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[PATCH] r/o bind mounts: prepare for write access checks: collapse if()

Browse source 
We're shortly going to be adding a bunch more permission checks in these
functions.  That requires adding either a bunch of new if() conditions, or
some gotos.  This patch collapses existing if()s and uses gotos instead to
prepare for the upcoming changes.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Dave Hansen 2006-09-30 23:29:01 -07:00 committed by Linus Torvalds
parent db5fed26b2
commit 6902d925d5
2 changed files with 87 additions and 70 deletions
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41
fs/namei.c
View file

@ -1934,30 +1934,32 @@ asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode)
{
int error = 0;
char * tmp;
struct dentry *dentry;
struct nameidata nd;
tmp = getname(pathname);
error = PTR_ERR(tmp);
if (!IS_ERR(tmp)) {
struct dentry *dentry;
struct nameidata nd;
if (IS_ERR(tmp))
goto out_err;
error = do_path_lookup(dfd, tmp, LOOKUP_PARENT, &nd);
if (error)
goto out;
dentry = lookup_create(&nd, 1);
error = PTR_ERR(dentry);
if (!IS_ERR(dentry)) {
if (IS_ERR(dentry))
goto out_unlock;
if (!IS_POSIXACL(nd.dentry->d_inode))
mode &= ~current->fs->umask;
error = vfs_mkdir(nd.dentry->d_inode, dentry, mode);
dput(dentry);
}
out_unlock:
mutex_unlock(&nd.dentry->d_inode->i_mutex);
path_release(&nd);
out:
putname(tmp);
}
out_err:
return error;
}
@ -2056,10 +2058,11 @@ static long do_rmdir(int dfd, const char __user *pathname)
mutex_lock_nested(&nd.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
dentry = lookup_hash(&nd);
error = PTR_ERR(dentry);
if (!IS_ERR(dentry)) {
if (IS_ERR(dentry))
goto exit2;
error = vfs_rmdir(nd.dentry->d_inode, dentry);
dput(dentry);
}
exit2:
mutex_unlock(&nd.dentry->d_inode->i_mutex);
exit1:
path_release(&nd);
@ -2199,30 +2202,33 @@ asmlinkage long sys_symlinkat(const char __user *oldname,
int error = 0;
char * from;
char * to;
struct dentry *dentry;
struct nameidata nd;
from = getname(oldname);
if(IS_ERR(from))
return PTR_ERR(from);
to = getname(newname);
error = PTR_ERR(to);
if (!IS_ERR(to)) {
struct dentry *dentry;
struct nameidata nd;
if (IS_ERR(to))
goto out_putname;
error = do_path_lookup(newdfd, to, LOOKUP_PARENT, &nd);
if (error)
goto out;
dentry = lookup_create(&nd, 0);
error = PTR_ERR(dentry);
if (!IS_ERR(dentry)) {
if (IS_ERR(dentry))
goto out_unlock;
error = vfs_symlink(nd.dentry->d_inode, dentry, from, S_IALLUGO);
dput(dentry);
}
out_unlock:
mutex_unlock(&nd.dentry->d_inode->i_mutex);
path_release(&nd);
out:
putname(to);
}
out_putname:
putname(from);
return error;
}
@ -2308,10 +2314,11 @@ asmlinkage long sys_linkat(int olddfd, const char __user *oldname,
goto out_release;
new_dentry = lookup_create(&nd, 0);
error = PTR_ERR(new_dentry);
if (!IS_ERR(new_dentry)) {
if (IS_ERR(new_dentry))
goto out_unlock;
error = vfs_link(old_nd.dentry, nd.dentry->d_inode, new_dentry);
dput(new_dentry);
}
out_unlock:
mutex_unlock(&nd.dentry->d_inode->i_mutex);
out_release:
path_release(&nd);

40
fs/open.c
View file

@ -386,15 +386,21 @@ asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
current->cap_effective = current->cap_permitted;
res = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW|LOOKUP_ACCESS, &nd);
if (!res) {
if (res)
goto out;
res = vfs_permission(&nd, mode);
/* SuS v2 requires we report a read only fs too */
if(!res && (mode & S_IWOTH) && IS_RDONLY(nd.dentry->d_inode)
&& !special_file(nd.dentry->d_inode->i_mode))
res = -EROFS;
path_release(&nd);
}
if(res || !(mode & S_IWOTH) ||
special_file(nd.dentry->d_inode->i_mode))
goto out_path_release;
if(IS_RDONLY(nd.dentry->d_inode))
res = -EROFS;
out_path_release:
path_release(&nd);
out:
current->fsuid = old_fsuid;
current->fsgid = old_fsgid;
current->cap_effective = old_cap;
@ -603,10 +609,11 @@ asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group)
int error;
error = user_path_walk(filename, &nd);
if (!error) {
if (error)
goto out;
error = chown_common(nd.dentry, user, group);
path_release(&nd);
}
out:
return error;
}
@ -622,10 +629,10 @@ asmlinkage long sys_fchownat(int dfd, const char __user *filename, uid_t user,
follow = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
error = __user_walk_fd(dfd, filename, follow, &nd);
if (!error) {
if (error)
goto out;
error = chown_common(nd.dentry, user, group);
path_release(&nd);
}
out:
return error;
}
@ -636,10 +643,11 @@ asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group
int error;
error = user_path_walk_link(filename, &nd);
if (!error) {
if (error)
goto out;
error = chown_common(nd.dentry, user, group);
path_release(&nd);
}
out:
return error;
}
@ -648,15 +656,17 @@ asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group)
{
struct file * file;
int error = -EBADF;
struct dentry * dentry;
file = fget(fd);
if (file) {
struct dentry * dentry;
if (!file)
goto out;
dentry = file->f_dentry;
audit_inode(NULL, dentry->d_inode);
error = chown_common(dentry, user, group);
fput(file);
}
out:
return error;
}