X-Git-Url: http://git.annexia.org/?a=blobdiff_plain;f=hivex%2Fhivex.c;h=6752da08ab9f56585028ec3c013df9710eeeba41;hb=348bcd59b3fdfd9f8de353260fb31d745388a64e;hp=e0118affeeee6f51f5643360ffcd3a8f3fe1db33;hpb=933505a3be8ea5675151048a48b4746295b56d9b;p=libguestfs.git diff --git a/hivex/hivex.c b/hivex/hivex.c index e0118af..6752da0 100644 --- a/hivex/hivex.c +++ b/hivex/hivex.c @@ -34,6 +34,14 @@ #include #include +#include "c-ctype.h" +#include "full-read.h" +#include "full-write.h" + +#ifndef O_CLOEXEC +#define O_CLOEXEC 0 +#endif + #define STREQ(a,b) (strcmp((a),(b)) == 0) #define STRCASEEQ(a,b) (strcasecmp((a),(b)) == 0) //#define STRNEQ(a,b) (strcmp((a),(b)) != 0) @@ -42,11 +50,17 @@ //#define STRCASEEQLEN(a,b,n) (strncasecmp((a),(b),(n)) == 0) //#define STRNEQLEN(a,b,n) (strncmp((a),(b),(n)) != 0) //#define STRCASENEQLEN(a,b,n) (strncasecmp((a),(b),(n)) != 0) -//#define STRPREFIX(a,b) (strncmp((a),(b),strlen((b))) == 0) +#define STRPREFIX(a,b) (strncmp((a),(b),strlen((b))) == 0) #include "hivex.h" #include "byte_conversions.h" +/* These limits are in place to stop really stupid stuff and/or exploits. */ +#define HIVEX_MAX_SUBKEYS 10000 +#define HIVEX_MAX_VALUES 1000 +#define HIVEX_MAX_VALUE_LEN 1000000 +#define HIVEX_MAX_ALLOCATION 1000000 + static char *windows_utf16_to_utf8 (/* const */ char *input, size_t len); struct hive_h { @@ -54,8 +68,9 @@ struct hive_h { int fd; size_t size; int msglvl; + int writable; - /* Memory-mapped (readonly) registry file. */ + /* Registry file, memory mapped if read-only, or malloc'd if writing. */ union { char *addr; struct ntreg_header *hdr; @@ -81,6 +96,10 @@ struct hive_h { /* Fields from the header, extracted from little-endianness hell. */ size_t rootoffs; /* Root key offset (always an nk-block). */ size_t endpages; /* Offset of end of pages. */ + + /* For writing. */ + size_t endblocks; /* Offset to next block allocation (0 + if not allocated anything yet). */ }; /* NB. All fields are little endian. */ @@ -183,7 +202,7 @@ struct ntreg_nk_record { struct ntreg_lf_record { int32_t seg_len; - char id[2]; /* "lf" */ + char id[2]; /* "lf"|"lh" */ uint16_t nr_keys; /* number of keys in this record */ struct { uint32_t offset; /* offset of nk-record for this subkey */ @@ -224,6 +243,17 @@ struct ntreg_vk_record { char name[1]; /* key name follows here */ } __attribute__((__packed__)); +struct ntreg_sk_record { + int32_t seg_len; /* length (always -ve because used) */ + char id[2]; /* "sk" */ + uint16_t unknown1; + uint32_t sk_next; /* linked into a circular list */ + uint32_t sk_prev; + uint32_t refcount; /* reference count */ + uint32_t sec_len; /* length of security info */ + char sec_desc[1]; /* security info follows */ +} __attribute__((__packed__)); + static uint32_t header_checksum (const hive_h *h) { @@ -260,11 +290,12 @@ hivex_open (const char *filename, int flags) if (h->msglvl >= 2) fprintf (stderr, "hivex_open: created handle %p\n", h); + h->writable = !!(flags & HIVEX_OPEN_WRITE); h->filename = strdup (filename); if (h->filename == NULL) goto error; - h->fd = open (filename, O_RDONLY); + h->fd = open (filename, O_RDONLY | O_CLOEXEC); if (h->fd == -1) goto error; @@ -274,12 +305,21 @@ hivex_open (const char *filename, int flags) h->size = statbuf.st_size; - h->addr = mmap (NULL, h->size, PROT_READ, MAP_SHARED, h->fd, 0); - if (h->addr == MAP_FAILED) - goto error; + if (!h->writable) { + h->addr = mmap (NULL, h->size, PROT_READ, MAP_SHARED, h->fd, 0); + if (h->addr == MAP_FAILED) + goto error; - if (h->msglvl >= 2) - fprintf (stderr, "hivex_open: mapped file at %p\n", h->addr); + if (h->msglvl >= 2) + fprintf (stderr, "hivex_open: mapped file at %p\n", h->addr); + } else { + h->addr = malloc (h->size); + if (h->addr == NULL) + goto error; + + if (full_read (h->fd, h->addr, h->size) < h->size) + goto error; + } /* Check header. */ if (h->hdr->magic[0] != 'r' || @@ -471,8 +511,12 @@ hivex_open (const char *filename, int flags) int err = errno; if (h) { free (h->bitmap); - if (h->addr && h->size && h->addr != MAP_FAILED) - munmap (h->addr, h->size); + if (h->addr && h->size && h->addr != MAP_FAILED) { + if (!h->writable) + munmap (h->addr, h->size); + else + free (h->addr); + } if (h->fd >= 0) close (h->fd); free (h->filename); @@ -488,7 +532,10 @@ hivex_close (hive_h *h) int r; free (h->bitmap); - munmap (h->addr, h->size); + if (!h->writable) + munmap (h->addr, h->size); + else + free (h->addr); r = close (h->fd); free (h->filename); free (h); @@ -496,6 +543,10 @@ hivex_close (hive_h *h) return r; } +/*---------------------------------------------------------------------- + * Reading. + */ + hive_node_h hivex_root (hive_h *h) { @@ -650,9 +701,12 @@ return_offset_list (struct offset_list *list) } /* Iterate over children, returning child nodes and intermediate blocks. */ +#define GET_CHILDREN_NO_CHECK_NK 1 + static int get_children (hive_h *h, hive_node_h node, - hive_node_h **children_ret, size_t **blocks_ret) + hive_node_h **children_ret, size_t **blocks_ret, + int flags) { if (!IS_VALID_BLOCK (h, node) || !BLOCK_ID_EQ (h, node, "nk")) { errno = EINVAL; @@ -671,7 +725,7 @@ get_children (hive_h *h, hive_node_h node, goto ok; /* Arbitrarily limit the number of subkeys we will ever deal with. */ - if (nr_subkeys_in_nk > 1000000) { + if (nr_subkeys_in_nk > HIVEX_MAX_SUBKEYS) { errno = ERANGE; goto error; } @@ -688,7 +742,7 @@ get_children (hive_h *h, hive_node_h node, subkey_lf += 0x1000; if (!IS_VALID_BLOCK (h, subkey_lf)) { if (h->msglvl >= 2) - fprintf (stderr, "hivex_node_children: returning EFAULT because subkey_lf is not a valid block (%zu)\n", + fprintf (stderr, "hivex_node_children: returning EFAULT because subkey_lf is not a valid block (0x%zx)\n", subkey_lf); errno = EFAULT; goto error; @@ -733,12 +787,14 @@ get_children (hive_h *h, hive_node_h node, for (i = 0; i < nr_subkeys_in_lf; ++i) { hive_node_h subkey = le32toh (lf->keys[i].offset); subkey += 0x1000; - if (!IS_VALID_BLOCK (h, subkey)) { - if (h->msglvl >= 2) - fprintf (stderr, "hivex_node_children: returning EFAULT because subkey is not a valid block (0x%zx)\n", - subkey); - errno = EFAULT; - goto error; + if (!(flags & GET_CHILDREN_NO_CHECK_NK)) { + if (!IS_VALID_BLOCK (h, subkey)) { + if (h->msglvl >= 2) + fprintf (stderr, "hivex_node_children: returning EFAULT because subkey is not a valid block (0x%zx)\n", + subkey); + errno = EFAULT; + goto error; + } } if (add_to_offset_list (&children, subkey) == -1) goto error; @@ -754,7 +810,7 @@ get_children (hive_h *h, hive_node_h node, /* Count total number of children. */ size_t i, count = 0; for (i = 0; i < nr_offsets; ++i) { - hive_node_h offset = ri->offset[i]; + hive_node_h offset = le32toh (ri->offset[i]); offset += 0x1000; if (!IS_VALID_BLOCK (h, offset)) { if (h->msglvl >= 2) @@ -764,6 +820,9 @@ get_children (hive_h *h, hive_node_h node, goto error; } if (!BLOCK_ID_EQ (h, offset, "lf") && !BLOCK_ID_EQ (h, offset, "lh")) { + if (h->msglvl >= 2) + fprintf (stderr, "get_children: returning ENOTSUP because ri-record offset does not point to lf/lh (0x%zx)\n", + offset); errno = ENOTSUP; goto error; } @@ -790,7 +849,7 @@ get_children (hive_h *h, hive_node_h node, * something reasonable above. */ for (i = 0; i < nr_offsets; ++i) { - hive_node_h offset = ri->offset[i]; + hive_node_h offset = le32toh (ri->offset[i]); offset += 0x1000; if (!IS_VALID_BLOCK (h, offset)) { if (h->msglvl >= 2) @@ -800,6 +859,9 @@ get_children (hive_h *h, hive_node_h node, goto error; } if (!BLOCK_ID_EQ (h, offset, "lf") && !BLOCK_ID_EQ (h, offset, "lh")) { + if (h->msglvl >= 2) + fprintf (stderr, "get_children: returning ENOTSUP because ri-record offset does not point to lf/lh (0x%zx)\n", + offset); errno = ENOTSUP; goto error; } @@ -811,12 +873,14 @@ get_children (hive_h *h, hive_node_h node, for (j = 0; j < le16toh (lf->nr_keys); ++j) { hive_node_h subkey = le32toh (lf->keys[j].offset); subkey += 0x1000; - if (!IS_VALID_BLOCK (h, subkey)) { - if (h->msglvl >= 2) - fprintf (stderr, "hivex_node_children: returning EFAULT because indirect subkey is not a valid block (0x%zx)\n", - subkey); - errno = EFAULT; - goto error; + if (!(flags & GET_CHILDREN_NO_CHECK_NK)) { + if (!IS_VALID_BLOCK (h, subkey)) { + if (h->msglvl >= 2) + fprintf (stderr, "hivex_node_children: returning EFAULT because indirect subkey is not a valid block (0x%zx)\n", + subkey); + errno = EFAULT; + goto error; + } } if (add_to_offset_list (&children, subkey) == -1) goto error; @@ -825,6 +889,9 @@ get_children (hive_h *h, hive_node_h node, goto ok; } /* else not supported, set errno and fall through */ + if (h->msglvl >= 2) + fprintf (stderr, "get_children: returning ENOTSUP because subkey block is not lf/lh/ri (0x%zx, %d, %d)\n", + subkey_lf, block->id[0], block->id[1]); errno = ENOTSUP; error: free_offset_list (&children); @@ -845,7 +912,7 @@ hivex_node_children (hive_h *h, hive_node_h node) hive_node_h *children; size_t *blocks; - if (get_children (h, node, &children, &blocks) == -1) + if (get_children (h, node, &children, &blocks, 0) == -1) return NULL; free (blocks); @@ -928,7 +995,7 @@ get_values (hive_h *h, hive_node_h node, goto ok; /* Arbitrarily limit the number of values we will ever deal with. */ - if (nr_values > 100000) { + if (nr_values > HIVEX_MAX_VALUES) { errno = ERANGE; goto error; } @@ -1127,7 +1194,7 @@ hivex_value_value (hive_h *h, hive_value_h value, *len_rtn = len; /* Arbitrarily limit the length that we will read. */ - if (len > 1000000) { + if (len > HIVEX_MAX_VALUE_LEN) { errno = ERANGE; return NULL; } @@ -1153,15 +1220,18 @@ hivex_value_value (hive_h *h, hive_value_h value, return NULL; } - /* Check that the declared size isn't larger than the block its in. */ + /* Check that the declared size isn't larger than the block its in. + * + * XXX Some apparently valid registries are seen to have this, + * so turn this into a warning and substitute the smaller length + * instead. + */ size_t blen = block_len (h, data_offset, NULL); if (len > blen - 4 /* subtract 4 for block header */) { if (h->msglvl >= 2) - fprintf (stderr, "hivex_value_value: returning EFAULT because data is longer than its block (data 0x%zx, data len %zu, block len %zu)\n", + fprintf (stderr, "hivex_value_value: warning: declared data length is longer than the block it is in (data 0x%zx, data len %zu, block len %zu)\n", data_offset, len, blen); - errno = EFAULT; - free (ret); - return NULL; + len = blen - 4; } char *data = h->addr + data_offset + 4; @@ -1375,6 +1445,10 @@ hivex_value_qword (hive_h *h, hive_value_h value) return ret; } +/*---------------------------------------------------------------------- + * Visiting. + */ + int hivex_visit (hive_h *h, const struct hivex_visitor *visitor, size_t len, void *opaque, int flags) @@ -1618,3 +1692,866 @@ hivex__visit_node (hive_h *h, hive_node_h node, free_strings (strs); return ret; } + +/*---------------------------------------------------------------------- + * Writing. + */ + +/* Allocate an hbin (page), extending the malloc'd space if necessary, + * and updating the hive handle fields (but NOT the hive disk header + * -- the hive disk header is updated when we commit). This function + * also extends the bitmap if necessary. + * + * 'allocation_hint' is the size of the block allocation we would like + * to make. Normally registry blocks are very small (avg 50 bytes) + * and are contained in standard-sized pages (4KB), but the registry + * can support blocks which are larger than a standard page, in which + * case it creates a page of 8KB, 12KB etc. + * + * Returns: + * > 0 : offset of first usable byte of new page (after page header) + * 0 : error (errno set) + */ +static size_t +allocate_page (hive_h *h, size_t allocation_hint) +{ + /* In almost all cases this will be 1. */ + size_t nr_4k_pages = + 1 + (allocation_hint + sizeof (struct ntreg_hbin_page) - 1) / 4096; + assert (nr_4k_pages >= 1); + + /* 'extend' is the number of bytes to extend the file by. Note that + * hives found in the wild often contain slack between 'endpages' + * and the actual end of the file, so we don't always need to make + * the file larger. + */ + ssize_t extend = h->endpages + nr_4k_pages * 4096 - h->size; + + if (h->msglvl >= 2) { + fprintf (stderr, "allocate_page: current endpages = 0x%zx, current size = 0x%zx\n", + h->endpages, h->size); + fprintf (stderr, "allocate_page: extending file by %zd bytes (<= 0 if no extension)\n", + extend); + } + + if (extend > 0) { + size_t oldsize = h->size; + size_t newsize = h->size + extend; + char *newaddr = realloc (h->addr, newsize); + if (newaddr == NULL) + return 0; + + size_t oldbitmapsize = 1 + oldsize / 32; + size_t newbitmapsize = 1 + newsize / 32; + char *newbitmap = realloc (h->bitmap, newbitmapsize); + if (newbitmap == NULL) { + free (newaddr); + return 0; + } + + h->addr = newaddr; + h->size = newsize; + h->bitmap = newbitmap; + + memset (h->addr + oldsize, 0, newsize - oldsize); + memset (h->bitmap + oldbitmapsize, 0, newbitmapsize - oldbitmapsize); + } + + size_t offset = h->endpages; + h->endpages += nr_4k_pages * 4096; + + if (h->msglvl >= 2) + fprintf (stderr, "allocate_page: new endpages = 0x%zx, new size = 0x%zx\n", + h->endpages, h->size); + + /* Write the hbin header. */ + struct ntreg_hbin_page *page = + (struct ntreg_hbin_page *) (h->addr + offset); + page->magic[0] = 'h'; + page->magic[1] = 'b'; + page->magic[2] = 'i'; + page->magic[3] = 'n'; + page->offset_first = htole32 (offset - 