diff options
Diffstat (limited to 'kernel/fs/isofs/rock.c')
-rw-r--r-- | kernel/fs/isofs/rock.c | 801 |
1 files changed, 801 insertions, 0 deletions
diff --git a/kernel/fs/isofs/rock.c b/kernel/fs/isofs/rock.c new file mode 100644 index 000000000..735d7522a --- /dev/null +++ b/kernel/fs/isofs/rock.c @@ -0,0 +1,801 @@ +/* + * linux/fs/isofs/rock.c + * + * (C) 1992, 1993 Eric Youngdale + * + * Rock Ridge Extensions to iso9660 + */ + +#include <linux/slab.h> +#include <linux/pagemap.h> + +#include "isofs.h" +#include "rock.h" + +/* + * These functions are designed to read the system areas of a directory record + * and extract relevant information. There are different functions provided + * depending upon what information we need at the time. One function fills + * out an inode structure, a second one extracts a filename, a third one + * returns a symbolic link name, and a fourth one returns the extent number + * for the file. + */ + +#define SIG(A,B) ((A) | ((B) << 8)) /* isonum_721() */ + +struct rock_state { + void *buffer; + unsigned char *chr; + int len; + int cont_size; + int cont_extent; + int cont_offset; + int cont_loops; + struct inode *inode; +}; + +/* + * This is a way of ensuring that we have something in the system + * use fields that is compatible with Rock Ridge. Return zero on success. + */ + +static int check_sp(struct rock_ridge *rr, struct inode *inode) +{ + if (rr->u.SP.magic[0] != 0xbe) + return -1; + if (rr->u.SP.magic[1] != 0xef) + return -1; + ISOFS_SB(inode->i_sb)->s_rock_offset = rr->u.SP.skip; + return 0; +} + +static void setup_rock_ridge(struct iso_directory_record *de, + struct inode *inode, struct rock_state *rs) +{ + rs->len = sizeof(struct iso_directory_record) + de->name_len[0]; + if (rs->len & 1) + (rs->len)++; + rs->chr = (unsigned char *)de + rs->len; + rs->len = *((unsigned char *)de) - rs->len; + if (rs->len < 0) + rs->len = 0; + + if (ISOFS_SB(inode->i_sb)->s_rock_offset != -1) { + rs->len -= ISOFS_SB(inode->i_sb)->s_rock_offset; + rs->chr += ISOFS_SB(inode->i_sb)->s_rock_offset; + if (rs->len < 0) + rs->len = 0; + } +} + +static void init_rock_state(struct rock_state *rs, struct inode *inode) +{ + memset(rs, 0, sizeof(*rs)); + rs->inode = inode; +} + +/* Maximum number of Rock Ridge continuation entries */ +#define RR_MAX_CE_ENTRIES 32 + +/* + * Returns 0 if the caller should continue scanning, 1 if the scan must end + * and -ve on error. + */ +static int rock_continue(struct rock_state *rs) +{ + int ret = 1; + int blocksize = 1 << rs->inode->i_blkbits; + const int min_de_size = offsetof(struct rock_ridge, u); + + kfree(rs->buffer); + rs->buffer = NULL; + + if ((unsigned)rs->cont_offset > blocksize - min_de_size || + (unsigned)rs->cont_size > blocksize || + (unsigned)(rs->cont_offset + rs->cont_size) > blocksize) { + printk(KERN_NOTICE "rock: corrupted directory entry. " + "extent=%d, offset=%d, size=%d\n", + rs->cont_extent, rs->cont_offset, rs->cont_size); + ret = -EIO; + goto out; + } + + if (rs->cont_extent) { + struct buffer_head *bh; + + rs->buffer = kmalloc(rs->cont_size, GFP_KERNEL); + if (!rs->buffer) { + ret = -ENOMEM; + goto out; + } + ret = -EIO; + if (++rs->cont_loops >= RR_MAX_CE_ENTRIES) + goto out; + bh = sb_bread(rs->inode->i_sb, rs->cont_extent); + if (bh) { + memcpy(rs->buffer, bh->b_data + rs->cont_offset, + rs->cont_size); + put_bh(bh); + rs->chr = rs->buffer; + rs->len = rs->cont_size; + rs->cont_extent = 0; + rs->cont_size = 0; + rs->cont_offset = 0; + return 0; + } + printk("Unable to read rock-ridge attributes\n"); + } +out: + kfree(rs->buffer); + rs->buffer = NULL; + return ret; +} + +/* + * We think there's a record of type `sig' at rs->chr. Parse the signature + * and make