cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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amigaffs.c (12437B)


      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 *  linux/fs/affs/amigaffs.c
      4 *
      5 *  (c) 1996  Hans-Joachim Widmaier - Rewritten
      6 *
      7 *  (C) 1993  Ray Burr - Amiga FFS filesystem.
      8 *
      9 *  Please send bug reports to: hjw@zvw.de
     10 */
     11
     12#include <linux/math64.h>
     13#include <linux/iversion.h>
     14#include "affs.h"
     15
     16/*
     17 * Functions for accessing Amiga-FFS structures.
     18 */
     19
     20
     21/* Insert a header block bh into the directory dir
     22 * caller must hold AFFS_DIR->i_hash_lock!
     23 */
     24
     25int
     26affs_insert_hash(struct inode *dir, struct buffer_head *bh)
     27{
     28	struct super_block *sb = dir->i_sb;
     29	struct buffer_head *dir_bh;
     30	u32 ino, hash_ino;
     31	int offset;
     32
     33	ino = bh->b_blocknr;
     34	offset = affs_hash_name(sb, AFFS_TAIL(sb, bh)->name + 1, AFFS_TAIL(sb, bh)->name[0]);
     35
     36	pr_debug("%s(dir=%lu, ino=%d)\n", __func__, dir->i_ino, ino);
     37
     38	dir_bh = affs_bread(sb, dir->i_ino);
     39	if (!dir_bh)
     40		return -EIO;
     41
     42	hash_ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[offset]);
     43	while (hash_ino) {
     44		affs_brelse(dir_bh);
     45		dir_bh = affs_bread(sb, hash_ino);
     46		if (!dir_bh)
     47			return -EIO;
     48		hash_ino = be32_to_cpu(AFFS_TAIL(sb, dir_bh)->hash_chain);
     49	}
     50	AFFS_TAIL(sb, bh)->parent = cpu_to_be32(dir->i_ino);
     51	AFFS_TAIL(sb, bh)->hash_chain = 0;
     52	affs_fix_checksum(sb, bh);
     53
     54	if (dir->i_ino == dir_bh->b_blocknr)
     55		AFFS_HEAD(dir_bh)->table[offset] = cpu_to_be32(ino);
     56	else
     57		AFFS_TAIL(sb, dir_bh)->hash_chain = cpu_to_be32(ino);
     58
     59	affs_adjust_checksum(dir_bh, ino);
     60	mark_buffer_dirty_inode(dir_bh, dir);
     61	affs_brelse(dir_bh);
     62
     63	dir->i_mtime = dir->i_ctime = current_time(dir);
     64	inode_inc_iversion(dir);
     65	mark_inode_dirty(dir);
     66
     67	return 0;
     68}
     69
     70/* Remove a header block from its directory.
     71 * caller must hold AFFS_DIR->i_hash_lock!
