;
+ bool sig_valid = false;
+ uint8_t *sig = NULL;
+
+ const uint8_t exponent[] = { 0x01, 0x00, 0x01 };
+ uint8_t *modulus = kalloc(keylen);
+ rsa_pub_ctx *rsa_ctx = kalloc(sizeof(rsa_pub_ctx));
+ sig = kalloc(siglen);
+
+ if (modulus == NULL || rsa_ctx == NULL || sig == NULL) {
+ err = ENOMEM;
+ goto out;
+ }
+
+ bzero(rsa_ctx, sizeof(rsa_pub_ctx));
+ key_byteswap(modulus, key_msb, keylen);
+ key_byteswap(sig, sig_msb, siglen);
+
+ err = rsa_make_pub(rsa_ctx,
+ sizeof(exponent), exponent,
+ CHUNKLIST_PUBKEY_LEN, modulus);
+ if (err) {
+ AUTHPRNT("rsa_make_pub() failed");
+ goto out;
+ }
+
+ err = rsa_verify_pkcs1v15(rsa_ctx, CC_DIGEST_OID_SHA256,
+ SHA256_DIGEST_LENGTH, digest,
+ siglen, sig,
+ &sig_valid);
+ if (err) {
+ sig_valid = false;
+ AUTHPRNT("rsa_verify() failed");
+ err = EINVAL;
+ goto out;
+ }
+
+out:
+ kfree_safe(sig);
+ kfree_safe(rsa_ctx);
+ kfree_safe(modulus);
+
+ if (err) {
+ return err;
+ } else if (sig_valid == true) {
+ return 0; /* success */
+ } else {
+ return INVALID_SIG;
+ }
+}
+
+static int
+validate_chunklist(void *buf, size_t len)
+{
+ int err = 0;
+ size_t sigsz = 0;
+ size_t sig_end = 0;
+ size_t chunks_end = 0;
+ bool valid_sig = false;
+ struct chunklist_hdr *hdr = buf;
+
+ if (len < sizeof(struct chunklist_hdr)) {
+ AUTHPRNT("no space for header");
+ return EINVAL;
+ }
+
+ /* recognized file format? */
+ if (hdr->cl_magic != CHUNKLIST_MAGIC ||
+ hdr->cl_file_ver != CHUNKLIST_FILE_VERSION_10 ||
+ hdr->cl_chunk_method != CHUNKLIST_SIGNATURE_METHOD_10 ||
+ hdr->cl_sig_method != CHUNKLIST_SIGNATURE_METHOD_10) {
+ AUTHPRNT("unrecognized chunklist format");
+ return EINVAL;
+ }
+
+ /* does the chunk list fall within the bounds of the buffer? */
+ if (os_mul_and_add_overflow(hdr->cl_chunk_count, sizeof(struct chunklist_chunk), hdr->cl_chunk_offset, &chunks_end) ||
+ hdr->cl_chunk_offset < sizeof(struct chunklist_hdr) || chunks_end > len) {
+ AUTHPRNT("invalid chunk_count (%llu) or chunk_offset (%llu)",
+ hdr->cl_chunk_count, hdr->cl_chunk_offset);
+ return EINVAL;
+ }
+
+ /* does the signature fall within the bounds of the buffer? */
+ if (os_add_overflow(hdr->cl_sig_offset, sizeof(struct chunklist_sig), &sig_end) ||
+ hdr->cl_sig_offset < sizeof(struct chunklist_hdr) ||
+ hdr->cl_sig_offset < chunks_end ||
+ hdr->cl_sig_offset > len) {
+ AUTHPRNT("invalid signature offset (%llu)", hdr->cl_sig_offset);
+ return EINVAL;
+ }
+
+ if (sig_end > len || os_sub_overflow(len, hdr->cl_sig_offset, &sigsz) || sigsz != CHUNKLIST_SIG_LEN) {
+ /* missing or incorrect signature size */
+ return MISSING_SIG;
+ }
+
+ AUTHDBG("hashing chunklist");
+
+ /* hash the chunklist (excluding the signature) */
+ uint8_t sha_digest[SHA256_DIGEST_LENGTH];
