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@xxxxxxx>
---
fs/udf/directory.c | 395 +++++++++++++++++++++++++++++++++++++++++++++
fs/udf/udfdecl.h | 23 +++
2 files changed, 418 insertions(+)
diff --git a/fs/udf/directory.c b/fs/udf/directory.c
index 16bcf2c6b8b3..66117e834e29 100644
--- a/fs/udf/directory.c
+++ b/fs/udf/directory.c
@@ -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 (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,
diff --git a/fs/udf/udfdecl.h b/fs/udf/udfdecl.h
index 7e258f15b8ef..22a8466e335c 100644
--- a/fs/udf/udfdecl.h
+++ b/fs/udf/udfdecl.h
@@ -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 *,
--
2.35.3
