On Fri, Sep 23, 2022 at 05:42:07PM +0200, Mickaël Salaün wrote: > It seems that all code should use double backquotes, which is also used > to convert "%" defines. Let's use an homogeneous style and remove all > use of simple backquotes (which should only be used for emphasis). > > Cc: Günther Noack <gnoack3000@xxxxxxxxx> > Cc: Paul Moore <paul@xxxxxxxxxxxxxx> > Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxx> > Link: https://lore.kernel.org/r/20220923154207.3311629-4-mic@xxxxxxxxxxx > --- > Documentation/security/landlock.rst | 4 +-- > Documentation/userspace-api/landlock.rst | 25 ++++++++------- > include/uapi/linux/landlock.h | 10 +++--- > security/landlock/syscalls.c | 40 ++++++++++++------------ > 4 files changed, 40 insertions(+), 39 deletions(-) > > diff --git a/Documentation/security/landlock.rst b/Documentation/security/landlock.rst > index cc9617f3175b..c0029d5d02eb 100644 > --- a/Documentation/security/landlock.rst > +++ b/Documentation/security/landlock.rst > @@ -54,8 +54,8 @@ content of a listed inode. Indeed, a file name is local to its parent > directory, and an inode can be referenced by multiple file names thanks to > (hard) links. Being able to unlink a file only has a direct impact on the > directory, not the unlinked inode. This is the reason why > -`LANDLOCK_ACCESS_FS_REMOVE_FILE` or `LANDLOCK_ACCESS_FS_REFER` are not allowed > -to be tied to files but only to directories. > +``LANDLOCK_ACCESS_FS_REMOVE_FILE`` or ``LANDLOCK_ACCESS_FS_REFER`` are not > +allowed to be tied to files but only to directories. > > Tests > ===== > diff --git a/Documentation/userspace-api/landlock.rst b/Documentation/userspace-api/landlock.rst > index 83bae71bf042..cec780c2f497 100644 > --- a/Documentation/userspace-api/landlock.rst > +++ b/Documentation/userspace-api/landlock.rst > @@ -69,7 +69,7 @@ should try to protect users as much as possible whatever the kernel they are > using. To avoid binary enforcement (i.e. either all security features or > none), we can leverage a dedicated Landlock command to get the current version > of the Landlock ABI and adapt the handled accesses. Let's check if we should > -remove the `LANDLOCK_ACCESS_FS_REFER` access right which is only supported > +remove the ``LANDLOCK_ACCESS_FS_REFER`` access right which is only supported > starting with the second version of the ABI. > > .. code-block:: c > @@ -128,7 +128,7 @@ descriptor. > It may also be required to create rules following the same logic as explained > for the ruleset creation, by filtering access rights according to the Landlock > ABI version. In this example, this is not required because > -`LANDLOCK_ACCESS_FS_REFER` is not allowed by any rule. > +``LANDLOCK_ACCESS_FS_REFER`` is not allowed by any rule. > > We now have a ruleset with one rule allowing read access to ``/usr`` while > denying all other handled accesses for the filesystem. The next step is to > @@ -154,8 +154,8 @@ The current thread is now ready to sandbox itself with the ruleset. > } > close(ruleset_fd); > > -If the `landlock_restrict_self` system call succeeds, the current thread is now > -restricted and this policy will be enforced on all its subsequently created > +If the ``landlock_restrict_self`` system call succeeds, the current thread is > +now restricted and this policy will be enforced on all its subsequently created > children as well. Once a thread is landlocked, there is no way to remove its > security policy; only adding more restrictions is allowed. These threads are > now in a new Landlock domain, merge of their parent one (if any) with the new > @@ -175,7 +175,8 @@ depend on their location (i.e. parent directories). This is particularly > relevant when we want to allow linking or renaming. Indeed, having consistent > access rights per directory enables to change the location of such directory > without relying on the destination directory access rights (except those that > -are required for this operation, see `LANDLOCK_ACCESS_FS_REFER` documentation). > +are required for this operation, see ``LANDLOCK_ACCESS_FS_REFER`` > +documentation). > Having self-sufficient hierarchies also helps to tighten the required access > rights to the minimal set of data. This also helps avoid sinkhole directories, > i.e. directories where data can be linked to but not linked from. However, > @@ -259,7 +260,7 @@ Backward and forward compatibility > > Landlock is designed