     72 */
     73
     74int
     75affs_remove_hash(struct inode *dir, struct buffer_head *rem_bh)
     76{
     77	struct super_block *sb;
     78	struct buffer_head *bh;
     79	u32 rem_ino, hash_ino;
     80	__be32 ino;
     81	int offset, retval;
     82
     83	sb = dir->i_sb;
     84	rem_ino = rem_bh->b_blocknr;
     85	offset = affs_hash_name(sb, AFFS_TAIL(sb, rem_bh)->name+1, AFFS_TAIL(sb, rem_bh)->name[0]);
     86	pr_debug("%s(dir=%lu, ino=%d, hashval=%d)\n", __func__, dir->i_ino,
     87		 rem_ino, offset);
     88
     89	bh = affs_bread(sb, dir->i_ino);
     90	if (!bh)
     91		return -EIO;
     92
     93	retval = -ENOENT;
     94	hash_ino = be32_to_cpu(AFFS_HEAD(bh)->table[offset]);
     95	while (hash_ino) {
     96		if (hash_ino == rem_ino) {
     97			ino = AFFS_TAIL(sb, rem_bh)->hash_chain;
     98			if (dir->i_ino == bh->b_blocknr)
     99				AFFS_HEAD(bh)->table[offset] = ino;
    100			else
    101				AFFS_TAIL(sb, bh)->hash_chain = ino;
    102			affs_adjust_checksum(bh, be32_to_cpu(ino) - hash_ino);
    103			mark_buffer_dirty_inode(bh, dir);
    104			AFFS_TAIL(sb, rem_bh)->parent = 0;
    105			retval = 0;
    106			break;
    107		}
    108		affs_brelse(bh);
    109		bh = affs_bread(sb, hash_ino);
    110		if (!bh)
    111			return -EIO;
    112		hash_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
    113	}
    114
    115	affs_brelse(bh);
    116
    117	dir->i_mtime = dir->i_ctime = current_time(dir);
    118	inode_inc_iversion(dir);
    119	mark_inode_dirty(dir);
    120
    121	return retval;
    122}
    123
    124static void
    125affs_fix_dcache(struct inode *inode, u32 entry_ino)
    126{
    127	struct dentry *dentry;
    128	spin_lock(&inode->i_lock);
    129	hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
    130		if (entry_ino == (u32)(long)dentry->d_fsdata) {
    131			dentry->d_fsdata = (void *)inode->i_ino;
    132			break;
    133		}
    134	}
    135	spin_unlock(&inode->i_lock);
    136}
    137
    138
    139/* Remove header from link chain */
    140
    141static int
    142affs_remove_link(struct dentry *dentry)
    143{
    144	struct inode *dir, *inode = d_inode(dentry);
    145	struct super_block *sb = inode->i_sb;
    146	struct buffer_head *bh, *link_bh = NULL;
    147	u32 link_ino, ino;
    148	int retval;
    149
    150	pr_debug("%s(key=%ld)\n", __func__, inode->i_ino);
    151	retval = -EIO;
    152	bh = affs_bread(sb, inode->i_ino);
    153	if (!bh)
    154		goto done;
    155
    156	link_ino = (u32)(long)dentry->d_fsdata;
    157	if (inode->i_ino == link_ino) {
    158		/* we can't remove the head of the link, as its blocknr is still used as ino,
    159		 * so we remove the block of the first link instead.
    160		 */ 
    161		link_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain);
    162		link_bh = affs_bread(sb, link_ino);
    163		if (!link_bh)
    164			goto done;
    165
    166		dir = affs_iget(sb, be32_to_cpu(AFFS_TAIL(sb, link_bh)->parent));
    167		if (IS_ERR(dir)) {
    168			retval = PTR_ERR(dir);
    169			goto done;
    170		}
    171
    172		affs_lock_dir(dir);
    173		/*
    174		 * if there's a dentry for that block, make it
    175		 * refer to inode itself.
