| Message ID | 1438689218-6921-3-git-send-email-agruenba@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Aug 04, 2015 at 01:53:00PM +0200, Andreas Gruenbacher wrote: > Richacls distinguish between creating non-directories and directories. To > support that, add an isdir parameter to may_create(). When checking > inode_permission() for create permission, pass in an additional > MAY_CREATE_FILE or MAY_CREATE_DIR mask flag. > > To allow checking for delete *and* create access when replacing an existing > file via vfs_rename(), add a replace parameter to may_delete(). > > Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> > --- > fs/namei.c | 42 ++++++++++++++++++++++++------------------ > include/linux/fs.h | 2 ++ > 2 files changed, 26 insertions(+), 18 deletions(-) > > diff --git a/fs/namei.c b/fs/namei.c > index 8f3db24..3504d36 100644 > --- a/fs/namei.c > +++ b/fs/namei.c > @@ -453,7 +453,8 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask) > * this, letting us set arbitrary permissions 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. Why? (Also: written as a simple list like that, it's a ambiguous how to parse that comment: I think you mean that MAY_WRITE must be set whenever MAY_APPEND, MAY_CREATE_FILE, or MAY_CREATE_DIR are set.) --b. > */ > int inode_permission(struct inode *inode, int mask) > { > @@ -2522,10 +2523,11 @@ EXPORT_SYMBOL(__check_sticky); > * 10. We don't allow removal of NFS sillyrenamed files; it's handled by > * nfs_async_unlink(). > */ > -static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) > +static int may_delete(struct inode *dir, struct dentry *victim, > + bool isdir, bool replace) > { > struct inode *inode = d_backing_inode(victim); > - int error; > + int error, mask = MAY_WRITE | MAY_EXEC; > > if (d_is_negative(victim)) > return -ENOENT; > @@ -2534,7 +2536,9 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) > BUG_ON(victim->d_parent->d_inode != dir); > audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE); > > - error = inode_permission(dir, MAY_WRITE | MAY_EXEC); > + if (replace) > + mask |= isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE; > + error = inode_permission(dir, mask); > if (error) > return error; > if (IS_APPEND(dir)) > @@ -2565,14 +2569,16 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool 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, bool isdir) > { > + int mask = isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE; > + > audit_inode_child(dir, child, AUDIT_TYPE_CHILD_CREATE); > 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); > } > > /* > @@ -2622,7 +2628,7 @@ EXPORT_SYMBOL(unlock_rename); > int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, > bool want_excl) > { > - int error = may_create(dir, dentry); > + int error = may_create(dir, dentry, false); > if (error) > return error; > > @@ -3467,7 +3473,7 @@ EXPORT_SYMBOL(user_path_create); > > int vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) > { > - int error = may_create(dir, dentry); > + int error = may_create(dir, dentry, false); > > if (error) > return error; > @@ -3559,7 +3565,7 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d > > int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) > { > - int error = may_create(dir, dentry); > + int error = may_create(dir, dentry, true); > unsigned max_links = dir->i_sb->s_max_links; > > if (error) > @@ -3640,7 +3646,7 @@ EXPORT_SYMBOL(dentry_unhash); > > int vfs_rmdir(struct inode *dir, struct dentry *dentry) > { > - int error = may_delete(dir, dentry, 1); > + int error = may_delete(dir, dentry, true, false); > > if (error) > return error; > @@ -3762,7 +3768,7 @@ SYSCALL_DEFINE1(rmdir, const char __user *, pathname) > int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegated_inode) > { > struct inode *target = dentry->d_inode; > - int error = may_delete(dir, dentry, 0); > + int error = may_delete(dir, dentry, false, false); > > if (error) > return error; > @@ -3896,7 +3902,7 @@ 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, false); > > if (error) > return error; > @@ -3979,7 +3985,7 @@ 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, false); > if (error) > return error; > > @@ -4167,19 +4173,19 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, > if (source == target) > return 0; > > - error = may_delete(old_dir, old_dentry, is_dir); > + error = may_delete(old_dir, old_dentry, is_dir, false); > if (error) > return error; > > if (!target) { > - error = may_create(new_dir, new_dentry); > + error = may_create(new_dir, new_dentry, is_dir); > } else { > new_is_dir = d_is_dir(new_dentry); > > if (!(flags & RENAME_EXCHANGE)) > - error = may_delete(new_dir, new_dentry, is_dir); > + error = may_delete(new_dir, new_dentry, is_dir, true); > else > - error = may_delete(new_dir, new_dentry, new_is_dir); > + error = may_delete(new_dir, new_dentry, new_is_dir, true); > } > if (error) > return error; > @@ -4442,7 +4448,7 @@ SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newna > > int vfs_whiteout(struct inode *dir, struct dentry *dentry) > { > - int error = may_create(dir, dentry); > + int error = may_create(dir, dentry, false); > if (error) > return error; > > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 44e696e..9c44f27 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -81,6 +81,8 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate); > #define MAY_CHDIR 0x00000040 > /* called from RCU mode, don't block */ > #define MAY_NOT_BLOCK 0x00000080 > +#define MAY_CREATE_FILE 0x00000100 > +#define MAY_CREATE_DIR 0x00000200 > > /* > * flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond > -- > 2.5.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
