[Libguestfs] [PATCH] Report last-modified time of hive root and nodes
Alex Nelson
ajnelson at cs.ucsc.edu
Wed Aug 10 04:54:40 UTC 2011
The infrastructure for modified-time reporting has been essentially
unused. These changes report the registry time by treating the
time fields as Windows filetime fields stored in little-Endian
(which means they can be treated as a single 64-bit little-Endian
integer). Some of the code changes necessary include:
* Exposing the hive_h structure in the hivex header file (via
generator.ml)
* Adding an additional argument to the node_start function, which
should cause no complications since the change is specific to the
C API.
Signed-off-by: Alex Nelson <ajnelson at cs.ucsc.edu>
---
generator/generator.ml | 44 ++++++++++++++++-
lib/hivex.c | 124 +++++++++++++++++++++++++++++++-----------------
xml/hivexml.c | 11 ++++-
3 files changed, 132 insertions(+), 47 deletions(-)
diff --git a/generator/generator.ml b/generator/generator.ml
index 31478cd..f1aa799 100755
--- a/generator/generator.ml
+++ b/generator/generator.ml
@@ -695,6 +695,46 @@ extern \"C\" {
/* NOTE: This API is documented in the man page hivex(3). */
/* Hive handle. */
+struct hive_h {
+ char *filename;
+ int fd;
+ size_t size;
+ int msglvl;
+ int writable;
+
+ /* Registry file, memory mapped if read-only, or malloc'd if writing. */
+ union {
+ char *addr;
+ struct ntreg_header *hdr;
+ };
+
+ /* Use a bitmap to store which file offsets are valid (point to a
+ * used block). We only need to store 1 bit per 32 bits of the file
+ * (because blocks are 4-byte aligned). We found that the average
+ * block size in a registry file is ~50 bytes. So roughly 1 in 12
+ * bits in the bitmap will be set, making it likely a more efficient
+ * structure than a hash table.
+ */
+ char *bitmap;
+#define BITMAP_SET(bitmap,off) (bitmap[(off)>>5] |= 1 << (((off)>>2)&7))
+#define BITMAP_CLR(bitmap,off) (bitmap[(off)>>5] &= ~ (1 << (((off)>>2)&7)))
+#define BITMAP_TST(bitmap,off) (bitmap[(off)>>5] & (1 << (((off)>>2)&7)))
+#define IS_VALID_BLOCK(h,off) \
+ (((off) & 3) == 0 && \
+ (off) >= 0x1000 && \
+ (off) < (h)->size && \
+ BITMAP_TST((h)->bitmap,(off)))
+
+ /* 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. */
+ char *last_modified; /* mtime of base block. */
+
+ /* For writing. */
+ size_t endblocks; /* Offset to next block allocation (0
+ if not allocated anything yet). */
+};
+
typedef struct hive_h hive_h;
/* Nodes and values. */
@@ -761,7 +801,7 @@ typedef struct hive_set_value hive_set_value;
* languages make it much simpler to iterate over a tree.
*/
struct hivex_visitor {
- int (*node_start) (hive_h *, void *opaque, hive_node_h, const char *name);
+ int (*node_start) (hive_h *, void *opaque, hive_node_h, const char *name, const char *last_modified);
int (*node_end) (hive_h *, void *opaque, hive_node_h, const char *name);
int (*value_string) (hive_h *, void *opaque, hive_node_h, hive_value_h, hive_type t, size_t len, const char *key, const char *str);
int (*value_multiple_strings) (hive_h *, void *opaque, hive_node_h, hive_value_h, hive_type t, size_t len, const char *key, char **argv);
@@ -1110,7 +1150,7 @@ terminates immediately. If you don't need a callback function at
all, set the function pointer to NULL.