sure that there's really room for a record of that type. + */ +static int rock_check_overflow(struct rock_state *rs, int sig) +{ + int len; + + switch (sig) { + case SIG('S', 'P'): + len = sizeof(struct SU_SP_s); + break; + case SIG('C', 'E'): + len = sizeof(struct SU_CE_s); + break; + case SIG('E', 'R'): + len = sizeof(struct SU_ER_s); + break; + case SIG('R', 'R'): + len = sizeof(struct RR_RR_s); + break; + case SIG('P', 'X'): + len = sizeof(struct RR_PX_s); + break; + case SIG('P', 'N'): + len = sizeof(struct RR_PN_s); + break; + case SIG('S', 'L'): + len = sizeof(struct RR_SL_s); + break; + case SIG('N', 'M'): + len = sizeof(struct RR_NM_s); + break; + case SIG('C', 'L'): + len = sizeof(struct RR_CL_s); + break; + case SIG('P', 'L'): + len = sizeof(struct RR_PL_s); + break; + case SIG('T', 'F'): + len = sizeof(struct RR_TF_s); + break; + case SIG('Z', 'F'): + len = sizeof(struct RR_ZF_s); + break; + default: + len = 0; + break; + } + len += offsetof(struct rock_ridge, u); + if (len > rs->len) { + printk(KERN_NOTICE "rock: directory entry would overflow " + "storage\n"); + printk(KERN_NOTICE "rock: sig=0x%02x, size=%d, remaining=%d\n", + sig, len, rs->len); + return -EIO; + } + return 0; +} + +/* + * return length of name field; 0: not found, -1: to be ignored + */ +int get_rock_ridge_filename(struct iso_directory_record *de, + char *retname, struct inode *inode) +{ + struct rock_state rs; + struct rock_ridge *rr; + int sig; + int retnamlen = 0; + int truncate = 0; + int ret = 0; + + if (!ISOFS_SB(inode->i_sb)->s_rock) + return 0; + *retname = 0; + + init_rock_state(&rs, inode); + setup_rock_ridge(de, inode, &rs); +repeat: + + while (rs.len > 2) { /* There may be one byte for padding somewhere */ + rr = (struct rock_ridge *)rs.chr; + /* + * Ignore rock ridge info if rr->len is out of range, but + * don't return -EIO because that would make the file + * invisible. + */ + if (rr->len < 3) + goto out; /* Something got screwed up here */ + sig = isonum_721(rs.chr); + if (rock_check_overflow(&rs, sig)) + goto eio; + rs.chr += rr->len; + rs.len -= rr->len; + /* + * As above, just ignore the rock ridge info if rr->len + * is bogus. + */ + if (rs.len < 0) + goto out; /* Something got screwed up here */ + + switch (sig) { + case SIG('R', 'R'): + if ((rr->u.RR.flags[0] & RR_NM) == 0) + goto out; + break; + case SIG('S', 'P'): + if (check_sp(rr, inode)) + goto out; + break; + case SIG('C', 'E'): + rs.cont_extent = isonum_733(rr->u.CE.extent); + rs.cont_offset = isonum_733(rr->u.CE.offset); + rs.cont_size = isonum_733(rr->u.CE.size); + break; + case SIG('N', 'M'): + if (truncate) + break; + if (rr->len < 5) + break; + /* + * If the flags are 2 or 4, this indicates '.' or '..'. + * We don't want to do anything with this, because it + * screws up the code that calls us. We don't really + * care anyways, since we can just use the non-RR + * name. + */ + if (rr->u.NM.flags & 6) + break; + + if (rr->u.NM.flags & ~1) { + printk("Unsupported NM flag settings (%d)\n", + rr->u.NM.flags); + break; + } + if ((strlen(retname) + rr->len - 5) >= 254) { + truncate = 1; + break; + } + strncat(retname, rr->u.NM.name, rr->len - 5); + retnamlen += rr->len - 5; + break; + case SIG('R', 'E'): + kfree(rs.buffer); + return -1; + default: + break; + } + } + ret = rock_continue(&rs); + if (ret == 0) + goto repeat; + if (ret == 1) + return retnamlen; /* If 0, this file did not have a NM field */ +out: + kfree(rs.buffer); + return ret; +eio: + ret = -EIO; + goto out; +} + +#define RR_REGARD_XA 1 +#define RR_RELOC_DE 2 + +static int +parse_rock_ridge_inode_internal(struct iso_directory_record *de, + struct inode *inode, int flags) +{ + int symlink_len = 0; + int cnt, sig; + unsigned