]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/kern/ubc_subr.c
xnu-3789.70.16.tar.gz
[apple/xnu.git] / bsd / kern / ubc_subr.c
index 0222981a2f31a9fad3e56316c9544ad37c89f614..8e6f569298675ee9a768ebed4ae7fd23cf91d86f 100644 (file)
@@ -110,6 +110,9 @@ static int ubc_umcallback(vnode_t, void *);
 static int ubc_msync_internal(vnode_t, off_t, off_t, off_t *, int, int *);
 static void ubc_cs_free(struct ubc_info *uip);
 
+static boolean_t ubc_cs_supports_multilevel_hash(struct cs_blob *blob);
+static void ubc_cs_convert_to_multilevel_hash(struct cs_blob *blob);
+
 struct zone    *ubc_info_zone;
 static uint32_t        cs_blob_generation_count = 1;
 
@@ -121,9 +124,6 @@ static uint32_t     cs_blob_generation_count = 1;
 extern int cs_debug;
 
 #define        PAGE_SHIFT_4K           (12)
-#define        PAGE_SIZE_4K            ((1<<PAGE_SHIFT_4K))
-#define        PAGE_MASK_4K            ((PAGE_SIZE_4K-1))
-#define round_page_4K(x)       (((vm_offset_t)(x) + PAGE_MASK_4K) & ~((vm_offset_t)PAGE_MASK_4K))
 
 static boolean_t
 cs_valid_range(
@@ -150,18 +150,16 @@ typedef void (*cs_md_update)(void *ctx, const void *data, size_t size);
 typedef void (*cs_md_final)(void *hash, void *ctx);
 
 struct cs_hash {
-    uint8_t            cs_type;
-    size_t             cs_cd_size;
-    size_t             cs_size;
-    size_t             cs_digest_size;
+    uint8_t            cs_type;        /* type code as per code signing */
+    size_t             cs_size;        /* size of effective hash (may be truncated) */
+    size_t             cs_digest_size; /* size of native hash */
     cs_md_init         cs_init;
     cs_md_update       cs_update;
     cs_md_final                cs_final;
 };
 
-static struct cs_hash cs_hash_sha1 = {
+static const struct cs_hash cs_hash_sha1 = {
     .cs_type = CS_HASHTYPE_SHA1,
-    .cs_cd_size = CS_SHA1_LEN,
     .cs_size = CS_SHA1_LEN,
     .cs_digest_size = SHA_DIGEST_LENGTH,
     .cs_init = (cs_md_init)SHA1Init,
@@ -169,27 +167,33 @@ static struct cs_hash cs_hash_sha1 = {
     .cs_final = (cs_md_final)SHA1Final,
 };
 #if CRYPTO_SHA2
-static struct cs_hash cs_hash_sha256 = {
+static const struct cs_hash cs_hash_sha256 = {
     .cs_type = CS_HASHTYPE_SHA256,
-    .cs_cd_size = SHA256_DIGEST_LENGTH,
     .cs_size = SHA256_DIGEST_LENGTH,
     .cs_digest_size = SHA256_DIGEST_LENGTH,
     .cs_init = (cs_md_init)SHA256_Init,
     .cs_update = (cs_md_update)SHA256_Update,
     .cs_final = (cs_md_final)SHA256_Final,
 };
-static struct cs_hash cs_hash_sha256_truncate = {
+static const struct cs_hash cs_hash_sha256_truncate = {
     .cs_type = CS_HASHTYPE_SHA256_TRUNCATED,
-    .cs_cd_size = CS_SHA256_TRUNCATED_LEN,
     .cs_size = CS_SHA256_TRUNCATED_LEN,
     .cs_digest_size = SHA256_DIGEST_LENGTH,
     .cs_init = (cs_md_init)SHA256_Init,
     .cs_update = (cs_md_update)SHA256_Update,
     .cs_final = (cs_md_final)SHA256_Final,
 };
+static const struct cs_hash cs_hash_sha384 = {
+    .cs_type = CS_HASHTYPE_SHA384,
+    .cs_size = SHA384_DIGEST_LENGTH,
+    .cs_digest_size = SHA384_DIGEST_LENGTH,
+    .cs_init = (cs_md_init)SHA384_Init,
+    .cs_update = (cs_md_update)SHA384_Update,
+    .cs_final = (cs_md_final)SHA384_Final,
+};
 #endif
-    
-static struct cs_hash *
+
+static struct cs_hash const *
 cs_find_md(uint8_t type)
 {
        if (type == CS_HASHTYPE_SHA1) {
@@ -199,6 +203,8 @@ cs_find_md(uint8_t type)
                return &cs_hash_sha256;
        } else if (type == CS_HASHTYPE_SHA256_TRUNCATED) {
                return &cs_hash_sha256_truncate;
+       } else if (type == CS_HASHTYPE_SHA384) {
+               return &cs_hash_sha384;
 #endif
        }
        return NULL;
@@ -207,65 +213,31 @@ cs_find_md(uint8_t type)
 union cs_hash_union {
        SHA1_CTX                sha1ctxt;
        SHA256_CTX              sha256ctx;
+       SHA384_CTX              sha384ctx;
 };
 
 
 /*
- * Locate the CodeDirectory from an embedded signature blob
+ * Choose among different hash algorithms.
+ * Higher is better, 0 => don't use at all.
  */
-const 
-CS_CodeDirectory *findCodeDirectory(
-       const CS_SuperBlob *embedded,
-       const char *lower_bound,
-       const char *upper_bound)
-{
-       const CS_CodeDirectory *cd = NULL;
-
-       if (embedded &&
-           cs_valid_range(embedded, embedded + 1, lower_bound, upper_bound) &&
-           ntohl(embedded->magic) == CSMAGIC_EMBEDDED_SIGNATURE) {
-               const CS_BlobIndex *limit;
-               const CS_BlobIndex *p;
-
-               limit = &embedded->index[ntohl(embedded->count)];
-               if (!cs_valid_range(&embedded->index[0], limit,
-                                   lower_bound, upper_bound)) {
-                       return NULL;
-               }
-               for (p = embedded->index; p < limit; ++p) {
-                       if (ntohl(p->type) == CSSLOT_CODEDIRECTORY) {
-                               const unsigned char *base;
-
-                               base = (const unsigned char *)embedded;
-                               cd = (const CS_CodeDirectory *)(base + ntohl(p->offset));
-                               break;
-                       }
-               }
-       } else {
-               /*
-                * Detached signatures come as a bare CS_CodeDirectory,
-                * without a blob.
-                */
-               cd = (const CS_CodeDirectory *) embedded;
-       }
+static const uint32_t hashPriorities[] = {
+       CS_HASHTYPE_SHA1,
+       CS_HASHTYPE_SHA256_TRUNCATED,
+       CS_HASHTYPE_SHA256,
+       CS_HASHTYPE_SHA384,
+};
 
