mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-01 06:33:07 +00:00
udf: New directory iteration code
Add new support code for iterating directory entries. The code is also more carefully verifying validity of on-disk directory entries to avoid crashes on malicious media. Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara
parent
3d2d7e6155
commit
d16076d9b6
2 changed files with 418 additions and 0 deletions
|
|
@ -17,6 +17,401 @@
|
|||
#include <linux/fs.h>
|
||||
#include <linux/string.h>
|
||||
#include <linux/bio.h>
|
||||
#include <linux/crc-itu-t.h>
|
||||
#include <linux/iversion.h>
|
||||
|
||||
static int udf_verify_fi(struct udf_fileident_iter *iter)
|
||||
{
|
||||
unsigned int len;
|
||||
|
||||
if (iter->fi.descTag.tagIdent != cpu_to_le16(TAG_IDENT_FID)) {
|
||||
udf_err(iter->dir->i_sb,
|
||||
"directory (ino %lu) has entry at pos %llu with incorrect tag %x\n",
|
||||
iter->dir->i_ino, (unsigned long long)iter->pos,
|
||||
le16_to_cpu(iter->fi.descTag.tagIdent));
|
||||
return -EFSCORRUPTED;
|
||||
}
|
||||
len = udf_dir_entry_len(&iter->fi);
|
||||
if (le16_to_cpu(iter->fi.lengthOfImpUse) & 3) {
|
||||
udf_err(iter->dir->i_sb,
|
||||
"directory (ino %lu) has entry at pos %llu with unaligned lenght of impUse field\n",
|
||||
iter->dir->i_ino, (unsigned long long)iter->pos);
|
||||
return -EFSCORRUPTED;
|
||||
}
|
||||
/*
|
||||
* This is in fact allowed by the spec due to long impUse field but
|
||||
* we don't support it. If there is real media with this large impUse
|
||||
* field, support can be added.
|
||||
*/
|
||||
if (len > 1 << iter->dir->i_blkbits) {
|
||||
udf_err(iter->dir->i_sb,
|
||||
"directory (ino %lu) has too big (%u) entry at pos %llu\n",
|
||||
iter->dir->i_ino, len, (unsigned long long)iter->pos);
|
||||
return -EFSCORRUPTED;
|
||||
}
|
||||
if (iter->pos + len > iter->dir->i_size) {
|
||||
udf_err(iter->dir->i_sb,
|
||||
"directory (ino %lu) has entry past directory size at pos %llu\n",
|
||||
iter->dir->i_ino, (unsigned long long)iter->pos);
|
||||
return -EFSCORRUPTED;
|
||||
}
|
||||
if (udf_dir_entry_len(&iter->fi) !=
|
||||
sizeof(struct tag) + le16_to_cpu(iter->fi.descTag.descCRCLength)) {
|
||||
udf_err(iter->dir->i_sb,
|
||||
"directory (ino %lu) has entry where CRC length (%u) does not match entry length (%u)\n",
|
||||
iter->dir->i_ino,
|
||||
(unsigned)le16_to_cpu(iter->fi.descTag.descCRCLength),
|
||||
(unsigned)(udf_dir_entry_len(&iter->fi) -
|
||||
sizeof(struct tag)));
|
||||
return -EFSCORRUPTED;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int udf_copy_fi(struct udf_fileident_iter *iter)
|
||||
{
|
||||
struct udf_inode_info *iinfo = UDF_I(iter->dir);
|
||||
int blksize = 1 << iter->dir->i_blkbits;
|
||||
int err, off, len, nameoff;
|
||||
|
||||
/* Skip copying when we are at EOF */
|
||||
if (iter->pos >= iter->dir->i_size) {
|
||||
iter->name = NULL;
|
||||
return 0;
|
||||
}
|
||||
if (iter->dir->i_size < iter->pos + sizeof(struct fileIdentDesc)) {
|
||||
udf_err(iter->dir->i_sb,
