fs/ntfs3: Check fields while reading

Added new functions index_hdr_check and index_buf_check.
Now we check all stuff for correctness while reading from disk.
Also fixed bug with stale nfs data.
Reported-by: van fantasy <g1042620637@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

fs/ntfs3/index.c

@@ -605,11 +605,58 @@ static const struct NTFS_DE *hdr_insert_head(struct INDEX_HDR *hdr,
 	return e;
 }
 
+/*
+ * index_hdr_check
+ *
+ * return true if INDEX_HDR is valid
+ */
+static bool index_hdr_check(const struct INDEX_HDR *hdr, u32 bytes)
+{
+	u32 end = le32_to_cpu(hdr->used);
+	u32 tot = le32_to_cpu(hdr->total);
+	u32 off = le32_to_cpu(hdr->de_off);
+
+	if (!IS_ALIGNED(off, 8) || tot > bytes || end > tot ||
+	    off + sizeof(struct NTFS_DE) > end) {
+		/* incorrect index buffer. */
+		return false;
+	}
+
+	return true;
+}
+
+/*
+ * index_buf_check
+ *
+ * return true if INDEX_BUFFER seems is valid
+ */
+static bool index_buf_check(const struct INDEX_BUFFER *ib, u32 bytes,
+			    const CLST *vbn)
+{
+	const struct NTFS_RECORD_HEADER *rhdr = &ib->rhdr;
+	u16 fo = le16_to_cpu(rhdr->fix_off);
+	u16 fn = le16_to_cpu(rhdr->fix_num);
+
+	if (bytes <= offsetof(struct INDEX_BUFFER, ihdr) ||
+	    rhdr->sign != NTFS_INDX_SIGNATURE ||
+	    fo < sizeof(struct INDEX_BUFFER)
+	    /* Check index buffer vbn. */
+	    || (vbn && *vbn != le64_to_cpu(ib->vbn)) || (fo % sizeof(short)) ||
+	    fo + fn * sizeof(short) >= bytes ||
+	    fn != ((bytes >> SECTOR_SHIFT) + 1)) {
+		/* incorrect index buffer. */
+		return false;
+	}
+
+	return index_hdr_check(&ib->ihdr,
+			       bytes - offsetof(struct INDEX_BUFFER, ihdr));
+}
+
 void fnd_clear(struct ntfs_fnd *fnd)
 {
 	int i;
 
-	for (i = 0; i < fnd->level; i++) {
+	for (i = fnd->level - 1; i >= 0; i--) {
 		struct indx_node *n = fnd->nodes[i];
 
 		if (!n)
@@ -819,9 +866,16 @@ int indx_init(struct ntfs_index *indx, struct ntfs_sb_info *sbi,
 	u32 t32;
 	const struct INDEX_ROOT *root = resident_data(attr);
 
+	t32 = le32_to_cpu(attr->res.data_size);
+	if (t32 <= offsetof(struct INDEX_ROOT, ihdr) ||
+	    !index_hdr_check(&root->ihdr,
+			     t32 - offsetof(struct INDEX_ROOT, ihdr))) {
+		goto out;
+	}
+
 	/* Check root fields. */
 	if (!root->index_block_clst)
-		return -EINVAL;
+		goto out;
 
 	indx->type = type;
 	indx->idx2vbn_bits = __ffs(root->index_block_clst);
@@ -833,19 +887,19 @@ int indx_init(struct ntfs_index *indx, struct ntfs_sb_info *sbi,
 	if (t32 < sbi->cluster_size) {
 		/* Index record is smaller than a cluster, use 512 blocks. */
 		if (t32 != root->index_block_clst * SECTOR_SIZE)
-			return -EINVAL;
+			goto out;
 
 		/* Check alignment to a cluster. */
 		if ((sbi->cluster_size >> SECTOR_SHIFT) &
 		    (root->index_block_clst - 1)) {
-			return -EINVAL;
+			goto out;
 		}
 
 		indx->vbn2vbo_bits = SECTOR_SHIFT;
 	} else {
 		/* Index record must be a multiple of cluster size. */
 		if (t32 != root->index_block_clst << sbi->cluster_bits)
-			return -EINVAL;
+			goto out;
 
 		indx->vbn2vbo_bits = sbi->cluster_bits;
 	}
@@ -853,7 +907,14 @@ int indx_init(struct ntfs_index *indx, struct ntfs_sb_info *sbi,
 	init_rwsem(&indx->run_lock);
 
