#include <linux/fs_struct.h>
#include <linux/posix_acl.h>
#include <linux/hash.h>
+#include <linux/bitops.h>
+#include <linux/init_task.h>
#include <asm/uaccess.h>
#include "internal.h"
if (!acl)
return -EAGAIN;
/* no ->get_acl() calls in RCU mode... */
- if (acl == ACL_NOT_CACHED)
+ if (is_uncached_acl(acl))
return -ECHILD;
return posix_acl_permission(inode, acl, mask & ~MAY_NOT_BLOCK);
}
*/
if (IS_IMMUTABLE(inode))
return -EACCES;
+
+ /*
+ * Updating mtime will likely cause i_uid and i_gid to be
+ * written back improperly if their true value is unknown
+ * to the vfs.
+ */
+ if (HAS_UNMAPPED_ID(inode))
+ return -EACCES;
}
retval = do_inode_permission(inode, mask);
{
const struct inode *inode;
const struct inode *parent;
+ kuid_t puid;
if (!sysctl_protected_symlinks)
return 0;
return 0;
/* Allowed if parent directory and link owner match. */
- if (uid_eq(parent->i_uid, inode->i_uid))
+ puid = parent->i_uid;
+ if (uid_valid(puid) && uid_eq(puid, inode->i_uid))
return 0;
if (nd->flags & LOOKUP_RCU)
bool *need_mntput)
{
struct vfsmount *mnt;
+ const struct cred *old_cred;
int err;
if (!path->dentry->d_op || !path->dentry->d_op->d_automount)
path->dentry->d_inode)
return -EISDIR;
+ if (path->dentry->d_sb->s_user_ns != &init_user_ns)
+ return -EACCES;
+
nd->total_link_count++;
if (nd->total_link_count >= 40)
return -ELOOP;
+ old_cred = override_creds(&init_cred);
mnt = path->dentry->d_op->d_automount(path);
+ revert_creds(old_cred);
if (IS_ERR(mnt)) {
/*
* The filesystem is allowed to return -EISDIR here to indicate
}
}
+static int path_parent_directory(struct path *path)
+{
+ struct dentry *old = path->dentry;
+ /* rare case of legitimate dget_parent()... */
+ path->dentry = dget_parent(path->dentry);
+ dput(old);
+ if (unlikely(!path_connected(path)))
+ return -ENOENT;
+ return 0;
+}
+
static int follow_dotdot(struct nameidata *nd)
{
while(1) {
- struct dentry *old = nd->path.dentry;
-
if (nd->path.dentry == nd->root.dentry &&
nd->path.mnt == nd->root.mnt) {
break;
}
if (nd->path.dentry != nd->path.mnt->mnt_root) {
- /* rare case of legitimate dget_parent()... */
- nd->path.dentry = dget_parent(nd->path.dentry);
- dput(old);
- if (unlikely(!path_connected(&nd->path)))
- return -ENOENT;
+ int ret = path_parent_directory(&nd->path);
+ if (ret)
+ return ret;
break;
}
if (!follow_up(&nd->path))
}
/*
- * This looks up the name in dcache, possibly revalidates the old dentry and
- * allocates a new one if not found or not valid. In the need_lookup argument
- * returns whether i_op->lookup is necessary.
+ * This looks up the name in dcache and possibly revalidates the found dentry.
+ * NULL is returned if the dentry does not exist in the cache.
*/
static struct dentry *lookup_dcache(const struct qstr *name,
struct dentry *dir,
struct dentry *dir,
unsigned int flags)
{
- struct dentry *dentry;
- inode_lock(dir->d_inode);
- dentry = d_lookup(dir, name);
- if (unlikely(dentry)) {
+ struct dentry *dentry = ERR_PTR(-ENOENT), *old;
+ struct inode *inode = dir->d_inode;
+ DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+
+ inode_lock_shared(inode);
+ /* Don't go there if it's already dead */
+ if (unlikely(IS_DEADDIR(inode)))
+ goto out;
+again:
+ dentry = d_alloc_parallel(dir, name, &wq);
+ if (IS_ERR(dentry))
+ goto out;
+ if (unlikely(!d_in_lookup(dentry))) {
if ((dentry->d_flags & DCACHE_OP_REVALIDATE) &&
!(flags & LOOKUP_NO_REVAL)) {
int error = d_revalidate(dentry, flags);
if (unlikely(error <= 0)) {
- if (!error)
+ if (!error) {
d_invalidate(dentry);
+ dput(dentry);
+ goto again;
+ }
dput(dentry);
dentry = ERR_PTR(error);
}
}
- if (dentry) {
- inode_unlock(dir->d_inode);
- return dentry;
+ } else {
+ old = inode->i_op->lookup(inode, dentry, flags);
+ d_lookup_done(dentry);
+ if (unlikely(old)) {
+ dput(dentry);
+ dentry = old;
}
}
- dentry = d_alloc(dir, name);
- if (unlikely(!dentry)) {
- inode_unlock(dir->d_inode);
- return ERR_PTR(-ENOMEM);
- }
- dentry = lookup_real(dir->d_inode, dentry, flags);
- inode_unlock(dir->d_inode);
+out:
+ inode_unlock_shared(inode);
return dentry;
}
#include <asm/word-at-a-time.h>
-#ifdef CONFIG_64BIT
+#ifdef HASH_MIX
-static inline unsigned int fold_hash(unsigned long hash)
+/* Architecture provides HASH_MIX and fold_hash() in <asm/hash.h> */
+
+#elif defined(CONFIG_64BIT)
+/*
+ * Register pressure in the mixing function is an issue, particularly
+ * on 32-bit x86, but almost any function requires one state value and
+ * one temporary. Instead, use a function designed for two state values
+ * and no temporaries.