-       if (cd &&
-           cs_valid_range(cd, cd + 1, lower_bound, upper_bound) &&
-           cs_valid_range(cd, (const char *) cd + ntohl(cd->length),
-                          lower_bound, upper_bound) &&
-           cs_valid_range(cd, (const char *) cd + ntohl(cd->hashOffset),
-                          lower_bound, upper_bound) &&
-           cs_valid_range(cd, (const char *) cd +
-                          ntohl(cd->hashOffset) +
-                          (ntohl(cd->nCodeSlots) * SHA1_RESULTLEN),
-                          lower_bound, upper_bound) &&
-           
-           ntohl(cd->magic) == CSMAGIC_CODEDIRECTORY) {
-               return cd;
-       }
+static unsigned int
+hash_rank(const CS_CodeDirectory *cd)
+{
+       uint32_t type = cd->hashType;
+       unsigned int n;
 
-       // not found or not a valid code directory
-       return NULL;
+       for (n = 0; n < sizeof(hashPriorities) / sizeof(hashPriorities[0]); ++n)
+               if (hashPriorities[n] == type)
+                       return n + 1;
+       return 0;       /* not supported */
 }
 
 
@@ -382,22 +354,21 @@ hashes(
 static int
 cs_validate_codedirectory(const CS_CodeDirectory *cd, size_t length)
 {
-       struct cs_hash *hashtype;
+       struct cs_hash const *hashtype;
 
        if (length < sizeof(*cd))
                return EBADEXEC;
        if (ntohl(cd->magic) != CSMAGIC_CODEDIRECTORY)
                return EBADEXEC;
-       if (cd->pageSize != PAGE_SHIFT_4K)
+       if (cd->pageSize < PAGE_SHIFT_4K || cd->pageSize > PAGE_SHIFT)
                return EBADEXEC;
        hashtype = cs_find_md(cd->hashType);
        if (hashtype == NULL)
                return EBADEXEC;
 
-       if (cd->hashSize != hashtype->cs_cd_size)
+       if (cd->hashSize != hashtype->cs_size)
                return EBADEXEC;
 
-
        if (length < ntohl(cd->hashOffset))
                return EBADEXEC;
 
@@ -497,27 +468,40 @@ cs_validate_blob(const CS_GenericBlob *blob, size_t length)
  */
 
 static int
-cs_validate_csblob(const uint8_t *addr, size_t length,
-                  const CS_CodeDirectory **rcd)
+cs_validate_csblob(
+       const uint8_t *addr,
+       size_t *blob_size_p,
+       const CS_CodeDirectory **rcd,
+       const CS_GenericBlob **rentitlements)
 {
-       const CS_GenericBlob *blob = (const CS_GenericBlob *)(const void *)addr;
+       const CS_GenericBlob *blob;
        int error;
+       size_t length, blob_size;
 
        *rcd = NULL;
+       *rentitlements = NULL;
+
+       blob = (const CS_GenericBlob *)(const void *)addr;
+       blob_size = *blob_size_p;
 
+       length = blob_size;
        error = cs_validate_blob(blob, length);
        if (error)
                return error;
-
        length = ntohl(blob->length);
 
        if (ntohl(blob->magic) == CSMAGIC_EMBEDDED_SIGNATURE) {
-               const CS_SuperBlob *sb = (const CS_SuperBlob *)blob;
-               uint32_t n, count = ntohl(sb->count);
+               const CS_SuperBlob *sb;
+               uint32_t n, count;
+               const CS_CodeDirectory *best_cd = NULL;
+               unsigned int best_rank = 0;
 
                if (length < sizeof(CS_SuperBlob))
                        return EBADEXEC;
 
+               sb = (const CS_SuperBlob *)blob;
+               count = ntohl(sb->count);
+
                /* check that the array of BlobIndex fits in the rest of the data */
                if ((length - sizeof(CS_SuperBlob)) / sizeof(CS_BlobIndex) < count)
                        return EBADEXEC;
@@ -525,24 +509,49 @@ cs_validate_csblob(const uint8_t *addr, size_t length,
                /* now check each BlobIndex */
                for (n = 0; n < count; n++) {
                        const CS_BlobIndex *blobIndex = &sb->index[n];
-                       if (length < ntohl(blobIndex->offset))
+                       uint32_t type = ntohl(blobIndex->type);
+                       uint32_t offset = ntohl(blobIndex->offset);
+                       if (length < offset)
                                return EBADEXEC;
 
                        const CS_GenericBlob *subBlob =
-                               (const CS_GenericBlob *)(const void *)(addr + ntohl(blobIndex->offset));
+                               (const CS_GenericBlob *)(const void *)(addr + offset);
 
-                       size_t subLength = length - ntohl(blobIndex->offset);
+                       size_t subLength = length - offset;
 
                        if ((error = cs_validate_blob(subBlob, subLength)) != 0)
                                return error;
                        subLength = ntohl(subBlob->length);
 
                        /* extra validation for CDs, that is also returned */
-                       if (ntohl(blobIndex->type) == CSSLOT_CODEDIRECTORY) {
-                               const CS_CodeDirectory *cd = (const CS_CodeDirectory *)subBlob;
-                               if ((error = cs_validate_codedirectory(cd, subLength)) != 0)
+                       if (type == CSSLOT_CODEDIRECTORY || (type >= CSSLOT_ALTERNATE_CODEDIRECTORIES && type < CSSLOT_ALTERNATE_CODEDIRECTORY_LIMIT)) {
+                               const CS_CodeDirectory *candidate = (const CS_CodeDirectory *)subBlob;
+                               if ((error = cs_validate_codedirectory(candidate, subLength)) != 0)
                                        return error;
-                               *rcd = cd;
+                               unsigned int rank = hash_rank(candidate);
+                               if (cs_debug > 3)
+                                       printf("CodeDirectory type %d rank %d at slot 0x%x index %d\n", candidate->hashType, (int)rank, (int)type, (int)n);
+                               if (best_cd == NULL || rank > best_rank) {
+                                       best_cd = candidate;
+                                       best_rank = rank;
+
+                                       if (cs_debug > 2)
+                                               printf("using CodeDirectory type %d (rank %d)\n", (int)best_cd->hashType, best_rank);
+                                       *rcd = best_cd;
+                               } else if (best_cd != NULL && rank == best_rank) {
+                                       /* repeat of a hash type (1:1 mapped to ranks), illegal and suspicious */
+                                       printf("multiple hash=%d CodeDirectories in signature; rejecting\n", best_cd->hashType);
+                                       return EBADEXEC;
+                               }
+                       } else if (type == CSSLOT_ENTITLEMENTS) {
+                               if (ntohl(subBlob->magic) != CSMAGIC_EMBEDDED_ENTITLEMENTS) {
+                                       return EBADEXEC;
+                               }
+                               if (*rentitlements != NULL) {
+                                       printf("multiple entitlements blobs\n");
+                                       return EBADEXEC;
+                               }
+                               *rentitlements = subBlob;
                        }
                }
 
