| Message ID | 20230303182602.1088032-1-roberto.sassu@huaweicloud.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | security: Move IMA and EVM to the LSM infrastructure | expand |
On 3/3/23 13:25, Roberto Sassu wrote: > From: Roberto Sassu <roberto.sassu@huawei.com> > > Introduce LSM_ORDER_LAST, to satisfy the requirement of LSMs willing to be > the last, e.g. the 'integrity' LSM, without changing the kernel command > line or configuration. > > As for LSM_ORDER_FIRST, LSMs with LSM_ORDER_LAST are always enabled and put > at the end of the LSM list in no particular order. > I think you should describe the reason for the change for LSM_ORDER_MUTABLE as well. > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > --- > include/linux/lsm_hooks.h | 1 + > security/security.c | 12 +++++++++--- > 2 files changed, 10 insertions(+), 3 deletions(-) > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > index 21a8ce23108..05c4b831d99 100644 > --- a/include/linux/lsm_hooks.h > +++ b/include/linux/lsm_hooks.h > @@ -93,6 +93,7 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count, > enum lsm_order { > LSM_ORDER_FIRST = -1, /* This is only for capabilities. */ > LSM_ORDER_MUTABLE = 0, > + LSM_ORDER_LAST = 1, > }; > > struct lsm_info { > diff --git a/security/security.c b/security/security.c > index 322090a50cd..24f52ba3218 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -284,9 +284,9 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) > bool found = false; > > for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > - if (lsm->order == LSM_ORDER_MUTABLE && > - strcmp(lsm->name, name) == 0) { > - append_ordered_lsm(lsm, origin); > + if (strcmp(lsm->name, name) == 0) { > + if (lsm->order == LSM_ORDER_MUTABLE) > + append_ordered_lsm(lsm, origin); > found = true; > } > } > @@ -306,6 +306,12 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) > } > } > > + /* LSM_ORDER_LAST is always last. */ > + for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > + if (lsm->order == LSM_ORDER_LAST) > + append_ordered_lsm(lsm, " last"); > + } > + > /* Disable all LSMs not in the ordered list. */ > for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > if (exists_ordered_lsm(lsm))
On Tue, 2023-03-07 at 13:04 -0500, Stefan Berger wrote: > > On 3/3/23 13:25, Roberto Sassu wrote: > > From: Roberto Sassu <roberto.sassu@huawei.com> > > > > Introduce LSM_ORDER_LAST, to satisfy the requirement of LSMs willing to be > > the last, e.g. the 'integrity' LSM, without changing the kernel command > > line or configuration. > > > > As for LSM_ORDER_FIRST, LSMs with LSM_ORDER_LAST are always enabled and put > > at the end of the LSM list in no particular order. > > > > I think you should describe the reason for the change for LSM_ORDER_MUTABLE as well. Right. Thanks Roberto > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > > --- > > include/linux/lsm_hooks.h | 1 + > > security/security.c | 12 +++++++++--- > > 2 files changed, 10 insertions(+), 3 deletions(-) > > > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > > index 21a8ce23108..05c4b831d99 100644 > > --- a/include/linux/lsm_hooks.h > > +++ b/include/linux/lsm_hooks.h > > @@ -93,6 +93,7 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count, > > enum lsm_order { > > LSM_ORDER_FIRST = -1, /* This is only for capabilities. */ > > LSM_ORDER_MUTABLE = 0, > > + LSM_ORDER_LAST = 1, > > }; > > > > struct lsm_info { > > diff --git a/security/security.c b/security/security.c > > index 322090a50cd..24f52ba3218 100644 > > --- a/security/security.c > > +++ b/security/security.c > > @@ -284,9 +284,9 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) > > bool found = false; > > > > for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > > - if (lsm->order == LSM_ORDER_MUTABLE && > > - strcmp(lsm->name, name) == 0) { > > - append_ordered_lsm(lsm, origin); > > + if (strcmp(lsm->name, name) == 0) { > > + if (lsm->order == LSM_ORDER_MUTABLE) > > + append_ordered_lsm(lsm, origin); > > found = true; > > } > > } > > @@ -306,6 +306,12 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) > > } > > } > > > > + /* LSM_ORDER_LAST is always last. */ > > + for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > > + if (lsm->order == LSM_ORDER_LAST) > > + append_ordered_lsm(lsm, " last"); > > + } > > + > > /* Disable all LSMs not in the ordered list. */ > > for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > > if (exists_ordered_lsm(lsm))