+ *
+ * This function cannot create a collision in only two iterations, so
+ * we have two iterations to achieve avalanche. In those two iterations,
+ * we have six layers of mixing, which is enough to spread one bit's
+ * influence out to 2^6 = 64 state bits.
+ *
+ * Rotate constants are scored by considering either 64 one-bit input
+ * deltas or 64*63/2 = 2016 two-bit input deltas, and finding the
+ * probability of that delta causing a change to each of the 128 output
+ * bits, using a sample of random initial states.
+ *
+ * The Shannon entropy of the computed probabilities is then summed
+ * to produce a score. Ideally, any input change has a 50% chance of
+ * toggling any given output bit.
+ *
+ * Mixing scores (in bits) for (12,45):
+ * Input delta: 1-bit 2-bit
+ * 1 round: 713.3 42542.6
+ * 2 rounds: 2753.7 140389.8
+ * 3 rounds: 5954.1 233458.2
+ * 4 rounds: 7862.6 256672.2
+ * Perfect: 8192 258048
+ * (64*128) (64*63/2 * 128)
+ */
+#define HASH_MIX(x, y, a) \
+ ( x ^= (a), \
+ y ^= x, x = rol64(x,12),\
+ x += y, y = rol64(y,45),\
+ y *= 9 )
+
+/*
+ * Fold two longs into one 32-bit hash value. This must be fast, but
+ * latency isn't quite as critical, as there is a fair bit of additional
+ * work done before the hash value is used.
+ */
+static inline unsigned int fold_hash(unsigned long x, unsigned long y)
{
- return hash_64(hash, 32);
+ y ^= x * GOLDEN_RATIO_64;
+ y *= GOLDEN_RATIO_64;
+ return y >> 32;
}
#else /* 32-bit case */
-#define fold_hash(x) (x)
+/*
+ * Mixing scores (in bits) for (7,20):
+ * Input delta: 1-bit 2-bit
+ * 1 round: 330.3 9201.6
+ * 2 rounds: 1246.4 25475.4
+ * 3 rounds: 1907.1 31295.1
+ * 4 rounds: 2042.3 31718.6
+ * Perfect: 2048 31744
+ * (32*64) (32*31/2 * 64)
+ */
+#define HASH_MIX(x, y, a) \
+ ( x ^= (a), \
+ y ^= x, x = rol32(x, 7),\
+ x += y, y = rol32(y,20),\
+ y *= 9 )
+
+static inline unsigned int fold_hash(unsigned long x, unsigned long y)
+{
+ /* Use arch-optimized multiply if one exists */
+ return __hash_32(y ^ __hash_32(x));
+}
#endif
-unsigned int full_name_hash(const unsigned char *name, unsigned int len)
+/*
+ * Return the hash of a string of known length. This is carfully
+ * designed to match hash_name(), which is the more critical function.
+ * In particular, we must end by hashing a final word containing 0..7
+ * payload bytes, to match the way that hash_name() iterates until it
+ * finds the delimiter after the name.
