cregit-Linux how code gets into the kernel

Release 4.11 fs/isofs/rock.c

Directory: fs/isofs
/*
 *  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; }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton7297.30%150.00%
Linus Torvalds (pre-git)22.70%150.00%
Total74100.00%2100.00%


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; } }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton15398.08%266.67%
Linus Torvalds (pre-git)31.92%133.33%
Total156100.00%3100.00%


static void init_rock_state(struct rock_state *rs, struct inode *inode) { memset(rs, 0, sizeof(*rs)); rs->inode = inode; }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton3291.43%150.00%
Linus Torvalds (pre-git)38.57%150.00%
Total35100.00%2100.00%

/* 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; }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton27195.76%266.67%
Jan Kara124.24%133.33%
Total283100.00%3100.00%

/* * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton281100.00%1100.00%
Total281100.00%1100.00%

/* * 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; char *p; int len; 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; } len = rr->len - 5; if (retnamlen + len >= 254) { truncate = 1; break; } p = memchr(rr->u.NM.name, '\0', len); if (unlikely(p)) len = p - rr->u.NM.name; memcpy(retname + retnamlen, rr->u.NM.name, len); retnamlen += len; retname[retnamlen] = '\0'; 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; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)27453.31%423.53%
Andrew Morton14728.60%741.18%
Al Viro6011.67%15.88%
Linus Torvalds234.47%211.76%
Adam Greenblatt40.78%15.88%
Brian Gerst30.58%15.88%
Dave Jones30.58%15.88%
Total514100.00%17100.00%

#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(KERN_CONT "%c", rr->u.ER.data[p]); } printk(KERN_CONT "\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; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)88358.63%1336.11%
Linus Torvalds24716.40%411.11%
Andrew Morton18412.22%719.44%
Jan Kara966.37%25.56%
Andi Kleen483.19%12.78%
David Howells120.80%12.78%
Brian Gerst90.60%12.78%
Eric W. Biedermann80.53%12.78%
Miklos Szeredi80.53%12.78%
Adam Greenblatt40.27%12.78%
Al Viro20.13%12.78%
Mike Rapoport20.13%12.78%
Paul Serice20.13%12.78%
Andries E. Brouwer10.07%12.78%
Total1506100.00%36100.00%


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; rootfla