/* * Copyright (c) 2000-2006 Silicon Graphics, Inc. * Copyright (c) 2012-2013 Red Hat, Inc. * All rights reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation. * * This program is distributed in the hope that it would be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include "xfs.h" #include "xfs_fs.h" #include "xfs_format.h" #include "xfs_log.h" #include "xfs_trans.h" #include "xfs_sb.h" #include "xfs_mount.h" #include "xfs_bmap_btree.h" #include "xfs_inode.h" #include "xfs_error.h" #include "xfs_trace.h" #include "xfs_symlink.h" #include "xfs_cksum.h" #include "xfs_buf_item.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_sb_version_hascrc(&mp->m_sb)) return 0; 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_uuid); dsl->sl_owner = cpu_to_be64(ino); dsl->sl_blkno = cpu_to_be64(bp->b_bn); 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( 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 (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 bool xfs_symlink_verify( struct xfs_buf *bp) { struct xfs_mount *mp = bp->b_target->bt_mount; struct xfs_dsymlink_hdr *dsl = bp->b_addr; if (!xfs_sb_version_hascrc(&mp->m_sb)) return false; if (dsl->sl_magic != cpu_to_be32(XFS_SYMLINK_MAGIC)) return false; if (!uuid_equal(&dsl->sl_uuid, &mp->m_sb.sb_uuid)) return false; if (bp->b_bn != be64_to_cpu(dsl->sl_blkno)) return false; if (be32_to_cpu(dsl->sl_offset) + be32_to_cpu(dsl->sl_bytes) >= MAXPATHLEN) return false; if (dsl->sl_owner == 0) return false; return true; } static void xfs_symlink_read_verify( struct xfs_buf *bp) { struct xfs_mount *mp = bp->b_target->bt_mount; /* no verification of non-crc buffers */ if (!xfs_sb_version_hascrc(&mp->m_sb)) return; if (!xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length), offsetof(struct xfs_dsymlink_hdr, sl_crc)) || !xfs_symlink_verify(bp)) { XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr); xfs_buf_ioerror(bp, EFSCORRUPTED); } } static void xfs_symlink_write_verify( struct xfs_buf *bp) { struct xfs_mount *mp = bp->b_target->bt_mount; struct xfs_buf_log_item *bip = bp->b_fspriv; /* no verification of non-crc buffers */ if (!xfs_sb_version_hascrc(&mp->m_sb)) return; if (!xfs_symlink_verify(bp)) { XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr); xfs_buf_ioerror(bp, EFSCORRUPTED); return; } if (bip) { struct xfs_dsymlink_hdr *dsl = bp->b_addr; dsl->sl_lsn = cpu_to_be64(bip->bli_item.li_lsn); } xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length), offsetof(struct xfs_dsymlink_hdr, sl_crc)); } const struct xfs_buf_ops xfs_symlink_buf_ops = { .verify_read = xfs_symlink_read_verify, .verify_write = xfs_symlink_write_verify, }; void xfs_symlink_local_to_remote( struct xfs_trans *tp, struct xfs_buf *bp, struct xfs_inode *ip, struct xfs_ifork *ifp) { struct xfs_mount *mp = ip->i_mount; char *buf; if (!xfs_sb_version_hascrc(&mp->m_sb)) { bp->b_ops = NULL; memcpy(bp->b_addr, ifp->if_u1.if_data, ifp->if_bytes); 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_u1.if_data, ifp->if_bytes); }