 	indx->cmp = get_cmp_func(root);
-	return indx->cmp ? 0 : -EINVAL;
+	if (!indx->cmp)
+		goto out;
+
+	return 0;
+
+out:
+	ntfs_set_state(sbi, NTFS_DIRTY_DIRTY);
+	return -EINVAL;
 }
 
 static struct indx_node *indx_new(struct ntfs_index *indx,
@@ -1011,6 +1072,13 @@ int indx_read(struct ntfs_index *indx, struct ntfs_inode *ni, CLST vbn,
 		goto out;
 
 ok:
+	if (!index_buf_check(ib, bytes, &vbn)) {
+		ntfs_inode_err(&ni->vfs_inode, "directory corrupted");
+		ntfs_set_state(ni->mi.sbi, NTFS_DIRTY_ERROR);
+		err = -EINVAL;
+		goto out;
+	}
+
 	if (err == -E_NTFS_FIXUP) {
 		ntfs_write_bh(ni->mi.sbi, &ib->rhdr, &in->nb, 0);
 		err = 0;
@@ -1601,9 +1669,9 @@ static int indx_insert_into_root(struct ntfs_index *indx, struct ntfs_inode *ni,
 
 	if (err) {
 		/* Restore root. */
-		if (mi_resize_attr(mi, attr, -ds_root))
+		if (mi_resize_attr(mi, attr, -ds_root)) {
 			memcpy(attr, a_root, asize);
-		else {
+		} else {
 			/* Bug? */
 			ntfs_set_state(sbi, NTFS_DIRTY_ERROR);
 		}

fs/ntfs3/inode.c

@@ -81,7 +81,7 @@ static struct inode *ntfs_read_mft(struct inode *inode,
 			 le16_to_cpu(ref->seq), le16_to_cpu(rec->seq));
 		goto out;
 	} else if (!is_rec_inuse(rec)) {
-		err = -EINVAL;
+		err = -ESTALE;
 		ntfs_err(sb, "Inode r=%x is not in use!", (u32)ino);
 		goto out;
 	}
@@ -92,8 +92,10 @@ static struct inode *ntfs_read_mft(struct inode *inode,
 		goto out;
 	}
 
-	if (!is_rec_base(rec))
-		goto Ok;
+	if (!is_rec_base(rec)) {
+		err = -EINVAL;
+		goto out;
+	}
 
 	/* Record should contain $I30 root. */
 	is_dir = rec->flags & RECORD_FLAG_DIR;
@@ -466,7 +468,6 @@ static struct inode *ntfs_read_mft(struct inode *inode,
 		inode->i_flags |= S_NOSEC;
 	}
 
-Ok:
 	if (ino == MFT_REC_MFT && !sb->s_root)
 		sbi->mft.ni = NULL;
 
@@ -520,6 +521,9 @@ struct inode *ntfs_iget5(struct super_block *sb, const struct MFT_REF *ref,
 		_ntfs_bad_inode(inode);
 	}
 
+	if (IS_ERR(inode) && name)
+		ntfs_set_state(sb->s_fs_info, NTFS_DIRTY_ERROR);
+
 	return inode;
 }
 
@@ -1660,10 +1664,8 @@ struct inode *ntfs_create_inode(struct user_namespace *mnt_userns,
 		ntfs_remove_reparse(sbi, IO_REPARSE_TAG_SYMLINK, &new_de->ref);
 
 out5:
-	if (S_ISDIR(mode) || run_is_empty(&ni->file.run))
-		goto out4;
-
-	run_deallocate(sbi, &ni->file.run, false);
+	if (!S_ISDIR(mode))
+		run_deallocate(sbi, &ni->file.run, false);
 
 out4:
 	clear_rec_inuse(rec);

fs/ntfs3/ntfs_fs.h

@@ -797,12 +797,12 @@ int run_pack(const struct runs_tree *run, CLST svcn, CLST len, u8 *run_buf,
 	     u32 run_buf_size, CLST *packed_vcns);
 int run_unpack(struct runs_tree *run, struct ntfs_sb_info *sbi, CLST ino,
 	       CLST svcn, CLST evcn, CLST vcn, const u8 *run_buf,
-	       u32 run_buf_size);
+	       int run_buf_size);
 