to be compatible with past and future versions of the > kernel. This is achieved thanks to the system call attributes and the > -associated bitflags, particularly the ruleset's `handled_access_fs`. Making > +associated bitflags, particularly the ruleset's ``handled_access_fs``. Making > handled access right explicit enables the kernel and user space to have a clear > contract with each other. This is required to make sure sandboxing will not > get stricter with a system update, which could break applications. > @@ -394,7 +395,7 @@ according to the potentially lost constraints. To protect against privilege > escalations through renaming or linking, and for the sake of simplicity, > Landlock previously limited linking and renaming to the same directory. > Starting with the Landlock ABI version 2, it is now possible to securely > -control renaming and linking thanks to the new `LANDLOCK_ACCESS_FS_REFER` > +control renaming and linking thanks to the new ``LANDLOCK_ACCESS_FS_REFER`` > access right. > > .. _kernel_support: > @@ -403,14 +404,14 @@ Kernel support > ============== > > Landlock was first introduced in Linux 5.13 but it must be configured at build > -time with `CONFIG_SECURITY_LANDLOCK=y`. Landlock must also be enabled at boot > +time with ``CONFIG_SECURITY_LANDLOCK=y``. Landlock must also be enabled at boot > time as the other security modules. The list of security modules enabled by > -default is set with `CONFIG_LSM`. The kernel configuration should then > -contains `CONFIG_LSM=landlock,[...]` with `[...]` as the list of other > +default is set with ``CONFIG_LSM``. The kernel configuration should then > +contains ``CONFIG_LSM=landlock,[...]`` with ``[...]`` as the list of other > potentially useful security modules for the running system (see the > -`CONFIG_LSM` help). > +``CONFIG_LSM`` help). > > -If the running kernel does not have `landlock` in `CONFIG_LSM`, then we can > +If the running kernel does not have ``landlock`` in ``CONFIG_LSM``, then we can > still enable it by adding ``lsm=landlock,[...]`` to > Documentation/admin-guide/kernel-parameters.rst thanks to the bootloader > configuration. > diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h > index 23df4e0e8ace..9c4bcc37a455 100644 > --- a/include/uapi/linux/landlock.h > +++ b/include/uapi/linux/landlock.h > @@ -26,7 +26,7 @@ struct landlock_ruleset_attr { > * Landlock filesystem access rights that are not part of > * handled_access_fs are allowed. This is needed for backward > * compatibility reasons. One exception is the > - * LANDLOCK_ACCESS_FS_REFER access right, which is always implicitly > + * %LANDLOCK_ACCESS_FS_REFER access right, which is always implicitly At the risk of asking a newbie question, why is this access right prefixed with % in this command, but most others are surrounded by double-backticks in other places? According to [1], % is used to denote a constant - should these LANDLOCK_ACCESS_FS* rights not all be showing up as constants? [1] https://docs.kernel.org/doc-guide/kernel-doc.html#highlights-and-cross-references Apart from this item, this change looks good. > * handled, but must still be explicitly handled to add new rules with > * this access right. > */ > @@ -128,11 +128,11 @@ struct landlock_path_beneath_attr { > * hierarchy must also always have the same or a superset of restrictions of > * the source hierarchy. If it is not the case, or if the domain doesn't > * handle this access right, such actions are denied by default with errno > - * set to EXDEV. Linking also requires a LANDLOCK_ACCESS_FS_MAKE_* access > - * right on the destination directory, and renaming also requires a > - * LANDLOCK_ACCESS_FS_REMOVE_* access right on the source's (file or > + * set to ``EXDEV``. Linking also requires a ``LANDLOCK_ACCESS_FS_MAKE_*`` > + * access right on the destination directory, and renaming also requires a > + * ``LANDLOCK_ACCESS_FS_REMOVE_*`` access right on the source's (file or > * directory) parent. Otherwise, such actions are denied with errno set to > - * EACCES. The EACCES errno prevails over EXDEV to let user space > + * ``EACCES``. The ``EACCES`` errno prevails over ``EXDEV`` to let user space > * efficiently deal with an unrecoverable error. > * > * .. warning:: > diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c > index 735a0865ea11..2ca0ccbd905a 100644 > --- a/security/landlock/syscalls.c > +++ b/security/landlock/syscalls.c > @@ -149,10 +149,10 @@ static const struct file_operations ruleset_fops = { > * > * Possible returned errors are: > * > - * - EOPNOTSUPP: Landlock is supported by the kernel but disabled at boot time; > - * - EINVAL: unknown @flags, or unknown access, or too small @size; > - * - E2BIG or EFAULT: @attr or @size inconsistencies; > - * - ENOMSG: empty &landlock_ruleset_attr.handled_access_fs. > + * - %EOPNOTSUPP: Landlock is supported by the kernel but disabled at boot time; > + * - %EINVAL: unknown @flags, or unknown access, or too small @size; > + * - %E2BIG or %EFAULT: @attr or @size inconsistencies; > + * - %ENOMSG: empty &landlock_ruleset_attr.handled_access_fs. > */ > SYSCALL_DEFINE3(landlock_create_ruleset, > const struct landlock_ruleset_attr __user *const, attr, > @@ -280,7 +280,7 @@ static int get_path_from_fd(const s32 fd, struct path *const path) > * @ruleset_fd: File descriptor tied to the ruleset that should be extended > * with the new rule. > * @rule_type: Identify the structure type pointed to by @rule_attr (only > - * LANDLOCK_RULE_PATH_BENEATH for now). > + * %LANDLOCK_RULE_PATH_BENEATH for now). > * @rule_attr: Pointer to a rule (only of type &struct > * landlock_path_beneath_attr for now). > * @flags: Must be 0. > @@ -290,17 +290,17 @@ static int get_path_from_fd(const s32 fd, struct path *const path) > * > * Possible returned errors are: > * > - * - EOPNOTSUPP: Landlock is supported by the kernel but disabled at boot time; > - * - EINVAL: @flags is not 0, or inconsistent access in the rule (i.e. > + * - %EOPNOTSUPP: Landlock is supported by the kernel but disabled at boot time; > + * - %EINVAL: @flags is not 0, or inconsistent access in the rule (i.e. > * &landlock_path_beneath_attr.allowed_access is not a subset of the > * ruleset handled accesses); > - * - ENOMSG: Empty accesses (e.g. &landlock_path_beneath_attr.allowed_access); > - * - EBADF: @ruleset_fd is not a file descriptor for the current thread, or a > + * - %ENOMSG: Empty accesses (e.g. &landlock_path_beneath_attr.allowed_access); > + * - %EBADF: @ruleset_fd is not a file descriptor for the current thread, or a > * member of @rule_attr is not a file descriptor as expected; > - * - EBADFD: @ruleset_fd is not a ruleset file descriptor, or a member of > + * - %EBADFD: @ruleset_fd is not a ruleset file descriptor, or a member of > * @rule_attr is not the expected file descriptor type; > - * - EPERM: @ruleset_fd has no write access to the underlying ruleset; > - * - EFAULT: @rule_attr inconsistency. > + * - %EPERM: @ruleset_fd has no write access to the underlying ruleset; > + * - %EFAULT: @rule_attr inconsistency. > */ > SYSCALL_DEFINE4(landlock_add_rule, const int, ruleset_fd, > const enum landlock_rule_type, rule_type, > @@ -378,20 +378,20 @@ SYSCALL_DEFINE4(landlock_add_rule, const int, ruleset_fd, > * @flags: Must be 0. > * > * This system call enables to enforce a Landlock ruleset on the current > - * thread. Enforcing a ruleset requires that the task has CAP_SYS_ADMIN in its > + * thread. Enforcing a ruleset requires that the task has %CAP_SYS_ADMIN in its > * namespace or is running with no_new_privs. This avoids scenarios where > * unprivileged tasks can affect the behavior of privileged children. > * > * Possible returned errors are: > * > - * - EOPNOTSUPP: Landlock is supported by the kernel but disabled at boot time; > - * - EINVAL: @flags is not 0. > - * - EBADF: @ruleset_fd is not a file descriptor for the current thread; > - * - EBADFD: @ruleset_fd is not a ruleset file descriptor; > - * - EPERM: @ruleset_fd has no read access to the underlying ruleset, or the > + * - %EOPNOTSUPP: Landlock is supported by the kernel but disabled at boot time; > + * - %EINVAL: @flags is not 0. > + * - %EBADF: @ruleset_fd is not a file descriptor for the current thread; > + * - %EBADFD: @ruleset_fd is not a ruleset file descriptor; > + * - %EPERM: @ruleset_fd has no read access to the underlying ruleset, or the > * current thread is not running with no_new_privs, or it doesn't have > - * CAP_SYS_ADMIN in its namespace. > - * - E2BIG: The maximum number of stacked rulesets is reached for the current > + * %CAP_SYS_ADMIN in its namespace. > + * - %E2BIG: The maximum number of stacked rulesets is reached for the current > * thread. > */ > SYSCALL_DEFINE2(landlock_restrict_self, const int, ruleset_fd, const __u32, > -- > 2.37.2 > --