+ */
+unsigned int full_name_hash(const void *salt, const char *name, unsigned int len)
{
- unsigned long a, mask;
- unsigned long hash = 0;
+ unsigned long a, x = 0, y = (unsigned long)salt;
for (;;) {
+ if (!len)
+ goto done;
a = load_unaligned_zeropad(name);
if (len < sizeof(unsigned long))
break;
- hash += a;
- hash *= 9;
+ HASH_MIX(x, y, a);
name += sizeof(unsigned long);
len -= sizeof(unsigned long);
- if (!len)
- goto done;
}
- mask = bytemask_from_count(len);
- hash += mask & a;
+ x ^= a & bytemask_from_count(len);
done:
- return fold_hash(hash);
+ return fold_hash(x, y);
}
EXPORT_SYMBOL(full_name_hash);
+/* Return the "hash_len" (hash and length) of a null-terminated string */
+u64 hashlen_string(const void *salt, const char *name)
+{
+ unsigned long a = 0, x = 0, y = (unsigned long)salt;
+ unsigned long adata, mask, len;
+ const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
+
+ len = 0;
+ goto inside;
+
+ do {
+ HASH_MIX(x, y, a);
+ len += sizeof(unsigned long);
+inside:
+ a = load_unaligned_zeropad(name+len);
+ } while (!has_zero(a, &adata, &constants));
+
+ adata = prep_zero_mask(a, adata, &constants);
+ mask = create_zero_mask(adata);
+ x ^= a & zero_bytemask(mask);
+
+ return hashlen_create(fold_hash(x, y), len + find_zero(mask));
+}
+EXPORT_SYMBOL(hashlen_string);
+
/*
* Calculate the length and hash of the path component, and
* return the "hash_len" as the result.
*/
-static inline u64 hash_name(const char *name)
+static inline u64 hash_name(const void *salt, const char *name)
{
- unsigned long a, b, adata, bdata, mask, hash, len;
+ unsigned long a = 0, b, x = 0, y = (unsigned long)salt;
+ unsigned long adata, bdata, mask, len;
const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
- hash = a = 0;
- len = -sizeof(unsigned long);
+ len = 0;
+ goto inside;
+
do {
- hash = (hash + a) * 9;
+ HASH_MIX(x, y, a);
len += sizeof(unsigned long);
+inside:
a = load_unaligned_zeropad(name+len);
b = a ^ REPEAT_BYTE('/');
} while (!(has_zero(a, &adata, &constants) | has_zero(b, &bdata, &constants)));
adata = prep_zero_mask(a, adata, &constants);
bdata = prep_zero_mask(b, bdata, &constants);
-
mask = create_zero_mask(adata | bdata);
+ x ^= a & zero_bytemask(mask);
- hash += a & zero_bytemask(mask);
- len += find_zero(mask);
- return hashlen_create(fold_hash(hash), len);
+ return hashlen_create(fold_hash(x, y), len + find_zero(mask));
}
-#else
+#else /* !CONFIG_DCACHE_WORD_ACCESS: Slow, byte-at-a-time version */
-unsigned int full_name_hash(const unsigned char *name, unsigned int len)
+/* Return the hash of a string of known length */
+unsigned int full_name_hash(const void *salt, const char *name, unsigned int len)
{
- unsigned long hash = init_name_hash();
+ unsigned long hash = init_name_hash(salt);
while (len--)
- hash = partial_name_hash(*name++, hash);
+ hash = partial_name_hash((unsigned char)*name++, hash);
return end_name_hash(hash);
}
EXPORT_SYMBOL(full_name_hash);
+/* Return the "hash_len" (hash and length) of a null-terminated string */
+u64 hashlen_string(const void *salt, const char *name)
+{
+ unsigned long hash = init_name_hash(salt);
+ unsigned long len = 0, c;
+
+ c = (unsigned char)*name;
+ while (c) {
+ len++;
+ hash = partial_name_hash(c, hash);
+ c = (unsigned char)name[len];
+ }
+ return hashlen_create(end_name_hash(hash), len);
+}
+EXPORT_SYMBOL(hashlen_string);
+
/*
* We know there's a real path component here of at least
* one character.
*/
-static inline u64 hash_name(const char *name)
+static inline u64 hash_name(const void *salt, const char *name)
{
- unsigned long hash = init_name_hash();
+ unsigned long hash = init_name_hash(salt);
unsigned long len = 0, c;
c = (unsigned char)*name;
int type;
err = may_lookup(nd);
- if (err)
+ if (err)
return err;
- hash_len = hash_name(name);
+ hash_len = hash_name(nd->path.dentry, name);
type = LAST_NORM;
if (name[0] == '.') switch (hashlen_len(hash_len)) {
}
EXPORT_SYMBOL(vfs_path_lookup);
-/**
- * lookup_hash - lookup single pathname component on already hashed name
- * @name: name and hash to lookup
- * @base: base directory to lookup from
- *
- * The name must have been verified and hashed (see lookup_one_len()). Using
- * this after just full_name_hash() is unsafe.
- *
- * This function also doesn't check for search permission on base directory.
- *
- * Use lookup_one_len_unlocked() instead, unless you really know what you are
- * doing.
