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fsck: repair corrupted dentry sets
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Repair the following corrupted dentry sets:

* invalid File dentry's SetChecksum.
* invalid File dentry's SecondaryCount.
* Absent Stream Extension dentry.
* mismatch between the file size and the number of clusters.
* invalid NameHash.
* mismatch between the length of name and NameLength.

Signed-off-by: Hyunchul Lee <[email protected]>
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@hclee
hclee committed Aug 25, 2022
1 parent 58a13e2 commit c850418
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Showing 4 changed files with 137 additions and 47 deletions.
158 changes: 116 additions & 42 deletions fsck/fsck.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -603,61 +603,116 @@ static int check_inode(struct exfat_de_iter *iter, struct exfat_inode *node)
checksum = file_calc_checksum(iter);
exfat_de_iter_get(iter, 0, &dentry);
if (checksum != le16_to_cpu(dentry->file_checksum)) {
if (repair_file_ask(iter, node, ER_DE_CHECKSUM,
"the checksum of a file is wrong")) {
exfat_de_iter_get_dirty(iter, 0, &dentry);
dentry->file_checksum = cpu_to_le16(checksum);
ret = 1;
} else
valid = false;
exfat_de_iter_get_dirty(iter, 0, &dentry);
dentry->file_checksum = cpu_to_le16(checksum);
ret = 1;
}

return valid ? ret : -EINVAL;
}

static int check_name_dentry_set(struct exfat_de_iter *iter,
struct exfat_inode *inode)
{
struct exfat_dentry *stream_de;
size_t name_len;
__u16 hash;

exfat_de_iter_get(iter, 1, &stream_de);

name_len = exfat_utf16_len(inode->name, NAME_BUFFER_SIZE);
if (stream_de->stream_name_len != name_len) {
if (repair_file_ask(iter, NULL, ER_DE_NAME_LEN,
"the name length of a file is wrong")) {
exfat_de_iter_get_dirty(iter, 1, &stream_de);
stream_de->stream_name_len = (__u8)name_len;
} else {
return -EINVAL;
}
}

hash = exfat_calc_name_hash(iter->exfat, inode->name, (int)name_len);
if (cpu_to_le16(hash) != stream_de->stream_name_hash) {
if (repair_file_ask(iter, NULL, ER_DE_NAME_HASH,
"the name hash of a file is wrong")) {
exfat_de_iter_get_dirty(iter, 1, &stream_de);
stream_de->stream_name_hash = cpu_to_le16(hash);
} else {
return -EINVAL;
}
}
return 0;
}

static int read_file_dentry_set(struct exfat_de_iter *iter,
struct exfat_inode **new_node, int *skip_dentries)
{
struct exfat_dentry *file_de, *stream_de, *name_de;
struct exfat_inode *node;
struct exfat_dentry *file_de, *stream_de, *dentry;
struct exfat_inode *node = NULL;
int i, ret;

/* TODO: mtime, atime, ... */
bool need_delete = false;
uint16_t checksum;

ret = exfat_de_iter_get(iter, 0, &file_de);
if (ret || file_de->type != EXFAT_FILE) {
exfat_err("failed to get file dentry. %d\n", ret);
exfat_err("failed to get file dentry\n");
return -EINVAL;
}

checksum = file_calc_checksum(iter);
if (checksum != le16_to_cpu(file_de->file_checksum)) {
if (repair_file_ask(iter, NULL, ER_DE_CHECKSUM,
"the checksum of a file is wrong"))
need_delete = true;
*skip_dentries = 1;
goto skip_dset;
}

if (file_de->file_num_ext < 2) {
if (repair_file_ask(iter, NULL, ER_DE_SECONDARY_COUNT,
"a file has too few secondary count. %d",
file_de->file_num_ext))
need_delete = true;
*skip_dentries = 1;
goto skip_dset;
}

ret = exfat_de_iter_get(iter, 1, &stream_de);
if (ret || stream_de->type != EXFAT_STREAM) {
exfat_err("failed to get stream dentry. %d\n", ret);
return -EINVAL;
if (repair_file_ask(iter, NULL, ER_DE_STREAM,
"failed to get stream dentry"))
need_delete = true;
*skip_dentries = 2;
goto skip_dset;
}

*new_node = NULL;
node = exfat_alloc_inode(le16_to_cpu(file_de->file_attr));
if (!node)
return -ENOMEM;

if (file_de->file_num_ext < 2) {
exfat_err("too few secondary count. %d\n",
file_de->file_num_ext);
exfat_free_inode(node);
return -EINVAL;
}

for (i = 2; i <= file_de->file_num_ext; i++) {
ret = exfat_de_iter_get(iter, i, &name_de);
if (ret || name_de->type != EXFAT_NAME) {
exfat_err("failed to get name dentry. %d\n", ret);
ret = -EINVAL;
goto err;
ret = exfat_de_iter_get(iter, i, &dentry);
if (ret || dentry->type != EXFAT_NAME) {
if (i > 2 && repair_file_ask(iter, NULL, ER_DE_NAME,
"failed to get name dentry")) {
exfat_de_iter_get_dirty(iter, 0, &file_de);
file_de->file_num_ext = i - 1;
break;
}
*skip_dentries = i + 1;
goto skip_dset;
}

memcpy(node->name +
(i-2) * ENTRY_NAME_MAX, name_de->name_unicode,
sizeof(name_de->name_unicode));
(i - 2) * ENTRY_NAME_MAX, dentry->name_unicode,
sizeof(dentry->name_unicode));
}

ret = check_name_dentry_set(iter, node);
if (ret) {
*skip_dentries = file_de->file_num_ext + 1;
goto skip_dset;
}

