xref: /kernel/linux/linux-6.6/fs/adfs/dir_fplus.c (revision 62306a36)
162306a36Sopenharmony_ci// SPDX-License-Identifier: GPL-2.0-only
262306a36Sopenharmony_ci/*
362306a36Sopenharmony_ci *  linux/fs/adfs/dir_fplus.c
462306a36Sopenharmony_ci *
562306a36Sopenharmony_ci *  Copyright (C) 1997-1999 Russell King
662306a36Sopenharmony_ci */
762306a36Sopenharmony_ci#include "adfs.h"
862306a36Sopenharmony_ci#include "dir_fplus.h"
962306a36Sopenharmony_ci
1062306a36Sopenharmony_ci/* Return the byte offset to directory entry pos */
1162306a36Sopenharmony_cistatic unsigned int adfs_fplus_offset(const struct adfs_bigdirheader *h,
1262306a36Sopenharmony_ci				      unsigned int pos)
1362306a36Sopenharmony_ci{
1462306a36Sopenharmony_ci	return offsetof(struct adfs_bigdirheader, bigdirname) +
1562306a36Sopenharmony_ci	       ALIGN(le32_to_cpu(h->bigdirnamelen), 4) +
1662306a36Sopenharmony_ci	       pos * sizeof(struct adfs_bigdirentry);
1762306a36Sopenharmony_ci}
1862306a36Sopenharmony_ci
1962306a36Sopenharmony_cistatic int adfs_fplus_validate_header(const struct adfs_bigdirheader *h)
2062306a36Sopenharmony_ci{
2162306a36Sopenharmony_ci	unsigned int size = le32_to_cpu(h->bigdirsize);
2262306a36Sopenharmony_ci	unsigned int len;
2362306a36Sopenharmony_ci
2462306a36Sopenharmony_ci	if (h->bigdirversion[0] != 0 || h->bigdirversion[1] != 0 ||
2562306a36Sopenharmony_ci	    h->bigdirversion[2] != 0 ||
2662306a36Sopenharmony_ci	    h->bigdirstartname != cpu_to_le32(BIGDIRSTARTNAME) ||
2762306a36Sopenharmony_ci	    !size || size & 2047 || size > SZ_4M)
2862306a36Sopenharmony_ci		return -EIO;
2962306a36Sopenharmony_ci
3062306a36Sopenharmony_ci	size -= sizeof(struct adfs_bigdirtail) +
3162306a36Sopenharmony_ci		offsetof(struct adfs_bigdirheader, bigdirname);
3262306a36Sopenharmony_ci
3362306a36Sopenharmony_ci	/* Check that bigdirnamelen fits within the directory */
3462306a36Sopenharmony_ci	len = ALIGN(le32_to_cpu(h->bigdirnamelen), 4);
3562306a36Sopenharmony_ci	if (len > size)
3662306a36Sopenharmony_ci		return -EIO;
3762306a36Sopenharmony_ci
3862306a36Sopenharmony_ci	size -= len;
3962306a36Sopenharmony_ci
4062306a36Sopenharmony_ci	/* Check that bigdirnamesize fits within the directory */
4162306a36Sopenharmony_ci	len = le32_to_cpu(h->bigdirnamesize);
4262306a36Sopenharmony_ci	if (len > size)
4362306a36Sopenharmony_ci		return -EIO;
4462306a36Sopenharmony_ci
4562306a36Sopenharmony_ci	size -= len;
4662306a36Sopenharmony_ci
4762306a36Sopenharmony_ci	/*
4862306a36Sopenharmony_ci	 * Avoid division, we know that absolute maximum number of entries
4962306a36Sopenharmony_ci	 * can not be so large to cause overflow of the multiplication below.