2015-09-02 20:53 GMT+02:00 J. Bruce Fields <bfields@fieldses.org>: >> @@ -453,7 +453,8 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask) >> * this, letting us set arbitrary permissions 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. > > Why? So that file systems that don't support MAY_APPEND can ignore the flag and will then automatically check for MAY_WRITE instead. > (Also: written as a simple list like that, it's a ambiguous how to > parse that comment: I think you mean that MAY_WRITE must be set whenever > MAY_APPEND, MAY_CREATE_FILE, or MAY_CREATE_DIR are set.) Yes, that's better. Thanks, Andreas -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Sep 02, 2015 at 09:06:32PM +0200, Andreas Gruenbacher wrote: > 2015-09-02 20:53 GMT+02:00 J. Bruce Fields <bfields@fieldses.org>: > >> @@ -453,7 +453,8 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask) > >> * this, letting us set arbitrary permissions 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. > > > > Why? > > So that file systems that don't support MAY_APPEND can ignore the flag > and will then automatically check for MAY_WRITE instead. Got it. And maybe it should be obvious, but it might be worth a sentence in the changelog if it's not already explained elsewhere.--b. > > > (Also: written as a simple list like that, it's a ambiguous how to > > parse that comment: I think you mean that MAY_WRITE must be set whenever > > MAY_APPEND, MAY_CREATE_FILE, or MAY_CREATE_DIR are set.) > > Yes, that's better. > > Thanks, > Andreas > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
2015-09-02 21:20 GMT+02:00 J. Bruce Fields <bfields@fieldses.org>: > Got it. And maybe it should be obvious, but it might be worth a > sentence in the changelog if it's not already explained elsewhere.--b. Let me try adding a comment. Also I'll fix the next commit which adds MAY_DELETE_SELF here: MAY_DELETE_SELF shouldn't go together with MAY_WRITE. Thanks, Andreas -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/namei.c b/fs/namei.c index 8f3db24..3504d36 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -453,7 +453,8 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask) * this, letting us set arbitrary permissions 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) { @@ -2522,10 +2523,11 @@ EXPORT_SYMBOL(__check_sticky); * 10. We don't allow removal of NFS sillyrenamed files; it's handled by * nfs_async_unlink(). */ -static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) +static int may_delete(struct inode *dir, struct dentry *victim, + bool isdir, bool replace) { struct inode *inode = d_backing_inode(victim); - int error; + int error, mask = MAY_WRITE | MAY_EXEC; if (d_is_negative(victim)) return -ENOENT; @@ -2534,7 +2536,9 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) BUG_ON(victim->d_parent->d_inode != dir); audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE); - error = inode_permission(dir, MAY_WRITE | MAY_EXEC); + if (replace) + mask |= isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE; + error = inode_permission(dir, mask); if (error) return error; if (IS_APPEND(dir)) @@ -2565,14 +2569,16 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool 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, bool isdir) { + int mask = isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE; + audit_inode_child(dir, child, AUDIT_TYPE_CHILD_CREATE); 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); } /* @@ -2622,7 +2628,7 @@ EXPORT_SYMBOL(unlock_rename); int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool want_excl) { - int error = may_create(dir, dentry); + int error = may_create(dir, dentry, false); if (error) return error; @@ -3467,7 +3473,7 @@ EXPORT_SYMBOL(user_path_create); int vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) { - int error = may_create(dir, dentry); + int error = may_create(dir, dentry, false); if (error) return error; @@ -3559,7 +3565,7 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) { - int error = may_create(dir, dentry); + int error = may_create(dir, dentry, true); unsigned max_links = dir->i_sb->s_max_links; if (error) @@ -3640,7 +3646,7 @@ EXPORT_SYMBOL(dentry_unhash); int vfs_rmdir(struct inode *dir, struct dentry *dentry) { - int error = may_delete(dir, dentry, 1); + int error = may_delete(dir, dentry, true, false); if (error) return error; @@ -3762,7 +3768,7 @@ SYSCALL_DEFINE1(rmdir, const char __user *, pathname) int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegated_inode) { struct inode *target = dentry->d_inode; - int error = may_delete(dir, dentry, 0); + int error = may_delete(dir, dentry, false, false); if (error) return error; @@ -3896,7 +3902,7 @@ 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, false); if (error) return error; @@ -3979,7 +3985,7 @@ 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, false); if (error) return error; @@ -4167,19 +4173,19 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, if (source == target) return 0; - error = may_delete(old_dir, old_dentry, is_dir); + error = may_delete(old_dir, old_dentry, is_dir, false); if (error) return error; if (!target) { - error = may_create(new_dir, new_dentry); + error = may_create(new_dir, new_dentry, is_dir); } else { new_is_dir = d_is_dir(new_dentry); if (!(flags & RENAME_EXCHANGE)) - error = may_delete(new_dir, new_dentry, is_dir); + error = may_delete(new_dir, new_dentry, is_dir, true); else - error = may_delete(new_dir, new_dentry, new_is_dir); + error = may_delete(new_dir, new_dentry, new_is_dir, true); } if (error) return error; @@ -4442,7 +4448,7 @@ SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newna int vfs_whiteout(struct inode *dir, struct dentry *dentry) { - int error = may_create(dir, dentry); + int error = may_create(dir, dentry, false); if (error) return error; diff --git a/include/linux/fs.h b/include/linux/fs.h index 44e696e..9c44f27 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -81,6 +81,8 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate); #define MAY_CHDIR 0x00000040 /* called from RCU mode, don't block */ #define MAY_NOT_BLOCK 0x00000080 +#define MAY_CREATE_FILE 0x00000100 +#define MAY_CREATE_DIR 0x00000200 /* * flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond
Richacls distinguish between creating non-directories and directories. To support that, add an isdir parameter to may_create(). When checking inode_permission() for create permission, pass in an additional MAY_CREATE_FILE or MAY_CREATE_DIR mask flag. To allow checking for delete *and* create access when replacing an existing file via vfs_rename(), add a replace parameter to may_delete(). Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> --- fs/namei.c | 42 ++++++++++++++++++++++++------------------ include/linux/fs.h | 2 ++ 2 files changed, 26 insertions(+), 18 deletions(-)