|
||||
"directory (ino %lu) has entry straddling EOF\n",
|
||||
iter->dir->i_ino);
|
||||
return -EFSCORRUPTED;
|
||||
}
|
||||
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
|
||||
memcpy(&iter->fi, iinfo->i_data + iinfo->i_lenEAttr + iter->pos,
|
||||
sizeof(struct fileIdentDesc));
|
||||
err = udf_verify_fi(iter);
|
||||
if (err < 0)
|
||||
return err;
|
||||
iter->name = iinfo->i_data + iinfo->i_lenEAttr + iter->pos +
|
||||
sizeof(struct fileIdentDesc) +
|
||||
le16_to_cpu(iter->fi.lengthOfImpUse);
|
||||
return 0;
|
||||
}
|
||||
|
||||
off = iter->pos & (blksize - 1);
|
||||
len = min_t(int, sizeof(struct fileIdentDesc), blksize - off);
|
||||
memcpy(&iter->fi, iter->bh[0]->b_data + off, len);
|
||||
if (len < sizeof(struct fileIdentDesc))
|
||||
memcpy((char *)(&iter->fi) + len, iter->bh[1]->b_data,
|
||||
sizeof(struct fileIdentDesc) - len);
|
||||
err = udf_verify_fi(iter);
|
||||
if (err < 0)
|
||||
return err;
|
||||
|
||||
/* Handle directory entry name */
|
||||
nameoff = off + sizeof(struct fileIdentDesc) +
|
||||
le16_to_cpu(iter->fi.lengthOfImpUse);
|
||||
if (off + udf_dir_entry_len(&iter->fi) <= blksize) {
|
||||
iter->name = iter->bh[0]->b_data + nameoff;
|
||||
} else if (nameoff >= blksize) {
|
||||
iter->name = iter->bh[1]->b_data + (nameoff - blksize);
|
||||
} else {
|
||||
iter->name = iter->namebuf;
|
||||
len = blksize - nameoff;
|
||||
memcpy(iter->name, iter->bh[0]->b_data + nameoff, len);
|
||||
memcpy(iter->name + len, iter->bh[1]->b_data,
|
||||
iter->fi.lengthFileIdent - len);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* Readahead 8k once we are at 8k boundary */
|
||||
static void udf_readahead_dir(struct udf_fileident_iter *iter)
|
||||
{
|
||||
unsigned int ralen = 16 >> (iter->dir->i_blkbits - 9);
|
||||
struct buffer_head *tmp, *bha[16];
|
||||
int i, num;
|
||||
udf_pblk_t blk;
|
||||
|
||||
if (iter->loffset & (ralen - 1))
|
||||
return;
|
||||
|
||||
if (iter->loffset + ralen > (iter->elen >> iter->dir->i_blkbits))
|
||||
ralen = (iter->elen >> iter->dir->i_blkbits) - iter->loffset;
|
||||
num = 0;
|
||||
for (i = 0; i < ralen; i++) {
|
||||
blk = udf_get_lb_pblock(iter->dir->i_sb, &iter->eloc,
|
||||
iter->loffset + i);
|
||||
tmp = udf_tgetblk(iter->dir->i_sb, blk);
|
||||
if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
|
||||
bha[num++] = tmp;
|
||||
else
|
||||
brelse(tmp);
|
||||
}
|
||||
if (num) {
|
||||
bh_readahead_batch(num, bha, REQ_RAHEAD);
|
||||
for (i = 0; i < num; i++)
|
||||
brelse(bha[i]);
|
||||
}
|
||||
}
|
||||
|
||||
static struct buffer_head *udf_fiiter_bread_blk(struct udf_fileident_iter *iter)
|
||||
{
|
||||
udf_pblk_t blk;
|
||||
|
||||
udf_readahead_dir(iter);
|
||||
blk = udf_get_lb_pblock(iter->dir->i_sb, &iter->eloc, iter->loffset);
|
||||
return udf_tread(iter->dir->i_sb, blk);
|
||||
}
|
||||
|
||||
/*
|
||||
* Updates loffset to point to next directory block; eloc, elen & epos are
|
||||
* updated if we need to traverse to the next extent as well.