+ SHA256_CTX sha_ctx;
+ SHA256_Init(&sha_ctx);
+ SHA256_Update(&sha_ctx, buf, hdr->cl_sig_offset);
+ SHA256_Final(sha_digest, &sha_ctx);
+
+ AUTHDBG("validating chunklist signature against pub keys");
+ for (size_t i = 0; i < CHUNKLIST_NPUBKEYS; i++) {
+ const struct chunklist_pubkey *key = &chunklist_pubkeys[i];
+ err = validate_signature(key->key, CHUNKLIST_PUBKEY_LEN,
+ buf + hdr->cl_sig_offset, sigsz, sha_digest);
+ if (err == 0) {
+ AUTHDBG("validated chunklist signature with key %lu (prod=%d)", i, key->isprod);
+ valid_sig = key->isprod;
+#if IMAGEBOOT_ALLOW_DEVKEYS
+ if (!key->isprod) {
+ /* allow dev keys in dev builds only */
+ AUTHDBG("*** allowing DEV key: this will fail in customer builds ***");
+ valid_sig = true;
+ }
+#endif
+ goto out;
+ } else if (err == INVALID_SIG) {
+ /* try the next key */
+ } else {
+ goto out; /* something bad happened */
+ }
+ }
+
+ /* At this point we tried all the keys: nothing went wrong but none of them
+ * signed our chunklist. */
+ AUTHPRNT("signature did not verify against any known public key");
+
+out:
+ if (err) {
+ return err;
+ } else if (valid_sig == true) {
+ return 0; /* signed, and everything checked out */
+ } else {
+ return EINVAL;
+ }
+}
+
+static int
+validate_root_image(const char *root_path, void *chunklist)
+{
+ int err = 0;
+ struct chunklist_hdr *hdr = chunklist;
+ struct chunklist_chunk *chk = NULL;
+ size_t ch = 0;
+ struct nameidata ndp = {};
+ struct vnode *vp = NULL;
+ off_t fsize = 0;
+ off_t offset = 0;
+ bool doclose = false;
+ size_t bufsz = 0;
+ void *buf = NULL;
+
+ vfs_context_t ctx = vfs_context_kernel();
+ kauth_cred_t kerncred = vfs_context_ucred(ctx);
+ proc_t p = vfs_context_proc(ctx);
+
+ AUTHDBG("validating root dmg %s", root_path);
+
+ /*
+ * Open the DMG
+ */
+ NDINIT(&ndp, LOOKUP, OP_OPEN, LOCKLEAF, UIO_SYSSPACE, CAST_USER_ADDR_T(root_path), ctx);
+ if ((err = namei(&ndp)) != 0) {
+ AUTHPRNT("namei failed (%s)", root_path);
+ goto out;
+ }
+ nameidone(&ndp);
+ vp = ndp.ni_vp;
+
+ if (vp->v_type != VREG) {
+ err = EINVAL;
+ goto out;
+ }
+
+ if ((err = vnode_size(vp, &fsize, ctx)) != 0) {
+ AUTHPRNT("failed to get vnode size");
+ goto out;
+ }
+
+ if ((err = VNOP_OPEN(vp, FREAD, ctx)) != 0) {
+ AUTHPRNT("failed to open vnode");
+ goto out;
+ }
+ doclose = true;
+
+ /*
+ * Iterate the chunk list and check each chunk
+ */
+ chk = chunklist + hdr->cl_chunk_offset;
+ for (ch = 0; ch < hdr->cl_chunk_count; ch++) {
+ int resid = 0;
+
+ if (!buf) {
+ /* allocate buffer based on first chunk size */
+ buf = kalloc(chk->chunk_size);
+ if (buf == NULL) {
+ err = ENOMEM;
+ goto out;
+ }
+ bufsz = chk->chunk_size;
+ }
+
+ if (chk->chunk_size > bufsz) {