node->first_clus = le32_to_cpu(stream_de->stream_start_clu);
Expand All @@ -666,27 +721,41 @@ static int read_file_dentry_set(struct exfat_de_iter *iter,
node->size = le64_to_cpu(stream_de->stream_size);

if (node->size < le64_to_cpu(stream_de->stream_valid_size)) {
*skip_dentries = file_de->file_num_ext + 1;
if (repair_file_ask(iter, node, ER_FILE_VALID_SIZE,
"valid size %" PRIu64 " greater than size %" PRIu64,
le64_to_cpu(stream_de->stream_valid_size),
node->size)) {
"valid size %" PRIu64 " greater than size %" PRIu64,
le64_to_cpu(stream_de->stream_valid_size),
node->size)) {
exfat_de_iter_get_dirty(iter, 1, &stream_de);
stream_de->stream_valid_size =
stream_de->stream_size;
} else {
ret = -EINVAL;
goto err;
*skip_dentries = file_de->file_num_ext + 1;
goto skip_dset;
}
}

*skip_dentries = (file_de->file_num_ext + 1);
*new_node = node;
return 0;
err:
*skip_dentries = 1;
skip_dset:
if (need_delete) {
exfat_de_iter_get_dirty(iter, 0, &dentry);
dentry->type &= EXFAT_DELETE;
}
for (i = 1; i < *skip_dentries; i++) {
exfat_de_iter_get(iter, i, &dentry);
if (dentry->type == EXFAT_FILE)
break;
if (need_delete) {
exfat_de_iter_get_dirty(iter, i, &dentry);
dentry->type &= EXFAT_DELETE;
}
}
*skip_dentries = i;
*new_node = NULL;
exfat_free_inode(node);
return ret;
return need_delete ? 1 : -EINVAL;
}

static int read_file(struct exfat_de_iter *de_iter,
Expand Down Expand Up @@ -948,12 +1017,17 @@ static int read_children(struct exfat_fsck *fsck, struct exfat_inode *dir)
exfat_stat.fixed_count++;
}

if ((node->attr & ATTR_SUBDIR) && node->size) {
node->parent = dir;
list_add_tail(&node->sibling, &dir->children);
list_add_tail(&node->list, &exfat->dir_list);
} else
exfat_free_inode(node);
if (node) {
if ((node->attr & ATTR_SUBDIR) && node->size) {
node->parent = dir;
list_add_tail(&node->sibling,
&dir->children);
list_add_tail(&node->list,
&exfat->dir_list);
} else {
exfat_free_inode(node);
}
}
break;
case EXFAT_LAST:
goto out;
Expand Down
12 changes: 10 additions & 2 deletions fsck/repair.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,18 +27,26 @@ struct exfat_repair_problem {
/* Prompt types */
#define ERP_FIX 0x00000001
#define ERP_TRUNCATE 0x00000002
#define ERP_DELETE 0x00000003

static const char *prompts[] = {
"Repair",
"Fix",
"Truncate",
"Delete",
};

static struct exfat_repair_problem problems[] = {
{ER_BS_CHECKSUM, ERF_PREEN_YES, ERP_FIX},
{ER_BS_BOOT_REGION, 0, ERP_FIX},
{ER_DE_CHECKSUM, ERF_PREEN_YES, ERP_FIX},
{ER_DE_UNKNOWN, ERF_PREEN_YES, ERP_FIX},
{ER_DE_CHECKSUM, ERF_PREEN_YES, ERP_DELETE},
{ER_DE_UNKNOWN, ERF_PREEN_YES, ERP_DELETE},
{ER_DE_FILE, ERF_PREEN_YES, ERP_DELETE},
{ER_DE_SECONDARY_COUNT, ERF_PREEN_YES, ERP_DELETE},
{ER_DE_STREAM, ERF_PREEN_YES, ERP_DELETE},
{ER_DE_NAME, ERF_PREEN_YES, ERP_DELETE},
{ER_DE_NAME_HASH, ERF_PREEN_YES, ERP_FIX},
{ER_DE_NAME_LEN, ERF_PREEN_YES, ERP_FIX},
{ER_FILE_VALID_SIZE, ERF_PREEN_YES, ERP_FIX},
{ER_FILE_INVALID_CLUS, ERF_PREEN_YES, ERP_TRUNCATE},
{ER_FILE_FIRST_CLUS, ERF_PREEN_YES, ERP_TRUNCATE},
Expand Down
6 changes: 6 additions & 0 deletions fsck/repair.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,12 @@
#define ER_BS_BOOT_REGION 0x00000002
#define ER_DE_CHECKSUM 0x00001001
#define ER_DE_UNKNOWN 0x00001002
#define ER_DE_FILE 0x00001010
#define ER_DE_SECONDARY_COUNT 0x00001011
#define ER_DE_STREAM 0x00001020
#define ER_DE_NAME 0x00001030
#define ER_DE_NAME_HASH 0x00001031
#define ER_DE_NAME_LEN 0x00001032
#define ER_FILE_VALID_SIZE 0x00002001
#define ER_FILE_INVALID_CLUS 0x00002002
#define ER_FILE_FIRST_CLUS 0x00002003
Expand Down
8 changes: 5 additions & 3 deletions lib/exfat_fs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -37,9 +37,11 @@ struct exfat_inode *exfat_alloc_inode(__u16 attr)

void exfat_free_inode(struct exfat_inode *node)
{
if (node->dentry_set)
free(node->dentry_set);
free(node);
if (node) {
if (node->dentry_set)
free(node->dentry_set);
free(node);
}
}

void exfat_free_children(struct exfat_inode *dir, bool file_only)
Expand Down

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