- *
- * Do not hold i_mutex; this helper takes i_mutex if necessary.
- */
-struct dentry *lookup_hash(const struct qstr *name, struct dentry *base)
-{
- struct dentry *ret;
-
- ret = lookup_dcache(name, base, 0);
- if (!ret)
- ret = lookup_slow(name, base, 0);
-
- return ret;
-}
-EXPORT_SYMBOL(lookup_hash);
-
/**
* lookup_one_len - filesystem helper to lookup single pathname component
* @name: pathname component to lookup
this.name = name;
this.len = len;
- this.hash = full_name_hash(name, len);
+ this.hash = full_name_hash(base, name, len);
if (!len)
return ERR_PTR(-EACCES);
struct qstr this;
unsigned int c;
int err;
+ struct dentry *ret;
this.name = name;
this.len = len;
- this.hash = full_name_hash(name, len);
+ this.hash = full_name_hash(base, name, len);
if (!len)
return ERR_PTR(-EACCES);
if (err)
return ERR_PTR(err);
- return lookup_hash(&this, base);
+ ret = lookup_dcache(&this, base, 0);
+ if (!ret)
+ ret = lookup_slow(&this, base, 0);
+ return ret;
}
EXPORT_SYMBOL(lookup_one_len_unlocked);
+#ifdef CONFIG_UNIX98_PTYS
+int path_pts(struct path *path)
+{
+ /* Find something mounted on "pts" in the same directory as
+ * the input path.
+ */
+ struct dentry *child, *parent;
+ struct qstr this;
+ int ret;
+
+ ret = path_parent_directory(path);
+ if (ret)
+ return ret;
+
+ parent = path->dentry;
+ this.name = "pts";
+ this.len = 3;
+ child = d_hash_and_lookup(parent, &this);
+ if (!child)
+ return -ENOENT;
+
+ path->dentry = child;
+ dput(parent);
+ follow_mount(path);
+ return 0;
+}
+#endif
+
int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
struct path *path, int *empty)
{
* c. have CAP_FOWNER capability
* 6. If the victim is append-only or immutable we can't do antyhing with
* links pointing to it.
- * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
- * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
- * 9. We can't remove a root or mountpoint.
- * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
+ * 7. If the victim has an unknown uid or gid we can't change the inode.
+ * 8. If we were asked to remove a directory and victim isn't one - ENOTDIR.
+ * 9. If we were asked to remove a non-directory and victim isn't one - EISDIR.
+ * 10. We can't remove a root or mountpoint.
+ * 11. We don't allow removal of NFS sillyrenamed files; it's handled by
* nfs_async_unlink().
*/
static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
return -EPERM;
if (check_sticky(dir, inode) || IS_APPEND(inode) ||
- IS_IMMUTABLE(inode) || IS_SWAPFILE(inode))
+ IS_IMMUTABLE(inode) || IS_SWAPFILE(inode) || HAS_UNMAPPED_ID(inode))
return -EPERM;
if (isdir) {
if (!d_is_dir(victim))
* 1. We can't do it if child already exists (open has special treatment for
* this case, but since we are inlined it's OK)
* 2. We can't do it if dir is read-only (done in permission())
- * 3. We should have write and exec permissions on dir
- * 4. We can't do it if dir is immutable (done in permission())
+ * 3. We can't do it if the fs can't represent the fsuid or fsgid.