|
||||
*/
|
||||
static int udf_fiiter_advance_blk(struct udf_fileident_iter *iter)
|
||||
{
|
||||
iter->loffset++;
|
||||
if (iter->loffset < iter->elen >> iter->dir->i_blkbits)
|
||||
return 0;
|
||||
|
||||
iter->loffset = 0;
|
||||
if (udf_next_aext(iter->dir, &iter->epos, &iter->eloc, &iter->elen, 1)
|
||||
!= (EXT_RECORDED_ALLOCATED >> 30)) {
|
||||
if (iter->pos == iter->dir->i_size) {
|
||||
iter->elen = 0;
|
||||
return 0;
|
||||
}
|
||||
udf_err(iter->dir->i_sb,
|
||||
"extent after position %llu not allocated in directory (ino %lu)\n",
|
||||
(unsigned long long)iter->pos, iter->dir->i_ino);
|
||||
return -EFSCORRUPTED;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int udf_fiiter_load_bhs(struct udf_fileident_iter *iter)
|
||||
{
|
||||
int blksize = 1 << iter->dir->i_blkbits;
|
||||
int off = iter->pos & (blksize - 1);
|
||||
int err;
|
||||
struct fileIdentDesc *fi;
|
||||
|
||||
/* Is there any further extent we can map from? */
|
||||
if (!iter->bh[0] && iter->elen) {
|
||||
iter->bh[0] = udf_fiiter_bread_blk(iter);
|
||||
if (!iter->bh[0]) {
|
||||
err = -ENOMEM;
|
||||
goto out_brelse;
|
||||
}
|
||||
if (!buffer_uptodate(iter->bh[0])) {
|
||||
err = -EIO;
|
||||
goto out_brelse;
|
||||
}
|
||||
}
|
||||
/* There's no next block so we are done */
|
||||
if (iter->pos >= iter->dir->i_size)
|
||||
return 0;
|
||||
/* Need to fetch next block as well? */
|
||||
if (off + sizeof(struct fileIdentDesc) > blksize)
|
||||
goto fetch_next;
|
||||
fi = (struct fileIdentDesc *)(iter->bh[0]->b_data + off);
|
||||
/* Need to fetch next block to get name? */
|
||||
if (off + udf_dir_entry_len(fi) > blksize) {
|
||||
fetch_next:
|
||||
udf_fiiter_advance_blk(iter);
|
||||
iter->bh[1] = udf_fiiter_bread_blk(iter);
|
||||
if (!iter->bh[1]) {
|
||||
err = -ENOMEM;
|
||||
goto out_brelse;
|
||||
}
|
||||
if (!buffer_uptodate(iter->bh[1])) {
|
||||
err = -EIO;
|
||||
goto out_brelse;
|
||||
}
|
||||
}
|
||||
return 0;
|
||||
out_brelse:
|
||||
brelse(iter->bh[0]);
|
||||
brelse(iter->bh[1]);
|
||||
iter->bh[0] = iter->bh[1] = NULL;
|
||||
return err;
|
||||
}
|
||||
|
||||
int udf_fiiter_init(struct udf_fileident_iter *iter, struct inode *dir,
|
||||
loff_t pos)
|
||||
{
|
||||
struct udf_inode_info *iinfo = UDF_I(dir);
|
||||
int err = 0;
|
||||
|
||||
iter->dir = dir;
|
||||
iter->bh[0] = iter->bh[1] = NULL;
|
||||
iter->pos = pos;
|
||||
iter->elen = 0;
|
||||
iter->epos.bh = NULL;
|
||||
iter->name = NULL;
|
||||
|
||||
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
|
||||
return udf_copy_fi(iter);
|
||||
|
||||
if (inode_bmap(dir, iter->pos >> dir->i_blkbits, &iter->epos,
|
||||
&iter->eloc, &iter->elen, &iter->loffset) !=
|
||||
(EXT_RECORDED_ALLOCATED >> 30)) {
|
||||
if (pos == dir->i_size)
|
||||
return 0;
|
||||
udf_err(dir->i_sb,
|
||||
"position %llu not allocated in directory (ino %lu)\n",
|
||||
(unsigned long long)pos, dir->i_ino);
|
||||
return -EFSCORRUPTED;
|
||||
}
|
||||
err = udf_fiiter_load_bhs(iter);
|
||||
if (err < 0)
|
||||
return err;
|
||||
err = udf_copy_fi(iter);
|
||||
if (err < 0) {
|
||||
udf_fiiter_release(iter);
|
||||
