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authorDave Hansen <haveblue@us.ibm.com>2008-02-15 14:37:57 -0800
committerAl Viro <viro@zeniv.linux.org.uk>2008-04-19 00:25:34 -0400
commit463c3197263bd26ac59a00d2484990e17e35c50e (patch)
treeb27c04f978ccd447ae33f7387b6a4aba0033acc5 /fs/namei.c
parent0622753b800e4cc6cb9319b36b27658c72dd7cdc (diff)
downloadlinux-463c3197263bd26ac59a00d2484990e17e35c50e.tar.bz2
[PATCH] r/o bind mounts: get callers of vfs_mknod/create/mkdir()
This takes care of all of the direct callers of vfs_mknod(). Since a few of these cases also handle normal file creation as well, this also covers some calls to vfs_create(). So that we don't have to make three mnt_want/drop_write() calls inside of the switch statement, we move some of its logic outside of the switch and into a helper function suggested by Christoph. This also encapsulates a fix for mknod(S_IFREG) that Miklos found. [AV: merged mkdir handling, added missing nfsd pieces] Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c48
1 files changed, 37 insertions, 11 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 89ef3178eaaa..3fbcf2021a2e 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1984,6 +1984,23 @@ int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
return error;
}
+static int may_mknod(mode_t mode)
+{
+ switch (mode & S_IFMT) {
+ case S_IFREG:
+ case S_IFCHR:
+ case S_IFBLK:
+ case S_IFIFO:
+ case S_IFSOCK:
+ case 0: /* zero mode translates to S_IFREG */
+ return 0;
+ case S_IFDIR:
+ return -EPERM;
+ default:
+ return -EINVAL;
+ }
+}
+
asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode,
unsigned dev)
{
@@ -2002,12 +2019,19 @@ asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode,
if (error)
goto out;
dentry = lookup_create(&nd, 0);
- error = PTR_ERR(dentry);
-
+ if (IS_ERR(dentry)) {
+ error = PTR_ERR(dentry);
+ goto out_unlock;
+ }
if (!IS_POSIXACL(nd.path.dentry->d_inode))
mode &= ~current->fs->umask;
- if (!IS_ERR(dentry)) {
- switch (mode & S_IFMT) {
+ error = may_mknod(mode);
+ if (error)
+ goto out_dput;
+ error = mnt_want_write(nd.path.mnt);
+ if (error)
+ goto out_dput;
+ switch (mode & S_IFMT) {
case 0: case S_IFREG:
error = vfs_create(nd.path.dentry->d_inode,dentry,mode,&nd);
break;
@@ -2018,14 +2042,11 @@ asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode,
case S_IFIFO: case S_IFSOCK:
error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0);
break;
- case S_IFDIR:
- error = -EPERM;
- break;
- default:
- error = -EINVAL;
- }
- dput(dentry);
}
+ mnt_drop_write(nd.path.mnt);
+out_dput:
+ dput(dentry);
+out_unlock:
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
path_put(&nd.path);
out:
@@ -2083,7 +2104,12 @@ asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode)
if (!IS_POSIXACL(nd.path.dentry->d_inode))
mode &= ~current->fs->umask;
+ error = mnt_want_write(nd.path.mnt);
+ if (error)
+ goto out_dput;
error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode);
+ mnt_drop_write(nd.path.mnt);
+out_dput:
dput(dentry);
out_unlock:
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);