+ AUTHPRNT("chunk size too big");
+ err = EINVAL;
+ goto out;
+ }
+
+ err = vn_rdwr(UIO_READ, vp, (caddr_t)buf, chk->chunk_size, offset, UIO_SYSSPACE, IO_NODELOCKED, kerncred, &resid, p);
+ if (err) {
+ AUTHPRNT("vn_rdrw fail (err = %d, resid = %d)", err, resid);
+ goto out;
+ }
+ if (resid) {
+ err = EINVAL;
+ AUTHPRNT("chunk covered non-existant part of image");
+ goto out;
+ }
+
+ /* calculate the SHA256 of this chunk */
+ uint8_t sha_digest[SHA256_DIGEST_LENGTH];
+ SHA256_CTX sha_ctx;
+ SHA256_Init(&sha_ctx);
+ SHA256_Update(&sha_ctx, buf, chk->chunk_size);
+ SHA256_Final(sha_digest, &sha_ctx);
+
+ /* Check the calculated SHA matches the chunk list */
+ if (bcmp(sha_digest, chk->chunk_sha256, SHA256_DIGEST_LENGTH) != 0) {
+ AUTHPRNT("SHA mismatch on chunk %lu (offset %lld, size %u)", ch, offset, chk->chunk_size);
+ err = EINVAL;
+ goto out;
+ }
+
+ if (os_add_overflow(offset, chk->chunk_size, &offset)) {
+ err = EINVAL;
+ goto out;
+ }
+ chk++;
+ }
+
+ if (offset != fsize) {
+ AUTHPRNT("chunklist did not cover entire file (offset = %lld, fsize = %lld)", offset, fsize);
+ err = EINVAL;
+ goto out;
+ }
+
+out:
+ kfree_safe(buf);
+ if (doclose) {
+ VNOP_CLOSE(vp, FREAD, ctx);
+ }
+ if (vp) {
+ vnode_put(vp);
+ vp = NULL;
+ }
+
+ return err;
+}
+
+static int
+construct_chunklist_path(const char *root_path, char **bufp)
+{
+ int err = 0;
+ char *path = NULL;
+ size_t len = 0;
+
+ path = kalloc(MAXPATHLEN);
+ if (path == NULL) {
+ AUTHPRNT("failed to allocate space for chunklist path");
+ err = ENOMEM;
+ goto out;
+ }
+
+ len = strnlen(root_path, MAXPATHLEN);
+ if (len < MAXPATHLEN && len > strlen(".dmg")) {
+ /* correctly terminated string with space for extension */
+ } else {
+ AUTHPRNT("malformed root path");
+ err = EINVAL;
+ goto out;
+ }
+
+ len = strlcpy(path, root_path, MAXPATHLEN);
+ if (len >= MAXPATHLEN) {
+ AUTHPRNT("root path is too long");
+ err = EINVAL;
+ goto out;
+ }
+
+ path[len - strlen(".dmg")] = '\0';
+ len = strlcat(path, ".chunklist", MAXPATHLEN);
+ if (len >= MAXPATHLEN) {
+ AUTHPRNT("chunklist path is too long");
+ err = EINVAL;
+ goto out;
+ }
+
+out:
+ if (err) {
+ kfree_safe(path);
+ } else {
+ *bufp = path;
+ }
+ return err;
+}
+
+static int
+authenticate_root(const char *root_path)
+{
+ char *chunklist_path = NULL;
+ void *chunklist_buf = NULL;
+ size_t chunklist_len = 32 * 1024 * 1024UL;
+ int err = 0;
+
+ err = construct_chunklist_path(root_path, &chunklist_path);
+ if (err) {
+ AUTHPRNT("failed creating chunklist path");
+ goto out;
+ }
+
+ AUTHDBG("validating root against chunklist %s", chunklist_path);
+
+ /*
+ * Read and authenticate the chunklist, then validate the root image against
+ * the chunklist.