struct hivex_visitor {
- int (*node_start) (hive_h *, void *opaque, hive_node_h, const char *name);
+ int (*node_start) (hive_h *, void *opaque, hive_node_h, const char *name, const char *last_modified);
int (*node_end) (hive_h *, void *opaque, hive_node_h, const char *name);
int (*value_string) (hive_h *, void *opaque, hive_node_h, hive_value_h,
hive_type t, size_t len, const char *key, const char *str);
diff --git a/lib/hivex.c b/lib/hivex.c
index fedbb6c..474249f 100644
--- a/lib/hivex.c
+++ b/lib/hivex.c
@@ -33,6 +33,7 @@
#include <sys/mman.h>
#include <sys/stat.h>
#include <assert.h>
+#include <time.h>
#include "c-ctype.h"
#include "full-read.h"
@@ -60,51 +61,12 @@
static char *windows_utf16_to_utf8 (/* const */ char *input, size_t len);
static size_t utf16_string_len_in_bytes_max (const char *str, size_t len);
-struct hive_h {
- char *filename;
- int fd;
- size_t size;
- int msglvl;
- int writable;
-
- /* Registry file, memory mapped if read-only, or malloc'd if writing. */
- union {
- char *addr;
- struct ntreg_header *hdr;
- };
-
- /* Use a bitmap to store which file offsets are valid (point to a
- * used block). We only need to store 1 bit per 32 bits of the file
- * (because blocks are 4-byte aligned). We found that the average
- * block size in a registry file is ~50 bytes. So roughly 1 in 12
- * bits in the bitmap will be set, making it likely a more efficient
- * structure than a hash table.
- */
- char *bitmap;
-#define BITMAP_SET(bitmap,off) (bitmap[(off)>>5] |= 1 << (((off)>>2)&7))
-#define BITMAP_CLR(bitmap,off) (bitmap[(off)>>5] &= ~ (1 << (((off)>>2)&7)))
-#define BITMAP_TST(bitmap,off) (bitmap[(off)>>5] & (1 << (((off)>>2)&7)))
-#define IS_VALID_BLOCK(h,off) \
- (((off) & 3) == 0 && \
- (off) >= 0x1000 && \
- (off) < (h)->size && \
- BITMAP_TST((h)->bitmap,(off)))
-
- /* 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. */
struct ntreg_header {
char magic[4]; /* "regf" */
uint32_t sequence1;
uint32_t sequence2;
- char last_modified[8];
+ uint64_t last_modified;
uint32_t major_ver; /* 1 */
uint32_t minor_ver; /* 3 */
uint32_t unknown5; /* 0 */
@@ -173,7 +135,7 @@ struct ntreg_nk_record {
int32_t seg_len; /* length (always -ve because used) */
char id[2]; /* "nk" */
uint16_t flags;
- char timestamp[8];
+ uint64_t timestamp;
uint32_t unknown1;
uint32_t parent; /* offset of owner/parent */
uint32_t nr_subkeys; /* number of subkeys */
@@ -265,7 +227,34 @@ header_checksum (const hive_h *h)
return sum;
}
+#define WINDOWS_TICK 10000000LL
+#define SEC_TO_UNIX_EPOCH 11644473600LL
+/**
+ * Convert Windows filetime to ISO 8601 format.
+ * Source for filetime->time_t conversion: http://stackoverflow.com/questions/6161776/convert-windows-filetime-to-second-in-unix-linux/6161842#6161842
+ * Source for time_t->char* conversion: Fiwalk version 0.6.14's fiwalk.cpp.
+ * @param windows_ticks Expected to not have any remaining Endian issues.