@@ -558,6 +567,8 @@ cs_validate_csblob(const uint8_t *addr, size_t length,
        if (*rcd == NULL)
                return EBADEXEC;
 
+       *blob_size_p = blob_size;
+
        return 0;
 }
 
@@ -643,18 +654,25 @@ csblob_get_entitlements(struct cs_blob *csblob, void **out_start, size_t *out_le
        if (csblob->csb_hashtype == NULL || csblob->csb_hashtype->cs_digest_size > sizeof(computed_hash))
            return EBADEXEC;
 
-       if ((code_dir = (const CS_CodeDirectory *)csblob_find_blob(csblob, CSSLOT_CODEDIRECTORY, CSMAGIC_CODEDIRECTORY)) == NULL)
-               return 0;
+       code_dir = csblob->csb_cd;
 
-       entitlements = csblob_find_blob(csblob, CSSLOT_ENTITLEMENTS, CSMAGIC_EMBEDDED_ENTITLEMENTS);
+       if ((csblob->csb_flags & CS_VALID) == 0) {
+               entitlements = NULL;
+       } else {
+               entitlements = csblob->csb_entitlements_blob;
+       }
        embedded_hash = find_special_slot(code_dir, csblob->csb_hashtype->cs_size, CSSLOT_ENTITLEMENTS);
 
        if (embedded_hash == NULL) {
                if (entitlements)
                        return EBADEXEC;
                return 0;
-       } else if (entitlements == NULL && memcmp(embedded_hash, cshash_zero, csblob->csb_hashtype->cs_size) != 0) {
-               return EBADEXEC;
+       } else if (entitlements == NULL) {
+               if (memcmp(embedded_hash, cshash_zero, csblob->csb_hashtype->cs_size) != 0) {
+                       return EBADEXEC;
+               } else {
+                       return 0;
+               }
        }
 
        csblob->csb_hashtype->cs_init(&context);
@@ -771,7 +789,7 @@ ubc_info_init_withsize(struct vnode *vp, off_t filesize)
 static int
 ubc_info_init_internal(vnode_t vp, int withfsize, off_t filesize)
 {
-       register struct ubc_info        *uip;
+       struct ubc_info *uip;
        void *  pager;
        int error = 0;
        kern_return_t kret;
@@ -1772,8 +1790,19 @@ ubc_map(vnode_t vp, int flags)
 
                error = VNOP_MMAP(vp, flags, vfs_context_current());
 
-               if (error != EPERM)
-                       error = 0;
+               /*
+                * rdar://problem/22587101 required that we stop propagating
+                * EPERM up the stack. Otherwise, we would have to funnel up 
+                * the error at all the call sites for memory_object_map().
+                * The risk is in having to undo the map/object/entry state at 
+                * all these call sites. It would also affect more than just mmap()
+                * e.g. vm_remap().
+                *
+                *      if (error != EPERM)
+                *              error = 0;
+                */
+
+               error = 0;
 
                vnode_lock_spin(vp);
 
@@ -1796,8 +1825,13 @@ ubc_map(vnode_t vp, int flags)
                if (need_wakeup)
                        wakeup(&uip->ui_flags);
 
-               if (need_ref)
-                       vnode_ref(vp);
+               if (need_ref) {
+                       /*
+                        * Make sure we get a ref as we can't unwind from here
+                        */
+                       if (vnode_ref_ext(vp, 0, VNODE_REF_FORCE))
+                               panic("%s : VNODE_REF_FORCE failed\n", __FUNCTION__);
+               }
        }
        return (error);
 }
@@ -2688,7 +2722,6 @@ boolean_t ubc_is_mapped_writable(const struct vnode *vp)
 /*
  * CODE SIGNING
  */
-#define CS_BLOB_PAGEABLE 0
 static volatile SInt32 cs_blob_size = 0;
 static volatile SInt32 cs_blob_count = 0;
 static SInt32 cs_blob_size_peak = 0;
@@ -2718,9 +2751,7 @@ csblob_parse_teamid(struct cs_blob *csblob)
 {
        const CS_CodeDirectory *cd;
 
-       if ((cd = (const CS_CodeDirectory *)csblob_find_blob(
-                                               csblob, CSSLOT_CODEDIRECTORY, CSMAGIC_CODEDIRECTORY)) == NULL)
-               return NULL;
+       cd = csblob->csb_cd;
 
        if (ntohl(cd->version) < CS_SUPPORTSTEAMID)
                return NULL;
@@ -2743,17 +2774,12 @@ ubc_cs_blob_allocate(
 {
        kern_return_t   kr;
 
-#if CS_BLOB_PAGEABLE
-       *blob_size_p = round_page(*blob_size_p);
-       kr = kmem_alloc(kernel_map, blob_addr_p, *blob_size_p, VM_KERN_MEMORY_SECURITY);
-#else  /* CS_BLOB_PAGEABLE */
        *blob_addr_p = (vm_offset_t) kalloc_tag(*blob_size_p, VM_KERN_MEMORY_SECURITY);
        if (*blob_addr_p == 0) {
                kr = KERN_NO_SPACE;
        } else {
                kr = KERN_SUCCESS;
        }
-#endif /* CS_BLOB_PAGEABLE */
        return kr;
 }
 