Hi Roberto, On Fri, 2023-03-03 at 19:25 +0100, Roberto Sassu wrote: > From: Roberto Sassu <roberto.sassu@huawei.com> > > Introduce LSM_ORDER_LAST, to satisfy the requirement of LSMs willing to be > the last, e.g. the 'integrity' LSM, without changing the kernel command > line or configuration. Please reframe this as a bug fix for 79f7865d844c ("LSM: Introduce "lsm=" for boottime LSM selection") and upstream it first, with 'integrity' as the last LSM. The original bug fix commit 92063f3ca73a ("integrity: double check iint_cache was initialized") could then be removed. > > As for LSM_ORDER_FIRST, LSMs with LSM_ORDER_LAST are always enabled and put > at the end of the LSM list in no particular order. ^Similar to LSM_ORDER_FIRST ... And remove "in no particular order". > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > --- > include/linux/lsm_hooks.h | 1 + > security/security.c | 12 +++++++++--- > 2 files changed, 10 insertions(+), 3 deletions(-) > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > index 21a8ce23108..05c4b831d99 100644 > --- a/include/linux/lsm_hooks.h > +++ b/include/linux/lsm_hooks.h > @@ -93,6 +93,7 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count, > enum lsm_order { > LSM_ORDER_FIRST = -1, /* This is only for capabilities. */ > LSM_ORDER_MUTABLE = 0, > + LSM_ORDER_LAST = 1, > }; > > struct lsm_info { > diff --git a/security/security.c b/security/security.c > index 322090a50cd..24f52ba3218 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -284,9 +284,9 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) > bool found = false; > > for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > - if (lsm->order == LSM_ORDER_MUTABLE && > - strcmp(lsm->name, name) == 0) { > - append_ordered_lsm(lsm, origin); > + if (strcmp(lsm->name, name) == 0) { > + if (lsm->order == LSM_ORDER_MUTABLE) > + append_ordered_lsm(lsm, origin); > found = true; > } > } > @@ -306,6 +306,12 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) > } > } > > + /* LSM_ORDER_LAST is always last. */ > + for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > + if (lsm->order == LSM_ORDER_LAST) > + append_ordered_lsm(lsm, " last"); > + } > + > /* Disable all LSMs not in the ordered list. */ > for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > if (exists_ordered_lsm(lsm))
On Wed, 2023-03-08 at 08:13 -0500, Mimi Zohar wrote: > Hi Roberto, > > On Fri, 2023-03-03 at 19:25 +0100, Roberto Sassu wrote: > > From: Roberto Sassu <roberto.sassu@huawei.com> > > > > Introduce LSM_ORDER_LAST, to satisfy the requirement of LSMs willing to be > > the last, e.g. the 'integrity' LSM, without changing the kernel command > > line or configuration. > > Please reframe this as a bug fix for 79f7865d844c ("LSM: Introduce > "lsm=" for boottime LSM selection") and upstream it first, with > 'integrity' as the last LSM. The original bug fix commit 92063f3ca73a > ("integrity: double check iint_cache was initialized") could then be > removed. Ok, I should complete the patch by checking the cache initialization in iint.c. > > As for LSM_ORDER_FIRST, LSMs with LSM_ORDER_LAST are always enabled and put > > at the end of the LSM list in no particular order. > > ^Similar to LSM_ORDER_FIRST ... > > And remove "in no particular order". The reason for this is that I originally thought that the relative order of LSMs specified in the kernel configuration or the command line was respected (if more than one LSM specifies LSM_ORDER_LAST). In fact not. To do this, we would have to parse the LSM string again, as it is done for LSM_ORDER_MUTABLE LSMs. Thanks Roberto > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > > --- > > include/linux/lsm_hooks.h | 1 + > > security/security.c | 12 +++++++++--- > > 2 files changed, 10 insertions(+), 3 