[Libguestfs] [PATCH 11/14] hivex: Complete the implementation of adding child nodes.

--- hivex/example5 | 54 ++++++++++ hivex/hivex.c | 287 +++++++++++++++++++++++++++++++++++++++++++++++++++- hivex/hivex.pod | 19 +++- hivex/hivexsh.c | 16 +++- hivex/hivexsh.pod | 14 +++ 5 files changed, 378 insertions(+), 12 deletions(-) create mode 100755 hivex/example5 diff --git a/hivex/example5 b/hivex/example5 new file mode 100755 index 0000000..ccf711c --- /dev/null +++ b/hivex/example5 @@ -0,0 +1,54 @@ +#!/bin/bash - +# Copyright (C) 2009-2010 Red Hat Inc. +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + +set -e + +# This script adds a new node under \Microsoft in an existing software +# hive. + +if [ $# -ne 2 ]; then + echo "$0 software software.new" + exit 1 +fi + +d=`dirname $0` + +$d/hivexsh -w <<EOF +load $1 +cd \Microsoft +add TestNode +cd TestNode +add Test1 +add Test2 +add Test3 +add Test4 +add Test5 +cd Test1 +setval 2 +@ +string:This is the default key of Test1 +ThisIsTest1 +dword:0x12345678 +cd .. +cd Test5 +setval 2 +@ +string:This is the default key of Test5 +ThisIsTest5 +dword:0x87654321 +commit $2 +EOF \ No newline at end of file diff --git a/hivex/hivex.c b/hivex/hivex.c index 2a094b8..148d837 100644 --- a/hivex/hivex.c +++ b/hivex/hivex.c @@ -34,6 +34,7 @@ #include <sys/stat.h> #include <assert.h> +#include "c-ctype.h" #include "full-read.h" #include "full-write.h" @@ -49,7 +50,7 @@ //#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" @@ -1987,7 +1988,117 @@ 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 +2109,185 @@ 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. diff --git a/hivex/hivex.pod b/hivex/hivex.pod index 34ff253..275eb42 100644 --- a/hivex/hivex.pod +++ b/hivex/hivex.pod @@ -383,9 +383,12 @@ C<hivex_close> after this. Add a new child node named C<name> to the existing node C<parent>. The new child initially has no subnodes and contains no keys or -values. The parent must not have an existing child called C<name>, so -if you want to overwrite an existing child, call -C<hivex_node_delete_child> first. +values. The sk-record (security descriptor) is inherited from +the parent. + +The parent must not have an existing child called C<name>, so if you +want to overwrite an existing child, call C<hivex_node_delete_child> +first. Returns the node handle. On error this returns 0 and sets errno. @@ -460,8 +463,10 @@ Modifying or deleting single values at a node. =item * -Modifying security key (sk) records or classnames. These are not -well understood. +Modifying security key (sk) records or classnames. +Previously we did not understand these records. However now they +are well-understood and we could add support if it was required +(but nothing much really uses them). =back @@ -591,6 +596,10 @@ Registry contains cycles. Field in the registry out of range. +=item EEXIST + +Registry key already exists. + =item EROFS Tried to write to a registry which is not opened for writing. diff --git a/hivex/hivexsh.c b/hivex/hivexsh.c index d5d9ada..9c54536 100644 --- a/hivex/hivexsh.c +++ b/hivex/hivexsh.c @@ -76,6 +76,7 @@ static char *rl_gets (const char *prompt_string); static void sort_strings (char **strings, int len); static int get_xdigit (char c); static int dispatch (char *cmd, char *args); +static int cmd_add (char *name); static int cmd_cd (char *path); static int cmd_close (char *path); static int cmd_commit (char *path); @@ -411,7 +412,9 @@ dispatch (char *cmd, char *args) return -1; } - if (STRCASEEQ (cmd, "cd")) + if (STRCASEEQ (cmd, "add")) + return cmd_add (args); + else if (STRCASEEQ (cmd, "cd")) return cmd_cd (args); else if (STRCASEEQ (cmd, "close") || STRCASEEQ (cmd, "unload")) return cmd_close (args); @@ -1077,3 +1080,14 @@ cmd_del (char *args) set_prompt_string (); return 0; } + +static int +cmd_add (char *name) +{ + hive_node_h node = hivex_node_add_child (h, cwd, name); + if (node == 0) { + perror ("hivexsh: add"); + return -1; + } + return 0; +} diff --git a/hivex/hivexsh.pod b/hivex/hivexsh.pod index 9336798..a31d9e0 100644 --- a/hivex/hivexsh.pod +++ b/hivex/hivexsh.pod @@ -79,6 +79,20 @@ If this option is not given, then write commands are disabled. =over 4 +=item B<add> name + +Add a subkey named C<name> below the current node. The name may +contain spaces and punctuation characters, and does not need to be +quoted. + +The new key will have no subkeys and no values (see C<setval>). + +There must be no existing subkey called C<name>, or this command will +fail. To replace an existing subkey, delete it first like this: + + cd name + del + =item B<cd> path Change to the subkey C<path>. Use Windows-style backslashes to -- 1.6.5.2