int reloc_block; + struct inode *reloc; + struct rock_ridge *rr; + int rootflag; + struct rock_state rs; + int ret = 0; + + if (!ISOFS_SB(inode->i_sb)->s_rock) + return 0; + + init_rock_state(&rs, inode); + setup_rock_ridge(de, inode, &rs); + if (flags & RR_REGARD_XA) { + rs.chr += 14; + rs.len -= 14; + if (rs.len < 0) + rs.len = 0; + } + +repeat: + while (rs.len > 2) { /* There may be one byte for padding somewhere */ + rr = (struct rock_ridge *)rs.chr; + /* + * Ignore rock ridge info if rr->len is out of range, but + * don't return -EIO because that would make the file + * invisible. + */ + if (rr->len < 3) + goto out; /* Something got screwed up here */ + sig = isonum_721(rs.chr); + if (rock_check_overflow(&rs, sig)) + goto eio; + rs.chr += rr->len; + rs.len -= rr->len; + /* + * As above, just ignore the rock ridge info if rr->len + * is bogus. + */ + if (rs.len < 0) + goto out; /* Something got screwed up here */ + + switch (sig) { +#ifndef CONFIG_ZISOFS /* No flag for SF or ZF */ + case SIG('R', 'R'): + if ((rr->u.RR.flags[0] & + (RR_PX | RR_TF | RR_SL | RR_CL)) == 0) + goto out; + break; +#endif + case SIG('S', 'P'): + if (check_sp(rr, inode)) + goto out; + break; + case SIG('C', 'E'): + rs.cont_extent = isonum_733(rr->u.CE.extent); + rs.cont_offset = isonum_733(rr->u.CE.offset); + rs.cont_size = isonum_733(rr->u.CE.size); + break; + case SIG('E', 'R'): + /* Invalid length of ER tag id? */ + if (rr->u.ER.len_id + offsetof(struct rock_ridge, u.ER.data) > rr->len) + goto out; + ISOFS_SB(inode->i_sb)->s_rock = 1; + printk(KERN_DEBUG "ISO 9660 Extensions: "); + { + int p; + for (p = 0; p < rr->u.ER.len_id; p++) + printk("%c", rr->u.ER.data[p]); + } + printk("\n"); + break; + case SIG('P', 'X'): + inode->i_mode = isonum_733(rr->u.PX.mode); + set_nlink(inode, isonum_733(rr->u.PX.n_links)); + i_uid_write(inode, isonum_733(rr->u.PX.uid)); + i_gid_write(inode, isonum_733(rr->u.PX.gid)); + break; + case SIG('P', 'N'): + { + int high, low; + high = isonum_733(rr->u.PN.dev_high); + low = isonum_733(rr->u.PN.dev_low); + /* + * The Rock Ridge standard specifies that if + * sizeof(dev_t) <= 4, then the high field is + * unused, and the device number is completely + * stored in the low field. Some writers may + * ignore this subtlety, + * and as a result we test to see if the entire + * device number is + * stored in the low field, and use that. + */ + if ((low & ~0xff) && high == 0) { + inode->i_rdev = + MKDEV(low >> 8, low & 0xff); + } else { + inode->i_rdev = + MKDEV(high, low); + } + } + break; + case SIG('T', 'F'): + /* + * Some RRIP writers incorrectly place ctime in the + * TF_CREATE field. Try to handle this correctly for + * either case. + */ + /* Rock ridge never appears on a High Sierra disk */ + cnt = 0; + if (rr->u.TF.flags & TF_CREATE) { + inode->i_ctime.tv_sec = + iso_date(rr->u.TF.times[cnt++].time, + 0); + inode->i_ctime.tv_nsec = 0; + } + if (rr->u.TF.flags & TF_MODIFY) { + inode->i_mtime.tv_sec = + iso_date(rr->u.TF.times[cnt++].time, + 0); + inode->i_mtime.tv_nsec = 0; + } + if (rr->u.TF.flags & TF_ACCESS) { + inode->i_atime.tv_sec = + iso_date(rr->u.TF.times[cnt++].time, + 0); + inode->i_atime.tv_nsec = 0; + } + if (rr->u.TF.flags & TF_ATTRIBUTES) { + inode->i_ctime.tv_sec = + iso_date(rr->u.TF.times[cnt++].time, + 0); + inode->i_ctime.tv_nsec = 0; + } + break; + case SIG('S', 'L'): + { + int slen; + struct SL_component *slp; + struct SL_component *oldslp; + slen = rr->len - 5; + slp = &rr->u.SL.link; + inode->i_size = symlink_len; + while (slen > 1) { + rootflag = 0; + switch (slp->flags & ~1) { + case 0: + inode->i_size += + slp->len; + break; + case 2: + inode->i_size += 1; + break; + case 4: + inode->i_size += 