    176		 */
    177		affs_fix_dcache(inode, link_ino);
    178		retval = affs_remove_hash(dir, link_bh);
    179		if (retval) {
    180			affs_unlock_dir(dir);
    181			goto done;
    182		}
    183		mark_buffer_dirty_inode(link_bh, inode);
    184
    185		memcpy(AFFS_TAIL(sb, bh)->name, AFFS_TAIL(sb, link_bh)->name, 32);
    186		retval = affs_insert_hash(dir, bh);
    187		if (retval) {
    188			affs_unlock_dir(dir);
    189			goto done;
    190		}
    191		mark_buffer_dirty_inode(bh, inode);
    192
    193		affs_unlock_dir(dir);
    194		iput(dir);
    195	} else {
    196		link_bh = affs_bread(sb, link_ino);
    197		if (!link_bh)
    198			goto done;
    199	}
    200
    201	while ((ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain)) != 0) {
    202		if (ino == link_ino) {
    203			__be32 ino2 = AFFS_TAIL(sb, link_bh)->link_chain;
    204			AFFS_TAIL(sb, bh)->link_chain = ino2;
    205			affs_adjust_checksum(bh, be32_to_cpu(ino2) - link_ino);
    206			mark_buffer_dirty_inode(bh, inode);
    207			retval = 0;
    208			/* Fix the link count, if bh is a normal header block without links */
    209			switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
    210			case ST_LINKDIR:
    211			case ST_LINKFILE:
    212				break;
    213			default:
    214				if (!AFFS_TAIL(sb, bh)->link_chain)
    215					set_nlink(inode, 1);
    216			}
    217			affs_free_block(sb, link_ino);
    218			goto done;
    219		}
    220		affs_brelse(bh);
    221		bh = affs_bread(sb, ino);
    222		if (!bh)
    223			goto done;
    224	}
    225	retval = -ENOENT;
    226done:
    227	affs_brelse(link_bh);
    228	affs_brelse(bh);
    229	return retval;
    230}
    231
    232
    233static int
    234affs_empty_dir(struct inode *inode)
    235{
    236	struct super_block *sb = inode->i_sb;
    237	struct buffer_head *bh;
    238	int retval, size;
    239
    240	retval = -EIO;
    241	bh = affs_bread(sb, inode->i_ino);
    242	if (!bh)
    243		goto done;
    244
    245	retval = -ENOTEMPTY;
    246	for (size = AFFS_SB(sb)->s_hashsize - 1; size >= 0; size--)
    247		if (AFFS_HEAD(bh)->table[size])
    248			goto not_empty;
    249	retval = 0;
    250not_empty:
    251	affs_brelse(bh);
    252done:
    253	return retval;
    254}
    255
    256
    257/* Remove a filesystem object. If the object to be removed has
    258 * links to it, one of the links must be changed to inherit
    259 * the file or directory. As above, any inode will do.
    260 * The buffer will not be freed. If the header is a link, the
    261 * block will be marked as free.
    262 * This function returns a negative error number in case of
    263 * an error, else 0 if the inode is to be deleted or 1 if not.
    264 */
    265
    266int
    267affs_remove_header(struct dentry *dentry)
    268{
    269	struct super_block *sb;
    270	struct inode *inode, *dir;
    271	struct buffer_head *bh = NULL;
    272	int retval;
    273
    274	dir = d_inode(dentry->d_parent);
    275	sb = dir->i_sb;
    276
    277	retval = -ENOENT;
    278	inode = d_inode(dentry);
    279	if (!inode)
    280		goto done;
    281
    282	pr_debug("%s(key=%ld)\n", __func__, inode->i_ino);
    283	retval = -EIO;
    284	bh = affs_bread(sb, (u32)(long)dentry->d_fsdata);
    285	if (!bh)
    286		goto done;
    287
    288	affs_lock_link(inode);
    289	affs_lock_dir(dir);
    290	switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
    291	case ST_USERDIR:
    292		/* if we ever want to support links to dirs
    293		 * i_hash_lock of the inode must only be
    294		 * taken after some checks
    295		 */
    296		affs_lock_dir(inode);
    297		retval = affs_empty_dir(inode);
    298		affs_unlock_dir(inode);
    299		if (retval)
    300			goto done_unlock;
    301		break;
    302	default:
    303		break;
    304	}
    305
    306	retval = affs_remove_hash(dir, bh);
    307	if (retval)
    308		goto done_unlock;
    309	mark_buffer_dirty_inode(bh, inode);
    310
    311	affs_unlock_dir(dir);
    312
    313	if (inode->i_nlink > 1)
    314		retval = affs_remove_link(dentry);
    315	else
    316		clear_nlink(inode);
    317	affs_unlock_link(inode);
    318	inode->i_ctime = current_time(inode);
    319	mark_inode_dirty(inode);
    320
    321done:
    322	affs_brelse(bh);
    323	return retval;
    324
    325done_unlock:
    326	affs_unlock_dir(dir);
    327	affs_unlock_link(inode);
    328	goto done;
    329}
    330
    331/* Checksum a block, do various consistency checks and optionally return
    332   the blocks type number.  DATA points to the block.  If their pointers
    333   are non-null, *PTYPE and *STYPE are set to the primary and secondary
    334   block types respectively, *HASHSIZE is set to the size of the hashtable
    335   (which lets us calculate the block size).
