[PATCH] libsepol: fix validation of user declarations in modules

[PATCH] libsepol: fix validation of user declarations in modules

[Christian Göttsche]

Users are allowed to be declared in modules. Modules do not get expanded
leaving the `struct user_datum` members `exp_range` and `exp_dfltlevel`
empty.
Do no validate the expanded range and level for modular polices.

Reported-by: bauen1 <j2468h@gmail.com>
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
---
 libsepol/src/policydb_validate.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/libsepol/src/policydb_validate.c b/libsepol/src/policydb_validate.c
index da18282b..99d4eb7f 100644
--- a/libsepol/src/policydb_validate.c
+++ b/libsepol/src/policydb_validate.c
@@ -18,7 +18,7 @@ typedef struct validate {
 typedef struct map_arg {
 	validate_t *flavors;
 	sepol_handle_t *handle;
-	int mls;
+	policydb_t *policy;
 } map_arg_t;
 
 static int create_gap_ebitmap(char **val_to_name, uint32_t nprim, ebitmap_t *gaps)
@@ -571,7 +571,7 @@ static int validate_mls_range(mls_range_t *range, validate_t *sens, validate_t *
 	return -1;
 }
 
-static int validate_user_datum(sepol_handle_t *handle, user_datum_t *user, validate_t flavors[], int mls)
+static int validate_user_datum(sepol_handle_t *handle, user_datum_t *user, validate_t flavors[], policydb_t *p)
 {
 	if (validate_value(user->s.value, &flavors[SYM_USERS]))
 		goto bad;
@@ -581,9 +581,9 @@ static int validate_user_datum(sepol_handle_t *handle, user_datum_t *user, valid
 		goto bad;
 	if (validate_mls_semantic_level(&user->dfltlevel, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
 		goto bad;
-	if (mls && validate_mls_range(&user->exp_range, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
+	if (p->mls && p->policy_type != POLICY_MOD && validate_mls_range(&user->exp_range, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
 		goto bad;
-	if (mls && validate_mls_level(&user->exp_dfltlevel, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
+	if (p->mls && p->policy_type != POLICY_MOD && validate_mls_level(&user->exp_dfltlevel, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
 		goto bad;
 	if (user->bounds && validate_value(user->bounds, &flavors[SYM_USERS]))
 		goto bad;
@@ -599,7 +599,7 @@ static int validate_user_datum_wrapper(__attribute__((unused)) hashtab_key_t k,
 {
 	map_arg_t *margs = args;
 
-	return validate_user_datum(margs->handle, d, margs->flavors, margs->mls);
+	return validate_user_datum(margs->handle, d, margs->flavors, margs->policy);
 }
 
 static int validate_bool_datum(sepol_handle_t *handle, cond_bool_datum_t *boolean, validate_t flavors[])
@@ -689,7 +689,7 @@ static int validate_datum(__attribute__ ((unused))hashtab_key_t k, hashtab_datum
 
 static int validate_datum_array_entries(sepol_handle_t *handle, policydb_t *p, validate_t flavors[])
 {
-	map_arg_t margs = { flavors, handle, p->mls };
+	map_arg_t margs = { flavors, handle, p };
 
 	if (hashtab_map(p->p_commons.table, validate_common_datum_wrapper, &margs))
 		goto bad;
-- 
2.36.1

Re: [PATCH] libsepol: fix validation of user declarations in modules

[James Carter]

On Tue, Jun 7, 2022 at 11:54 AM Christian Göttsche
<cgzones@googlemail.com> wrote:
>
> Users are allowed to be declared in modules. Modules do not get expanded
> leaving the `struct user_datum` members `exp_range` and `exp_dfltlevel`
> empty.
> Do no validate the expanded range and level for modular polices.
>
> Reported-by: bauen1 <j2468h@gmail.com>
> Signed-off-by: Christian Göttsche <cgzones@googlemail.com>