2; + break; + case 8: + rootflag = 1; + inode->i_size += 1; + break; + default: + printk("Symlink component flag " + "not implemented\n"); + } + slen -= slp->len + 2; + oldslp = slp; + slp = (struct SL_component *) + (((char *)slp) + slp->len + 2); + + if (slen < 2) { + if (((rr->u.SL. + flags & 1) != 0) + && + ((oldslp-> + flags & 1) == 0)) + inode->i_size += + 1; + break; + } + + /* + * If this component record isn't + * continued, then append a '/'. + */ + if (!rootflag + && (oldslp->flags & 1) == 0) + inode->i_size += 1; + } + } + symlink_len = inode->i_size; + break; + case SIG('R', 'E'): + printk(KERN_WARNING "Attempt to read inode for " + "relocated directory\n"); + goto out; + case SIG('C', 'L'): + if (flags & RR_RELOC_DE) { + printk(KERN_ERR + "ISOFS: Recursive directory relocation " + "is not supported\n"); + goto eio; + } + reloc_block = isonum_733(rr->u.CL.location); + if (reloc_block == ISOFS_I(inode)->i_iget5_block && + ISOFS_I(inode)->i_iget5_offset == 0) { + printk(KERN_ERR + "ISOFS: Directory relocation points to " + "itself\n"); + goto eio; + } + ISOFS_I(inode)->i_first_extent = reloc_block; + reloc = isofs_iget_reloc(inode->i_sb, reloc_block, 0); + if (IS_ERR(reloc)) { + ret = PTR_ERR(reloc); + goto out; + } + inode->i_mode = reloc->i_mode; + set_nlink(inode, reloc->i_nlink); + inode->i_uid = reloc->i_uid; + inode->i_gid = reloc->i_gid; + inode->i_rdev = reloc->i_rdev; + inode->i_size = reloc->i_size; + inode->i_blocks = reloc->i_blocks; + inode->i_atime = reloc->i_atime; + inode->i_ctime = reloc->i_ctime; + inode->i_mtime = reloc->i_mtime; + iput(reloc); + break; +#ifdef CONFIG_ZISOFS + case SIG('Z', 'F'): { + int algo; + + if (ISOFS_SB(inode->i_sb)->s_nocompress) + break; + algo = isonum_721(rr->u.ZF.algorithm); + if (algo == SIG('p', 'z')) { + int block_shift = + isonum_711(&rr->u.ZF.parms[1]); + if (block_shift > 17) { + printk(KERN_WARNING "isofs: " + "Can't handle ZF block " + "size of 2^%d\n", + block_shift); + } else { + /* + * Note: we don't change + * i_blocks here + */ + ISOFS_I(inode)->i_file_format = + isofs_file_compressed; + /* + * Parameters to compression + * algorithm (header size, + * block size) + */ + ISOFS_I(inode)->i_format_parm[0] = + isonum_711(&rr->u.ZF.parms[0]); + ISOFS_I(inode)->i_format_parm[1] = + isonum_711(&rr->u.ZF.parms[1]); + inode->i_size = + isonum_733(rr->u.ZF. + real_size); + } + } else { + printk(KERN_WARNING + "isofs: Unknown ZF compression " + "algorithm: %c%c\n", + rr->u.ZF.algorithm[0], + rr->u.ZF.algorithm[1]); + } + break; + } +#endif + default: + break; + } + } + ret = rock_continue(&rs); + if (ret == 0) + goto repeat; + if (ret == 1) + ret = 0; +out: + kfree(rs.buffer); + return ret; +eio: + ret = -EIO; + goto out; +} + +static char *get_symlink_chunk(char *rpnt, struct rock_ridge *rr, char *plimit) +{ + int slen; + int rootflag; + struct SL_component *oldslp; + struct SL_component *slp; + slen = rr->len - 5; + slp = &rr->u.SL.link; + while (slen > 1) { + rootflag = 0; + switch (slp->flags & ~1) { + case 0: + if (slp->len > plimit - rpnt) + return NULL; + memcpy(rpnt, slp->text, slp->len); + rpnt += slp->len; + break; + case 2: + if (rpnt >= plimit) + return NULL; + *rpnt++ = '.'; + break; + case 4: + if (2 > plimit - rpnt) + return NULL; + *rpnt++ = '.'; + *rpnt++ = '.'; + break; + case 8: + if (rpnt >= plimit) + return NULL; + rootflag = 1; + *rpnt++ = '/'; + break; + default: + printk("Symlink component flag not implemented (%d)\n", + slp->flags); + } + slen -= slp->len + 2; + oldslp = slp; + slp = (struct SL_component *)((char *)slp + slp->len + 2); + + if (slen < 2) { + /* + * If there is another SL record, and this component + * record isn't continued, then add a slash. + */ + if ((!rootflag) && (rr->u.SL.flags & 1) && + !