+ */
+
+ AUTHDBG("reading chunklist");
+ err = read_file(chunklist_path, &chunklist_buf, &chunklist_len);
+ if (err) {
+ AUTHPRNT("failed to read chunklist");
+ goto out;
+ }
+
+ AUTHDBG("validating chunklist");
+ err = validate_chunklist(chunklist_buf, chunklist_len);
+ if (err < 0) {
+ AUTHDBG("missing or incorrect signature on chunklist");
+ goto out;
+ } else if (err) {
+ AUTHPRNT("failed to validate chunklist");
+ goto out;
+ } else {
+ AUTHDBG("successfully validated chunklist");
+ }
+
+ AUTHDBG("validating root image against chunklist");
+ err = validate_root_image(root_path, chunklist_buf);
+ if (err) {
+ AUTHPRNT("failed to validate root image against chunklist (%d)", err);
+ goto out;
+ }
+
+ /* everything checked out - go ahead and mount this */
+ AUTHDBG("root image authenticated");
+
+out:
+ kfree_safe(chunklist_buf);
+ kfree_safe(chunklist_path);
+ return err;
+}
+
+static const uuid_t *
+getuuidfromheader_safe(const void *buf, size_t bufsz, size_t *uuidsz)
+{
+ const struct uuid_command *cmd = NULL;
+ const kernel_mach_header_t *mh = buf;
+
+ /* space for the header and at least one load command? */
+ if (bufsz < sizeof(kernel_mach_header_t) + sizeof(struct uuid_command)) {
+ AUTHPRNT("libkern image too small");
+ return NULL;
+ }
+
+ /* validate the mach header */
+ if (mh->magic != MH_MAGIC_64 || (mh->sizeofcmds > bufsz - sizeof(kernel_mach_header_t))) {
+ AUTHPRNT("invalid MachO header");
+ return NULL;
+ }
+
+ /* iterate the load commands */
+ size_t offset = sizeof(kernel_mach_header_t);
+ for (size_t i = 0; i < mh->ncmds; i++) {
+ cmd = buf + offset;
+
+ if (cmd->cmd == LC_UUID) {
+ *uuidsz = sizeof(cmd->uuid);
+ return &cmd->uuid;
+ }
+
+ if (os_add_overflow(cmd->cmdsize, offset, &offset) ||
+ offset > bufsz - sizeof(struct uuid_command)) {
+ return NULL;
+ }
+ }
+
+ return NULL;
+}
+
+static const char *libkern_path = "/System/Library/Extensions/System.kext/PlugIns/Libkern.kext/Libkern";
+static const char *libkern_bundle = "com.apple.kpi.libkern";
/*
- * We know there's an image. Attach it, and
- * switch over to root off it
- *
- * NB: p is always kernproc
+ * Check that the UUID of the libkern currently loaded matches the one on disk.
*/
+static int
+auth_version_check(void)
+{
+ int err = 0;
+ void *buf = NULL;
+ size_t bufsz = 4 * 1024 * 1024UL;
+
+ /* get the UUID of the libkern in /S/L/E */
+
+ err = read_file(libkern_path, &buf, &bufsz);
+ if (err) {
+ goto out;
+ }
+
+ unsigned long uuidsz = 0;
+ const uuid_t *img_uuid = getuuidfromheader_safe(buf, bufsz, &uuidsz);
+ if (img_uuid == NULL || uuidsz != sizeof(uuid_t)) {
+ AUTHPRNT("invalid UUID (sz = %lu)", uuidsz);
+ err = EINVAL;
+ goto out;
+ }
+
+ /* Get the UUID of the loaded libkern */
+ uuid_t live_uuid;
+ err = OSKextGetUUIDForName(libkern_bundle, live_uuid);
+ if (err) {
+ AUTHPRNT("could not find loaded libkern");
+ goto out;
+ }
+
+ /* ... and compare them */
+ if (bcmp(live_uuid, img_uuid, uuidsz) != 0) {
+ AUTHPRNT("UUID of running libkern does not match %s", libkern_path);
+
+ uuid_string_t img_uuid_str, live_uuid_str;
+ uuid_unparse(*img_uuid, img_uuid_str);