    336   Returns non-zero if the block is not consistent. */
    337
    338u32
    339affs_checksum_block(struct super_block *sb, struct buffer_head *bh)
    340{
    341	__be32 *ptr = (__be32 *)bh->b_data;
    342	u32 sum;
    343	int bsize;
    344
    345	sum = 0;
    346	for (bsize = sb->s_blocksize / sizeof(__be32); bsize > 0; bsize--)
    347		sum += be32_to_cpu(*ptr++);
    348	return sum;
    349}
    350
    351/*
    352 * Calculate the checksum of a disk block and store it
    353 * at the indicated position.
    354 */
    355
    356void
    357affs_fix_checksum(struct super_block *sb, struct buffer_head *bh)
    358{
    359	int cnt = sb->s_blocksize / sizeof(__be32);
    360	__be32 *ptr = (__be32 *)bh->b_data;
    361	u32 checksum;
    362	__be32 *checksumptr;
    363
    364	checksumptr = ptr + 5;
    365	*checksumptr = 0;
    366	for (checksum = 0; cnt > 0; ptr++, cnt--)
    367		checksum += be32_to_cpu(*ptr);
    368	*checksumptr = cpu_to_be32(-checksum);
    369}
    370
    371void
    372affs_secs_to_datestamp(time64_t secs, struct affs_date *ds)
    373{
    374	u32	 days;
    375	u32	 minute;
    376	s32	 rem;
    377
    378	secs -= sys_tz.tz_minuteswest * 60 + AFFS_EPOCH_DELTA;
    379	if (secs < 0)
    380		secs = 0;
    381	days    = div_s64_rem(secs, 86400, &rem);
    382	minute  = rem / 60;
    383	rem    -= minute * 60;
    384
    385	ds->days = cpu_to_be32(days);
    386	ds->mins = cpu_to_be32(minute);
    387	ds->ticks = cpu_to_be32(rem * 50);
    388}
    389
    390umode_t
    391affs_prot_to_mode(u32 prot)
    392{
    393	umode_t mode = 0;
    394
    395	if (!(prot & FIBF_NOWRITE))
    396		mode |= 0200;
    397	if (!(prot & FIBF_NOREAD))
    398		mode |= 0400;
    399	if (!(prot & FIBF_NOEXECUTE))
    400		mode |= 0100;
    401	if (prot & FIBF_GRP_WRITE)
    402		mode |= 0020;
    403	if (prot & FIBF_GRP_READ)
    404		mode |= 0040;
    405	if (prot & FIBF_GRP_EXECUTE)
    406		mode |= 0010;
    407	if (prot & FIBF_OTR_WRITE)
    408		mode |= 0002;
    409	if (prot & FIBF_OTR_READ)
    410		mode |= 0004;
    411	if (prot & FIBF_OTR_EXECUTE)
    412		mode |= 0001;
    413
    414	return mode;
    415}
    416
    417void
    418affs_mode_to_prot(struct inode *inode)
    419{
    420	u32 prot = AFFS_I(inode)->i_protect;
    421	umode_t mode = inode->i_mode;
    422
    423	/*
    424	 * First, clear all RWED bits for owner, group, other.
    425	 * Then, recalculate them afresh.
    426	 *
    427	 * We'll always clear the delete-inhibit bit for the owner, as that is
    428	 * the classic single-user mode AmigaOS protection bit and we need to
    429	 * stay compatible with all scenarios.
    430	 *
    431	 * Since multi-user AmigaOS is an extension, we'll only set the
    432	 * delete-allow bit if any of the other bits in the same user class
    433	 * (group/other) are used.