+ * 4. We should have write and exec permissions on dir
+ * 5. We can't do it if dir is immutable (done in permission())
*/
static inline int may_create(struct inode *dir, struct dentry *child)
{
+ struct user_namespace *s_user_ns;
audit_inode_child(dir, child, AUDIT_TYPE_CHILD_CREATE);
if (child->d_inode)
return -EEXIST;
if (IS_DEADDIR(dir))
return -ENOENT;
+ s_user_ns = dir->i_sb->s_user_ns;
+ if (!kuid_has_mapping(s_user_ns, current_fsuid()) ||
+ !kgid_has_mapping(s_user_ns, current_fsgid()))
+ return -EOVERFLOW;
return inode_permission(dir, MAY_WRITE | MAY_EXEC);
}
return NULL;
}
- mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex);
+ mutex_lock(&p1->d_sb->s_vfs_rename_mutex);
p = d_ancestor(p2, p1);
if (p) {
inode_unlock(p1->d_inode);
if (p1 != p2) {
inode_unlock(p2->d_inode);
- mutex_unlock(&p1->d_inode->i_sb->s_vfs_rename_mutex);
+ mutex_unlock(&p1->d_sb->s_vfs_rename_mutex);
}
}
EXPORT_SYMBOL(unlock_rename);
}
EXPORT_SYMBOL(vfs_create);
+bool may_open_dev(const struct path *path)
+{
+ return !(path->mnt->mnt_flags & MNT_NODEV) &&
+ !(path->mnt->mnt_sb->s_iflags & SB_I_NODEV);
+}
+
static int may_open(struct path *path, int acc_mode, int flag)
{
struct dentry *dentry = path->dentry;
break;
case S_IFBLK:
case S_IFCHR:
- if (path->mnt->mnt_flags & MNT_NODEV)
+ if (!may_open_dev(path))
return -EACCES;
/*FALLTHRU*/
case S_IFIFO:
return flag;
}
-static int may_o_create(struct path *dir, struct dentry *dentry, umode_t mode)
+static int may_o_create(const struct path *dir, struct dentry *dentry, umode_t mode)
{
int error = security_path_mknod(dir, dentry, mode, 0);
if (error)
static int atomic_open(struct nameidata *nd, struct dentry *dentry,
struct path *path, struct file *file,
const struct open_flags *op,
- bool got_write, bool need_lookup,
+ int open_flag, umode_t mode,
int *opened)
{
+ struct dentry *const DENTRY_NOT_SET = (void *) -1UL;
struct inode *dir = nd->path.dentry->d_inode;
- unsigned open_flag = open_to_namei_flags(op->open_flag);
- umode_t mode;
int error;
- int acc_mode;
- int create_error = 0;
- struct dentry *const DENTRY_NOT_SET = (void *) -1UL;
- bool excl;
-
- BUG_ON(dentry->d_inode);
-
- /* Don't create child dentry for a dead directory. */
- if (unlikely(IS_DEADDIR(dir))) {
- error = -ENOENT;
- goto out;
- }
-
- mode = op->mode;
- if ((open_flag & O_CREAT) && !IS_POSIXACL(dir))
- mode &= ~current_umask();
- excl = (open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT);
- if (excl)
+ if (!(~open_flag & (O_EXCL | O_CREAT))) /* both O_EXCL and O_CREAT */
open_flag &= ~O_TRUNC;
- /*
- * Checking write permission is tricky, bacuse we don't know if we are
- * going to actually need it: O_CREAT opens should work as long as the
- * file exists. But checking existence breaks atomicity. The trick is
- * to check access and if not granted clear O_CREAT from the flags.
- *
- * Another problem is returing the "right" error value (e.g. for an
- * O_EXCL open we want to return EEXIST not EROFS).
- */
- if (((open_flag & (O_CREAT | O_TRUNC)) ||
- (open_flag & O_ACCMODE) != O_RDONLY) && unlikely(!got_write)) {
- if (!(open_flag & O_CREAT)) {
- /*
- * No O_CREATE -> atomicity not a requirement -> fall
- * back to lookup + open
- */
- goto no_open;
- } else if (open_flag & (O_EXCL | O_TRUNC)) {
- /* Fall back and fail with the right error */
- create_error = -EROFS;
- goto no_open;
- } else {
- /* No side effects, safe to clear O_CREAT */
- create_error = -EROFS;
- open_flag &= ~O_CREAT;
- }
- }
-
- if (open_flag & O_CREAT) {
- error = may_o_create(&nd->path, dentry, mode);
- if (error) {
- create_error = error;
- if (open_flag & O_EXCL)
- goto no_open;
- open_flag &= ~O_CREAT;
- }
- }
-
if (nd->flags & LOOKUP_DIRECTORY)
open_flag |= O_DIRECTORY;
file->f_path.dentry = DENTRY_NOT_SET;
file->f_path.mnt = nd->path.mnt;
- error = dir->i_op->atomic_open(dir, dentry, file, open_flag, mode,
- opened);
- if (error < 0) {
- if (create_error && error == -ENOENT)
- error = create_error;
- goto out;
- }
-
- if (error) { /* returned 1, that is */
+ error = dir->i_op->atomic_open(dir, dentry, file,
+ open_to_namei_flags(open_flag),
+ mode, opened);
+ d_lookup_done(dentry);
+ if (!error) {
+ /*
+ * We didn't have the inode before the open, so check open
+ * permission here.