return err;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
int udf_fiiter_advance(struct udf_fileident_iter *iter)
|
||||
{
|
||||
unsigned int oldoff, len;
|
||||
int blksize = 1 << iter->dir->i_blkbits;
|
||||
int err;
|
||||
|
||||
oldoff = iter->pos & (blksize - 1);
|
||||
len = udf_dir_entry_len(&iter->fi);
|
||||
iter->pos += len;
|
||||
if (UDF_I(iter->dir)->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
|
||||
if (oldoff + len >= blksize) {
|
||||
brelse(iter->bh[0]);
|
||||
iter->bh[0] = NULL;
|
||||
/* Next block already loaded? */
|
||||
if (iter->bh[1]) {
|
||||
iter->bh[0] = iter->bh[1];
|
||||
iter->bh[1] = NULL;
|
||||
} else {
|
||||
udf_fiiter_advance_blk(iter);
|
||||
}
|
||||
}
|
||||
err = udf_fiiter_load_bhs(iter);
|
||||
if (err < 0)
|
||||
return err;
|
||||
}
|
||||
return udf_copy_fi(iter);
|
||||
}
|
||||
|
||||
void udf_fiiter_release(struct udf_fileident_iter *iter)
|
||||
{
|
||||
iter->dir = NULL;
|
||||
brelse(iter->bh[0]);
|
||||
brelse(iter->bh[1]);
|
||||
iter->bh[0] = iter->bh[1] = NULL;
|
||||
}
|
||||
|
||||
static void udf_copy_to_bufs(void *buf1, int len1, void *buf2, int len2,
|
||||
int off, void *src, int len)
|
||||
{
|
||||
int copy;
|
||||
|
||||
if (off >= len1) {
|
||||
off -= len1;
|
||||
} else {
|
||||
copy = min(off + len, len1) - off;
|
||||
memcpy(buf1 + off, src, copy);
|
||||
src += copy;
|
||||
len -= copy;
|
||||
off = 0;
|
||||
}
|
||||
if (len > 0) {
|
||||
if (WARN_ON_ONCE(off + len > len2 || !buf2))
|
||||
return;
|
||||
memcpy(buf2 + off, src, len);
|
||||
}
|
||||
}
|
||||
|
||||
static uint16_t udf_crc_fi_bufs(void *buf1, int len1, void *buf2, int len2,
|
||||
int off, int len)
|
||||
{
|
||||
int copy;
|
||||
uint16_t crc = 0;
|
||||
|
||||
if (off >= len1) {
|
||||
off -= len1;
|
||||
} else {
|
||||
copy = min(off + len, len1) - off;
|
||||
crc = crc_itu_t(crc, buf1 + off, copy);
|
||||
len -= copy;
|
||||
off = 0;
|
||||
}
|
||||
if (len > 0) {
|
||||
if (WARN_ON_ONCE(off + len > len2 || !buf2))
|
||||
return 0;
|
||||
crc = crc_itu_t(crc, buf2 + off, len);
|
||||
}
|
||||
return crc;
|
||||
}
|
||||
|
||||
static void udf_copy_fi_to_bufs(char *buf1, int len1, char *buf2, int len2,
|
||||
int off, struct fileIdentDesc *fi,
|
||||
uint8_t *impuse, uint8_t *name)
|
||||
{
|
||||
uint16_t crc;
|
||||
int fioff = off;
|
||||
int crcoff = off + sizeof(struct tag);
|
||||
unsigned int crclen = udf_dir_entry_len(fi) - sizeof(struct tag);
|
||||
|
||||
udf_copy_to_bufs(buf1, len1, buf2, len2, off, fi,
|
||||
sizeof(struct fileIdentDesc));
|
||||
off += sizeof(struct fileIdentDesc);
|
||||
if (impuse)
|
||||
udf_copy_to_bufs(buf1, len1, buf2, len2, off, impuse,
|
||||
le16_to_cpu(fi->lengthOfImpUse));
|
||||
off += le16_to_cpu(fi->lengthOfImpUse);
|
||||
if (name)
|
||||
udf_copy_to_bufs(buf1, len1, buf2, len2, off, name,
|
||||
fi->lengthFileIdent);
|
||||
|
||||
crc = udf_crc_fi_bufs(buf1, len1, buf2, len2, crcoff, crclen);
|
||||
fi->descTag.descCRC = cpu_to_le16(crc);
|
||||
fi->descTag.descCRCLength = cpu_to_le16(crclen);
|
||||
fi->descTag.tagChecksum = udf_tag_checksum(&fi->descTag);
|
||||
|
||||