 #ifdef NTFS3_CHECK_FREE_CLST
 int run_unpack_ex(struct runs_tree *run, struct ntfs_sb_info *sbi, CLST ino,
 		  CLST svcn, CLST evcn, CLST vcn, const u8 *run_buf,
-		  u32 run_buf_size);
+		  int run_buf_size);
 #else
 #define run_unpack_ex run_unpack
 #endif

fs/ntfs3/run.c

@@ -919,12 +919,15 @@ int run_pack(const struct runs_tree *run, CLST svcn, CLST len, u8 *run_buf,
  */
 int run_unpack(struct runs_tree *run, struct ntfs_sb_info *sbi, CLST ino,
 	       CLST svcn, CLST evcn, CLST vcn, const u8 *run_buf,
-	       u32 run_buf_size)
+	       int run_buf_size)
 {
 	u64 prev_lcn, vcn64, lcn, next_vcn;
 	const u8 *run_last, *run_0;
 	bool is_mft = ino == MFT_REC_MFT;
 
+	if (run_buf_size < 0)
+		return -EINVAL;
+
 	/* Check for empty. */
 	if (evcn + 1 == svcn)
 		return 0;
@@ -1046,7 +1049,7 @@ int run_unpack(struct runs_tree *run, struct ntfs_sb_info *sbi, CLST ino,
  */
 int run_unpack_ex(struct runs_tree *run, struct ntfs_sb_info *sbi, CLST ino,
 		  CLST svcn, CLST evcn, CLST vcn, const u8 *run_buf,
-		  u32 run_buf_size)
+		  int run_buf_size)
 {
 	int ret, err;
 	CLST next_vcn, lcn, len;

fs/ntfs3/xattr.c

@@ -43,28 +43,26 @@ static inline size_t packed_ea_size(const struct EA_FULL *ea)
  * Assume there is at least one xattr in the list.
  */
 static inline bool find_ea(const struct EA_FULL *ea_all, u32 bytes,
-			   const char *name, u8 name_len, u32 *off)
+			   const char *name, u8 name_len, u32 *off, u32 *ea_sz)
 {
-	*off = 0;
+	u32 ea_size;
 
-	if (!ea_all || !bytes)
+	*off = 0;
+	if (!ea_all)
 		return false;
 
-	for (;;) {
+	for (; *off < bytes; *off += ea_size) {
 		const struct EA_FULL *ea = Add2Ptr(ea_all, *off);
-		u32 next_off = *off + unpacked_ea_size(ea);
-
-		if (next_off > bytes)
-			return false;
-
+		ea_size = unpacked_ea_size(ea);
 		if (ea->name_len == name_len &&
-		    !memcmp(ea->name, name, name_len))
+		    !memcmp(ea->name, name, name_len)) {
+			if (ea_sz)
+				*ea_sz = ea_size;
 			return true;
-
-		*off = next_off;
-		if (next_off >= bytes)
-			return false;
+		}
 	}
+
+	return false;
 }
 
 /*
@@ -75,12 +73,12 @@ static inline bool find_ea(const struct EA_FULL *ea_all, u32 bytes,
 static int ntfs_read_ea(struct ntfs_inode *ni, struct EA_FULL **ea,
 			size_t add_bytes, const struct EA_INFO **info)
 {
-	int err;
+	int err = -EINVAL;
 	struct ntfs_sb_info *sbi = ni->mi.sbi;
 	struct ATTR_LIST_ENTRY *le = NULL;
 	struct ATTRIB *attr_info, *attr_ea;
 	void *ea_p;
-	u32 size;
+	u32 size, off, ea_size;
 
 	static_assert(le32_to_cpu(ATTR_EA_INFO) < le32_to_cpu(ATTR_EA));
 
@@ -97,24 +95,31 @@ static int ntfs_read_ea(struct ntfs_inode *ni, struct EA_FULL **ea,
 
 	*info = resident_data_ex(attr_info, sizeof(struct EA_INFO));
 	if (!*info)
-		return -EINVAL;
+		goto out;
 
 	/* Check Ea limit. */
 	size = le32_to_cpu((*info)->size);
-	if (size > sbi->ea_max_size)
-		return -EFBIG;
+	if (size > sbi->ea_max_size) {
+		err = -EFBIG;
+		goto out;
+	}
+
+	if (attr_size(attr_ea) > sbi->ea_max_size) {
+		err = -EFBIG;
+		goto out;
+	}
 
-	if (attr_size(attr_ea) > sbi->ea_max_size)
-		return -EFBIG;
+	if (!size) {
+		/* EA info persists, but xattr is empty. Looks like EA problem. */
+		goto out;
+	}
 
 	/* Allocate memory for packed Ea. */
 	ea_p = kmalloc(size_add(size, add_bytes), GFP_NOFS);
 	if (!ea_p)
 		return -ENOMEM;
 