5062306a36Sopenharmony_ci	 */
5162306a36Sopenharmony_ci	len = le32_to_cpu(h->bigdirentries);
5262306a36Sopenharmony_ci	if (len > SZ_4M / sizeof(struct adfs_bigdirentry) ||
5362306a36Sopenharmony_ci	    len * sizeof(struct adfs_bigdirentry) > size)
5462306a36Sopenharmony_ci		return -EIO;
5562306a36Sopenharmony_ci
5662306a36Sopenharmony_ci	return 0;
5762306a36Sopenharmony_ci}
5862306a36Sopenharmony_ci
5962306a36Sopenharmony_cistatic int adfs_fplus_validate_tail(const struct adfs_bigdirheader *h,
6062306a36Sopenharmony_ci				    const struct adfs_bigdirtail *t)
6162306a36Sopenharmony_ci{
6262306a36Sopenharmony_ci	if (t->bigdirendname != cpu_to_le32(BIGDIRENDNAME) ||
6362306a36Sopenharmony_ci	    t->bigdirendmasseq != h->startmasseq ||
6462306a36Sopenharmony_ci	    t->reserved[0] != 0 || t->reserved[1] != 0)
6562306a36Sopenharmony_ci		return -EIO;
6662306a36Sopenharmony_ci
6762306a36Sopenharmony_ci	return 0;
6862306a36Sopenharmony_ci}
6962306a36Sopenharmony_ci
7062306a36Sopenharmony_cistatic u8 adfs_fplus_checkbyte(struct adfs_dir *dir)
7162306a36Sopenharmony_ci{
7262306a36Sopenharmony_ci	struct adfs_bigdirheader *h = dir->bighead;
7362306a36Sopenharmony_ci	struct adfs_bigdirtail *t = dir->bigtail;
7462306a36Sopenharmony_ci	unsigned int end, bs, bi, i;
7562306a36Sopenharmony_ci	__le32 *bp;
7662306a36Sopenharmony_ci	u32 dircheck;
7762306a36Sopenharmony_ci
7862306a36Sopenharmony_ci	end = adfs_fplus_offset(h, le32_to_cpu(h->bigdirentries)) +
7962306a36Sopenharmony_ci		le32_to_cpu(h->bigdirnamesize);
8062306a36Sopenharmony_ci
8162306a36Sopenharmony_ci	/* Accumulate the contents of the header, entries and names */
8262306a36Sopenharmony_ci	for (dircheck = 0, bi = 0; end; bi++) {
8362306a36Sopenharmony_ci		bp = (void *)dir->bhs[bi]->b_data;
8462306a36Sopenharmony_ci		bs = dir->bhs[bi]->b_size;
8562306a36Sopenharmony_ci		if (bs > end)
8662306a36Sopenharmony_ci			bs = end;
8762306a36Sopenharmony_ci
8862306a36Sopenharmony_ci		for (i = 0; i < bs; i += sizeof(u32))
8962306a36Sopenharmony_ci			dircheck = ror32(dircheck, 13) ^ le32_to_cpup(bp++);
9062306a36Sopenharmony_ci
9162306a36Sopenharmony_ci		end -= bs;
9262306a36Sopenharmony_ci	}
9362306a36Sopenharmony_ci
9462306a36Sopenharmony_ci	/* Accumulate the contents of the tail except for the check byte */
9562306a36Sopenharmony_ci	dircheck = ror32(dircheck, 13) ^ le32_to_cpu(t->bigdirendname);
9662306a36Sopenharmony_ci	dircheck = ror32(dircheck, 13) ^ t->bigdirendmasseq;
9762306a36Sopenharmony_ci	dircheck = ror32(dircheck, 13) ^ t->reserved[0];
9862306a36Sopenharmony_ci	dircheck = ror32(dircheck, 13) ^ t->reserved[1];
9962306a36Sopenharmony_ci
10062306a36Sopenharmony_ci	return dircheck ^ dircheck >> 8 ^ dircheck >> 16 ^ dircheck >> 24;
10162306a36Sopenharmony_ci}
10262306a36Sopenharmony_ci
10362306a36Sopenharmony_cistatic int adfs_fplus_read(struct super_block *sb, u32 indaddr,
10462306a36Sopenharmony_ci			   unsigned int size, struct adfs_dir *dir)
10562306a36Sopenharmony_ci{
10662306a36Sopenharmony_ci	struct adfs_bigdirheader *h;