@@ -2762,11 +2788,258 @@ ubc_cs_blob_deallocate(
        vm_offset_t     blob_addr,
        vm_size_t       blob_size)
 {
-#if CS_BLOB_PAGEABLE
-       kmem_free(kernel_map, blob_addr, blob_size);
-#else  /* CS_BLOB_PAGEABLE */
        kfree((void *) blob_addr, blob_size);
-#endif /* CS_BLOB_PAGEABLE */
+}
+
+/*
+ * Some codesigned files use a lowest common denominator page size of
+ * 4KiB, but can be used on systems that have a runtime page size of
+ * 16KiB. Since faults will only occur on 16KiB ranges in
+ * cs_validate_range(), we can convert the original Code Directory to
+ * a multi-level scheme where groups of 4 hashes are combined to form
+ * a new hash, which represents 16KiB in the on-disk file.  This can
+ * reduce the wired memory requirement for the Code Directory by
+ * 75%. Care must be taken for binaries that use the "fourk" VM pager
+ * for unaligned access, which may still attempt to validate on
+ * non-16KiB multiples for compatibility with 3rd party binaries.
+ */
+static boolean_t
+ubc_cs_supports_multilevel_hash(struct cs_blob *blob)
+{
+       const CS_CodeDirectory *cd;
+
+       /*
+        * Only applies to binaries that ship as part of the OS,
+        * primarily the shared cache.
+        */
+       if (!blob->csb_platform_binary || blob->csb_teamid != NULL) {
+               return FALSE;
+       }
+
+       /*
+        * If the runtime page size matches the code signing page
+        * size, there is no work to do.
+        */
+       if (PAGE_SHIFT <= blob->csb_hash_pageshift) {
+               return FALSE;
+       }
+
+       cd = blob->csb_cd;
+
+       /*
+        * There must be a valid integral multiple of hashes
+        */
+       if (ntohl(cd->nCodeSlots) & (PAGE_MASK >> blob->csb_hash_pageshift)) {
+               return FALSE;
+       }
+
+       /*
+        * Scatter lists must also have ranges that have an integral number of hashes
+        */
+       if ((ntohl(cd->version) >= CS_SUPPORTSSCATTER) && (ntohl(cd->scatterOffset))) {
+
+               const SC_Scatter *scatter = (const SC_Scatter*)
+                       ((const char*)cd + ntohl(cd->scatterOffset));
+               /* iterate all scatter structs to make sure they are all aligned */
+               do {
+                       uint32_t sbase = ntohl(scatter->base);
+                       uint32_t scount = ntohl(scatter->count);
+
+                       /* last scatter? */
+                       if (scount == 0) {
+                               break;
+                       }
+
+                       if (sbase & (PAGE_MASK >> blob->csb_hash_pageshift)) {
+                               return FALSE;
+                       }
+
+                       if (scount & (PAGE_MASK >> blob->csb_hash_pageshift)) {
+                               return FALSE;
+                       }
+
+                       scatter++;
+               } while(1);
+       }
+
+       /* Covered range must be a multiple of the new page size */
+       if (ntohl(cd->codeLimit) & PAGE_MASK) {
+               return FALSE;
+       }
+
+       /* All checks pass */
+       return TRUE;
+}
+
+/*
+ * All state and preconditions were checked before, so this
+ * function cannot fail.
+ */
+static void
+ubc_cs_convert_to_multilevel_hash(struct cs_blob *blob)
+{
+       const CS_CodeDirectory  *old_cd, *cd;
+       CS_CodeDirectory        *new_cd;
+       const CS_GenericBlob *entitlements;
+       vm_offset_t     new_blob_addr;
+       vm_size_t       new_blob_size;
+       vm_size_t       new_cdsize;
+       kern_return_t   kr;
+       int                             error;
+       size_t          length;
+
+       uint32_t                hashes_per_new_hash_shift = (uint32_t)(PAGE_SHIFT - blob->csb_hash_pageshift);
+
+       if (cs_debug > 1) {
+               printf("CODE SIGNING: Attempting to convert Code Directory for %lu -> %lu page shift\n",
+                          (unsigned long)blob->csb_hash_pageshift, (unsigned long)PAGE_SHIFT);
+       }
+
+       old_cd = blob->csb_cd;
+
+       /* Up to the hashes, we can copy all data */
+       new_cdsize  = ntohl(old_cd->hashOffset);
+       new_cdsize += (ntohl(old_cd->nCodeSlots) >> hashes_per_new_hash_shift) * old_cd->hashSize;
+
+       new_blob_size  = sizeof(CS_SuperBlob);
+       new_blob_size += sizeof(CS_BlobIndex);
+       new_blob_size += new_cdsize;
+
+       if (blob->csb_entitlements_blob) {
+               /* We need to add a slot for the entitlements */
+               new_blob_size += sizeof(CS_BlobIndex);
+               new_blob_size += ntohl(blob->csb_entitlements_blob->length);
+       }
+
+       kr = ubc_cs_blob_allocate(&new_blob_addr, &new_blob_size);
+       if (kr != KERN_SUCCESS) {
+               if (cs_debug > 1) {
+                       printf("CODE SIGNING: Failed to allocate memory for new Code Signing Blob: %d\n",
+                                  kr);
+               }
+               return;
+       }
+
+       CS_SuperBlob            *new_superblob;
+
+       new_superblob = (CS_SuperBlob *)new_blob_addr;
+       new_superblob->magic = htonl(CSMAGIC_EMBEDDED_SIGNATURE);
+       new_superblob->length = htonl((uint32_t)new_blob_size);
+       if (blob->csb_entitlements_blob) {
+               vm_size_t                       ent_offset, cd_offset;
+
+               cd_offset  = sizeof(CS_SuperBlob) + 2 * sizeof(CS_BlobIndex);
+               ent_offset = cd_offset +  new_cdsize;
+
+               new_superblob->count = htonl(2);
+               new_superblob->index[0].type = htonl(CSSLOT_CODEDIRECTORY);
+               new_superblob->index[0].offset = htonl((uint32_t)cd_offset);
+               new_superblob->index[1].type = htonl(CSSLOT_ENTITLEMENTS);
+               new_superblob->index[1].offset = htonl((uint32_t)ent_offset);
+
+               memcpy((void *)(new_blob_addr + ent_offset), blob->csb_entitlements_blob, ntohl(blob->csb_entitlements_blob->length));
+
+               new_cd = (CS_CodeDirectory *)(new_blob_addr + cd_offset);
+       } else {
+               vm_size_t                       cd_offset;
+
+               cd_offset  = sizeof(CS_SuperBlob) + 1 * sizeof(CS_BlobIndex);
+
+               new_superblob->count = htonl(1);
+               new_superblob->index[0].type = htonl(CSSLOT_CODEDIRECTORY);
+               new_superblob->index[0].offset = htonl((uint32_t)cd_offset);
+
+               new_cd = (CS_CodeDirectory *)new_blob_addr;
+       }
+
+       memcpy(new_cd, old_cd, ntohl(old_cd->hashOffset));
+
+       /* Update fields in the Code Directory structure */
+       new_cd->length = htonl((uint32_t)new_cdsize);
+
+       uint32_t nCodeSlots = ntohl(new_cd->nCodeSlots);
+       nCodeSlots >>= hashes_per_new_hash_shift;
+       new_cd->nCodeSlots = htonl(nCodeSlots);
+
+       new_cd->pageSize = PAGE_SHIFT; /* Not byte-swapped */
+
+       if ((ntohl(new_cd->version) >= CS_SUPPORTSSCATTER) && (ntohl(new_cd->scatterOffset))) {
+               SC_Scatter *scatter = (SC_Scatter*)
+                       ((char *)new_cd + ntohl(new_cd->scatterOffset));
+               /* iterate all scatter structs to scale their counts */
+               do {
+                       uint32_t scount = ntohl(scatter->count);
+                       uint32_t sbase  = ntohl(scatter->base);
+
+                       /* last scatter? */
+                       if (scount == 0) {
+                               break;
+                       }
+
+                       scount >>= hashes_per_new_hash_shift;
+                       scatter->count = htonl(scount);
+
+                       sbase >>= hashes_per_new_hash_shift;
+                       scatter->base = htonl(sbase);
+
+                       scatter++;
+               } while(1);
+       }
+
+       /* For each group of hashes, hash them together */
+       const unsigned char *src_base = (const unsigned char *)old_cd + ntohl(old_cd->hashOffset);
+       unsigned char *dst_base = (unsigned char *)new_cd + ntohl(new_cd->hashOffset);
+
+       uint32_t hash_index;
+       for (hash_index = 0; hash_index < nCodeSlots; hash_index++) {
+               union cs_hash_union     mdctx;
+
+               uint32_t source_hash_len = old_cd->hashSize << hashes_per_new_hash_shift;
+               const unsigned char *src = src_base + hash_index * source_hash_len;
+               unsigned char *dst = dst_base + hash_index * new_cd->hashSize;
+
+               blob->csb_hashtype->cs_init(&mdctx);
+               blob->csb_hashtype->cs_update(&mdctx, src, source_hash_len);
+               blob->csb_hashtype->cs_final(dst, &mdctx);
+       }
+
+       length = new_blob_size;
+       error = cs_validate_csblob((const uint8_t *)new_blob_addr, &length, &cd, &entitlements);
+       assert(length == new_blob_size);
+       if (error) {
+
+               if (cs_debug > 1) {
+                       printf("CODE SIGNING: Failed to validate new Code Signing Blob: %d\n",
+                                  error);
+               }
+
+               ubc_cs_blob_deallocate(new_blob_addr, new_blob_size);
+               return;
+       }
+
+       /* New Code Directory is ready for use, swap it out in the blob structure */
+       ubc_cs_blob_deallocate(blob->csb_mem_kaddr, blob->csb_mem_size);
+
+       blob->csb_mem_size = new_blob_size;
+       blob->csb_mem_kaddr = new_blob_addr;
+       blob->csb_cd = cd;
+       blob->csb_entitlements_blob = entitlements;
+
+       /* The blob has some cached attributes of the Code Directory, so update those */
+
+       blob->csb_hash_firstlevel_pagesize = blob->csb_hash_pagesize; /* Save the original page size */
+
+       blob->csb_hash_pagesize = PAGE_SIZE;
+       blob->csb_hash_pagemask = PAGE_MASK;
+       blob->csb_hash_pageshift = PAGE_SHIFT;
+       blob->csb_end_offset = ntohl(cd->codeLimit);
+       if((ntohl(cd->version) >= CS_SUPPORTSSCATTER) && (ntohl(cd->scatterOffset))) {
+               const SC_Scatter *scatter = (const SC_Scatter*)
+                       ((const char*)cd + ntohl(cd->scatterOffset));
+               blob->csb_start_offset = ((off_t)ntohl(scatter->base)) * PAGE_SIZE;
+       } else {
+               blob->csb_start_offset = 0;
+       }
 }
 