+ */
+int
+filetime_to_8601 (char *buf, int bufsize, uint64_t windows_ticks)
+{
+ if (buf == NULL) {
+ fprintf (stderr, "filetime_to_8601: Received null output buffer, unable to proceed.\n");
+ return -1;
+ }
+ uint64_t nanos = windows_ticks % WINDOWS_TICK;
+ time_t tt = (windows_ticks / WINDOWS_TICK - SEC_TO_UNIX_EPOCH);
+ struct tm time_tm;
+ if (gmtime_r (&tt, &time_tm) == NULL) {
+ fprintf (stderr, "filetime_to_8601: Error running gmtime_r on timestamp (decimal hundreds of ns: %" PRIu64 ").\n", windows_ticks);
+ return -1;
+ }
+ strftime(buf, bufsize, "%FT%TZ", &time_tm);
+ return 0;
+}
+
#define HIVEX_OPEN_MSGLVL_MASK (HIVEX_OPEN_VERBOSE|HIVEX_OPEN_DEBUG)
+#define TIMESTAMP_BUF_LEN 32
hive_h *
hivex_open (const char *filename, int flags)
@@ -359,6 +348,15 @@ hivex_open (const char *filename, int flags)
goto error;
}
+ /* Last-modified time. */
+ h->last_modified = (char *) calloc(1 + TIMESTAMP_BUF_LEN, sizeof(char));
+ int ft_rc = filetime_to_8601(h->last_modified, TIMESTAMP_BUF_LEN, le64toh ((uint64_t) h->hdr->last_modified));
+ if (ft_rc) {
+ fprintf (stderr, "hivex: failed to parse time value\n");
+ free(h->last_modified);
+ h->last_modified = NULL;
+ }
+
if (h->msglvl >= 2) {
char *name = windows_utf16_to_utf8 (h->hdr->name, 64);
@@ -367,6 +365,8 @@ hivex_open (const char *filename, int flags)
" file version %" PRIu32 ".%" PRIu32 "\n"
" sequence nos %" PRIu32 " %" PRIu32 "\n"
" (sequences nos should match if hive was synched at shutdown)\n"
+ " last modified %s\n"
+ " (decimal, 100 ns) %" PRIu64 "\n"
" original file name %s\n"
" (only 32 chars are stored, name is probably truncated)\n"
" root offset 0x%x + 0x1000\n"
@@ -374,6 +374,8 @@ hivex_open (const char *filename, int flags)
" checksum 0x%x (calculated 0x%x)\n",
major_ver, le32toh (h->hdr->minor_ver),
le32toh (h->hdr->sequence1), le32toh (h->hdr->sequence2),
+ h->last_modified,
+ le64toh (h->hdr->last_modified),
name ? name : "(conversion failed)",
le32toh (h->hdr->offset),
le32toh (h->hdr->blocks), h->size,
@@ -541,6 +543,10 @@ hivex_close (hive_h *h)
if (h->msglvl >= 1)
fprintf (stderr, "hivex_close\n");
+ if (h->last_modified) {
+ free (h->last_modified);
+ h->last_modified = NULL;
+ }
free (h->bitmap);
if (!h->writable)
munmap (h->addr, h->size);
@@ -608,6 +614,33 @@ hivex_node_name (hive_h *h, hive_node_h node)
return ret;
}
+/* Caller responsible for freeing returned char* if non-null. */
+char *
+hivex_node_mtime (hive_h *h, hive_node_h node)
+{
+ int ft_rc;
+ if (!IS_VALID_BLOCK (h, node) || !BLOCK_ID_EQ (h, node, "nk")) {
+ errno = EINVAL;
+ return NULL;
+ }
+
+ struct ntreg_nk_record *nk = (struct ntreg_nk_record *) (h->addr + node);
+
+ char *ret = calloc (32 + 1, sizeof(char));
+ if (ret == NULL)
+ return ret;
+ ft_rc = filetime_to_8601 (ret, 32, le64toh (nk->timestamp));
+ if (h->msglvl >= 2) {
+ fprintf(stderr, "hivex_node_mtime: nk->timestamp: %" PRIu64 "\n", nk->timestamp);
+ fprintf(stderr, "hivex_node_mtime: ret: %s\n", ret);
+ }
+ if (ft_rc) {
+ free(ret);
+ ret = NULL;
+ }
+ return ret;
+}
+
#if 0
/* I think the documentation for the sk and classname fields in the nk
* record is wrong, or else the offset field is in the wrong place.
