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Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c160
1 files changed, 97 insertions, 63 deletions
diff --git a/fs/namei.c b/fs/namei.c
index af3783fff1d..f05bed24242 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -226,6 +226,16 @@ int generic_permission(struct inode *inode, int mask,
return -EACCES;
}
+/**
+ * inode_permission - check for access rights to a given inode
+ * @inode: inode to check permission on
+ * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
+ *
+ * Used to check for read/write/execute permissions on an inode.
+ * We use "fsuid" for this, letting us set arbitrary permissions
+ * for filesystem access without changing the "normal" uids which
+ * are used for other things.
+ */
int inode_permission(struct inode *inode, int mask)
{
int retval;
@@ -247,8 +257,7 @@ int inode_permission(struct inode *inode, int mask)
return -EACCES;
}
- /* Ordinary permission routines do not understand MAY_APPEND. */
- if (inode->i_op && inode->i_op->permission)
+ if (inode->i_op->permission)
retval = inode->i_op->permission(inode, mask);
else
retval = generic_permission(inode, mask, NULL);
@@ -265,21 +274,6 @@ int inode_permission(struct inode *inode, int mask)
}
/**
- * vfs_permission - check for access rights to a given path
- * @nd: lookup result that describes the path
- * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
- *
- * Used to check for read/write/execute permissions on a path.
- * We use "fsuid" for this, letting us set arbitrary permissions
- * for filesystem access without changing the "normal" uids which
- * are used for other things.
- */
-int vfs_permission(struct nameidata *nd, int mask)
-{
- return inode_permission(nd->path.dentry->d_inode, mask);
-}
-
-/**
* file_permission - check for additional access rights to a given file
* @file: file to check access rights for
* @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
@@ -289,7 +283,7 @@ int vfs_permission(struct nameidata *nd, int mask)
*
* Note:
* Do not use this function in new code. All access checks should
- * be done using vfs_permission().
+ * be done using inode_permission().
*/
int file_permission(struct file *file, int mask)
{
@@ -438,7 +432,7 @@ static int exec_permission_lite(struct inode *inode)
{
umode_t mode = inode->i_mode;
- if (inode->i_op && inode->i_op->permission)
+ if (inode->i_op->permission)
return -EAGAIN;
if (current_fsuid() == inode->i_uid)
@@ -527,18 +521,6 @@ out_unlock:
return result;
}
-/* SMP-safe */
-static __always_inline void
-walk_init_root(const char *name, struct nameidata *nd)
-{
- struct fs_struct *fs = current->fs;
-
- read_lock(&fs->lock);
- nd->path = fs->root;
- path_get(&fs->root);
- read_unlock(&fs->lock);
-}
-
/*
* Wrapper to retry pathname resolution whenever the underlying
* file system returns an ESTALE.
@@ -576,9 +558,16 @@ static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *l
goto fail;
if (*link == '/') {
+ struct fs_struct *fs = current->fs;
+
path_put(&nd->path);
- walk_init_root(link, nd);
+
+ read_lock(&fs->lock);
+ nd->path = fs->root;
+ path_get(&fs->root);
+ read_unlock(&fs->lock);
}
+
res = link_path_walk(link, nd);
if (nd->depth || res || nd->last_type!=LAST_NORM)
return res;
@@ -859,7 +848,8 @@ static int __link_path_walk(const char *name, struct nameidata *nd)
nd->flags |= LOOKUP_CONTINUE;