10762306a36Sopenharmony_ci	struct adfs_bigdirtail *t;
10862306a36Sopenharmony_ci	unsigned int dirsize;
10962306a36Sopenharmony_ci	int ret;
11062306a36Sopenharmony_ci
11162306a36Sopenharmony_ci	/* Read first buffer */
11262306a36Sopenharmony_ci	ret = adfs_dir_read_buffers(sb, indaddr, sb->s_blocksize, dir);
11362306a36Sopenharmony_ci	if (ret)
11462306a36Sopenharmony_ci		return ret;
11562306a36Sopenharmony_ci
11662306a36Sopenharmony_ci	dir->bighead = h = (void *)dir->bhs[0]->b_data;
11762306a36Sopenharmony_ci	ret = adfs_fplus_validate_header(h);
11862306a36Sopenharmony_ci	if (ret) {
11962306a36Sopenharmony_ci		adfs_error(sb, "dir %06x has malformed header", indaddr);
12062306a36Sopenharmony_ci		goto out;
12162306a36Sopenharmony_ci	}
12262306a36Sopenharmony_ci
12362306a36Sopenharmony_ci	dirsize = le32_to_cpu(h->bigdirsize);
12462306a36Sopenharmony_ci	if (size && dirsize != size) {
12562306a36Sopenharmony_ci		adfs_msg(sb, KERN_WARNING,
12662306a36Sopenharmony_ci			 "dir %06x header size %X does not match directory size %X",
12762306a36Sopenharmony_ci			 indaddr, dirsize, size);
12862306a36Sopenharmony_ci	}
12962306a36Sopenharmony_ci
13062306a36Sopenharmony_ci	/* Read remaining buffers */
13162306a36Sopenharmony_ci	ret = adfs_dir_read_buffers(sb, indaddr, dirsize, dir);
13262306a36Sopenharmony_ci	if (ret)
13362306a36Sopenharmony_ci		return ret;
13462306a36Sopenharmony_ci
13562306a36Sopenharmony_ci	dir->bigtail = t = (struct adfs_bigdirtail *)
13662306a36Sopenharmony_ci		(dir->bhs[dir->nr_buffers - 1]->b_data + (sb->s_blocksize - 8));
13762306a36Sopenharmony_ci
13862306a36Sopenharmony_ci	ret = adfs_fplus_validate_tail(h, t);
13962306a36Sopenharmony_ci	if (ret) {
14062306a36Sopenharmony_ci		adfs_error(sb, "dir %06x has malformed tail", indaddr);
14162306a36Sopenharmony_ci		goto out;
14262306a36Sopenharmony_ci	}
14362306a36Sopenharmony_ci
14462306a36Sopenharmony_ci	if (adfs_fplus_checkbyte(dir) != t->bigdircheckbyte) {
14562306a36Sopenharmony_ci		adfs_error(sb, "dir %06x checkbyte mismatch\n", indaddr);
14662306a36Sopenharmony_ci		goto out;
14762306a36Sopenharmony_ci	}
14862306a36Sopenharmony_ci
14962306a36Sopenharmony_ci	dir->parent_id = le32_to_cpu(h->bigdirparent);
15062306a36Sopenharmony_ci	return 0;
15162306a36Sopenharmony_ci
15262306a36Sopenharmony_ciout:
15362306a36Sopenharmony_ci	adfs_dir_relse(dir);
15462306a36Sopenharmony_ci
15562306a36Sopenharmony_ci	return ret;
15662306a36Sopenharmony_ci}
15762306a36Sopenharmony_ci
15862306a36Sopenharmony_cistatic int
15962306a36Sopenharmony_ciadfs_fplus_setpos(struct adfs_dir *dir, unsigned int fpos)
16062306a36Sopenharmony_ci{
16162306a36Sopenharmony_ci	int ret = -ENOENT;
16262306a36Sopenharmony_ci
16362306a36Sopenharmony_ci	if (fpos <= le32_to_cpu(dir->bighead->bigdirentries)) {
16462306a36Sopenharmony_ci		dir->pos = fpos;
16562306a36Sopenharmony_ci		ret = 0;
16662306a36Sopenharmony_ci	}
16762306a36Sopenharmony_ci
16862306a36Sopenharmony_ci	return ret;
16962306a36Sopenharmony_ci}
17062306a36Sopenharmony_ci