@@ -1560,6 +1593,7 @@ hivex__visit_node (hive_h *h, hive_node_h node,
{
int skip_bad = flags & HIVEX_VISIT_SKIP_BAD;
char *name = NULL;
+ char *last_modified = NULL;
hive_value_h *values = NULL;
hive_node_h *children = NULL;
char *key = NULL;
@@ -1584,8 +1618,11 @@ hivex__visit_node (hive_h *h, hive_node_h node,
BITMAP_CLR (unvisited, node);
name = hivex_node_name (h, node);
+ last_modified = hivex_node_mtime (h, node);
+ if (h->msglvl >= 2)
+ fprintf(stderr, "hivex__visit_node: last_modified: %s\n", last_modified ? last_modified : "NULL" );
if (!name) return skip_bad ? 0 : -1;
- if (vtor->node_start && vtor->node_start (h, opaque, node, name) == -1)
+ if (vtor->node_start && vtor->node_start (h, opaque, node, name, last_modified) == -1)
goto error;
values = hivex_node_values (h, node);
@@ -1764,6 +1801,7 @@ hivex__visit_node (hive_h *h, hive_node_h node,
error:
free (name);
+ free (last_modified);
free (values);
free (children);
free (key);
@@ -2264,7 +2302,7 @@ hivex_node_add_child (hive_h *h, hive_node_h parent, const char *name)
nk->sk = htole32 (parent_sk_offset - 0x1000);
/* Inherit parent timestamp. */
- memcpy (nk->timestamp, parent_nk->timestamp, sizeof (parent_nk->timestamp));
+ nk->timestamp = 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
diff --git a/xml/hivexml.c b/xml/hivexml.c
index 90cb22b..b32eaa2 100644
--- a/xml/hivexml.c
+++ b/xml/hivexml.c
@@ -40,7 +40,7 @@
#endif
/* Callback functions. */
-static int node_start (hive_h *, void *, hive_node_h, const char *name);
+static int node_start (hive_h *, void *, hive_node_h, const char *name, const char *last_modified);
static int node_end (hive_h *, void *, hive_node_h, const char *name);
static int value_string (hive_h *, void *, hive_node_h, hive_value_h, hive_type t, size_t len, const char *key, const char *str);
static int value_multiple_strings (hive_h *, void *, hive_node_h, hive_value_h, hive_type t, size_t len, const char *key, char **argv);
@@ -123,6 +123,8 @@ main (int argc, char *argv[])
XML_CHECK (xmlTextWriterStartDocument, (writer, NULL, "utf-8", NULL));
XML_CHECK (xmlTextWriterStartElement, (writer, BAD_CAST "hive"));
+ if (h->last_modified)
+ XML_CHECK (xmlTextWriterWriteAttribute, (writer, BAD_CAST "mtime", BAD_CAST (h->last_modified)));
if (hivex_visit (h, &visitor, sizeof visitor, writer, visit_flags) == -1) {
perror (argv[optind]);
@@ -142,11 +144,16 @@ main (int argc, char *argv[])
}
static int
-node_start (hive_h *h, void *writer_v, hive_node_h node, const char *name)
+node_start (hive_h *h, void *writer_v, hive_node_h node, const char *name, const char *last_modified)
{
xmlTextWriterPtr writer = (xmlTextWriterPtr) writer_v;
XML_CHECK (xmlTextWriterStartElement, (writer, BAD_CAST "node"));
XML_CHECK (xmlTextWriterWriteAttribute, (writer, BAD_CAST "name", BAD_CAST name));
+ if (last_modified) {
+ XML_CHECK (xmlTextWriterWriteAttribute, (writer, BAD_CAST "mtime", BAD_CAST last_modified));
+ } else {
+ fprintf(stderr, "node_start: last_modified came across NULL.\n");
+ }
return 0;
}
--
1.7.6
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