 int
@@ -2774,8 +3047,9 @@ ubc_cs_blob_add(
        struct vnode    *vp,
        cpu_type_t      cputype,
        off_t           base_offset,
-       vm_address_t    addr,
+       vm_address_t    *addr,
        vm_size_t       size,
+       struct image_params *imgp,
        __unused int    flags,
        struct cs_blob  **ret_blob)
 {
@@ -2783,98 +3057,117 @@ ubc_cs_blob_add(
        struct ubc_info         *uip;
        struct cs_blob          *blob, *oblob;
        int                     error;
-       ipc_port_t              blob_handle;
-       memory_object_size_t    blob_size;
        const CS_CodeDirectory *cd;
+       const CS_GenericBlob *entitlements;
        off_t                   blob_start_offset, blob_end_offset;
        union cs_hash_union     mdctx;
        boolean_t               record_mtime;
-       int                     cs_flags;
+       size_t                  length;
 
        record_mtime = FALSE;
-       cs_flags = 0;
        if (ret_blob)
            *ret_blob = NULL;
 
-       blob_handle = IPC_PORT_NULL;
-
        blob = (struct cs_blob *) kalloc(sizeof (struct cs_blob));
        if (blob == NULL) {
                return ENOMEM;
        }
 
-#if CS_BLOB_PAGEABLE
-       /* get a memory entry on the blob */
-       blob_size = (memory_object_size_t) size;
-       kr = mach_make_memory_entry_64(kernel_map,
-                                      &blob_size,
-                                      addr,
-                                      VM_PROT_READ,
-                                      &blob_handle,
-                                      IPC_PORT_NULL);
-       if (kr != KERN_SUCCESS) {
-               error = ENOMEM;
-               goto out;
-       }
-       if (memory_object_round_page(blob_size) !=
-           (memory_object_size_t) round_page(size)) {
-               printf("ubc_cs_blob_add: size mismatch 0x%llx 0x%lx !?\n",
-                      blob_size, (size_t)size);
-               panic("XXX FBDP size mismatch 0x%llx 0x%lx\n", blob_size, (size_t)size);
-               error = EINVAL;
-               goto out;
-       }
-#else
-       blob_size = (memory_object_size_t) size;
-       blob_handle = IPC_PORT_NULL;
-#endif
-
        /* fill in the new blob */
        blob->csb_cpu_type = cputype;
        blob->csb_base_offset = base_offset;
        blob->csb_mem_size = size;
        blob->csb_mem_offset = 0;
-       blob->csb_mem_handle = blob_handle;
-       blob->csb_mem_kaddr = addr;
+       blob->csb_mem_kaddr = *addr;
        blob->csb_flags = 0;
        blob->csb_platform_binary = 0;
        blob->csb_platform_path = 0;
        blob->csb_teamid = NULL;
+       blob->csb_entitlements_blob = NULL;
+       blob->csb_entitlements = NULL;
        
+       /* Transfer ownership. Even on error, this function will deallocate */
+       *addr = 0;
+
        /*
         * Validate the blob's contents
         */
-
-       error = cs_validate_csblob((const uint8_t *)addr, size, &cd);
+       length = (size_t) size;
+       error = cs_validate_csblob((const uint8_t *)blob->csb_mem_kaddr,
+                                  &length, &cd, &entitlements);
        if (error) {
+
                if (cs_debug)
                        printf("CODESIGNING: csblob invalid: %d\n", error);
-               blob->csb_flags = 0;
-               blob->csb_start_offset = 0;
-               blob->csb_end_offset = 0;
-               memset(blob->csb_cdhash, 0, sizeof(blob->csb_cdhash));
-               /* let the vnode checker determine if the signature is valid or not */
+               /*
+                * The vnode checker can't make the rest of this function
+                * succeed if csblob validation failed, so bail */
+               goto out;
+
        } else {
                const unsigned char *md_base;
                uint8_t hash[CS_HASH_MAX_SIZE];
                int md_size;
 