0x1000); + page->page_size = htole32 (nr_4k_pages * 4096); + memset (page->unknown, 0, sizeof (page->unknown)); + + if (h->msglvl >= 2) + fprintf (stderr, "allocate_page: new page at 0x%zx\n", offset); + + /* Offset of first usable byte after the header. */ + return offset + sizeof (struct ntreg_hbin_page); +} + +/* Allocate a single block, first allocating an hbin (page) at the end + * of the current file if necessary. NB. To keep the implementation + * simple and more likely to be correct, we do not reuse existing free + * blocks. + * + * seg_len is the size of the block (this INCLUDES the block header). + * The header of the block is initialized to -seg_len (negative to + * indicate used). id[2] is the block ID (type), eg. "nk" for nk- + * record. The block bitmap is updated to show this block as valid. + * The rest of the contents of the block will be zero. + * + * Returns: + * > 0 : offset of new block + * 0 : error (errno set) + */ +static size_t +allocate_block (hive_h *h, size_t seg_len, const char id[2]) +{ + if (!h->writable) { + errno = EROFS; + return 0; + } + + if (seg_len < 4) { + /* The caller probably forgot to include the header. Note that + * value lists have no ID field, so seg_len == 4 would be possible + * for them, albeit unusual. + */ + if (h->msglvl >= 2) + fprintf (stderr, "allocate_block: refusing too small allocation (%zu), returning ERANGE\n", + seg_len); + errno = ERANGE; + return 0; + } + + /* Refuse really large allocations. */ + if (seg_len > HIVEX_MAX_ALLOCATION) { + if (h->msglvl >= 2) + fprintf (stderr, "allocate_block: refusing large allocation (%zu), returning ERANGE\n", + seg_len); + errno = ERANGE; + return 0; + } + + /* Round up allocation to multiple of 8 bytes. All blocks must be + * on an 8 byte boundary. + */ + seg_len = (seg_len + 7) & ~7; + + /* Allocate a new page if necessary. */ + if (h->endblocks == 0 || h->endblocks + seg_len > h->endpages) { + size_t newendblocks = allocate_page (h, seg_len); + if (newendblocks == 0) + return 0; + h->endblocks = newendblocks; + } + + size_t offset = h->endblocks; + + if (h->msglvl >= 2) + fprintf (stderr, "allocate_block: new block at 0x%zx, size %zu\n", + offset, seg_len); + + struct ntreg_hbin_block *blockhdr = + (struct ntreg_hbin_block *) (h->addr + offset); + + blockhdr->seg_len = htole32 (- (int32_t) seg_len); + if (id[0] && id[1] && seg_len >= sizeof (struct ntreg_hbin_block)) { + blockhdr->id[0] = id[0]; + blockhdr->id[1] = id[1]; + } + + BITMAP_SET (h->bitmap, offset); + + h->endblocks += seg_len; + + /* If there is space after the last block in the last page, then we + * have to put a dummy free block header here to mark the rest of + * the page as free. + */ + ssize_t rem = h->endpages - h->endblocks; + if (rem > 0) { + if (h->msglvl >= 2) + fprintf (stderr, "allocate_block: marking remainder of page free starting at 0x%zx, size %zd\n", + h->endblocks, rem); + + assert (rem >= 4); + + blockhdr = (struct ntreg_hbin_block *) (h->addr + h->endblocks); + blockhdr->seg_len = htole32 ((int32_t) rem); + } + + return offset; +} + +/* 'offset' must point to a valid, used block. This function marks + * the block unused (by updating the seg_len field) and invalidates + * the bitmap. It does NOT do this recursively, so to avoid creating + * unreachable used blocks, callers may have to recurse over the hive + * structures. Also callers must ensure there are no references to + * this block from other parts of the hive. + */ +static void +mark_block_unused (hive_h *h, size_t offset) +{ + assert (h->writable); + assert (IS_VALID_BLOCK (h, offset)); + + if (h->msglvl >= 2) + fprintf (stderr, "mark_block_unused: marking 0x%zx unused\n", offset); + + struct ntreg_hbin_block *blockhdr = + (struct ntreg_hbin_block *) (h->addr + offset); + + size_t seg_len = block_len (h, offset, NULL); + blockhdr->seg_len = htole32 (seg_len); + + BITMAP_CLR (h->bitmap, offset); +} + +/* Delete all existing values at this node. */ +static int +delete_values (hive_h *h, hive_node_h node) +{ + assert (h->writable); + + hive_value_h *values; + size_t *blocks; + if (get_values (h, node, &values, &blocks) == -1) + return -1; + + size_t i; + for (i = 0; blocks[i] != 0; ++i) + mark_block_unused (h, blocks[i]); + + free (blocks); + + for (i = 0; values[i] != 0; ++i) { + struct ntreg_vk_record *vk = + (struct ntreg_vk_record *) (h->addr + values[i]); + + size_t len; + len = le32toh (vk->data_len); + if (len == 0x80000000) /* special case */ + len = 4; + len &= 0x7fffffff; + + if (len > 4) { /* non-inline, so remove data block */ + size_t data_offset = le32toh (vk->data_offset); + data_offset += 0x1000; + mark_block_unused (h, data_offset); + } + + /* remove vk record */ + mark_block_unused (h, values[i]); + } + + free (values); + + struct ntreg_nk_record *nk = (struct ntreg_nk_record *) (h->addr + node); + nk->nr_values = htole32 (0); + nk->vallist = htole32 (0xffffffff); + + return 0; +} + +int +hivex_commit (hive_h *h, const char *filename, int flags) +{ + if (flags != 0) { + errno = EINVAL; + return -1; + } + + if (!h->writable) { + errno = EROFS; + return -1; + } + + filename = filename ? : h->filename; + int fd = open (filename, O_WRONLY|O_CREAT|O_TRUNC|O_NOCTTY, 0666); + if (fd == -1) + return -1; + + /* Update the header fields. */ + uint32_t sequence = le32toh (h->hdr->sequence1); + sequence++; + h->hdr->sequence1 = htole32 (sequence); + h->hdr->sequence2 = htole32 (sequence); + /* XXX Ought to update h->hdr->last_modified. */ + h->hdr->blocks = htole32 (h->endpages - 0x1000); + + /* Recompute header checksum. */ + uint32_t sum = header_checksum (h); + h->hdr->csum = htole32 (sum); + + if (h->msglvl >= 2) + fprintf (stderr, "hivex_commit: new header checksum: 0x%x\n", sum); + + if (full_write (fd, h->addr, h->size) != h->size) { + int err = errno; + close (fd); + errno = err; + return -1; + } + + if (close (fd) == -1) + return -1; + + return 0; +} + +/* Calculate the hash for a lf or lh record offset. + */ +static void +calc_hash (const char *type, const char *name, char *ret) +{ + size_t len = strlen (name); + + if (STRPREFIX (type, "lf")) + /* Old-style, not used in current registries. */ + memcpy (ret, name, len < 4 ? len : 4); + else { + /* New-style for lh-records. */ + size_t i, c; + uint32_t h = 0; + for (i = 0; i < len; ++i) { + c = c_toupper (name[i]); + h *= 37; + h += c; + } + *((uint32_t *) ret) = htole32 (h); + } +} + +/* Create a completely new lh-record containing just the single node. */ +static size_t +new_lh_record (hive_h *h, const char *name, hive_node_h node) +{ + static const char id[2] = { 'l', 'h' }; + size_t seg_len = sizeof (struct ntreg_lf_record); + size_t offset = allocate_block (h, seg_len, id); + if (offset == 0) + return 0; + + struct ntreg_lf_record *lh = (struct ntreg_lf_record *) (h->addr + offset); + lh->nr_keys = htole16 (1); + lh->keys[0].offset = htole32 (node - 0x1000); + calc_hash ("lh", name, lh->keys[0].hash); + + return offset; +} + +/* Insert node into existing lf/lh-record at position. + * This allocates a new record and marks the old one as unused. + */ +static size_t +insert_lf_record (hive_h *h, size_t old_offs, size_t posn, + const char *name, hive_node_h node) +{ + assert (IS_VALID_BLOCK (h, old_offs)); + + /* Work around C stupidity. + * http://www.redhat.com/archives/libguestfs/2010-February/msg00056.html + */ + int test = BLOCK_ID_EQ (h, old_offs, "lf") || BLOCK_ID_EQ (h, old_offs, "lh"); + assert (test); + + struct ntreg_lf_record *old_lf = + (struct ntreg_lf_record *) (h->addr + old_offs); + size_t nr_keys = le16toh (old_lf->nr_keys); + + nr_keys++; /* in new record ... */ + + size_t seg_len = sizeof (struct ntreg_lf_record) + (nr_keys-1) * 8; + size_t new_offs = allocate_block (h, seg_len, old_lf->id); + if (new_offs == 0) + return 0; + + struct ntreg_lf_record *new_lf = + (struct ntreg_lf_record *) (h->addr + new_offs); + new_lf->nr_keys = htole16 (nr_keys); + + /* Copy the keys until we reach posn, insert the new key there, then + * copy the remaining keys. + */ + size_t i; + for (i = 0; i < posn; ++i) + new_lf->keys[i] = old_lf->keys[i]; + + new_lf->keys[i].offset = htole32 (node - 0x1000); + calc_hash (new_lf->id, name, new_lf->keys[i].hash); + + for (i = posn+1; i < nr_keys; ++i) + new_lf->keys[i] = old_lf->keys[i-1]; + + /* Old block is unused, return new block. */ + mark_block_unused (h, old_offs); + return new_offs; +} + +/* Compare name with name in nk-record. */ +static int +compare_name_with_nk_name (hive_h *h, const char *name, hive_node_h nk_offs) +{ + assert (IS_VALID_BLOCK (h, nk_offs)); + assert (BLOCK_ID_EQ (h, nk_offs, "nk")); + + /* Name in nk is not necessarily nul-terminated. */ + char *nname = hivex_node_name (h, nk_offs); + + /* Unfortunately we don't have a way to return errors here. */ + if (!nname) { + perror ("compare_name_with_nk_name"); + return 0; + } + + int r = strcasecmp (name, nname); + free (nname); + + return r; +} + +hive_node_h +hivex_node_add_child (hive_h *h, hive_node_h parent, const char *name) +{ + if (!h->writable) { + errno = EROFS; + return 0; + } + + if (!IS_VALID_BLOCK (h, parent) || !BLOCK_ID_EQ (h, parent, "nk")) { + errno = EINVAL; + return 0; + } + + if (name == NULL || strlen (name) == 0) { + errno = EINVAL; + return 0; + } + + if (hivex_node_get_child (h, parent, name) != 0) { + errno = EEXIST; + return 0; + } + + /* Create the new nk-record. */ + static const char nk_id[2] = { 'n', 'k' }; + size_t seg_len = sizeof (struct ntreg_nk_record) + strlen (name); + hive_node_h node = allocate_block (h, seg_len, nk_id); + if (node == 0) + return 0; + + if (h->msglvl >= 2) + fprintf (stderr, "hivex_node_add_child: allocated new nk-record for child at 0x%zx\n", node); + + struct ntreg_nk_record *nk = (struct ntreg_nk_record *) (h->addr + node); + nk->flags = htole16 (0x0020); /* key is ASCII. */ + nk->parent = htole32 (parent - 0x1000); + nk->subkey_lf = htole32 (0xffffffff); + nk->subkey_lf_volatile = htole32 (0xffffffff); + nk->vallist = htole32 (0xffffffff); + nk->classname = htole32 (0xffffffff); + nk->name_len = htole16 (strlen (name)); + strcpy (nk->name, name); + + /* Inherit parent sk. */ + struct ntreg_nk_record *parent_nk = + (struct ntreg_nk_record *) (h->addr + parent); + size_t parent_sk_offset = le32toh (parent_nk->sk); + parent_sk_offset += 0x1000; + if (!IS_VALID_BLOCK (h, parent_sk_offset) || + !BLOCK_ID_EQ (h, parent_sk_offset, "sk")) { + if (h->msglvl >= 2) + fprintf (stderr, "hivex_node_add_child: returning EFAULT because parent sk is not a valid block (%zu)\n", + parent_sk_offset); + errno = EFAULT; + return 0; + } + struct ntreg_sk_record *sk = + (struct ntreg_sk_record *) (h->addr + parent_sk_offset); + sk->refcount = htole32 (le32toh (sk->refcount) + 1); + nk->sk = htole32 (parent_sk_offset - 0x1000); + + /* Inherit parent timestamp. */ + memcpy (nk->timestamp, parent_nk->timestamp, sizeof (parent_nk->timestamp)); + + /* What I found out the hard way (not documented anywhere): the + * subkeys in lh-records must be kept sorted. If you just add a + * subkey in a non-sorted position (eg. just add it at the end) then + * Windows won't see the subkey _and_ Windows will corrupt the hive + * itself when it modifies or saves it. + * + * So use get_children() to get a list of intermediate + * lf/lh-records. get_children() returns these in reading order + * (which is sorted), so we look for the lf/lh-records in sequence + * until we find the key name just after the one we are inserting, + * and we insert the subkey just before it. + * + * The only other case is the no-subkeys case, where we have to + * create a brand new lh-record. + */ + hive_node_h *unused; + size_t *blocks; + + if (get_children (h, parent, &unused, &blocks, 0) == -1) + return 0; + free (unused); + + size_t i, j; + size_t nr_subkeys_in_parent_nk = le32toh (parent_nk->nr_subkeys); + if (nr_subkeys_in_parent_nk == 0) { /* No subkeys case. */ + /* Free up any existing intermediate blocks. */ + for (i = 0; blocks[i] != 0; ++i) + mark_block_unused (h, blocks[i]); + size_t lh_offs = new_lh_record (h, name, node); + if (lh_offs == 0) { + free (blocks); + return 0; + } + + if (h->msglvl >= 2) + fprintf (stderr, "hivex_node_add_child: no keys, allocated new lh-record at 0x%zx\n", lh_offs); + + parent_nk->subkey_lf = htole32 (lh_offs - 0x1000); + } + else { /* Insert subkeys case. */ + size_t old_offs = 0, new_offs = 0; + struct ntreg_lf_record *old_lf = NULL; + + /* Find lf/lh key name just after the one we are inserting. */ + for (i = 0; blocks[i] != 0; ++i) { + if (BLOCK_ID_EQ (h, blocks[i], "lf") || + BLOCK_ID_EQ (h, blocks[i], "lh")) { + old_offs = blocks[i]; + old_lf = (struct ntreg_lf_record *) (h->addr + old_offs); + for (j = 0; j < le16toh (old_lf->nr_keys); ++j) { + hive_node_h nk_offs = le32toh (old_lf->keys[j].offset); + nk_offs += 0x1000; + if (compare_name_with_nk_name (h, name, nk_offs) < 0) + goto insert_it; + } + } + } + + /* Insert it at the end. + * old_offs points to the last lf record, set j. + */ + assert (old_offs != 0); /* should never happen if nr_subkeys > 0 */ + j = le16toh (old_lf->nr_keys); + + /* Insert it. */ + insert_it: + if (h->msglvl >= 2) + fprintf (stderr, "hivex_node_add_child: insert key in existing lh-record at 0x%zx, posn %zu\n", old_offs, j); + + new_offs = insert_lf_record (h, old_offs, j, name, node); + if (new_offs == 0) { + free (blocks); + return 0; + } + + if (h->msglvl >= 2) + fprintf (stderr, "hivex_node_add_child: new lh-record at 0x%zx\n", + new_offs); + + /* If the lf/lh-record was directly referenced by the parent nk, + * then update the parent nk. + */ + if (le32toh (parent_nk->subkey_lf) + 0x1000 == old_offs) + parent_nk->subkey_lf = htole32 (new_offs - 0x1000); + /* Else we have to look for the intermediate ri-record and update + * that in-place. + */ + else { + for (i = 0; blocks[i] != 0; ++i) { + if (BLOCK_ID_EQ (h, blocks[i], "ri")) { + struct ntreg_ri_record *ri = + (struct ntreg_ri_record *) (h->addr + blocks[i]); + for (j = 0; j < le16toh (ri->nr_offsets); ++j) + if (le32toh (ri->offset[j] + 0x1000) == old_offs) { + ri->offset[j] = htole32 (new_offs - 0x1000); + goto found_it; + } + } + } + + /* Not found .. This is an internal error. */ + if (h->msglvl >= 2) + fprintf (stderr, "hivex_node_add_child: returning ENOTSUP because could not find ri->lf link\n"); + errno = ENOTSUP; + free (blocks); + return 0; + + found_it: + ; + } + } + + free (blocks); + + /* Update nr_subkeys in parent nk. */ + nr_subkeys_in_parent_nk++; + parent_nk->nr_subkeys = htole32 (nr_subkeys_in_parent_nk); + + /* Update max_subkey_name_len in parent nk. */ + uint16_t max = le16toh (parent_nk->max_subkey_name_len); + if (max < strlen (name) * 2) /* *2 because "recoded" in UTF16-LE. */ + parent_nk->max_subkey_name_len = htole16 (strlen (name) * 2); + + return node; +} + +/* Decrement the refcount of an sk-record, and if it reaches zero, + * unlink it from the chain and delete it. + */ +static int +delete_sk (hive_h *h, size_t sk_offset) +{ + if (!IS_VALID_BLOCK (h, sk_offset) || !BLOCK_ID_EQ (h, sk_offset, "sk")) { + if (h->msglvl >= 2) + fprintf (stderr, "delete_sk: not an sk record: 0x%zx\n", sk_offset); + errno = EFAULT; + return -1; + } + + struct ntreg_sk_record *sk = (struct ntreg_sk_record *) (h->addr + sk_offset); + + if (sk->refcount == 0) { + if (h->msglvl >= 2) + fprintf (stderr, "delete_sk: sk record already has refcount 0: 0x%zx\n", + sk_offset); + errno = EINVAL; + return -1; + } + + sk->refcount--; + + if (sk->refcount == 0) { + size_t sk_prev_offset = sk->sk_prev; + sk_prev_offset += 0x1000; + + size_t sk_next_offset = sk->sk_next; + sk_next_offset += 0x1000; + + /* Update sk_prev/sk_next SKs, unless they both point back to this + * cell in which case we are deleting the last SK. + */ + if (sk_prev_offset != sk_offset && sk_next_offset != sk_offset) { + struct ntreg_sk_record *sk_prev = + (struct ntreg_sk_record *) (h->addr + sk_prev_offset); + struct ntreg_sk_record *sk_next = + (struct ntreg_sk_record *) (h->addr + sk_next_offset); + + sk_prev->sk_next = htole32 (sk_next_offset - 0x1000); + sk_next->sk_prev = htole32 (sk_prev_offset - 0x1000); + } + + /* Refcount is zero so really delete this block. */ + mark_block_unused (h, sk_offset); + } + + return 0; +} + +/* Callback from hivex_node_delete_child which is called to delete a + * node AFTER its subnodes have been visited. The subnodes have been + * deleted but we still have to delete any lf/lh/li/ri records and the + * value list block and values, followed by deleting the node itself. + */ +static int +delete_node (hive_h *h, void *opaque, hive_node_h node, const char *name) +{ + /* Get the intermediate blocks. The subkeys have already been + * deleted by this point, so tell get_children() not to check for + * validity of the nk-records. + */ + hive_node_h *unused; + size_t *blocks; + if (get_children (h, node, &unused, &blocks, GET_CHILDREN_NO_CHECK_NK) == -1) + return -1; + free (unused); + + /* We don't care what's in these intermediate blocks, so we can just + * delete them unconditionally. + */ + size_t i; + for (i = 0; blocks[i] != 0; ++i) + mark_block_unused (h, blocks[i]); + + free (blocks); + + /* Delete the values in the node. */ + if (delete_values (h, node) == -1) + return -1; + + struct ntreg_nk_record *nk = (struct ntreg_nk_record *) (h->addr + node); + + /* If the NK references an SK, delete it. */ + size_t sk_offs = le32toh (nk->sk); + if (sk_offs != 0xffffffff) { + sk_offs += 0x1000; + if (delete_sk (h, sk_offs) == -1) + return -1; + nk->sk = htole32 (0xffffffff); + } + + /* If the NK references a classname, delete it. */ + size_t cl_offs = le32toh (nk->classname); + if (cl_offs != 0xffffffff) { + cl_offs += 0x1000; + mark_block_unused (h, cl_offs); + nk->classname = htole32 (0xffffffff); + } + + /* Delete the node itself. */ + mark_block_unused (h, node); + + return 0; +} + +int +hivex_node_delete_child (hive_h *h, hive_node_h node) +{ + if (!h->writable) { + errno = EROFS; + return -1; + } + + if (!IS_VALID_BLOCK (h, node) || !BLOCK_ID_EQ (h, node, "nk")) { + errno = EINVAL; + return -1; + } + + if (node == hivex_root (h)) { + if (h->msglvl >= 2) + fprintf (stderr, "hivex_node_delete_child: cannot delete root node\n"); + errno = EINVAL; + return -1; + } + + hive_node_h parent = hivex_node_parent (h, node); + if (parent == 0) + return -1; + + /* Delete node and all its children and values recursively. */ + static const struct hivex_visitor visitor = { .node_end = delete_node }; + if (hivex_visit_node (h, node, &visitor, sizeof visitor, NULL, 0) == -1) + return -1; + + /* Delete the link from parent to child. We need to find the lf/lh + * record which contains the offset and remove the offset from that + * record, then decrement the element count in that record, and + * decrement the overall number of subkeys stored in the parent + * node. + */ + hive_node_h *unused; + size_t *blocks; + if (get_children (h, parent, &unused, &blocks, GET_CHILDREN_NO_CHECK_NK)== -1) + return -1; + free (unused); + + size_t i, j; + for (i = 0; blocks[i] != 0; ++i) { + struct ntreg_hbin_block *block = + (struct ntreg_hbin_block *) (h->addr + blocks[i]); + + if (block->id[0] == 'l' && (block->id[1] == 'f' || block->id[1] == 'h')) { + struct ntreg_lf_record *lf = (struct ntreg_lf_record *) block; + + size_t nr_subkeys_in_lf = le16toh (lf->nr_keys); + + for (j = 0; j < nr_subkeys_in_lf; ++j) + if (le32toh (lf->keys[j].offset) + 0x1000 == node) { + for (; j < nr_subkeys_in_lf - 1; ++j) + memcpy (&lf->keys[j], &lf->keys[j+1], sizeof (lf->keys[j])); + lf->nr_keys = htole16 (nr_subkeys_in_lf - 1); + goto found; + } + } + } + if (h->msglvl >= 2) + fprintf (stderr, "hivex_node_delete_child: could not find parent to child link\n"); + errno = ENOTSUP; + return -1; + + found:; + struct ntreg_nk_record *nk = (struct ntreg_nk_record *) (h->addr + parent); + size_t nr_subkeys_in_nk = le32toh (nk->nr_subkeys); + nk->nr_subkeys = htole32 (nr_subkeys_in_nk - 1); + + if (h->msglvl >= 2) + fprintf (stderr, "hivex_node_delete_child: updating nr_subkeys in parent 0x%zx to %zu\n", + parent, nr_subkeys_in_nk); + + return 0; +} + +int +hivex_node_set_values (hive_h *h, hive_node_h node, + size_t nr_values, const hive_set_value *values, + int flags) +{ + if (!h->writable) { + errno = EROFS; + return -1; + } + + if (!IS_VALID_BLOCK (h, node) || !BLOCK_ID_EQ (h, node, "nk")) { + errno = EINVAL; + return -1; + } + + /* Delete all existing values. */ + if (delete_values (h, node) == -1) + return -1; + + if (nr_values == 0) + return 0; + + /* Allocate value list node. Value lists have no id field. */ + static const char nul_id[2] = { 0, 0 }; + size_t seg_len = + sizeof (struct ntreg_value_list) + (nr_values - 1) * sizeof (uint32_t); + size_t vallist_offs = allocate_block (h, seg_len, nul_id); + if (vallist_offs == 0) + return -1; + + struct ntreg_nk_record *nk = (struct ntreg_nk_record *) (h->addr + node); + nk->nr_values = htole32 (nr_values); + nk->vallist = htole32 (vallist_offs - 0x1000); + + struct ntreg_value_list *vallist = + (struct ntreg_value_list *) (h->addr + vallist_offs); + + size_t i; + for (i = 0; i < nr_values; ++i) { + /* Allocate vk record to store this (key, value) pair. */ + static const char vk_id[2] = { 'v', 'k' }; + seg_len = sizeof (struct ntreg_vk_record) + strlen (values[i].key); + size_t vk_offs = allocate_block (h, seg_len, vk_id); + if (vk_offs == 0) + return -1; + + vallist->offset[i] = htole32 (vk_offs - 0x1000); + + struct ntreg_vk_record *vk = (struct ntreg_vk_record *) (h->addr + vk_offs); + size_t name_len = strlen (values[i].key); + vk->name_len = htole16 (name_len); + strcpy (vk->name, values[i].key); + vk->data_type = htole32 (values[i].t); + vk->data_len = htole16 (values[i].len); + vk->flags = name_len == 0 ? 0 : 1; + + if (values[i].len <= 4) /* Store data inline. */ + memcpy (&vk->data_offset, values[i].value, values[i].len); + else { + size_t offs = allocate_block (h, values[i].len + 4, nul_id); + if (offs == 0) + return -1; + memcpy (h->addr + offs + 4, values[i].value, values[i].len); + vk->data_offset = htole32 (offs - 0x1000); + } + + if (name_len * 2 > le32toh (nk->max_vk_name_len)) + /* * 2 for UTF16-LE "reencoding" */ + nk->max_vk_name_len = htole32 (name_len * 2); + if (values[i].len > le32toh (nk->max_vk_data_len)) + nk->max_vk_data_len = htole32 (values[i].len); + } + + return 0; +}