+ uuid_unparse(live_uuid, live_uuid_str);
+ AUTHPRNT("loaded libkern UUID = %s", live_uuid_str);
+ AUTHPRNT("on-disk libkern UUID = %s", img_uuid_str);
+ err = EINVAL;
+ goto out;
+ }
+
+ /* UUID matches! */
+
+out:
+ kfree_safe(buf);
+ return err;
+}
+
+#if 0
int
+auth_imgboot_test(proc_t __unused ap, struct auth_imgboot_test_args *uap, int32_t *retval)
+{
+ int ret = 0;
+ int err;
+ char path[MAXPATHLEN];
+ vm_size_t len;
+ *retval = 0;
+
+ err = copyinstr(uap->path, path, MAXPATHLEN, &len);
+ if (err) {
+ return err;
+ }
+ if (len >= MAXPATHLEN) {
+ return ENAMETOOLONG;
+ }
+
+ AUTHDBG("authenticating root image at %s", path);
+ err = authenticate_root(path);
+ if (err) {
+ AUTHPRNT("root authentication FAIL (%d)", err);
+ ret = err;
+ } else {
+ AUTHDBG("successfully authenticated %s", path);
+ }
+
+ AUTHDBG("checking root image version");
+ err = auth_version_check();
+ if (err) {
+ AUTHPRNT("root image version check FAIL (%d)", err);
+ err = err ?: ret;
+ } else {
+ AUTHPRNT("root version check success (%d)", err);
+ }
+
+ if (ret < 0) {
+ return EINVAL; /* negative return values have special meaning */
+ }
+ return ret;
+}
+#endif
+
+/*
+ * Attach the image at 'path' as a ramdisk and mount it as our new rootfs.
+ * All existing mounts are first umounted.
+ */
+static int
+imageboot_mount_ramdisk(const char *path)
+{
+ int err = 0;
+ size_t bufsz = 0;
+ void *buf = NULL;
+ dev_t dev;
+ vnode_t newdp;
+ mount_t new_rootfs;
+
+ /* Read our target image from disk */
+ err = read_file(path, &buf, &bufsz);
+ if (err) {
+ printf("%s: failed: read_file() = %d\n", __func__, err);
+ goto out;
+ }
+ DBG_TRACE("%s: read '%s' sz = %lu\n", __func__, path, bufsz);
+
+#if CONFIG_IMGSRC_ACCESS
+ /* Re-add all root mounts to the mount list in the correct order... */
+ mount_list_remove(rootvnode->v_mount);
+ for (int i = 0; i < MAX_IMAGEBOOT_NESTING; i++) {
+ struct vnode *vn = imgsrc_rootvnodes[i];
+ if (vn) {
+ vnode_getalways(vn);
+ imgsrc_rootvnodes[i] = NULLVP;
+
+ mount_t mnt = vn->v_mount;
+ mount_lock(mnt);
+ mnt->mnt_flag |= MNT_ROOTFS;
+ mount_list_add(mnt);
+ mount_unlock(mnt);
+
+ vnode_rele(vn);
+ vnode_put(vn);
+ }
+ }
+ mount_list_add(rootvnode->v_mount);
+#endif
+
+ /* ... and unmount everything */
+ vnode_get_and_drop_always(rootvnode);
+ filedesc0.fd_cdir = NULL;
+ rootvnode = NULL;
+ vfs_unmountall();
+
+ /* Attach the ramfs image ... */
+ err = di_root_ramfile_buf(buf, bufsz, rootdevice, DEVMAXNAMESIZE, &dev);
+ if (err) {
+ printf("%s: failed: di_root_ramfile_buf() = %d\n", __func__, err);
+ goto out;
+ }
+
+ /* ... and mount it */
+ rootdev = dev;
+ mountroot = NULL;
+ err = vfs_mountroot();
+ if (err) {
+ printf("%s: failed: vfs_mountroot() = %d\n", __func__, err);
+ goto out;
+ }
+
+ /* Switch to new root vnode */
+ if (VFS_ROOT(TAILQ_LAST(&mountlist, mntlist), &newdp, vfs_context_kernel())) {
+ panic("%s: cannot find root vnode", __func__);
+ }
+ rootvnode = newdp;
+ rootvnode->v_flag |= VROOT;
+ new_rootfs = rootvnode->v_mount;
+ mount_lock(new_rootfs);
+ new_rootfs->mnt_flag |= MNT_ROOTFS;
+ mount_unlock(new_rootfs);
+
+ vnode_ref(newdp);
