X-Git-Url: http://git.annexia.org/?a=blobdiff_plain;f=hivex%2Fhivex.c;h=7d26eebde4872f969f2fd01933d45516d84dd6d7;hb=a1d388f25859b1c205aebb04dcd4846aa47027a1;hp=2a094b85c231371c684eda1a9db154c60283e587;hpb=3113582ef88d280cfa3c479cc705c3972c777fb7;p=libguestfs.git diff --git a/hivex/hivex.c b/hivex/hivex.c index 2a094b8..7d26eeb 100644 --- a/hivex/hivex.c +++ b/hivex/hivex.c @@ -34,6 +34,7 @@ #include #include +#include "c-ctype.h" #include "full-read.h" #include "full-write.h" @@ -49,11 +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 { @@ -222,8 +229,7 @@ struct ntreg_vk_record { uint16_t name_len; /* length of name */ /* length of the data: * If data_len is <= 4, then it's stored inline. - * If data_len is 0x80000000, then it's an inline dword. - * Top bit may be set or not set at random. + * Top bit is set to indicate inline. */ uint32_t data_len; uint32_t data_offset; /* pointer to the data (or data if inline) */ @@ -718,7 +724,7 @@ 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; } @@ -988,7 +994,7 @@ 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; } @@ -1144,11 +1150,7 @@ hivex_value_type (hive_h *h, hive_value_h value, hive_type *t, size_t *len) if (len) { *len = le32toh (vk->data_len); - if (*len == 0x80000000) { /* special case */ - *len = 4; - if (t) *t = hive_t_dword; - } - *len &= 0x7fffffff; + *len &= 0x7fffffff; /* top bit indicates if data is stored inline */ } return 0; @@ -1167,27 +1169,30 @@ hivex_value_value (hive_h *h, hive_value_h value, hive_type t; size_t len; + int is_inline; t = le32toh (vk->data_type); len = le32toh (vk->data_len); - if (len == 0x80000000) { /* special case */ - len = 4; - t = hive_t_dword; - } + is_inline = !!(len & 0x80000000); len &= 0x7fffffff; if (h->msglvl >= 2) - fprintf (stderr, "hivex_value_value: value=0x%zx, t=%d, len=%zu\n", - value, t, len); + fprintf (stderr, "hivex_value_value: value=0x%zx, t=%d, len=%zu, inline=%d\n", + value, t, len, is_inline); if (t_rtn) *t_rtn = t; if (len_rtn) *len_rtn = len; + if (is_inline && len > 4) { + errno = ENOTSUP; + return NULL; + } + /* Arbitrarily limit the length that we will read. */ - if (len > 1000000) { + if (len > HIVEX_MAX_VALUE_LEN) { errno = ERANGE; return NULL; } @@ -1196,8 +1201,7 @@ hivex_value_value (hive_h *h, hive_value_h value, if (ret == NULL) return NULL; - /* If length is <= 4 it's always stored inline. */ - if (len <= 4) { + if (is_inline) { memcpy (ret, (char *) &vk->data_offset, len); return ret; } @@ -1811,7 +1815,7 @@ allocate_block (hive_h *h, size_t seg_len, const char id[2]) } /* Refuse really large allocations. */ - if (seg_len > 1000000) { + if (seg_len > HIVEX_MAX_ALLOCATION) { if (h->msglvl >= 2) fprintf (stderr, "allocate_block: refusing large allocation (%zu), returning ERANGE\n", seg_len); @@ -1842,7 +1846,7 @@ allocate_block (hive_h *h, size_t seg_len, const char id[2]) (struct ntreg_hbin_block *) (h->addr + offset); blockhdr->seg_len = htole32 (- (int32_t) seg_len); - if (id[0] && id[1] && seg_len >= 6) { + if (id[0] && id[1] && seg_len >= sizeof (struct ntreg_hbin_block)) { blockhdr->id[0] = id[0]; blockhdr->id[1] = id[1]; } @@ -1917,12 +1921,12 @@ delete_values (hive_h *h, hive_node_h node) (struct ntreg_vk_record *) (h->addr + values[i]); size_t len; + int is_inline; len = le32toh (vk->data_len); - if (len == 0x80000000) /* special case */ - len = 4; + is_inline = !!(len & 0x80000000); /* top bit indicates is inline */ len &= 0x7fffffff; - if (len > 4) { /* non-inline, so remove data block */ + if (!is_inline) { /* non-inline, so remove data block */ size_t data_offset = le32toh (vk->data_offset); data_offset += 0x1000; mark_block_unused (h, data_offset); @@ -1987,7 +1991,117 @@ hivex_commit (hive_h *h, const char *filename, int flags) return 0; } -#if 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) { @@ -1998,21 +2112,185 @@ hivex_node_add_child (hive_h *h, hive_node_h parent, const char *name) if (!IS_VALID_BLOCK (h, parent) || !BLOCK_ID_EQ (h, parent, "nk")) { errno = EINVAL; - return -1; + return 0; } - if (name == NULL) { + if (name == NULL || strlen (name) == 0) { errno = EINVAL; - return -1; + 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; } -#endif /* Decrement the refcount of an sk-record, and if it reaches zero, * unlink it from the chain and delete it. @@ -2252,10 +2530,13 @@ hivex_node_set_values (hive_h *h, hive_node_h node, 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); + uint32_t len = values[i].len; + if (len <= 4) /* store it inline => set MSB flag */ + len |= 0x80000000; + vk->data_len = htole32 (len); vk->flags = name_len == 0 ? 0 : 1; - if (values[i].len <= 4) /* Store data inline. */ + if (values[i].len <= 4) /* store it inline */ memcpy (&vk->data_offset, values[i].value, values[i].len); else { size_t offs = allocate_block (h, values[i].len + 4, nul_id); @@ -2266,6 +2547,7 @@ hivex_node_set_values (hive_h *h, hive_node_h node, } 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);