+               size = (vm_size_t) length;
+               assert(size <= blob->csb_mem_size);
+               if (size < blob->csb_mem_size) {
+                       vm_address_t new_blob_addr;
+                       const CS_CodeDirectory *new_cd;
+                       const CS_GenericBlob *new_entitlements;
+
+                       kr = ubc_cs_blob_allocate(&new_blob_addr, &size);
+                       if (kr != KERN_SUCCESS) {
+                               if (cs_debug > 1) {
+                                       printf("CODE SIGNING: failed to "
+                                              "re-allocate blob (size "
+                                              "0x%llx->0x%llx) error 0x%x\n",
+                                              (uint64_t)blob->csb_mem_size,
+                                              (uint64_t)size,
+                                              kr);
+                               }
+                       } else {
+                               memcpy(new_blob_addr, blob->csb_mem_kaddr, size);
+                               if (cd == NULL) {
+                                       new_cd = NULL;
+                               } else {
+                                       new_cd = ((uintptr_t)cd
+                                                 - (uintptr_t)blob->csb_mem_kaddr
+                                                 + (uintptr_t)new_blob_addr);
+                               }
+                               if (entitlements == NULL) {
+                                       new_entitlements = NULL;
+                               } else {
+                                       new_entitlements = ((uintptr_t)entitlements
+                                                           - (uintptr_t)blob->csb_mem_kaddr
+                                                           + (uintptr_t)new_blob_addr);
+                               }
+//                             printf("CODE SIGNING: %s:%d kaddr 0x%llx cd %p ents %p -> blob 0x%llx cd %p ents %p\n", __FUNCTION__, __LINE__, (uint64_t)blob->csb_mem_kaddr, cd, entitlements, (uint64_t)new_blob_addr, new_cd, new_entitlements);
+                               ubc_cs_blob_deallocate(blob->csb_mem_kaddr,
+                                                      blob->csb_mem_size);
+                               blob->csb_mem_kaddr = new_blob_addr;
+                               blob->csb_mem_size = size;
+                               cd = new_cd;
+                               entitlements = new_entitlements;
+                       }
+               }
+
+               blob->csb_cd = cd;
+               blob->csb_entitlements_blob = entitlements; /* may be NULL, not yet validated */
                blob->csb_hashtype = cs_find_md(cd->hashType);
                if (blob->csb_hashtype == NULL || blob->csb_hashtype->cs_digest_size > sizeof(hash))
                        panic("validated CodeDirectory but unsupported type");
-               if (blob->csb_hashtype->cs_cd_size < CS_CDHASH_LEN) {
-                       if (cs_debug) 
-                               printf("cs_cd_size is too small for a cdhash\n");
-                       error = EINVAL;
-                       goto out;
-               }
-                   
+
+               blob->csb_hash_pageshift = cd->pageSize;
+               blob->csb_hash_pagesize = (1U << cd->pageSize);
+               blob->csb_hash_pagemask = blob->csb_hash_pagesize - 1;
+               blob->csb_hash_firstlevel_pagesize = 0;
                blob->csb_flags = (ntohl(cd->flags) & CS_ALLOWED_MACHO) | CS_VALID;
-               blob->csb_end_offset = round_page_4K(ntohl(cd->codeLimit));
+               blob->csb_end_offset = (((vm_offset_t)ntohl(cd->codeLimit) + blob->csb_hash_pagemask) & ~((vm_offset_t)blob->csb_hash_pagemask));
                if((ntohl(cd->version) >= CS_SUPPORTSSCATTER) && (ntohl(cd->scatterOffset))) {
                        const SC_Scatter *scatter = (const SC_Scatter*)
                                ((const char*)cd + ntohl(cd->scatterOffset));
-                       blob->csb_start_offset = ntohl(scatter->base) * PAGE_SIZE_4K;
+                       blob->csb_start_offset = ((off_t)ntohl(scatter->base)) * blob->csb_hash_pagesize;
                } else {
                        blob->csb_start_offset = 0;
                }
@@ -2893,17 +3186,16 @@ ubc_cs_blob_add(
         * Let policy module check whether the blob's signature is accepted.
         */
 #if CONFIG_MACF
-       error = mac_vnode_check_signature(vp, 
-                                         base_offset, 
-                                         blob->csb_cdhash, 
-                                         (const void*)addr, size,
-                                         flags, &cs_flags);
+    unsigned int cs_flags = blob->csb_flags;
+       error = mac_vnode_check_signature(vp, blob, imgp, &cs_flags, flags);
+    blob->csb_flags = cs_flags;
+
        if (error) {
                if (cs_debug) 
                        printf("check_signature[pid: %d], error = %d\n", current_proc()->p_pid, error);
                goto out;
        }
-       if ((flags & MAC_VNODE_CHECK_DYLD_SIM) && !(cs_flags & CS_PLATFORM_BINARY)) {
+       if ((flags & MAC_VNODE_CHECK_DYLD_SIM) && !(blob->csb_flags & CS_PLATFORM_BINARY)) {
                if (cs_debug)
                        printf("check_signature[pid: %d], is not apple signed\n", current_proc()->p_pid);
                error = EPERM;
@@ -2911,11 +3203,11 @@ ubc_cs_blob_add(
        }
 #endif 
        
-       if (cs_flags & CS_PLATFORM_BINARY) {
+       if (blob->csb_flags & CS_PLATFORM_BINARY) {
                if (cs_debug > 1)
                        printf("check_signature[pid: %d]: platform binary\n", current_proc()->p_pid);
                blob->csb_platform_binary = 1;
-               blob->csb_platform_path = !!(cs_flags & CS_PLATFORM_PATH);
+               blob->csb_platform_path = !!(blob->csb_flags & CS_PLATFORM_PATH);
        } else {
                blob->csb_platform_binary = 0;
                blob->csb_platform_path = 0;
@@ -2927,7 +3219,7 @@ ubc_cs_blob_add(
                                printf("check_signature[pid: %d]: no team-id\n", current_proc()->p_pid);
                }
        }
-       
+
        /*
         * Validate the blob's coverage
         */
@@ -2942,6 +3234,10 @@ ubc_cs_blob_add(
                goto out;
        }
 
+       if (ubc_cs_supports_multilevel_hash(blob)) {
+               ubc_cs_convert_to_multilevel_hash(blob);
+       }
+
        vnode_lock(vp);
        if (! UBCINFOEXISTS(vp)) {
                vnode_unlock(vp);
@@ -3101,13 +3397,17 @@ out:
 