+ vnode_put(newdp);
+ filedesc0.fd_cdir = newdp;
+
+ DBG_TRACE("%s: root switched\n", __func__);
+
+out:
+ if (err) {
+ kfree_safe(buf);
+ }
+ return err;
+}
+
+static boolean_t
+imageboot_setup_new()
+{
+ int error;
+ char *root_path = NULL;
+ int height = 0;
+ boolean_t done = FALSE;
+ boolean_t auth_root = FALSE;
+ boolean_t ramdisk_root = FALSE;
+
+ MALLOC_ZONE(root_path, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
+ assert(root_path != NULL);
+
+ unsigned imgboot_arg;
+ if (PE_parse_boot_argn("-rootdmg-ramdisk", &imgboot_arg, sizeof(imgboot_arg))) {
+ ramdisk_root = TRUE;
+ }
+
+ if (PE_parse_boot_argn(IMAGEBOOT_CONTAINER_ARG, root_path, MAXPATHLEN) == TRUE) {
+ printf("%s: container image url is %s\n", __FUNCTION__, root_path);
+ error = imageboot_mount_image(root_path, height);
+ if (error != 0) {
+ panic("Failed to mount container image.");
+ }
+
+ height++;
+ }
+
+ if (PE_parse_boot_argn(IMAGEBOOT_AUTHROOT_ARG, root_path, MAXPATHLEN) == TRUE) {
+ auth_root = TRUE;
+ } else if (PE_parse_boot_argn(IMAGEBOOT_ROOT_ARG, root_path, MAXPATHLEN) == FALSE) {
+ if (height > 0) {
+ panic("%s specified without %s?\n", IMAGEBOOT_CONTAINER_ARG, IMAGEBOOT_ROOT_ARG);
+ }
+ goto out;
+ }
+
+ printf("%s: root image url is %s\n", __func__, root_path);
+
+#if CONFIG_CSR
+ if (auth_root && (csr_check(CSR_ALLOW_ANY_RECOVERY_OS) == 0)) {
+ AUTHPRNT("CSR_ALLOW_ANY_RECOVERY_OS set, skipping root image authentication");
+ auth_root = false;
+ }
+#endif
+
+ /* Make a copy of the path to URL-decode */
+ char *path_alloc = kalloc(MAXPATHLEN);
+ if (path_alloc == NULL) {
+ panic("imageboot path allocation failed\n");
+ }
+ char *path = path_alloc;
+
+ size_t len = strlen(kIBFilePrefix);
+ strlcpy(path, root_path, MAXPATHLEN);
+ if (strncmp(kIBFilePrefix, path, len) == 0) {
+ /* its a URL - remove the file:// prefix and percent-decode */
+ path += len;
+ url_decode(path);
+ }
+
+ if (auth_root) {
+ AUTHDBG("authenticating root image at %s", path);
+ error = authenticate_root(path);
+ if (error) {
+ panic("root image authentication failed (err = %d)\n", error);
+ }
+ AUTHDBG("successfully authenticated %s", path);
+ }
+
+ if (ramdisk_root) {
+ error = imageboot_mount_ramdisk(path);
+ } else {
+ error = imageboot_mount_image(root_path, height);
+ }
+
+ kfree_safe(path_alloc);
+
+ if (error) {
+ panic("Failed to mount root image (err=%d, auth=%d, ramdisk=%d)\n",
+ error, auth_root, ramdisk_root);
+ }
+
+ if (auth_root) {
+ /* check that the image version matches the running kernel */
+ AUTHDBG("checking root image version");
+ error = auth_version_check();
+ if (error) {
+ panic("root image version check failed");
+ } else {
+ AUTHDBG("root image version matches kernel");
+ }
+ }
+
+ done = TRUE;
+
+out:
+ FREE_ZONE(root_path, MAXPATHLEN, M_NAMEI);
+ return done;
+}
+
+__private_extern__ void
imageboot_setup()
{
- dev_t dev;
int error = 0;
char *root_path = NULL;
DBG_TRACE("%s: entry\n", __FUNCTION__);
+ if (rootvnode == NULL) {
+ panic("imageboot_setup: rootvnode is NULL.");
+ }
+
+ /*
+ * New boot-arg scheme:
+ * root-dmg : the dmg that will be the root filesystem.