    434	 */
    435	prot &= ~(FIBF_NOEXECUTE | FIBF_NOREAD
    436		  | FIBF_NOWRITE | FIBF_NODELETE
    437		  | FIBF_GRP_EXECUTE | FIBF_GRP_READ
    438		  | FIBF_GRP_WRITE   | FIBF_GRP_DELETE
    439		  | FIBF_OTR_EXECUTE | FIBF_OTR_READ
    440		  | FIBF_OTR_WRITE   | FIBF_OTR_DELETE);
    441
    442	/* Classic single-user AmigaOS flags. These are inverted. */
    443	if (!(mode & 0100))
    444		prot |= FIBF_NOEXECUTE;
    445	if (!(mode & 0400))
    446		prot |= FIBF_NOREAD;
    447	if (!(mode & 0200))
    448		prot |= FIBF_NOWRITE;
    449
    450	/* Multi-user extended flags. Not inverted. */
    451	if (mode & 0010)
    452		prot |= FIBF_GRP_EXECUTE;
    453	if (mode & 0040)
    454		prot |= FIBF_GRP_READ;
    455	if (mode & 0020)
    456		prot |= FIBF_GRP_WRITE;
    457	if (mode & 0070)
    458		prot |= FIBF_GRP_DELETE;
    459
    460	if (mode & 0001)
    461		prot |= FIBF_OTR_EXECUTE;
    462	if (mode & 0004)
    463		prot |= FIBF_OTR_READ;
    464	if (mode & 0002)
    465		prot |= FIBF_OTR_WRITE;
    466	if (mode & 0007)
    467		prot |= FIBF_OTR_DELETE;
    468
    469	AFFS_I(inode)->i_protect = prot;
    470}
    471
    472void
    473affs_error(struct super_block *sb, const char *function, const char *fmt, ...)
    474{
    475	struct va_format vaf;
    476	va_list args;
    477
    478	va_start(args, fmt);
    479	vaf.fmt = fmt;
    480	vaf.va = &args;
    481	pr_crit("error (device %s): %s(): %pV\n", sb->s_id, function, &vaf);
    482	if (!sb_rdonly(sb))
    483		pr_warn("Remounting filesystem read-only\n");
    484	sb->s_flags |= SB_RDONLY;
    485	va_end(args);
    486}
    487
    488void
    489affs_warning(struct super_block *sb, const char *function, const char *fmt, ...)
    490{
    491	struct va_format vaf;
    492	va_list args;
    493
    494	va_start(args, fmt);
    495	vaf.fmt = fmt;
    496	vaf.va = &args;
    497	pr_warn("(device %s): %s(): %pV\n", sb->s_id, function, &vaf);
    498	va_end(args);
    499}
    500
    501bool
    502affs_nofilenametruncate(const struct dentry *dentry)
    503{
    504	return affs_test_opt(AFFS_SB(dentry->d_sb)->s_flags, SF_NO_TRUNCATE);
    505}
    506
    507/* Check if the name is valid for a affs object. */
    508
    509int
    510affs_check_name(const unsigned char *name, int len, bool notruncate)
    511{
    512	int	 i;
    513
    514	if (len > AFFSNAMEMAX) {
    515		if (notruncate)
    516			return -ENAMETOOLONG;
    517		len = AFFSNAMEMAX;
    518	}
    519	for (i = 0; i < len; i++) {
    520		if (name[i] < ' ' || name[i] == ':'
    521		    || (name[i] > 0x7e && name[i] < 0xa0))
    522			return -EINVAL;
    523	}
    524
    525	return 0;
    526}
    527
    528/* This function copies name to bstr, with at most 30
    529 * characters length. The bstr will be prepended by
    530 * a length byte.
    531 * NOTE: The name will must be already checked by
    532 *       affs_check_name()!
    533 */
    534
    535int
    536affs_copy_name(unsigned char *bstr, struct dentry *dentry)
    537{
    538	u32 len = min(dentry->d_name.len, AFFSNAMEMAX);
    539
    540	*bstr++ = len;
    541	memcpy(bstr, dentry->d_name.name, len);
    542	return len;
    543}