                /* we failed; release what we allocated */
                if (blob) {
+                       if (blob->csb_mem_kaddr) {
+                               ubc_cs_blob_deallocate(blob->csb_mem_kaddr, blob->csb_mem_size);
+                               blob->csb_mem_kaddr = 0;
+                       }
+                       if (blob->csb_entitlements != NULL) {
+                               osobject_release(blob->csb_entitlements);
+                               blob->csb_entitlements = NULL;
+                       }
                        kfree(blob, sizeof (*blob));
                        blob = NULL;
                }
-               if (blob_handle != IPC_PORT_NULL) {
-                       mach_memory_entry_port_release(blob_handle);
-                       blob_handle = IPC_PORT_NULL;
-               }
        }
 
        if (error == EAGAIN) {
@@ -3117,10 +3417,6 @@ out:
                 * blob and we want to return success.
                 */
                error = 0;
-               /*
-                * Since we're not failing, consume the data we received.
-                */
-               ubc_cs_blob_deallocate(addr, size);
        }
 
        return error;
@@ -3217,10 +3513,10 @@ ubc_cs_free(
                                               blob->csb_mem_size);
                        blob->csb_mem_kaddr = 0;
                }
-               if (blob->csb_mem_handle != IPC_PORT_NULL) {
-                       mach_memory_entry_port_release(blob->csb_mem_handle);
+               if (blob->csb_entitlements != NULL) {
+                       osobject_release(blob->csb_entitlements);
+                       blob->csb_entitlements = NULL;
                }
-               blob->csb_mem_handle = IPC_PORT_NULL;
                OSAddAtomic(-1, &cs_blob_count);
                OSAddAtomic((SInt32) -blob->csb_mem_size, &cs_blob_size);
                kfree(blob, sizeof (*blob));
@@ -3256,38 +3552,43 @@ int
 ubc_cs_blob_revalidate(
        struct vnode    *vp,
        struct cs_blob *blob,
-       __unused int flags
+       struct image_params *imgp,
+       int flags
        )
 {
        int error = 0;
-#if CONFIG_MACF
-       int cs_flags = 0;
-#endif
        const CS_CodeDirectory *cd = NULL;
-       
+       const CS_GenericBlob *entitlements = NULL;
+       size_t size;
        assert(vp != NULL);
        assert(blob != NULL);
 
-       error = cs_validate_csblob((const uint8_t *)blob->csb_mem_kaddr, blob->csb_mem_size, &cd);
+       size = blob->csb_mem_size;
+       error = cs_validate_csblob((const uint8_t *)blob->csb_mem_kaddr,
+                                  &size, &cd, &entitlements);
        if (error) {
                if (cs_debug) {
                        printf("CODESIGNING: csblob invalid: %d\n", error);
                }
                goto out;
        }
+       assert(size == blob->csb_mem_size);
 
+    unsigned int cs_flags = (ntohl(cd->flags) & CS_ALLOWED_MACHO) | CS_VALID;
+    
        /* callout to mac_vnode_check_signature */
 #if CONFIG_MACF
-       error = mac_vnode_check_signature(vp, blob->csb_base_offset, blob->csb_cdhash,
-                                         (const void*)blob->csb_mem_kaddr, (int)blob->csb_mem_size,
-                                         flags, &cs_flags);
+       error = mac_vnode_check_signature(vp, blob, imgp, &cs_flags, flags);
        if (cs_debug && error) {
                        printf("revalidate: check_signature[pid: %d], error = %d\n", current_proc()->p_pid, error);
        }
+#else
+       (void)flags;
 #endif
 
        /* update generation number if success */
        vnode_lock_spin(vp);
+    blob->csb_flags = cs_flags;
        if (UBCINFOEXISTS(vp)) {
                if (error == 0)
                        vp->v_ubcinfo->cs_add_gen = cs_blob_generation_count;
@@ -3363,22 +3664,22 @@ ubc_get_cs_mtime(
 
 unsigned long cs_validate_page_no_hash = 0;
 unsigned long cs_validate_page_bad_hash = 0;
-boolean_t
-cs_validate_page(
-       void                    *_blobs,
+static boolean_t
+cs_validate_hash(
+       struct cs_blob          *blobs,
        memory_object_t         pager,
        memory_object_offset_t  page_offset,
        const void              *data,
+       vm_size_t               *bytes_processed,
        unsigned                *tainted)
 {
        union cs_hash_union     mdctx;
-       struct cs_hash          *hashtype = NULL;
+       struct cs_hash const    *hashtype = NULL;
        unsigned char           actual_hash[CS_HASH_MAX_SIZE];
-       unsigned char           expected_hash[SHA1_RESULTLEN];
+       unsigned char           expected_hash[CS_HASH_MAX_SIZE];
        boolean_t               found_hash;
-       struct cs_blob          *blobs, *blob;
+       struct cs_blob          *blob;
        const CS_CodeDirectory  *cd;
-       const CS_SuperBlob      *embedded;
        const unsigned char     *hash;
        boolean_t               validated;
        off_t                   offset; /* page offset in the file */
@@ -3386,14 +3687,9 @@ cs_validate_page(
        off_t                   codeLimit = 0;
        const char              *lower_bound, *upper_bound;
        vm_offset_t             kaddr, blob_addr;
-       vm_size_t               ksize;
-       kern_return_t           kr;
-
-       offset = page_offset;
 
        /* retrieve the expected hash */
        found_hash = FALSE;
-       blobs = (struct cs_blob *) _blobs;
 
        for (blob = blobs;
             blob != NULL;
@@ -3405,61 +3701,35 @@ cs_validate_page(
                        continue;
                }
 
-               /* map the blob in the kernel address space */
+               /* blob data has been released */
                kaddr = blob->csb_mem_kaddr;
                if (kaddr == 0) {
-                       ksize = (vm_size_t) (blob->csb_mem_size +
-                                            blob->csb_mem_offset);
-                       kr = vm_map(kernel_map,
-                                   &kaddr,
-                                   ksize,
-                                   0,
-                                   VM_FLAGS_ANYWHERE,
-                                   blob->csb_mem_handle,
-                                   0,
-                                   TRUE,
-                                   VM_PROT_READ,
-                                   VM_PROT_READ,
-                                   VM_INHERIT_NONE);
-                       if (kr != KERN_SUCCESS) {
-                               /* XXX FBDP what to do !? */
-                               printf("cs_validate_page: failed to map blob, "
-                                      "size=0x%lx kr=0x%x\n",
-                                      (size_t)blob->csb_mem_size, kr);
-                               break;
-                       }
+                       continue;
                }
 
                blob_addr = kaddr + blob->csb_mem_offset;
-               
                lower_bound = CAST_DOWN(char *, blob_addr);
                upper_bound = lower_bound + blob->csb_mem_size;
-
-               embedded = (const CS_SuperBlob *) blob_addr;
-               cd = findCodeDirectory(embedded, lower_bound, upper_bound);
+               
+               cd = blob->csb_cd;
                if (cd != NULL) {
                        /* all CD's that have been injected is already validated */
 
