// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2006 Silicon Graphics, Inc.
* Copyright (c) 2012-2013 Red Hat, Inc.
* All rights reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_shared.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_error.h"
#include "xfs_trans.h"
#include "xfs_buf_item.h"
#include "xfs_log.h"
#include "xfs_symlink_remote.h"
#include "xfs_bit.h"
#include "xfs_bmap.h"
#include "xfs_health.h"
/*
* Each contiguous block has a header, so it is not just a simple pathlen
* to FSB conversion.
*/
int
xfs_symlink_blocks(
struct xfs_mount *mp,
int pathlen)
{
int buflen = XFS_SYMLINK_BUF_SPACE(mp, mp->m_sb.sb_blocksize);
return (pathlen + buflen - 1) / buflen;
}
int
xfs_symlink_hdr_set(
struct xfs_mount *mp,
xfs_ino_t ino,
uint32_t offset,
uint32_t size,
struct xfs_buf *bp)
{
struct xfs_dsymlink_hdr *dsl = bp->b_addr;
if (!xfs_has_crc(mp))
return 0;
memset(dsl, 0, sizeof(struct xfs_dsymlink_hdr));
dsl->sl_magic = cpu_to_be32(XFS_SYMLINK_MAGIC);
dsl->sl_offset = cpu_to_be32(offset);
dsl->sl_bytes = cpu_to_be32(size);
uuid_copy(&dsl->sl_uuid, &mp->m_sb.sb_meta_uuid);
dsl->sl_owner = cpu_to_be64(ino);
dsl->sl_blkno = cpu_to_be64(xfs_buf_daddr(bp));
bp->b_ops = &xfs_symlink_buf_ops;
return sizeof(struct xfs_dsymlink_hdr);
}
/*
* Checking of the symlink header is split into two parts. the verifier does
* CRC, location and bounds checking, the unpacking function checks the path
* parameters and owner.
*/
bool
xfs_symlink_hdr_ok(
xfs_ino_t ino,
uint32_t offset,
uint32_t size,
struct xfs_buf *bp)
{
struct xfs_dsymlink_hdr *dsl = bp->b_addr;
if (offset != be32_to_cpu(dsl->sl_offset))
return false;
if (size != be32_to_cpu(dsl->sl_bytes))
return false;
if (ino != be64_to_cpu(dsl->sl_owner))
return false;
/* ok */
return true;
}
static xfs_failaddr_t
xfs_symlink_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_mount;
struct xfs_dsymlink_hdr *dsl = bp->b_addr;
if (!xfs_has_crc(mp))
return __this_address;
if (!xfs_verify_magic(bp, dsl->sl_magic))
return __this_address;
if (!uuid_equal(&dsl->sl_uuid, &mp->m_sb.sb_meta_uuid))
return __this_address;
if (xfs_buf_daddr(bp) != be64_to_cpu(dsl->sl_blkno))
return __this_address;
if (be32_to_cpu(dsl->sl_offset) +
be32_to_cpu(dsl->sl_bytes) >= XFS_SYMLINK_MAXLEN)
return __this_address;
if (dsl->sl_owner == 0)
return __this_address;
if (!xfs_log_check_lsn(mp, be64_to_cpu(dsl->sl_lsn)))
return __this_address;
return NULL;
}
static void
xfs_symlink_read_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_mount;
xfs_failaddr_t fa;
/* no verification of non-crc buffers */
if (!xfs_has_crc(mp))
return;
if (!xfs_buf_verify_cksum(bp, XFS_SYMLINK_CRC_OFF))
xfs_verifier_error(bp, -EFSBADCRC, __this_address);
else {
fa = xfs_symlink_verify(bp);
if (fa)
xfs_verifier_error(bp, -EFSCORRUPTED, fa);
}
}
static void
xfs_symlink_write_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_mount;
struct xfs_buf_log_item *bip = bp->b_log_item;
xfs_failaddr_t fa;
/* no verification of non-crc buffers */
if (!xfs_has_crc(mp))
return;
fa = xfs_symlink_verify(bp);
if (fa) {
xfs_verifier_error(bp, -EFSCORRUPTED, fa);
return;
}
if (bip) {
struct xfs_dsymlink_hdr *dsl = bp->b_addr;
dsl->sl_lsn = cpu_to_be64(bip->bli_item.li_lsn);
}
xfs_buf_update_cksum(bp, XFS_SYMLINK_CRC_OFF);
}
const struct xfs_buf_ops xfs_symlink_buf_ops = {
.name = "xfs_symlink",
.magic = { 0, cpu_to_be32(XFS_SYMLINK_MAGIC) },
.verify_read = xfs_symlink_read_verify,
.verify_write = xfs_symlink_write_verify,
.verify_struct = xfs_symlink_verify,
};
void
xfs_symlink_local_to_remote(
struct xfs_trans *tp,
struct xfs_buf *bp,
struct xfs_inode *ip,
struct xfs_ifork *ifp,
void *priv)
{
struct xfs_mount *mp = ip->i_mount;
char *buf;
xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
if (!xfs_has_crc(mp)) {
bp->b_ops = NULL;
memcpy(bp->b_addr, ifp->if_data, ifp->if_bytes);
xfs_trans_log_buf(tp, bp, 0, ifp->if_bytes - 1);
return;
}
/*
* As this symlink fits in an inode literal area, it must also fit in
* the smallest buffer the filesystem supports.