+ */
+ int acc_mode = op->acc_mode;
+ if (*opened & FILE_CREATED) {
+ WARN_ON(!(open_flag & O_CREAT));
+ fsnotify_create(dir, dentry);
+ acc_mode = 0;
+ }
+ error = may_open(&file->f_path, acc_mode, open_flag);
+ if (WARN_ON(error > 0))
+ error = -EINVAL;
+ } else if (error > 0) {
if (WARN_ON(file->f_path.dentry == DENTRY_NOT_SET)) {
error = -EIO;
- goto out;
- }
- if (file->f_path.dentry) {
- dput(dentry);
- dentry = file->f_path.dentry;
- }
- if (*opened & FILE_CREATED)
- fsnotify_create(dir, dentry);
- if (!dentry->d_inode) {
- WARN_ON(*opened & FILE_CREATED);
- if (create_error) {
- error = create_error;
- goto out;
- }
} else {
- if (excl && !(*opened & FILE_CREATED)) {
- error = -EEXIST;
- goto out;
+ if (file->f_path.dentry) {
+ dput(dentry);
+ dentry = file->f_path.dentry;
+ }
+ if (*opened & FILE_CREATED)
+ fsnotify_create(dir, dentry);
+ if (unlikely(d_is_negative(dentry))) {
+ error = -ENOENT;
+ } else {
+ path->dentry = dentry;
+ path->mnt = nd->path.mnt;
+ return 1;
}
}
- goto looked_up;
- }
-
- /*
- * We didn't have the inode before the open, so check open permission
- * here.
- */
- acc_mode = op->acc_mode;
- if (*opened & FILE_CREATED) {
- WARN_ON(!(open_flag & O_CREAT));
- fsnotify_create(dir, dentry);
- acc_mode = 0;
}
- error = may_open(&file->f_path, acc_mode, open_flag);
- if (error)
- fput(file);
-
-out:
dput(dentry);
return error;
-
-no_open:
- if (need_lookup) {
- dentry = lookup_real(dir, dentry, nd->flags);
- if (IS_ERR(dentry))
- return PTR_ERR(dentry);
- }
- if (create_error && !dentry->d_inode) {
- error = create_error;
- goto out;
- }
-looked_up:
- path->dentry = dentry;
- path->mnt = nd->path.mnt;
- return 1;
}
/*
{
struct dentry *dir = nd->path.dentry;
struct inode *dir_inode = dir->d_inode;
+ int open_flag = op->open_flag;
struct dentry *dentry;
- int error;
- bool need_lookup = false;
+ int error, create_error = 0;
+ umode_t mode = op->mode;
+ DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+
+ if (unlikely(IS_DEADDIR(dir_inode)))
+ return -ENOENT;
*opened &= ~FILE_CREATED;
- dentry = lookup_dcache(&nd->last, dir, nd->flags);
- if (IS_ERR(dentry))
- return PTR_ERR(dentry);
+ dentry = d_lookup(dir, &nd->last);
+ for (;;) {
+ if (!dentry) {
+ dentry = d_alloc_parallel(dir, &nd->last, &wq);
+ if (IS_ERR(dentry))
+ return PTR_ERR(dentry);
+ }
+ if (d_in_lookup(dentry))
+ break;
- if (!dentry) {
- dentry = d_alloc(dir, &nd->last);
- if (unlikely(!dentry))
- return -ENOMEM;
- need_lookup = true;
- } else if (dentry->d_inode) {
+ if (!(dentry->d_flags & DCACHE_OP_REVALIDATE))
+ break;
+
+ error = d_revalidate(dentry, nd->flags);
+ if (likely(error > 0))
+ break;
+ if (error)
+ goto out_dput;
+ d_invalidate(dentry);
+ dput(dentry);
+ dentry = NULL;
+ }
+ if (dentry->d_inode) {
/* Cached positive dentry: will open in f_op->open */
goto out_no_open;
}
- if ((nd->flags & LOOKUP_OPEN) && dir_inode->i_op->atomic_open) {
- return atomic_open(nd, dentry, path, file, op, got_write,
- need_lookup, opened);
+ /*
+ * Checking write permission is tricky, bacuse we don't know if we are
+ * going to actually need it: O_CREAT opens should work as long as the
+ * file exists. But checking existence breaks atomicity. The trick is
+ * to check access and if not granted clear O_CREAT from the flags.
+ *
+ * Another problem is returing the "right" error value (e.g. for an
+ * O_EXCL open we want to return EEXIST not EROFS).