udf_copy_to_bufs(buf1, len1, buf2, len2, fioff, fi, sizeof(struct tag));
|
||||
}
|
||||
|
||||
void udf_fiiter_write_fi(struct udf_fileident_iter *iter, uint8_t *impuse)
|
||||
{
|
||||
struct udf_inode_info *iinfo = UDF_I(iter->dir);
|
||||
void *buf1, *buf2 = NULL;
|
||||
int len1, len2 = 0, off;
|
||||
int blksize = 1 << iter->dir->i_blkbits;
|
||||
|
||||
off = iter->pos & (blksize - 1);
|
||||
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
|
||||
buf1 = iinfo->i_data + iinfo->i_lenEAttr;
|
||||
len1 = iter->dir->i_size;
|
||||
} else {
|
||||
buf1 = iter->bh[0]->b_data;
|
||||
len1 = blksize;
|
||||
if (iter->bh[1]) {
|
||||
buf2 = iter->bh[1]->b_data;
|
||||
len2 = blksize;
|
||||
}
|
||||
}
|
||||
|
||||
udf_copy_fi_to_bufs(buf1, len1, buf2, len2, off, &iter->fi, impuse,
|
||||
iter->name == iter->namebuf ? iter->name : NULL);
|
||||
|
||||
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
|
||||
mark_inode_dirty(iter->dir);
|
||||
} else {
|
||||
mark_buffer_dirty_inode(iter->bh[0], iter->dir);
|
||||
if (iter->bh[1])
|
||||
mark_buffer_dirty_inode(iter->bh[1], iter->dir);
|
||||
}
|
||||
inode_inc_iversion(iter->dir);
|
||||
}
|
||||
|
||||
struct fileIdentDesc *udf_fileident_read(struct inode *dir, loff_t *nf_pos,
|
||||
struct udf_fileident_bh *fibh,
|
||||
|
|
|
|||
|
|
@ -86,6 +86,24 @@ extern const struct address_space_operations udf_aops;
|
|||
extern const struct address_space_operations udf_adinicb_aops;
|
||||
extern const struct address_space_operations udf_symlink_aops;
|
||||
|
||||
struct udf_fileident_iter {
|
||||
struct inode *dir; /* Directory we are working with */
|
||||
loff_t pos; /* Logical position in a dir */
|
||||
struct buffer_head *bh[2]; /* Buffer containing 'pos' and possibly
|
||||
* next buffer if entry straddles
|
||||
* blocks */
|
||||
struct kernel_lb_addr eloc; /* Start of extent containing 'pos' */
|
||||
uint32_t elen; /* Length of extent containing 'pos' */
|
||||
sector_t loffset; /* Block offset of 'pos' within above
|
||||
* extent */
|
||||
struct extent_position epos; /* Position after the above extent */
|
||||
struct fileIdentDesc fi; /* Copied directory entry */
|
||||
uint8_t *name; /* Pointer to entry name */
|
||||
uint8_t namebuf[UDF_NAME_LEN_CS0]; /* Storage for entry name in case
|
||||
* the name is split between two blocks
|
||||
*/
|
||||
};
|
||||
|
||||
struct udf_fileident_bh {
|
||||
struct buffer_head *sbh;
|
||||
struct buffer_head *ebh;
|
||||
|
|
@ -243,6 +261,11 @@ extern udf_pblk_t udf_new_block(struct super_block *sb, struct inode *inode,
|
|||
uint16_t partition, uint32_t goal, int *err);
|
||||
|
||||
/* directory.c */
|
||||
int udf_fiiter_init(struct udf_fileident_iter *iter, struct inode *dir,
|
||||
loff_t pos);
|
||||
int udf_fiiter_advance(struct udf_fileident_iter *iter);
|
||||
void udf_fiiter_release(struct udf_fileident_iter *iter);
|
||||
void udf_fiiter_write_fi(struct udf_fileident_iter *iter, uint8_t *impuse);
|
||||
extern struct fileIdentDesc *udf_fileident_read(struct inode *, loff_t *,
|
||||
struct udf_fileident_bh *,
|
||||
struct fileIdentDesc *,
|
||||
|
|
|
|||
Loading…
Reference in a new issue