err = exec_permission_lite(inode);
if (err == -EAGAIN)
- err = vfs_permission(nd, MAY_EXEC);
+ err = inode_permission(nd->path.dentry->d_inode,
+ MAY_EXEC);
if (err)
break;
@@ -918,9 +908,6 @@ static int __link_path_walk(const char *name, struct nameidata *nd)
inode = next.dentry->d_inode;
if (!inode)
goto out_dput;
- err = -ENOTDIR;
- if (!inode->i_op)
- goto out_dput;
if (inode->i_op->follow_link) {
err = do_follow_link(&next, nd);
@@ -930,9 +917,6 @@ static int __link_path_walk(const char *name, struct nameidata *nd)
inode = nd->path.dentry->d_inode;
if (!inode)
break;
- err = -ENOTDIR;
- if (!inode->i_op)
- break;
} else
path_to_nameidata(&next, nd);
err = -ENOTDIR;
@@ -971,7 +955,7 @@ last_component:
break;
inode = next.dentry->d_inode;
if ((lookup_flags & LOOKUP_FOLLOW)
- && inode && inode->i_op && inode->i_op->follow_link) {
+ && inode && inode->i_op->follow_link) {
err = do_follow_link(&next, nd);
if (err)
goto return_err;
@@ -983,7 +967,7 @@ last_component:
break;
if (lookup_flags & LOOKUP_DIRECTORY) {
err = -ENOTDIR;
- if (!inode->i_op || !inode->i_op->lookup)
+ if (!inode->i_op->lookup)
break;
}
goto return_base;
@@ -1479,7 +1463,7 @@ int vfs_create(struct inode *dir, struct dentry *dentry, int mode,
if (error)
return error;
- if (!dir->i_op || !dir->i_op->create)
+ if (!dir->i_op->create)
return -EACCES; /* shouldn't it be ENOSYS? */
mode &= S_IALLUGO;
mode |= S_IFREG;
@@ -1493,9 +1477,9 @@ int vfs_create(struct inode *dir, struct dentry *dentry, int mode,
return error;
}
-int may_open(struct nameidata *nd, int acc_mode, int flag)
+int may_open(struct path *path, int acc_mode, int flag)
{
- struct dentry *dentry = nd->path.dentry;
+ struct dentry *dentry = path->dentry;
struct inode *inode = dentry->d_inode;
int error;
@@ -1516,13 +1500,13 @@ int may_open(struct nameidata *nd, int acc_mode, int flag)
if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
flag &= ~O_TRUNC;
} else if (S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode)) {
- if (nd->path.mnt->mnt_flags & MNT_NODEV)
+ if (path->mnt->mnt_flags & MNT_NODEV)
return -EACCES;
flag &= ~O_TRUNC;
}
- error = vfs_permission(nd, acc_mode);
+ error = inode_permission(inode, acc_mode);
if (error)
return error;
/*
@@ -1556,6 +1540,9 @@ int may_open(struct nameidata *nd, int acc_mode, int flag)
* Refuse to truncate files with mandatory locks held on them.
*/
error = locks_verify_locked(inode);
+ if (!error)
+ error = security_path_truncate(path, 0,
+ ATTR_MTIME|ATTR_CTIME|ATTR_OPEN);
if (!error) {
DQUOT_INIT(inode);
@@ -1586,14 +1573,18 @@ static int __open_namei_create(struct nameidata *nd, struct path *path,
if (!IS_POSIXACL(dir->d_inode))
mode &= ~current->fs->umask;
+ error = security_path_mknod(&nd->path, path->dentry, mode, 0);
+ if (error)
+ goto out_unlock;
error = vfs_create(dir->d_inode, path->dentry, mode, nd);
+out_unlock:
mutex_unlock(&dir->d_inode->i_mutex);
dput(nd->path.dentry);
nd->path.dentry = path->dentry;
if (error)
return error;
/* Don't check for write permission, don't truncate */
- return may_open(nd, 0, flag & ~O_TRUNC);
+ return may_open(&nd->path, 0, flag & ~O_TRUNC);
}
/*
@@ -1755,7 +1746,7 @@ do_last:
error = -ENOENT;
if (!path.dentry->d_inode)
goto exit_dput;
- if (path.dentry->d_inode->i_op && path.dentry->d_inode->i_op->follow_link)
+ if (path.dentry->d_inode->i_op->follow_link)
goto do_link;
path_to_nameidata(&path, &nd);
