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Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c197
1 files changed, 115 insertions, 82 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 734f2b5591bf..199317642ad6 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -227,6 +227,16 @@ 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;
@@ -248,8 +258,7 @@ 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);
@@ -266,21 +275,6 @@ 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)
@@ -290,7 +284,7 @@ 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)
{
@@ -439,7 +433,7 @@ 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)
@@ -528,18 +522,6 @@ 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.
@@ -577,9 +559,16 @@ 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;
@@ -860,7 +849,8 @@ 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)
err = ima_path_check(&nd->path, MAY_EXEC);
if (err)
@@ -921,9 +911,6 @@ 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);
@@ -933,9 +920,6 @@ 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;
@@ -974,7 +958,7 @@ 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;
@@ -986,7 +970,7 @@ 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;
@@ -1482,7 +1466,7 @@ 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;
@@ -1496,9 +1480,9 @@ 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;
@@ -1519,17 +1503,17 @@ 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;
- error = ima_path_check(&nd->path,
+ error = ima_path_check(path,
acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC));
if (error)
return error;
@@ -1564,6 +1548,9 @@ 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);
@@ -1594,14 +1581,18 @@ 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);
}
/*
@@ -1763,7 +1754,7 @@ 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);
@@ -1787,7 +1778,7 @@ 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);
@@ -1944,7 +1935,7 @@ 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);
@@ -1979,8 +1970,8 @@ static int may_mknod(mode_t mode)
}
}
-asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode,
- unsigned dev)
+SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, int, mode,
+ unsigned, dev)
{
int error;
char *tmp;
@@ -2007,6 +1998,9 @@ 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);
@@ -2019,6 +2013,7 @@ 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);
@@ -2030,7 +2025,7 @@ out_unlock:
return error;
}
-asmlinkage long sys_mknod(const char __user *filename, int mode, unsigned dev)
+SYSCALL_DEFINE3(mknod, const char __user *, filename, int, mode, unsigned, dev)
{
return sys_mknodat(AT_FDCWD, filename, mode, dev);
}
@@ -2042,7 +2037,7 @@ 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);
@@ -2057,7 +2052,7 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
return error;
}
-asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode)
+SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, int, mode)
{
int error = 0;
char * tmp;
@@ -2078,7 +2073,11 @@ 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);
@@ -2090,7 +2089,7 @@ out_err:
return error;
}
-asmlinkage long sys_mkdir(const char __user *pathname, int mode)
+SYSCALL_DEFINE2(mkdir, const char __user *, pathname, int, mode)
{
return sys_mkdirat(AT_FDCWD, pathname, mode);
}
@@ -2129,7 +2128,7 @@ 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);
@@ -2188,7 +2187,11 @@ 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);
@@ -2200,7 +2203,7 @@ exit1:
return error;
}
-asmlinkage long sys_rmdir(const char __user *pathname)
+SYSCALL_DEFINE1(rmdir, const char __user *, pathname)
{
return do_rmdir(AT_FDCWD, pathname);
}
@@ -2212,7 +2215,7 @@ 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);
@@ -2273,7 +2276,11 @@ 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);
@@ -2292,7 +2299,7 @@ slashes:
goto exit2;
}
-asmlinkage long sys_unlinkat(int dfd, const char __user *pathname, int flag)
+SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag)
{
if ((flag & ~AT_REMOVEDIR) != 0)
return -EINVAL;
@@ -2303,7 +2310,7 @@ asmlinkage long sys_unlinkat(int dfd, const char __user *pathname, int flag)
return do_unlinkat(dfd, pathname);
}
-asmlinkage long sys_unlink(const char __user *pathname)
+SYSCALL_DEFINE1(unlink, const char __user *, pathname)
{
return do_unlinkat(AT_FDCWD, pathname);
}
@@ -2315,7 +2322,7 @@ 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);
@@ -2329,8 +2336,8 @@ int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
return error;
}
-asmlinkage long sys_symlinkat(const char __user *oldname,
- int newdfd, const char __user *newname)
+SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
+ int, newdfd, const char __user *, newname)
{
int error;
char *from;
@@ -2354,7 +2361,11 @@ 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);
@@ -2367,7 +2378,7 @@ out_putname:
return error;
}
-asmlinkage long sys_symlink(const char __user *oldname, const char __user *newname)
+SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname)
{
return sys_symlinkat(oldname, AT_FDCWD, newname);
}
@@ -2392,7 +2403,7 @@ 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;
@@ -2419,9 +2430,8 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
* with linux 2.0, and to avoid hard-linking to directories
* and other special files. --ADM
*/
-asmlinkage long sys_linkat(int olddfd, const char __user *oldname,
- int newdfd, const char __user *newname,
- int flags)
+SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
+ int, newdfd, const char __user *, newname, int, flags)
{
struct dentry *new_dentry;
struct nameidata nd;
@@ -2451,7 +2461,11 @@ 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);
@@ -2466,7 +2480,7 @@ out:
return error;
}
-asmlinkage long sys_link(const char __user *oldname, const char __user *newname)
+SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname)
{
return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
}
@@ -2595,7 +2609,7 @@ 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);
@@ -2617,8 +2631,8 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
return error;
}
-asmlinkage long sys_renameat(int olddfd, const char __user *oldname,
- int newdfd, const char __user *newname)
+SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
+ int, newdfd, const char __user *, newname)
{
struct dentry *old_dir, *new_dir;
struct dentry *old_dentry, *new_dentry;
@@ -2687,8 +2701,13 @@ 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);
@@ -2706,7 +2725,7 @@ exit:
return error;
}
-asmlinkage long sys_rename(const char __user *oldname, const char __user *newname)
+SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname)
{
return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname);
}
@@ -2758,13 +2777,16 @@ 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)
@@ -2796,18 +2818,23 @@ 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;
@@ -2831,7 +2858,7 @@ 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 = {
@@ -2857,7 +2884,6 @@ 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);
@@ -2873,3 +2899,10 @@ 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 (git 2.0.4) at 2024-11-05 03:26:17 +0000