+ */
+ if (open_flag & O_CREAT) {
+ if (!IS_POSIXACL(dir->d_inode))
+ mode &= ~current_umask();
+ if (unlikely(!got_write)) {
+ create_error = -EROFS;
+ open_flag &= ~O_CREAT;
+ if (open_flag & (O_EXCL | O_TRUNC))
+ goto no_open;
+ /* No side effects, safe to clear O_CREAT */
+ } else {
+ create_error = may_o_create(&nd->path, dentry, mode);
+ if (create_error) {
+ open_flag &= ~O_CREAT;
+ if (open_flag & O_EXCL)
+ goto no_open;
+ }
+ }
+ } else if ((open_flag & (O_TRUNC|O_WRONLY|O_RDWR)) &&
+ unlikely(!got_write)) {
+ /*
+ * No O_CREATE -> atomicity not a requirement -> fall
+ * back to lookup + open
+ */
+ goto no_open;
}
- if (need_lookup) {
- BUG_ON(dentry->d_inode);
+ if (dir_inode->i_op->atomic_open) {
+ error = atomic_open(nd, dentry, path, file, op, open_flag,
+ mode, opened);
+ if (unlikely(error == -ENOENT) && create_error)
+ error = create_error;
+ return error;
+ }
- dentry = lookup_real(dir_inode, dentry, nd->flags);
- if (IS_ERR(dentry))
- return PTR_ERR(dentry);
+no_open:
+ if (d_in_lookup(dentry)) {
+ struct dentry *res = dir_inode->i_op->lookup(dir_inode, dentry,
+ nd->flags);
+ d_lookup_done(dentry);
+ if (unlikely(res)) {
+ if (IS_ERR(res)) {
+ error = PTR_ERR(res);
+ goto out_dput;
+ }
+ dput(dentry);
+ dentry = res;
+ }
}
/* Negative dentry, just create the file */
- if (!dentry->d_inode && (op->open_flag & O_CREAT)) {
- umode_t mode = op->mode;
- if (!IS_POSIXACL(dir->d_inode))
- mode &= ~current_umask();
- /*
- * This write is needed to ensure that a
- * rw->ro transition does not occur between
- * the time when the file is created and when
- * a permanent write count is taken through
- * the 'struct file' in finish_open().
- */
- if (!got_write) {
- error = -EROFS;
- goto out_dput;
- }
+ if (!dentry->d_inode && (open_flag & O_CREAT)) {
*opened |= FILE_CREATED;
- error = security_path_mknod(&nd->path, dentry, mode, 0);
- if (error)
+ audit_inode_child(dir_inode, dentry, AUDIT_TYPE_CHILD_CREATE);
+ if (!dir_inode->i_op->create) {
+ error = -EACCES;
goto out_dput;
- error = vfs_create(dir->d_inode, dentry, mode,
- nd->flags & LOOKUP_EXCL);
+ }
+ error = dir_inode->i_op->create(dir_inode, dentry, mode,
+ open_flag & O_EXCL);
if (error)
goto out_dput;
+ fsnotify_create(dir_inode, dentry);
+ }
+ if (unlikely(create_error) && !dentry->d_inode) {
+ error = create_error;
+ goto out_dput;
}
out_no_open:
path->dentry = dentry;
int acc_mode = op->acc_mode;
unsigned seq;
struct inode *inode;
- struct path save_parent = { .dentry = NULL, .mnt = NULL };
struct path path;
- bool retried = false;
int error;
nd->flags &= ~LOOKUP_PARENT;
return -EISDIR;
}
-retry_lookup:
- if (op->open_flag & (O_CREAT | O_TRUNC | O_WRONLY | O_RDWR)) {
+ if (open_flag & (O_CREAT | O_TRUNC | O_WRONLY | O_RDWR)) {
error = mnt_want_write(nd->path.mnt);
if (!error)
got_write = true;
* dropping this one anyway.