@@ -1779,7 +1770,7 @@ ok:
if (error)
goto exit;
}
- error = may_open(&nd, acc_mode, flag);
+ error = may_open(&nd.path, acc_mode, flag);
if (error) {
if (will_write)
mnt_drop_write(nd.path.mnt);
@@ -1936,7 +1927,7 @@ int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD))
return -EPERM;
- if (!dir->i_op || !dir->i_op->mknod)
+ if (!dir->i_op->mknod)
return -EPERM;
error = devcgroup_inode_mknod(mode, dev);
@@ -1999,6 +1990,9 @@ asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode,
error = mnt_want_write(nd.path.mnt);
if (error)
goto out_dput;
+ error = security_path_mknod(&nd.path, dentry, mode, dev);
+ if (error)
+ goto out_drop_write;
switch (mode & S_IFMT) {
case 0: case S_IFREG:
error = vfs_create(nd.path.dentry->d_inode,dentry,mode,&nd);
@@ -2011,6 +2005,7 @@ asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode,
error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0);
break;
}
+out_drop_write:
mnt_drop_write(nd.path.mnt);
out_dput:
dput(dentry);
@@ -2034,7 +2029,7 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
if (error)
return error;
- if (!dir->i_op || !dir->i_op->mkdir)
+ if (!dir->i_op->mkdir)
return -EPERM;
mode &= (S_IRWXUGO|S_ISVTX);
@@ -2070,7 +2065,11 @@ asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode)
error = mnt_want_write(nd.path.mnt);
if (error)
goto out_dput;
+ error = security_path_mkdir(&nd.path, dentry, mode);
+ if (error)
+ goto out_drop_write;
error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode);
+out_drop_write:
mnt_drop_write(nd.path.mnt);
out_dput:
dput(dentry);
@@ -2121,7 +2120,7 @@ int vfs_rmdir(struct inode *dir, struct dentry *dentry)
if (error)
return error;
- if (!dir->i_op || !dir->i_op->rmdir)
+ if (!dir->i_op->rmdir)
return -EPERM;
DQUOT_INIT(dir);
@@ -2180,7 +2179,11 @@ static long do_rmdir(int dfd, const char __user *pathname)
error = mnt_want_write(nd.path.mnt);
if (error)
goto exit3;
+ error = security_path_rmdir(&nd.path, dentry);
+ if (error)
+ goto exit4;
error = vfs_rmdir(nd.path.dentry->d_inode, dentry);
+exit4:
mnt_drop_write(nd.path.mnt);
exit3:
dput(dentry);
@@ -2204,7 +2207,7 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry)
if (error)
return error;
- if (!dir->i_op || !dir->i_op->unlink)
+ if (!dir->i_op->unlink)
return -EPERM;
DQUOT_INIT(dir);
@@ -2265,7 +2268,11 @@ static long do_unlinkat(int dfd, const char __user *pathname)
error = mnt_want_write(nd.path.mnt);
if (error)
goto exit2;
+ error = security_path_unlink(&nd.path, dentry);
+ if (error)
+ goto exit3;
error = vfs_unlink(nd.path.dentry->d_inode, dentry);
+exit3:
mnt_drop_write(nd.path.mnt);
exit2:
dput(dentry);
@@ -2307,7 +2314,7 @@ int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
if (error)
return error;
- if (!dir->i_op || !dir->i_op->symlink)
+ if (!dir->i_op->symlink)
return -EPERM;
error = security_inode_symlink(dir, dentry, oldname);
@@ -2346,7 +2353,11 @@ asmlinkage long sys_symlinkat(const char __user *oldname,
error = mnt_want_write(nd.path.mnt);
if (error)
goto out_dput;
+ error = security_path_symlink(&nd.path, dentry, from);
+ if (error)
+ goto out_drop_write;
error = vfs_symlink(nd.path.dentry->d_inode, dentry, from);
+out_drop_write:
mnt_drop_write(nd.path.mnt);
out_dput:
dput(dentry);
@@ -2384,7 +2395,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
*/
if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
return -EPERM;