17162306a36Sopenharmony_cistatic int
17262306a36Sopenharmony_ciadfs_fplus_getnext(struct adfs_dir *dir, struct object_info *obj)
17362306a36Sopenharmony_ci{
17462306a36Sopenharmony_ci	struct adfs_bigdirheader *h = dir->bighead;
17562306a36Sopenharmony_ci	struct adfs_bigdirentry bde;
17662306a36Sopenharmony_ci	unsigned int offset;
17762306a36Sopenharmony_ci	int ret;
17862306a36Sopenharmony_ci
17962306a36Sopenharmony_ci	if (dir->pos >= le32_to_cpu(h->bigdirentries))
18062306a36Sopenharmony_ci		return -ENOENT;
18162306a36Sopenharmony_ci
18262306a36Sopenharmony_ci	offset = adfs_fplus_offset(h, dir->pos);
18362306a36Sopenharmony_ci
18462306a36Sopenharmony_ci	ret = adfs_dir_copyfrom(&bde, dir, offset,
18562306a36Sopenharmony_ci				sizeof(struct adfs_bigdirentry));
18662306a36Sopenharmony_ci	if (ret)
18762306a36Sopenharmony_ci		return ret;
18862306a36Sopenharmony_ci
18962306a36Sopenharmony_ci	obj->loadaddr = le32_to_cpu(bde.bigdirload);
19062306a36Sopenharmony_ci	obj->execaddr = le32_to_cpu(bde.bigdirexec);
19162306a36Sopenharmony_ci	obj->size     = le32_to_cpu(bde.bigdirlen);
19262306a36Sopenharmony_ci	obj->indaddr  = le32_to_cpu(bde.bigdirindaddr);
19362306a36Sopenharmony_ci	obj->attr     = le32_to_cpu(bde.bigdirattr);
19462306a36Sopenharmony_ci	obj->name_len = le32_to_cpu(bde.bigdirobnamelen);
19562306a36Sopenharmony_ci
19662306a36Sopenharmony_ci	offset = adfs_fplus_offset(h, le32_to_cpu(h->bigdirentries));
19762306a36Sopenharmony_ci	offset += le32_to_cpu(bde.bigdirobnameptr);
19862306a36Sopenharmony_ci
19962306a36Sopenharmony_ci	ret = adfs_dir_copyfrom(obj->name, dir, offset, obj->name_len);
20062306a36Sopenharmony_ci	if (ret)
20162306a36Sopenharmony_ci		return ret;
20262306a36Sopenharmony_ci
20362306a36Sopenharmony_ci	adfs_object_fixup(dir, obj);
20462306a36Sopenharmony_ci
20562306a36Sopenharmony_ci	dir->pos += 1;
20662306a36Sopenharmony_ci
20762306a36Sopenharmony_ci	return 0;
20862306a36Sopenharmony_ci}
20962306a36Sopenharmony_ci
21062306a36Sopenharmony_cistatic int adfs_fplus_iterate(struct adfs_dir *dir, struct dir_context *ctx)
21162306a36Sopenharmony_ci{
21262306a36Sopenharmony_ci	struct object_info obj;
21362306a36Sopenharmony_ci
21462306a36Sopenharmony_ci	if ((ctx->pos - 2) >> 32)
21562306a36Sopenharmony_ci		return 0;
21662306a36Sopenharmony_ci
21762306a36Sopenharmony_ci	if (adfs_fplus_setpos(dir, ctx->pos - 2))
21862306a36Sopenharmony_ci		return 0;
21962306a36Sopenharmony_ci
22062306a36Sopenharmony_ci	while (!adfs_fplus_getnext(dir, &obj)) {
22162306a36Sopenharmony_ci		if (!dir_emit(ctx, obj.name, obj.name_len,
22262306a36Sopenharmony_ci			      obj.indaddr, DT_UNKNOWN))
22362306a36Sopenharmony_ci			break;
22462306a36Sopenharmony_ci		ctx->pos++;
22562306a36Sopenharmony_ci	}
22662306a36Sopenharmony_ci
22762306a36Sopenharmony_ci	return 0;
22862306a36Sopenharmony_ci}
22962306a36Sopenharmony_ci
23062306a36Sopenharmony_cistatic int adfs_fplus_update(struct adfs_dir *dir, struct object_info *obj)
23162306a36Sopenharmony_ci{