*/
}
- inode_lock(dir->d_inode);
+ if (open_flag & O_CREAT)
+ inode_lock(dir->d_inode);
+ else
+ inode_lock_shared(dir->d_inode);
error = lookup_open(nd, &path, file, op, got_write, opened);
- inode_unlock(dir->d_inode);
+ if (open_flag & O_CREAT)
+ inode_unlock(dir->d_inode);
+ else
+ inode_unlock_shared(dir->d_inode);
if (error <= 0) {
if (error)
got_write = false;
}
+ error = follow_managed(&path, nd);
+ if (unlikely(error < 0))
+ return error;
+
if (unlikely(d_is_negative(path.dentry))) {
path_to_nameidata(&path, nd);
return -ENOENT;
return -EEXIST;
}
- error = follow_managed(&path, nd);
- if (unlikely(error < 0))
- return error;
-
seq = 0; /* out of RCU mode, so the value doesn't matter */
inode = d_backing_inode(path.dentry);
finish_lookup:
if (unlikely(error))
return error;
- if ((nd->flags & LOOKUP_RCU) || nd->path.mnt != path.mnt) {
- path_to_nameidata(&path, nd);
- } else {
- save_parent.dentry = nd->path.dentry;
- save_parent.mnt = mntget(path.mnt);
- nd->path.dentry = path.dentry;
-
- }
+ path_to_nameidata(&path, nd);
nd->inode = inode;
nd->seq = seq;
/* Why this, you ask? _Now_ we might have grown LOOKUP_JUMPED... */
finish_open:
error = complete_walk(nd);
- if (error) {
- path_put(&save_parent);
+ if (error)
return error;
- }
audit_inode(nd->name, nd->path.dentry, 0);
- if (unlikely(d_is_symlink(nd->path.dentry)) && !(open_flag & O_PATH)) {
- error = -ELOOP;
- goto out;
- }
error = -EISDIR;
if ((open_flag & O_CREAT) && d_is_dir(nd->path.dentry))
goto out;
got_write = true;
}
finish_open_created:
- if (likely(!(open_flag & O_PATH))) {
- error = may_open(&nd->path, acc_mode, open_flag);
- if (error)
- goto out;
- }
+ error = may_open(&nd->path, acc_mode, open_flag);
+ if (error)
+ goto out;
BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
error = vfs_open(&nd->path, file, current_cred());
- if (!error) {
- *opened |= FILE_OPENED;
- } else {
- if (error == -EOPENSTALE)
- goto stale_open;
+ if (error)
goto out;
- }
+ *opened |= FILE_OPENED;
opened:
error = open_check_o_direct(file);
- if (error)
- goto exit_fput;
- error = ima_file_check(file, op->acc_mode, *opened);
- if (error)
- goto exit_fput;
-
- if (will_truncate) {
+ if (!error)
+ error = ima_file_check(file, op->acc_mode, *opened);
+ if (!error && will_truncate)
error = handle_truncate(file);
- if (error)
- goto exit_fput;
- }
out:
+ if (unlikely(error) && (*opened & FILE_OPENED))
+ fput(file);
if (unlikely(error > 0)) {
WARN_ON(1);
error = -EINVAL;
}
if (got_write)
mnt_drop_write(nd->path.mnt);
- path_put(&save_parent);
return error;
-
-exit_fput:
- fput(file);
- goto out;
-
-stale_open:
- /* If no saved parent or already retried then can't retry */
- if (!save_parent.dentry || retried)
- goto out;
-
- BUG_ON(save_parent.dentry != dir);
- path_put(&nd->path);
- nd->path = save_parent;
- nd->inode = dir->d_inode;
- save_parent.mnt = NULL;
- save_parent.dentry = NULL;
- if (got_write) {
- mnt_drop_write(nd->path.mnt);
- got_write = false;
- }
- retried = true;
- goto retry_lookup;
}
static int do_tmpfile(struct nameidata *nd, unsigned flags,
return error;
}
+static int do_o_path(struct nameidata *nd, unsigned flags, struct file *file)
+{
+ struct path path;
+ int error = path_lookupat(nd, flags, &path);
+ if (!error) {
+ audit_inode(nd->name, path.dentry, 0);
+ error = vfs_open(&path, file, current_cred());
+ path_put(&path);
+ }
+ return error;
+}
+
static struct file *path_openat(struct nameidata *nd,
const struct open_flags *op, unsigned flags)
{
goto out2;
}
+ if (unlikely(file->f_flags & O_PATH)) {
+ error = do_o_path(nd, flags, file);
+ if (!error)
+ opened |= FILE_OPENED;
+ goto out2;
+ }
+
s = path_init(nd, flags);
if (IS_ERR(s)) {
put_filp(file);
switch (mode & S_IFMT) {
case 0: case S_IFREG:
error = vfs_create(path.dentry->d_inode,dentry,mode,true);
+ if (!error)
+ ima_post_path_mknod(dentry);
break;
case S_IFCHR: case S_IFBLK:
error = vfs_mknod(path.dentry->d_inode,dentry,mode,
*/
if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
return -EPERM;
+ /*
+ * Updating the link count will likely cause i_uid and i_gid to
+ * be writen back improperly if their true value is unknown to
+ * the vfs.
+ */
+ if (HAS_UNMAPPED_ID(inode))
+ return -EPERM;
if (!dir->i_op->link)
return -EPERM;
if (S_ISDIR(inode->i_mode))
* Check source == target.
* On overlayfs need to look at underlying inodes.
*/
- if (vfs_select_inode(old_dentry, 0) == vfs_select_inode(new_dentry, 0))
+ if (d_real_inode(old_dentry) == d_real_inode(new_dentry))
return 0;
error = may_delete(old_dir, old_dentry, is_dir);
out:
return len;
}
-EXPORT_SYMBOL(readlink_copy);
/*
* A helper for ->readlink(). This should be used *ONLY* for symlinks that
projects / linux-2.6-microblaze.git / blobdiff