[PATCH -V4 08/11] vfs: Add new file and directory create permission flags
From: Aneesh Kumar K.V <hidden>
Date: 2010-09-24 12:48:11
Also in:
linux-fsdevel, lkml
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
From: Andreas Gruenbacher <redacted> Some permission models distinguish between the permission to create a non-directory and a directory. Pass this information down to inode_permission() as mask flags Signed-off-by: Andreas Gruenbacher <redacted> Signed-off-by: Aneesh Kumar K.V <redacted> --- fs/namei.c | 21 ++++++++++++--------- include/linux/fs.h | 2 ++ 2 files changed, 14 insertions(+), 9 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index b0b8a71..ed786b2 100644
--- a/fs/namei.c
+++ b/fs/namei.c@@ -253,7 +253,8 @@ int generic_permission(struct inode *inode, int mask, * for filesystem access without changing the "normal" uids which * are used for other things. * - * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask. + * When checking for MAY_APPEND, MAY_CREATE_FILE, MAY_CREATE_DIR, + * MAY_WRITE must also be set in @mask. */ int inode_permission(struct inode *inode, int mask) {
@@ -1337,13 +1338,15 @@ static int may_delete(struct inode *dir,struct dentry *victim,int isdir) * 3. We should have write and exec permissions on dir * 4. We can't do it if dir is immutable (done in permission()) */ -static inline int may_create(struct inode *dir, struct dentry *child) +static inline int may_create(struct inode *dir, struct dentry *child, int isdir) { + int mask = isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE; + if (child->d_inode) return -EEXIST; if (IS_DEADDIR(dir)) return -ENOENT; - return inode_permission(dir, MAY_WRITE | MAY_EXEC); + return inode_permission(dir, MAY_WRITE | MAY_EXEC | mask); } /*
@@ -1391,7 +1394,7 @@ void unlock_rename(struct dentry *p1, struct dentry *p2) int vfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd) { - int error = may_create(dir, dentry); + int error = may_create(dir, dentry, 0); if (error) return error;
@@ -1953,7 +1956,7 @@ EXPORT_SYMBOL_GPL(lookup_create); int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) { - int error = may_create(dir, dentry); + int error = may_create(dir, dentry, 0); if (error) return error;
@@ -2057,7 +2060,7 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, int, mode, unsigned, dev) int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) { - int error = may_create(dir, dentry); + int error = may_create(dir, dentry, 1); if (error) return error;
@@ -2342,7 +2345,7 @@ SYSCALL_DEFINE1(unlink, const char __user *, pathname) int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname) { - int error = may_create(dir, dentry); + int error = may_create(dir, dentry, 0); if (error) return error;
@@ -2415,7 +2418,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de if (!inode) return -ENOENT; - error = may_create(dir, new_dentry); + error = may_create(dir, new_dentry, S_ISDIR(inode->i_mode)); if (error) return error;
@@ -2631,7 +2634,7 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, return error; if (!new_dentry->d_inode) - error = may_create(new_dir, new_dentry); + error = may_create(new_dir, new_dentry, is_dir); else error = may_delete(new_dir, new_dentry, is_dir); if (error)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 26fc8ae..5dc1ebd 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h@@ -55,6 +55,8 @@ struct inodes_stat_t { #define MAY_ACCESS 16 #define MAY_OPEN 32 #define MAY_CHDIR 64 +#define MAY_CREATE_FILE 128 +#define MAY_CREATE_DIR 256 /* * flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond
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1.7.0.4