deletions(-) > > > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > > index 21a8ce23108..05c4b831d99 100644 > > --- a/include/linux/lsm_hooks.h > > +++ b/include/linux/lsm_hooks.h > > @@ -93,6 +93,7 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count, > > enum lsm_order { > > LSM_ORDER_FIRST = -1, /* This is only for capabilities. */ > > LSM_ORDER_MUTABLE = 0, > > + LSM_ORDER_LAST = 1, > > }; > > > > struct lsm_info { > > diff --git a/security/security.c b/security/security.c > > index 322090a50cd..24f52ba3218 100644 > > --- a/security/security.c > > +++ b/security/security.c > > @@ -284,9 +284,9 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) > > bool found = false; > > > > for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > > - if (lsm->order == LSM_ORDER_MUTABLE && > > - strcmp(lsm->name, name) == 0) { > > - append_ordered_lsm(lsm, origin); > > + if (strcmp(lsm->name, name) == 0) { > > + if (lsm->order == LSM_ORDER_MUTABLE) > > + append_ordered_lsm(lsm, origin); > > found = true; > > } > > } > > @@ -306,6 +306,12 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) > > } > > } > > > > + /* LSM_ORDER_LAST is always last. */ > > + for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > > + if (lsm->order == LSM_ORDER_LAST) > > + append_ordered_lsm(lsm, " last"); > > + } > > + > > /* Disable all LSMs not in the ordered list. */ > > for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > > if (exists_ordered_lsm(lsm))
On Wed, 2023-03-08 at 14:26 +0100, Roberto Sassu wrote: > On Wed, 2023-03-08 at 08:13 -0500, Mimi Zohar wrote: > > Hi Roberto, > > > > On Fri, 2023-03-03 at 19:25 +0100, Roberto Sassu wrote: > > > From: Roberto Sassu <roberto.sassu@huawei.com> > > > > > > Introduce LSM_ORDER_LAST, to satisfy the requirement of LSMs willing to be > > > the last, e.g. the 'integrity' LSM, without changing the kernel command > > > line or configuration. > > > > Please reframe this as a bug fix for 79f7865d844c ("LSM: Introduce > > "lsm=" for boottime LSM selection") and upstream it first, with > > 'integrity' as the last LSM. The original bug fix commit 92063f3ca73a > > ("integrity: double check iint_cache was initialized") could then be > > removed. > > Ok, I should complete the patch by checking the cache initialization in > iint.c. > > > > As for LSM_ORDER_FIRST, LSMs with LSM_ORDER_LAST are always enabled and put > > > at the end of the LSM list in no particular order. > > > > ^Similar to LSM_ORDER_FIRST ... > > > > And remove "in no particular order". > > The reason for this is that I originally thought that the relative > order of LSMs specified in the kernel configuration or the command line > was respected (if more than one LSM specifies LSM_ORDER_LAST). In fact > not. To do this, we would have to parse the LSM string again, as it is > done for LSM_ORDER_MUTABLE LSMs. IMA and EVM are only configurable if 'integrity' is enabled. Similar to how LSM_ORDER_FIRST is reserved for capabilities, LSM_ORDER_LAST should be reserved for integrity (LSMs), if it is configured, for the reason as described in the "[PATCH 24/28] ima: Move to LSM infrastructure" patch description. > > Thanks > > Roberto > > > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > > > --- > > > include/linux/lsm_hooks.h | 1 + > > > security/security.c | 12 +++++++++--- > > > 2 files changed, 10 insertions(+), 3 deletions(-) > > > > > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > > > index 21a8ce23108..05c4b831d99 100644 > > > --- a/include/linux/lsm_hooks.h > > > +++ b/include/linux/lsm_hooks.h > > > @@ -93,6 +93,7 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count, > > > enum lsm_order { > > > LSM_ORDER_FIRST = -1, /* This is only for capabilities. */ > > > LSM_ORDER_MUTABLE = 0, > > > + LSM_ORDER_LAST = 1, > > > }; > > > > > > struct lsm_info { > > > diff --git a/security/security.c b/security/security.c > > > index 322090a50cd..24f52ba3218 100644 > > > --- a/security/security.c > > > +++ b/security/security.c > > > @@ -284,9 +284,9 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) > > > bool found = false; > > > > > > for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > > > - if (lsm->order == LSM_ORDER_MUTABLE && > > > - strcmp(lsm->name, name) == 0) { > > > - append_ordered_lsm(lsm, origin); > > > + if (strcmp(lsm->name, name) == 0) { > > > + if (lsm->order == LSM_ORDER_MUTABLE) > > > + append_ordered_lsm(lsm, origin); > > > found = true; > > > } > > > } > > > @@ -306,6 +306,12 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) > > > } > > > } > > > > > > + /* LSM_ORDER_LAST is always last. */ > > > + for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > > > + if (lsm->order == LSM_ORDER_LAST) > > > + append_ordered_lsm(lsm, " last"); > > > + } > > > + > > > /* Disable all LSMs not in the ordered list. */ > > > for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > > > if (exists_ordered_lsm(lsm)) >
On Wed, 2023-03-08 at 09:00 -0500, Mimi Zohar wrote: > On Wed, 2023-03-08 at 14:26 +0100, Roberto Sassu wrote: > > On Wed, 2023-03-08 at 08:13 -0500, Mimi Zohar wrote: > > > Hi Roberto, > > > > > > On Fri, 2023-03-03 at 19:25 +0100, Roberto Sassu wrote: > > > > From: Roberto Sassu <roberto.sassu@huawei.com> > > > > > > > > Introduce LSM_ORDER_LAST, to satisfy the requirement of LSMs willing to be > > > > the last, e.g. the 'integrity' LSM, without changing the kernel command > > > > line or configuration. > > > > > > Please reframe this as a bug fix for 79f7865d844c ("LSM: Introduce > > > "lsm=" for boottime LSM selection") and upstream it first, with > > > 'integrity' as the last LSM. The original bug fix commit 92063f3ca73a > > > ("integrity: double check iint_cache was initialized") could then be > > > removed. > > > > Ok, I should complete the patch by checking the cache initialization in > > iint.c. > > > > > > As for LSM_ORDER_FIRST, LSMs with LSM_ORDER_LAST are always enabled and put > > > > at the end of the LSM list in no particular order. > > > > > > ^Similar to LSM_ORDER_FIRST ... > > > > > > And remove "in no particular order". > > > > The reason for this is that I originally thought that the relative > > order of LSMs specified in the kernel configuration or the command line > > was respected (if more than one LSM specifies LSM_ORDER_LAST). In fact > > not. To do this, we would have to parse the LSM string again, as it is > > done for LSM_ORDER_MUTABLE LSMs. > > IMA and EVM are only configurable if 'integrity' is enabled. Similar > to how LSM_ORDER_FIRST is reserved for capabilities, LSM_ORDER_LAST > should be reserved for integrity (LSMs), if it is configured, for the > reason as described in the "[PATCH 24/28] ima: Move to LSM > infrastructure" patch description. Yes, it is just that nothing prevents to have multiple LSMs with order LSM_ORDER_LAST. I guess we will enforce that it is only one by reviewing the code. Thanks Roberto > > Thanks > > > > Roberto > > > > > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > > > > --- > > > > include/linux/lsm_hooks.h | 1 + > > > > security/security.c | 12 +++++++++--- > > > > 2 files changed, 10 insertions(+), 3 deletions(-) > > > > > > > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > > > > index 21a8ce23108..05c4b831d99 100644 > > > > --- a/include/linux/lsm_hooks.h > > > > +++ b/include/linux/lsm_hooks.h > > > > @@ -93,6 +93,7 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count, > > > > enum lsm_order { > > > > LSM_ORDER_FIRST = -1, /* This is only for capabilities. */ > > > > LSM_ORDER_MUTABLE = 0, > > > > + LSM_ORDER_LAST = 1, > > > > }; > > > > > > > > struct lsm_info { > > > > diff --git a/security/security.c b/security/security.c > > > > index 322090a50cd..24f52ba3218 100644 > > > > --- a/security/security.c > > > > +++ b/security/security.c > > > > @@ -284,9 +284,9 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) > > > > bool found = false; > > > > > > > > for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > > > > - if (lsm->order == LSM_ORDER_MUTABLE && > > > > - strcmp(lsm->name, name) == 0) { > > > > - append_ordered_lsm(lsm, origin); > > > > + if (strcmp(lsm->name, name) == 0) { > > > > + if (lsm->order == LSM_ORDER_MUTABLE) > > > > + append_ordered_lsm(lsm, origin); > > > > found = true; > > > > } > > > > } > > > > @@ -306,6 +306,12 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) > > > > } > > > > } > > > > > > > > + /* LSM_ORDER_LAST is always last. */ > > > > + for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > > > > + if (lsm->order == LSM_ORDER_LAST) > > > > + append_ordered_lsm(lsm, " last"); > > > > + } > > > > + > > > > /* Disable all LSMs not in the ordered list. */ > > > > for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > > > > if (exists_ordered_lsm(lsm))