- if (!dir->i_op || !dir->i_op->link)
+ if (!dir->i_op->link)
return -EPERM;
if (S_ISDIR(inode->i_mode))
return -EPERM;
@@ -2443,7 +2454,11 @@ asmlinkage long sys_linkat(int olddfd, const char __user *oldname,
error = mnt_want_write(nd.path.mnt);
if (error)
goto out_dput;
+ error = security_path_link(old_path.dentry, &nd.path, new_dentry);
+ if (error)
+ goto out_drop_write;
error = vfs_link(old_path.dentry, nd.path.dentry->d_inode, new_dentry);
+out_drop_write:
mnt_drop_write(nd.path.mnt);
out_dput:
dput(new_dentry);
@@ -2587,7 +2602,7 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
if (error)
return error;
- if (!old_dir->i_op || !old_dir->i_op->rename)
+ if (!old_dir->i_op->rename)
return -EPERM;
DQUOT_INIT(old_dir);
@@ -2679,8 +2694,13 @@ asmlinkage long sys_renameat(int olddfd, const char __user *oldname,
error = mnt_want_write(oldnd.path.mnt);
if (error)
goto exit5;
+ error = security_path_rename(&oldnd.path, old_dentry,
+ &newnd.path, new_dentry);
+ if (error)
+ goto exit6;
error = vfs_rename(old_dir->d_inode, old_dentry,
new_dir->d_inode, new_dentry);
+exit6:
mnt_drop_write(oldnd.path.mnt);
exit5:
dput(new_dentry);
@@ -2750,13 +2770,16 @@ int vfs_follow_link(struct nameidata *nd, const char *link)
/* get the link contents into pagecache */
static char *page_getlink(struct dentry * dentry, struct page **ppage)
{
- struct page * page;
+ char *kaddr;
+ struct page *page;
struct address_space *mapping = dentry->d_inode->i_mapping;
page = read_mapping_page(mapping, 0, NULL);
if (IS_ERR(page))
return (char*)page;
*ppage = page;
- return kmap(page);
+ kaddr = kmap(page);
+ nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1);
+ return kaddr;
}
int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)
@@ -2788,18 +2811,23 @@ void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
}
}
-int __page_symlink(struct inode *inode, const char *symname, int len,
- gfp_t gfp_mask)
+/*
+ * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS
+ */
+int __page_symlink(struct inode *inode, const char *symname, int len, int nofs)
{
struct address_space *mapping = inode->i_mapping;
struct page *page;
void *fsdata;
int err;
char *kaddr;
+ unsigned int flags = AOP_FLAG_UNINTERRUPTIBLE;
+ if (nofs)
+ flags |= AOP_FLAG_NOFS;
retry:
err = pagecache_write_begin(NULL, mapping, 0, len-1,
- AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata);
+ flags, &page, &fsdata);
if (err)
goto fail;
@@ -2823,7 +2851,7 @@ fail:
int page_symlink(struct inode *inode, const char *symname, int len)
{
return __page_symlink(inode, symname, len,
- mapping_gfp_mask(inode->i_mapping));
+ !(mapping_gfp_mask(inode->i_mapping) & __GFP_FS));
}
const struct inode_operations page_symlink_inode_operations = {
@@ -2849,7 +2877,6 @@ EXPORT_SYMBOL(path_lookup);
EXPORT_SYMBOL(kern_path);
EXPORT_SYMBOL(vfs_path_lookup);
EXPORT_SYMBOL(inode_permission);
-EXPORT_SYMBOL(vfs_permission);
EXPORT_SYMBOL(file_permission);
EXPORT_SYMBOL(unlock_rename);
EXPORT_SYMBOL(vfs_create);
@@ -2865,3 +2892,10 @@ EXPORT_SYMBOL(vfs_symlink);
EXPORT_SYMBOL(vfs_unlink);
EXPORT_SYMBOL(dentry_unhash);
EXPORT_SYMBOL(generic_readlink);
+
+/* to be mentioned only in INIT_TASK */
+struct fs_struct init_fs = {
+ .count = ATOMIC_INIT(1),
+ .lock = __RW_LOCK_UNLOCKED(init_fs.lock),
+ .umask = 0022,
+};
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-01-02 06:37:01 +0000