-	if (!size) {
-		/* EA info persists, but xattr is empty. Looks like EA problem. */
-	} else if (attr_ea->non_res) {
+	if (attr_ea->non_res) {
 		struct runs_tree run;
 
 		run_init(&run);
@@ -125,24 +130,52 @@ static int ntfs_read_ea(struct ntfs_inode *ni, struct EA_FULL **ea,
 		run_close(&run);
 
 		if (err)
-			goto out;
+			goto out1;
 	} else {
 		void *p = resident_data_ex(attr_ea, size);
 
-		if (!p) {
-			err = -EINVAL;
-			goto out;
-		}
+		if (!p)
+			goto out1;
 		memcpy(ea_p, p, size);
 	}
 
 	memset(Add2Ptr(ea_p, size), 0, add_bytes);
+
+	/* Check all attributes for consistency. */
+	for (off = 0; off < size; off += ea_size) {
+		const struct EA_FULL *ef = Add2Ptr(ea_p, off);
+		u32 bytes = size - off;
+
+		/* Check if we can use field ea->size. */
+		if (bytes < sizeof(ef->size))
+			goto out1;
+
+		if (ef->size) {
+			ea_size = le32_to_cpu(ef->size);
+			if (ea_size > bytes)
+				goto out1;
+			continue;
+		}
+
+		/* Check if we can use fields ef->name_len and ef->elength. */
+		if (bytes < offsetof(struct EA_FULL, name))
+			goto out1;
+
+		ea_size = ALIGN(struct_size(ef, name,
+					    1 + ef->name_len +
+						    le16_to_cpu(ef->elength)),
+				4);
+		if (ea_size > bytes)
+			goto out1;
+	}
+
 	*ea = ea_p;
 	return 0;
 
-out:
+out1:
 	kfree(ea_p);
-	*ea = NULL;
+out:
+	ntfs_set_state(sbi, NTFS_DIRTY_DIRTY);
 	return err;
 }
 
@@ -164,6 +197,7 @@ static ssize_t ntfs_list_ea(struct ntfs_inode *ni, char *buffer,
 	const struct EA_FULL *ea;
 	u32 off, size;
 	int err;
+	int ea_size;
 	size_t ret;
 
 	err = ntfs_read_ea(ni, &ea_all, 0, &info);
@@ -176,8 +210,9 @@ static ssize_t ntfs_list_ea(struct ntfs_inode *ni, char *buffer,
 	size = le32_to_cpu(info->size);
 
 	/* Enumerate all xattrs. */
-	for (ret = 0, off = 0; off < size; off += unpacked_ea_size(ea)) {
+	for (ret = 0, off = 0; off < size; off += ea_size) {
 		ea = Add2Ptr(ea_all, off);
+		ea_size = unpacked_ea_size(ea);
 
 		if (buffer) {
 			if (ret + ea->name_len + 1 > bytes_per_buffer) {
@@ -228,7 +263,8 @@ static int ntfs_get_ea(struct inode *inode, const char *name, size_t name_len,
 		goto out;
 
 	/* Enumerate all xattrs. */
-	if (!find_ea(ea_all, le32_to_cpu(info->size), name, name_len, &off)) {
+	if (!find_ea(ea_all, le32_to_cpu(info->size), name, name_len, &off,
+		     NULL)) {
 		err = -ENODATA;
 		goto out;
 	}
@@ -270,7 +306,7 @@ static noinline int ntfs_set_ea(struct inode *inode, const char *name,
 	struct EA_FULL *new_ea;
 	struct EA_FULL *ea_all = NULL;
 	size_t add, new_pack;
-	u32 off, size;
+	u32 off, size, ea_sz;
 	__le16 size_pack;
 	struct ATTRIB *attr;
 	struct ATTR_LIST_ENTRY *le;
@@ -305,9 +341,8 @@ static noinline int ntfs_set_ea(struct inode *inode, const char *name,
 		size_pack = ea_info.size_pack;
 	}
 
-	if (info && find_ea(ea_all, size, name, name_len, &off)) {
+	if (info && find_ea(ea_all, size, name, name_len, &off, &ea_sz)) {
 		struct EA_FULL *ea;
-		size_t ea_sz;
 
 		if (flags & XATTR_CREATE) {
 			err = -EEXIST;
@@ -330,8 +365,6 @@ static noinline int ntfs_set_ea(struct inode *inode, const char *name,
 		if (ea->flags & FILE_NEED_EA)
 			le16_add_cpu(&ea_info.count, -1);
 
-		ea_sz = unpacked_ea_size(ea);
-
 		le16_add_cpu(&ea_info.size_pack, 0 - packed_ea_size(ea));
 
 		memmove(ea, Add2Ptr(ea, ea_sz), size - off - ea_sz);