-                       offset = page_offset - blob->csb_base_offset;
-                       if (offset < blob->csb_start_offset ||
-                           offset >= blob->csb_end_offset) {
-                               /* our page is not covered by this blob */
-                               continue;
-                       }
-
                        hashtype = blob->csb_hashtype;
                        if (hashtype == NULL)
                                panic("unknown hash type ?");
                        if (hashtype->cs_digest_size > sizeof(actual_hash))
                                panic("hash size too large");
+                       if (offset & blob->csb_hash_pagemask)
+                               panic("offset not aligned to cshash boundary");
 
                        codeLimit = ntohl(cd->codeLimit);
 
-                       hash = hashes(cd, (uint32_t)(offset>>PAGE_SHIFT_4K),
+                       hash = hashes(cd, (uint32_t)(offset>>blob->csb_hash_pageshift),
                                      hashtype->cs_size,
                                      lower_bound, upper_bound);
                        if (hash != NULL) {
-                               bcopy(hash, expected_hash, sizeof(expected_hash));
+                               bcopy(hash, expected_hash, hashtype->cs_size);
                                found_hash = TRUE;
                        }
 
@@ -3488,23 +3758,45 @@ cs_validate_page(
 
                *tainted = 0;
 
-               size = PAGE_SIZE_4K;
+               size = blob->csb_hash_pagesize;
+               *bytes_processed = size;
+
                const uint32_t *asha1, *esha1;
                if ((off_t)(offset + size) > codeLimit) {
                        /* partial page at end of segment */
                        assert(offset < codeLimit);
-                       size = (size_t) (codeLimit & PAGE_MASK_4K);
+                       size = (size_t) (codeLimit & blob->csb_hash_pagemask);
                        *tainted |= CS_VALIDATE_NX;
                }
 
                hashtype->cs_init(&mdctx);
-               hashtype->cs_update(&mdctx, data, size);
+
+               if (blob->csb_hash_firstlevel_pagesize) {
+                       const unsigned char *partial_data = (const unsigned char *)data;
+                       size_t i;
+                       for (i=0; i < size;) {
+                               union cs_hash_union     partialctx;
+                               unsigned char partial_digest[CS_HASH_MAX_SIZE];
+                               size_t partial_size = MIN(size-i, blob->csb_hash_firstlevel_pagesize);
+
+                               hashtype->cs_init(&partialctx);
+                               hashtype->cs_update(&partialctx, partial_data, partial_size);
+                               hashtype->cs_final(partial_digest, &partialctx);
+
+                               /* Update cumulative multi-level hash */
+                               hashtype->cs_update(&mdctx, partial_digest, hashtype->cs_size);
+                               partial_data = partial_data + partial_size;
+                               i += partial_size;
+                       }
+               } else {
+                       hashtype->cs_update(&mdctx, data, size);
+               }
                hashtype->cs_final(actual_hash, &mdctx);
 
                asha1 = (const uint32_t *) actual_hash;
                esha1 = (const uint32_t *) expected_hash;
 
-               if (bcmp(expected_hash, actual_hash, hashtype->cs_cd_size) != 0) {
+               if (bcmp(expected_hash, actual_hash, hashtype->cs_size) != 0) {
                        if (cs_debug) {
                                printf("CODE SIGNING: cs_validate_page: "
                                       "mobj %p off 0x%llx size 0x%lx: "
@@ -3532,6 +3824,53 @@ cs_validate_page(
        return validated;
 }
 
+boolean_t
+cs_validate_range(
+       struct vnode    *vp,
+       memory_object_t         pager,
+       memory_object_offset_t  page_offset,
+       const void              *data,
+       vm_size_t               dsize,
+       unsigned                *tainted)
+{
+       vm_size_t offset_in_range;
+       boolean_t all_subranges_validated = TRUE; /* turn false if any subrange fails */
+
+       struct cs_blob *blobs = ubc_get_cs_blobs(vp);
+
+       *tainted = 0;
+
+       for (offset_in_range = 0;
+                offset_in_range < dsize;
+                /* offset_in_range updated based on bytes processed */) {
+               unsigned subrange_tainted = 0;
+               boolean_t subrange_validated;
+               vm_size_t bytes_processed = 0;
+
+               subrange_validated = cs_validate_hash(blobs,
+                                                                                         pager,
+                                                                                         page_offset + offset_in_range,
+                                                                                         (const void *)((const char *)data + offset_in_range),
+                                                                                         &bytes_processed,
+                                                                                         &subrange_tainted);
+
+               *tainted |= subrange_tainted;
+
+               if (bytes_processed == 0) {
+                       /* Cannote make forward progress, so return an error */
+                       all_subranges_validated = FALSE;
+                       break;
+               } else if (subrange_validated == FALSE) {
+                       all_subranges_validated = FALSE;
+                       /* Keep going to detect other types of failures in subranges */
+               }
+
+               offset_in_range += bytes_processed;
+       }
+
+       return all_subranges_validated;
+}
+
 int
 ubc_cs_getcdhash(
        vnode_t         vp,
@@ -3571,6 +3910,52 @@ ubc_cs_getcdhash(
        return ret;
 }
 
+boolean_t
+ubc_cs_is_range_codesigned(
+       vnode_t                 vp,
+       mach_vm_offset_t        start,
+       mach_vm_size_t          size)
+{
+       struct cs_blob          *csblob;
+       mach_vm_offset_t        blob_start;
+       mach_vm_offset_t        blob_end;
+
+       if (vp == NULL) {
+               /* no file: no code signature */
+               return FALSE;
+       }
+       if (size == 0) {
+               /* no range: no code signature */
+               return FALSE;
+       }
+       if (start + size < start) {
+               /* overflow */
+               return FALSE;
+       }
+
+       csblob = ubc_cs_blob_get(vp, -1, start);
+       if (csblob == NULL) {
+               return FALSE;
+       }
+
+       /*
+        * We currently check if the range is covered by a single blob,
+        * which should always be the case for the dyld shared cache.
+        * If we ever want to make this routine handle other cases, we
+        * would have to iterate if the blob does not cover the full range.
+        */
+       blob_start = (mach_vm_offset_t) (csblob->csb_base_offset +
+                                        csblob->csb_start_offset);
+       blob_end = (mach_vm_offset_t) (csblob->csb_base_offset +
+                                      csblob->csb_end_offset);
+       if (blob_start > start || blob_end < (start + size)) {
+               /* range not fully covered by this code-signing blob */
+               return FALSE;
+       }
+
+       return TRUE;
+}
+
 #if CHECK_CS_VALIDATION_BITMAP
 #define stob(s)        ((atop_64((s)) + 07) >> 3)
 extern boolean_t       root_fs_upgrade_try;