X-Git-Url: http://git.annexia.org/?a=blobdiff_plain;f=hivex%2Fhivex.c;h=af36868a7e8f01e5fd9fcbc92d8a1b427e14f063;hb=f604f9b0b44c17adcf7a799db06a7fc4c758c5e9;hp=d2c450fe192e3011425114d8718168e33828fd60;hpb=9a7640218c8c13d2924686d96457cfe0d3f91b1c;p=libguestfs.git diff --git a/hivex/hivex.c b/hivex/hivex.c index d2c450f..af36868 100644 --- a/hivex/hivex.c +++ b/hivex/hivex.c @@ -1,5 +1,5 @@ /* hivex - Windows Registry "hive" extraction library. - * Copyright (C) 2009 Red Hat Inc. + * Copyright (C) 2009-2010 Red Hat Inc. * Derived from code by Petter Nordahl-Hagen under a compatible license: * Copyright (c) 1997-2007 Petter Nordahl-Hagen. * Derived from code by Markus Stephany under a compatible license: @@ -33,11 +33,12 @@ #include #include #include -#ifdef HAVE_ENDIAN_H -#include -#endif -#ifdef HAVE_BYTESWAP_H -#include + +#include "full-read.h" +#include "full-write.h" + +#ifndef O_CLOEXEC +#define O_CLOEXEC 0 #endif #define STREQ(a,b) (strcmp((a),(b)) == 0) @@ -50,41 +51,8 @@ //#define STRCASENEQLEN(a,b,n) (strncasecmp((a),(b),(n)) != 0) //#define STRPREFIX(a,b) (strncmp((a),(b),strlen((b))) == 0) -#if __BYTE_ORDER == __LITTLE_ENDIAN -#ifndef be32toh -#define be32toh(x) __bswap_32 (x) -#endif -#ifndef be64toh -#define be64toh(x) __bswap_64 (x) -#endif -#ifndef le16toh -#define le16toh(x) (x) -#endif -#ifndef le32toh -#define le32toh(x) (x) -#endif -#ifndef le64toh -#define le64toh(x) (x) -#endif -#else -#ifndef be32toh -#define be32toh(x) (x) -#endif -#ifndef be64toh -#define be64toh(x) (x) -#endif -#ifndef le16toh -#define le16toh(x) __bswap_16 (x) -#endif -#ifndef le32toh -#define le32toh(x) __bswap_32 (x) -#endif -#ifndef le64toh -#define le64toh(x) __bswap_64 (x) -#endif -#endif - #include "hivex.h" +#include "byte_conversions.h" static char *windows_utf16_to_utf8 (/* const */ char *input, size_t len); @@ -93,8 +61,9 @@ 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; @@ -120,6 +89,10 @@ 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. */ @@ -257,7 +230,8 @@ struct ntreg_vk_record { uint32_t data_type; /* type of the data */ uint16_t flags; /* bit 0 set => key name ASCII, bit 0 clr => key name UTF-16. - Only seen ASCII here in the wild. */ + Only seen ASCII here in the wild. + NB: this is CLEAR for default key. */ uint16_t unknown2; char name[1]; /* key name follows here */ } __attribute__((__packed__)); @@ -298,11 +272,12 @@ 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; @@ -312,12 +287,21 @@ 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' || @@ -509,8 +493,12 @@ 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); @@ -526,7 +514,10 @@ 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); @@ -534,6 +525,10 @@ hivex_close (hive_h *h) return r; } +/*---------------------------------------------------------------------- + * Reading. + */ + hive_node_h hivex_root (hive_h *h) { @@ -1413,6 +1408,10 @@ 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) @@ -1656,3 +1655,374 @@ 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 > 1000000) { + 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 >= 6) { + blockhdr->id[0] = id[0]; + blockhdr->id[1] = id[1]; + } + + 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)); + + 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; +} + +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)) + 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; +}