On Wed, 2023-03-08 at 15:35 +0100, Roberto Sassu wrote: > On Wed, 2023-03-08 at 09:00 -0500, Mimi Zohar wrote: > > On Wed, 2023-03-08 at 14:26 +0100, Roberto Sassu wrote: > > > On Wed, 2023-03-08 at 08:13 -0500, Mimi Zohar wrote: > > > > Hi Roberto, > > > > > > > > On Fri, 2023-03-03 at 19:25 +0100, Roberto Sassu wrote: > > > > > From: Roberto Sassu <roberto.sassu@huawei.com> > > > > > > > > > > Introduce LSM_ORDER_LAST, to satisfy the requirement of LSMs willing to be > > > > > the last, e.g. the 'integrity' LSM, without changing the kernel command > > > > > line or configuration. > > > > > > > > Please reframe this as a bug fix for 79f7865d844c ("LSM: Introduce > > > > "lsm=" for boottime LSM selection") and upstream it first, with > > > > 'integrity' as the last LSM. The original bug fix commit 92063f3ca73a > > > > ("integrity: double check iint_cache was initialized") could then be > > > > removed. > > > > > > Ok, I should complete the patch by checking the cache initialization in > > > iint.c. > > > > > > > > As for LSM_ORDER_FIRST, LSMs with LSM_ORDER_LAST are always enabled and put > > > > > at the end of the LSM list in no particular order. > > > > > > > > ^Similar to LSM_ORDER_FIRST ... > > > > > > > > And remove "in no particular order". > > > > > > The reason for this is that I originally thought that the relative > > > order of LSMs specified in the kernel configuration or the command line > > > was respected (if more than one LSM specifies LSM_ORDER_LAST). In fact > > > not. To do this, we would have to parse the LSM string again, as it is > > > done for LSM_ORDER_MUTABLE LSMs. > > > > IMA and EVM are only configurable if 'integrity' is enabled. Similar > > to how LSM_ORDER_FIRST is reserved for capabilities, LSM_ORDER_LAST > > should be reserved for integrity (LSMs), if it is configured, for the > > reason as described in the "[PATCH 24/28] ima: Move to LSM > > infrastructure" patch description. > > Yes, it is just that nothing prevents to have multiple LSMs with order > LSM_ORDER_LAST. I guess we will enforce that it is only one by > reviewing the code. At least add a comment, like the existing one for LSM_ORDER_FIRST. > > > > enum lsm_order { > > > > > LSM_ORDER_FIRST = -1, /* This is only for capabilities. */ > > > > > LSM_ORDER_MUTABLE = 0, > > > > > + LSM_ORDER_LAST = 1, > > > > > };
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 21a8ce23108..05c4b831d99 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -93,6 +93,7 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count, enum lsm_order { LSM_ORDER_FIRST = -1, /* This is only for capabilities. */ LSM_ORDER_MUTABLE = 0, + LSM_ORDER_LAST = 1, }; struct lsm_info { diff --git a/security/security.c b/security/security.c index 322090a50cd..24f52ba3218 100644 --- a/security/security.c +++ b/security/security.c @@ -284,9 +284,9 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) bool found = false; for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { - if (lsm->order == LSM_ORDER_MUTABLE && - strcmp(lsm->name, name) == 0) { - append_ordered_lsm(lsm, origin); + if (strcmp(lsm->name, name) == 0) { + if (lsm->order == LSM_ORDER_MUTABLE) + append_ordered_lsm(lsm, origin); found = true; } } @@ -306,6 +306,12 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) } } + /* LSM_ORDER_LAST is always last. */ + for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { + if (lsm->order == LSM_ORDER_LAST) + append_ordered_lsm(lsm, " last"); + } + /* Disable all LSMs not in the ordered list. */ for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { if (exists_ordered_lsm(lsm))