On Mon, Oct 16, 2023 at 09:50:25AM +0800, Konstantin Meskhidze wrote: > Change the landlock_add_rule() syscall to support new rule types > in future Landlock versions. Add the add_rule_path_beneath() helper > to support current filesystem rules. > > Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@xxxxxxxxxx> > Link: https://lore.kernel.org/r/20230920092641.832134-8-konstantin.meskhidze@xxxxxxxxxx > Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxx> > --- > > Changes since v12: > * None. > > Changes since v11: > * None. > > Changes since v10: > * None. > > Changes since v9: > * Minor fixes: > - deletes unnecessary curly braces. > - deletes unnecessary empty line. > > Changes since v8: > * Refactors commit message. > * Minor fixes. > > Changes since v7: > * None > > Changes since v6: > * None > > Changes since v5: > * Refactors syscall landlock_add_rule() and add_rule_path_beneath() helper > to make argument check ordering consistent and get rid of partial revertings > in following patches. > * Rolls back refactoring base_test.c seltest. > * Formats code with clang-format-14. > > Changes since v4: > * Refactors add_rule_path_beneath() and landlock_add_rule() functions > to optimize code usage. > * Refactors base_test.c seltest: adds LANDLOCK_RULE_PATH_BENEATH > rule type in landlock_add_rule() call. > > Changes since v3: > * Split commit. > * Refactors landlock_add_rule syscall. > > --- > security/landlock/syscalls.c | 92 +++++++++++++++++++----------------- > 1 file changed, 48 insertions(+), 44 deletions(-) > > diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c > index d35cd5d304db..8a54e87dbb17 100644 > --- a/security/landlock/syscalls.c > +++ b/security/landlock/syscalls.c > @@ -274,6 +274,47 @@ static int get_path_from_fd(const s32 fd, struct path *const path) > return err; > } > > +static int add_rule_path_beneath(struct landlock_ruleset *const ruleset, > + const void __user *const rule_attr) > +{ > + struct landlock_path_beneath_attr path_beneath_attr; > + struct path path; > + int res, err; > + access_mask_t mask; > + > + /* Copies raw user space buffer, only one type for now. */ > + res = copy_from_user(&path_beneath_attr, rule_attr, > + sizeof(path_beneath_attr)); > + if (res) > + return -EFAULT; > + > + /* > + * Informs about useless rule: empty allowed_access (i.e. deny rules) > + * are ignored in path walks. > + */ > + if (!path_beneath_attr.allowed_access) > + return -ENOMSG; > + > + /* > + * Checks that allowed_access matches the @ruleset constraints > + * (ruleset->access_masks[0] is automatically upgraded to 64-bits). > + */ You now can replace this comment block with that: + /* Checks that allowed_access matches the @ruleset constraints. */ > + mask = landlock_get_raw_fs_access_mask(ruleset, 0); > + if ((path_beneath_attr.allowed_access | mask) != mask) > + return -EINVAL; > + > + /* Gets and checks the new rule. */ > + err = get_path_from_fd(path_beneath_attr.parent_fd, &path); > + if (err) > + return err; > + > + /* Imports the new rule. */ > + err = landlock_append_fs_rule(ruleset, &path, > + path_beneath_attr.allowed_access); > + path_put(&path); > + return err; > +}