+ * auth-root-dmg : same as root-dmg but with image authentication.
+ * container-dmg : an optional dmg that contains the root-dmg.
+ */
+ if (imageboot_setup_new()) {
+ return;
+ }
+
MALLOC_ZONE(root_path, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
- if (root_path == NULL)
- return (ENOMEM);
+ assert(root_path != NULL);
- if(PE_parse_boot_argn("rp", root_path, MAXPATHLEN) == FALSE) {
- error = ENOENT;
- goto done;
+ /*
+ * Look for outermost disk image to root from. If we're doing a nested boot,
+ * there's some sense in which the outer image never needs to be the root filesystem,
+ * but it does need very similar treatment: it must not be unmounted, needs a fake
+ * device vnode created for it, and should not show up in getfsstat() until exposed
+ * with MNT_IMGSRC. We just make it the temporary root.
+ */
+ if ((PE_parse_boot_argn("rp", root_path, MAXPATHLEN) == FALSE) &&
+ (PE_parse_boot_argn("rp0", root_path, MAXPATHLEN) == FALSE)) {
+ panic("%s: no valid path to image.\n", __FUNCTION__);
}
printf("%s: root image url is %s\n", __FUNCTION__, root_path);
- error = di_root_image(root_path, rootdevice, &dev);
- if(error) {
- printf("%s: di_root_image failed: %d\n", __FUNCTION__, error);
+
+ error = imageboot_mount_image(root_path, 0);
+ if (error) {
+ panic("Failed on first stage of imageboot.");
+ }
+
+ /*
+ * See if we are rooting from a nested image
+ */
+ if (PE_parse_boot_argn("rp1", root_path, MAXPATHLEN) == FALSE) {
goto done;
}
- rootdev = dev;
- mountroot = NULL;
- printf("%s: root device 0x%x\n", __FUNCTION__, rootdev);
- error = vfs_mountroot();
+ printf("%s: second level root image url is %s\n", __FUNCTION__, root_path);
- if (error == 0 && rootvnode != NULL) {
- struct vnode *tvp;
- struct vnode *newdp;
-
- /*
- * Get the vnode for '/'.
- * Set fdp->fd_fd.fd_cdir to reference it.
- */
- if (VFS_ROOT(TAILQ_LAST(&mountlist,mntlist), &newdp, vfs_context_kernel()))
- panic("%s: cannot find root vnode", __FUNCTION__);
-
- vnode_ref(newdp);
- vnode_put(newdp);
- tvp = rootvnode;
- vnode_rele(tvp);
- filedesc0.fd_cdir = newdp;
- rootvnode = newdp;
- mount_list_lock();
- TAILQ_REMOVE(&mountlist, TAILQ_FIRST(&mountlist), mnt_list);
- mount_list_unlock();
- mountlist.tqh_first->mnt_flag |= MNT_ROOTFS;
- DBG_TRACE("%s: root switched\n", __FUNCTION__);
+ /*
+ * If we fail to set up second image, it's not a given that we
+ * can safely root off the first.
+ */
+ error = imageboot_mount_image(root_path, 1);
+ if (error) {
+ panic("Failed on second stage of imageboot.");
}
+
done:
FREE_ZONE(root_path, MAXPATHLEN, M_NAMEI);
DBG_TRACE("%s: exit\n", __FUNCTION__);
- return (error);
+ return;
}
projects / apple / xnu.git / blobdiff