(oldslp->flags & 1)) { + if (rpnt >= plimit) + return NULL; + *rpnt++ = '/'; + } + break; + } + + /* + * If this component record isn't continued, then append a '/'. + */ + if (!rootflag && !(oldslp->flags & 1)) { + if (rpnt >= plimit) + return NULL; + *rpnt++ = '/'; + } + } + return rpnt; +} + +int parse_rock_ridge_inode(struct iso_directory_record *de, struct inode *inode, + int relocated) +{ + int flags = relocated ? RR_RELOC_DE : 0; + int result = parse_rock_ridge_inode_internal(de, inode, flags); + + /* + * if rockridge flag was reset and we didn't look for attributes + * behind eventual XA attributes, have a look there + */ + if ((ISOFS_SB(inode->i_sb)->s_rock_offset == -1) + && (ISOFS_SB(inode->i_sb)->s_rock == 2)) { + result = parse_rock_ridge_inode_internal(de, inode, + flags | RR_REGARD_XA); + } + return result; +} + +/* + * readpage() for symlinks: reads symlink contents into the page and either + * makes it uptodate and returns 0 or returns error (-EIO) + */ +static int rock_ridge_symlink_readpage(struct file *file, struct page *page) +{ + struct inode *inode = page->mapping->host; + struct iso_inode_info *ei = ISOFS_I(inode); + struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb); + char *link = kmap(page); + unsigned long bufsize = ISOFS_BUFFER_SIZE(inode); + struct buffer_head *bh; + char *rpnt = link; + unsigned char *pnt; + struct iso_directory_record *raw_de; + unsigned long block, offset; + int sig; + struct rock_ridge *rr; + struct rock_state rs; + int ret; + + if (!sbi->s_rock) + goto error; + + init_rock_state(&rs, inode); + block = ei->i_iget5_block; + bh = sb_bread(inode->i_sb, block); + if (!bh) + goto out_noread; + + offset = ei->i_iget5_offset; + pnt = (unsigned char *)bh->b_data + offset; + + raw_de = (struct iso_directory_record *)pnt; + + /* + * If we go past the end of the buffer, there is some sort of error. + */ + if (offset + *pnt > bufsize) + goto out_bad_span; + + /* + * Now test for possible Rock Ridge extensions which will override + * some of these numbers in the inode structure. + */ + + setup_rock_ridge(raw_de, inode, &rs); + +repeat: + while (rs.len > 2) { /* There may be one byte for padding somewhere */ + rr = (struct rock_ridge *)rs.chr; + if (rr->len < 3) + goto out; /* Something got screwed up here */ + sig = isonum_721(rs.chr); + if (rock_check_overflow(&rs, sig)) + goto out; + rs.chr += rr->len; + rs.len -= rr->len; + if (rs.len < 0) + goto out; /* corrupted isofs */ + + switch (sig) { + case SIG('R', 'R'): + if ((rr->u.RR.flags[0] & RR_SL) == 0) + goto out; + break; + case SIG('S', 'P'): + if (check_sp(rr, inode)) + goto out; + break; + case SIG('S', 'L'): + rpnt = get_symlink_chunk(rpnt, rr, + link + (PAGE_SIZE - 1)); + if (rpnt == NULL) + goto out; + break; + case SIG('C', 'E'): + /* This tells is if there is a continuation record */ + rs.cont_extent = isonum_733(rr->u.CE.extent); + rs.cont_offset = isonum_733(rr->u.CE.offset); + rs.cont_size = isonum_733(rr->u.CE.size); + default: + break; + } + } + ret = rock_continue(&rs); + if (ret == 0) + goto repeat; + if (ret < 0) + goto fail; + + if (rpnt == link) + goto fail; + brelse(bh); + *rpnt = '\0'; + SetPageUptodate(page); + kunmap(page); + unlock_page(page); + return 0; + + /* error exit from macro */ +out: + kfree(rs.buffer); + goto fail; +out_noread: + printk("unable to read i-node block"); + goto fail; +out_bad_span: + printk("symlink spans iso9660 blocks\n"); +fail: + brelse(bh); +error: + SetPageError(page); + kunmap(page); + unlock_page(page); + return -EIO; +} + +const struct address_space_operations isofs_symlink_aops = { + .readpage = rock_ridge_symlink_readpage +}; |