*/
ASSERT(BBTOB(bp->b_length) >=
ifp->if_bytes + sizeof(struct xfs_dsymlink_hdr));
bp->b_ops = &xfs_symlink_buf_ops;
buf = bp->b_addr;
buf += xfs_symlink_hdr_set(mp, ip->i_ino, 0, ifp->if_bytes, bp);
memcpy(buf, ifp->if_data, ifp->if_bytes);
xfs_trans_log_buf(tp, bp, 0, sizeof(struct xfs_dsymlink_hdr) +
ifp->if_bytes - 1);
}
/*
* Verify the in-memory consistency of an inline symlink data fork. This
* does not do on-disk format checks.
*/
xfs_failaddr_t
xfs_symlink_shortform_verify(
void *sfp,
int64_t size)
{
char *endp = sfp + size;
/*
* Zero length symlinks should never occur in memory as they are
* never allowed to exist on disk.
*/
if (!size)
return __this_address;
/* No negative sizes or overly long symlink targets. */
if (size < 0 || size > XFS_SYMLINK_MAXLEN)
return __this_address;
/* No NULLs in the target either. */
if (memchr(sfp, 0, size - 1))
return __this_address;
/* We /did/ null-terminate the buffer, right? */
if (*endp != 0)
return __this_address;
return NULL;
}
/* Read a remote symlink target into the buffer. */
int
xfs_symlink_remote_read(
struct xfs_inode *ip,
char *link)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
struct xfs_buf *bp;
xfs_daddr_t d;
char *cur_chunk;
int pathlen = ip->i_disk_size;
int nmaps = XFS_SYMLINK_MAPS;
int byte_cnt;
int n;
int error = 0;
int fsblocks = 0;
int offset;
xfs_assert_ilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL);
fsblocks = xfs_symlink_blocks(mp, pathlen);
error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
if (error)
goto out;
offset = 0;
for (n = 0; n < nmaps; n++) {
d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
error = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
&bp, &xfs_symlink_buf_ops);
if (xfs_metadata_is_sick(error))
xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK);
if (error)
return error;
byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
if (pathlen < byte_cnt)
byte_cnt = pathlen;
cur_chunk = bp->b_addr;
if (xfs_has_crc(mp)) {
if (!xfs_symlink_hdr_ok(ip->i_ino, offset,
byte_cnt, bp)) {
xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK);
error = -EFSCORRUPTED;
xfs_alert(mp,
"symlink header does not match required off/len/owner (0x%x/0x%x,0x%llx)",
offset, byte_cnt, ip->i_ino);
xfs_buf_relse(bp);
goto out;
}
cur_chunk += sizeof(struct xfs_dsymlink_hdr);
}
memcpy(link + offset, cur_chunk, byte_cnt);
pathlen -= byte_cnt;
offset += byte_cnt;
xfs_buf_relse(bp);
}
ASSERT(pathlen == 0);
link[ip->i_disk_size] = '\0';
error = 0;
out:
return error;
}
/* Write the symlink target into the inode. */
int
xfs_symlink_write_target(
struct xfs_trans *tp,
struct xfs_inode *ip,
xfs_ino_t owner,
const char *target_path,
int pathlen,
xfs_fsblock_t fs_blocks,
uint resblks)
{
struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
struct xfs_mount *mp = tp->t_mountp;
const char *cur_chunk;
struct xfs_buf *bp;
xfs_daddr_t d;
int byte_cnt;
int nmaps;
int offset = 0;
int n;
int error;
/*
* If the symlink will fit into the inode, write it inline.
*/
if (pathlen <= xfs_inode_data_fork_size(ip)) {
xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen);
ip->i_disk_size = pathlen;
ip->i_df.if_format = XFS_DINODE_FMT_LOCAL;
xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);
return 0;
}
nmaps = XFS_SYMLINK_MAPS;
error = xfs_bmapi_write(tp, ip, 0, fs_blocks, XFS_BMAPI_METADATA,
resblks, mval, &nmaps);
if (error)
return error;
ip->i_disk_size = pathlen;
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
cur_chunk = target_path;
offset = 0;
for (n = 0; n < nmaps; n++) {
char *buf;
d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
error = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
BTOBB(byte_cnt), 0, &bp);
if (error)
return error;
bp->b_ops = &xfs_symlink_buf_ops;
byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
byte_cnt = min(byte_cnt, pathlen);
buf = bp->b_addr;
buf += xfs_symlink_hdr_set(mp, owner, offset, byte_cnt, bp);
memcpy(buf, cur_chunk, byte_cnt);
cur_chunk += byte_cnt;
pathlen -= byte_cnt;
offset += byte_cnt;
xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
(char *)bp->b_addr);
}
ASSERT(pathlen == 0);
return 0;
}
/* Remove all the blocks from a symlink and invalidate buffers. */
int
xfs_symlink_remote_truncate(
struct xfs_trans *tp,
struct xfs_inode *ip)
{
struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
struct xfs_mount *mp = tp->t_mountp;
struct xfs_buf *bp;
int nmaps = XFS_SYMLINK_MAPS;
int done = 0;
int i;
int error;
/* Read mappings and invalidate buffers. */
error = xfs_bmapi_read(ip, 0, XFS_MAX_FILEOFF, mval, &nmaps, 0);
if (error)
return error;
for (i = 0; i < nmaps; i++) {
if (!xfs_bmap_is_real_extent(&mval[i]))
break;
error = xfs_trans_get_buf(tp, mp->m_ddev_targp,
XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0,
&bp);
if (error)
return error;
xfs_trans_binval(tp, bp);
}
/* Unmap the remote blocks. */
error = xfs_bunmapi(tp, ip, 0, XFS_MAX_FILEOFF, 0, nmaps, &done);
if (error)
return error;
if (!done) {
ASSERT(done);
xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK);
return -EFSCORRUPTED;
}
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
return 0;
}
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