23262306a36Sopenharmony_ci	struct adfs_bigdirheader *h = dir->bighead;
23362306a36Sopenharmony_ci	struct adfs_bigdirentry bde;
23462306a36Sopenharmony_ci	int offset, end, ret;
23562306a36Sopenharmony_ci
23662306a36Sopenharmony_ci	offset = adfs_fplus_offset(h, 0) - sizeof(bde);
23762306a36Sopenharmony_ci	end = adfs_fplus_offset(h, le32_to_cpu(h->bigdirentries));
23862306a36Sopenharmony_ci
23962306a36Sopenharmony_ci	do {
24062306a36Sopenharmony_ci		offset += sizeof(bde);
24162306a36Sopenharmony_ci		if (offset >= end) {
24262306a36Sopenharmony_ci			adfs_error(dir->sb, "unable to locate entry to update");
24362306a36Sopenharmony_ci			return -ENOENT;
24462306a36Sopenharmony_ci		}
24562306a36Sopenharmony_ci		ret = adfs_dir_copyfrom(&bde, dir, offset, sizeof(bde));
24662306a36Sopenharmony_ci		if (ret) {
24762306a36Sopenharmony_ci			adfs_error(dir->sb, "error reading directory entry");
24862306a36Sopenharmony_ci			return -ENOENT;
24962306a36Sopenharmony_ci		}
25062306a36Sopenharmony_ci	} while (le32_to_cpu(bde.bigdirindaddr) != obj->indaddr);
25162306a36Sopenharmony_ci
25262306a36Sopenharmony_ci	bde.bigdirload    = cpu_to_le32(obj->loadaddr);
25362306a36Sopenharmony_ci	bde.bigdirexec    = cpu_to_le32(obj->execaddr);
25462306a36Sopenharmony_ci	bde.bigdirlen     = cpu_to_le32(obj->size);
25562306a36Sopenharmony_ci	bde.bigdirindaddr = cpu_to_le32(obj->indaddr);
25662306a36Sopenharmony_ci	bde.bigdirattr    = cpu_to_le32(obj->attr);
25762306a36Sopenharmony_ci
25862306a36Sopenharmony_ci	return adfs_dir_copyto(dir, offset, &bde, sizeof(bde));
25962306a36Sopenharmony_ci}
26062306a36Sopenharmony_ci
26162306a36Sopenharmony_cistatic int adfs_fplus_commit(struct adfs_dir *dir)
26262306a36Sopenharmony_ci{
26362306a36Sopenharmony_ci	int ret;
26462306a36Sopenharmony_ci
26562306a36Sopenharmony_ci	/* Increment directory sequence number */
26662306a36Sopenharmony_ci	dir->bighead->startmasseq += 1;
26762306a36Sopenharmony_ci	dir->bigtail->bigdirendmasseq += 1;
26862306a36Sopenharmony_ci
26962306a36Sopenharmony_ci	/* Update directory check byte */
27062306a36Sopenharmony_ci	dir->bigtail->bigdircheckbyte = adfs_fplus_checkbyte(dir);
27162306a36Sopenharmony_ci
27262306a36Sopenharmony_ci	/* Make sure the directory still validates correctly */
27362306a36Sopenharmony_ci	ret = adfs_fplus_validate_header(dir->bighead);
27462306a36Sopenharmony_ci	if (ret == 0)
27562306a36Sopenharmony_ci		ret = adfs_fplus_validate_tail(dir->bighead, dir->bigtail);
27662306a36Sopenharmony_ci
27762306a36Sopenharmony_ci	return ret;
27862306a36Sopenharmony_ci}
27962306a36Sopenharmony_ci
28062306a36Sopenharmony_ciconst struct adfs_dir_ops adfs_fplus_dir_ops = {
28162306a36Sopenharmony_ci	.read		= adfs_fplus_read,
28262306a36Sopenharmony_ci	.iterate	= adfs_fplus_iterate,
28362306a36Sopenharmony_ci	.setpos		= adfs_fplus_setpos,
28462306a36Sopenharmony_ci	.getnext	= adfs_fplus_getnext,
28562306a36Sopenharmony_ci	.update		= adfs_fplus_update,
28662306a36Sopenharmony_ci	.commit		= adfs_fplus_commit,
28762306a36Sopenharmony_ci};
288