In function create_long_filname(), the array name[8 + 3] in
struct direntry_t is used as if it were defined as name[32].
This is intentional and works. It's nevertheless an out of
bounds array access. To avoid this problem, this patch adds a
struct lfn_direntry_t with multiple name arrays. A directory
entry for a long FAT file name is significantly different from
a directory entry for a regular FAT file name.
Signed-off-by: Volker Rümelin <vr_q...@t-online.de>
---
block/vvfat.c | 55 ++++++++++++++++++++++++++++++++++++++-------------
1 file changed, 41 insertions(+), 14 deletions(-)
diff --git a/block/vvfat.c b/block/vvfat.c
index 8ffe8b3b9b..626c4f0163 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -255,6 +255,17 @@ typedef struct direntry_t {
uint32_t size;
} QEMU_PACKED direntry_t;
+typedef struct lfn_direntry_t {
+ uint8_t sequence;
+ uint8_t name01[10];
+ uint8_t attributes;
+ uint8_t direntry_type;
+ uint8_t sfn_checksum;
+ uint8_t name0e[12];
+ uint16_t begin;
+ uint8_t name1c[4];
+} QEMU_PACKED lfn_direntry_t;
+
/* this structure are used to transparently access the files */
typedef struct mapping_t {
@@ -399,11 +410,28 @@ static void init_mbr(BDRVVVFATState *s, int cyls, int
heads, int secs)
/* direntry functions */
+static void write_long_filename(lfn_direntry_t *entry, int index, uint8_t c)
+{
+ if (index < ARRAY_SIZE(entry->name01)) {
+ entry->name01[index] = c;
+ return;
+ }
+ index -= ARRAY_SIZE(entry->name01);
+ if (index < ARRAY_SIZE(entry->name0e)) {
+ entry->name0e[index] = c;
+ return;
+ }
+ index -= ARRAY_SIZE(entry->name0e);
+ if (index < ARRAY_SIZE(entry->name1c)) {
+ entry->name1c[index] = c;
+ }
+}
+
static direntry_t *create_long_filename(BDRVVVFATState *s, const char
*filename)
{
int number_of_entries, i;
glong length;
- direntry_t *entry;
+ lfn_direntry_t *entry;
gunichar2 *longname = g_utf8_to_utf16(filename, -1, NULL, &length, NULL);
if (!longname) {
@@ -415,24 +443,23 @@ static direntry_t *create_long_filename(BDRVVVFATState
*s, const char *filename)
for(i=0;i<number_of_entries;i++) {
entry=array_get_next(&(s->directory));
+ entry->sequence = (number_of_entries - i) | (i == 0 ? 0x40 : 0);
entry->attributes=0xf;
- entry->reserved[0]=0;
+ entry->direntry_type = 0;
entry->begin=0;
- entry->name[0]=(number_of_entries-i)|(i==0?0x40:0);
- }
- for(i=0;i<26*number_of_entries;i++) {
- int offset=(i%26);
- if(offset<10) offset=1+offset;
- else if(offset<22) offset=14+offset-10;
- else offset=28+offset-22;
- entry=array_get(&(s->directory),s->directory.next-1-(i/26));
+ }
+ for (i = 0; i < 26 * number_of_entries; i++) {
+ uint8_t c;
+
+ entry = array_get(&s->directory, s->directory.next - i / 26 - 1);
if (i >= 2 * length + 2) {
- entry->name[offset] = 0xff;
+ c = 0xff;
} else if (i % 2 == 0) {
- entry->name[offset] = longname[i / 2] & 0xff;
+ c = longname[i / 2] & 0xff;
} else {
- entry->name[offset] = longname[i / 2] >> 8;
+ c = longname[i / 2] >> 8;
}
+ write_long_filename(entry, i % 26, c);
}
g_free(longname);
return array_get(&(s->directory),s->directory.next-number_of_entries);
@@ -731,7 +758,7 @@ static inline direntry_t*
create_short_and_long_name(BDRVVVFATState* s,
/* calculate anew, because realloc could have taken place */
entry_long=array_get(&(s->directory),long_index);
while(entry_long<entry && is_long_name(entry_long)) {
- entry_long->reserved[1]=chksum;
+ ((lfn_direntry_t *)entry_long)->sfn_checksum = chksum;
entry_long++;
}
}
--
2.43.0