Acked-by: James Carter <jwcart2@gmail.com>

> ---
>  libsepol/src/policydb_validate.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/libsepol/src/policydb_validate.c b/libsepol/src/policydb_validate.c
> index da18282b..99d4eb7f 100644
> --- a/libsepol/src/policydb_validate.c
> +++ b/libsepol/src/policydb_validate.c
> @@ -18,7 +18,7 @@ typedef struct validate {
>  typedef struct map_arg {
>         validate_t *flavors;
>         sepol_handle_t *handle;
> -       int mls;
> +       policydb_t *policy;
>  } map_arg_t;
>
>  static int create_gap_ebitmap(char **val_to_name, uint32_t nprim, ebitmap_t *gaps)
> @@ -571,7 +571,7 @@ static int validate_mls_range(mls_range_t *range, validate_t *sens, validate_t *
>         return -1;
>  }
>
> -static int validate_user_datum(sepol_handle_t *handle, user_datum_t *user, validate_t flavors[], int mls)
> +static int validate_user_datum(sepol_handle_t *handle, user_datum_t *user, validate_t flavors[], policydb_t *p)
>  {
>         if (validate_value(user->s.value, &flavors[SYM_USERS]))
>                 goto bad;
> @@ -581,9 +581,9 @@ static int validate_user_datum(sepol_handle_t *handle, user_datum_t *user, valid
>                 goto bad;
>         if (validate_mls_semantic_level(&user->dfltlevel, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
>                 goto bad;
> -       if (mls && validate_mls_range(&user->exp_range, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
> +       if (p->mls && p->policy_type != POLICY_MOD && validate_mls_range(&user->exp_range, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
>                 goto bad;
> -       if (mls && validate_mls_level(&user->exp_dfltlevel, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
> +       if (p->mls && p->policy_type != POLICY_MOD && validate_mls_level(&user->exp_dfltlevel, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
>                 goto bad;
>         if (user->bounds && validate_value(user->bounds, &flavors[SYM_USERS]))
>                 goto bad;
> @@ -599,7 +599,7 @@ static int validate_user_datum_wrapper(__attribute__((unused)) hashtab_key_t k,
>  {
>         map_arg_t *margs = args;
>
> -       return validate_user_datum(margs->handle, d, margs->flavors, margs->mls);
> +       return validate_user_datum(margs->handle, d, margs->flavors, margs->policy);
>  }
>
>  static int validate_bool_datum(sepol_handle_t *handle, cond_bool_datum_t *boolean, validate_t flavors[])
> @@ -689,7 +689,7 @@ static int validate_datum(__attribute__ ((unused))hashtab_key_t k, hashtab_datum
>
>  static int validate_datum_array_entries(sepol_handle_t *handle, policydb_t *p, validate_t flavors[])
>  {
> -       map_arg_t margs = { flavors, handle, p->mls };
> +       map_arg_t margs = { flavors, handle, p };
>
>         if (hashtab_map(p->p_commons.table, validate_common_datum_wrapper, &margs))
>                 goto bad;
> --
> 2.36.1
>

Re: [PATCH] libsepol: fix validation of user declarations in modules

[Nicolas Iooss]

On Tue, Jun 7, 2022 at 5:02 PM Christian Göttsche
<cgzones@googlemail.com> wrote:
>
> Users are allowed to be declared in modules. Modules do not get expanded
> leaving the `struct user_datum` members `exp_range` and `exp_dfltlevel`
> empty.
> Do no validate the expanded range and level for modular polices.
>
> Reported-by: bauen1 <j2468h@gmail.com>
> Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
> ---
>  libsepol/src/policydb_validate.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/libsepol/src/policydb_validate.c b/libsepol/src/policydb_validate.c
> index da18282b..99d4eb7f 100644
> --- a/libsepol/src/policydb_validate.c
> +++ b/libsepol/src/policydb_validate.c
> @@ -18,7 +18,7 @@ typedef struct validate {
>  typedef struct map_arg {
>         validate_t *flavors;
>         sepol_handle_t *handle;
> -       int mls;
> +       policydb_t *policy;
>  } map_arg_t;

Hello,
As the policy is not modified, could this pointer be "const policydb_t
*policy;"? (And the last parameter of validate_user_datum be "const
policydb_t *p"). On the other hand, as policydb_validate.c does not
use any const pointer, feel free to disregard my comment.

This patch nevertheless looks good to me too.
Thanks!
Nicolas

[PATCH v2] libsepol: fix validation of user declarations in non-base modules

[Christian Göttsche]

Users may be declared in non-base modules, which do not get expanded,
leaving the `struct user_datum` members `exp_range` and `exp_dfltlevel`
empty.
Skip validation of the expanded range and level for non-base module
polices.

Reported-by: bauen1 <j2468h@gmail.com>
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
---
v2:
   - update commit description and fix typos
---
 libsepol/src/policydb_validate.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/libsepol/src/policydb_validate.c b/libsepol/src/policydb_validate.c
index da18282b..99d4eb7f 100644
--- a/libsepol/src/policydb_validate.c
+++ b/libsepol/src/policydb_validate.c
@@ -18,7 +18,7 @@ typedef struct validate {
 typedef struct map_arg {
 	validate_t *flavors;
 	sepol_handle_t *handle;
-	int mls;
+	policydb_t *policy;
 } map_arg_t;
 
 static int create_gap_ebitmap(char **val_to_name, uint32_t nprim, ebitmap_t *gaps)
@@ -571,7 +571,7 @@ static int validate_mls_range(mls_range_t *range, validate_t *sens, validate_t *
 	return -1;
 }
 
-static int validate_user_datum(sepol_handle_t *handle, user_datum_t *user, validate_t flavors[], int mls)
+static int validate_user_datum(sepol_handle_t *handle, user_datum_t *user, validate_t flavors[], policydb_t *p)
 {
 	if (validate_value(user->s.value, &flavors[SYM_USERS]))
 		goto bad;
@@ -581,9 +581,9 @@ static int validate_user_datum(sepol_handle_t *handle, user_datum_t *user, valid
 		goto bad;
 	if (validate_mls_semantic_level(&user->dfltlevel, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
 		goto bad;
-	if (mls && validate_mls_range(&user->exp_range, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
+	if (p->mls && p->policy_type != POLICY_MOD && validate_mls_range(&user->exp_range, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
 		goto bad;
-	if (mls && validate_mls_level(&user->exp_dfltlevel, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
+	if (p->mls && p->policy_type != POLICY_MOD && validate_mls_level(&user->exp_dfltlevel, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
 		goto bad;
 	if (user->bounds && validate_value(user->bounds, &flavors[SYM_USERS]))
 		goto bad;
@@ -599,7 +599,7 @@ static int validate_user_datum_wrapper(__attribute__((unused)) hashtab_key_t k,
 {
 	map_arg_t *margs = args;
 
-	return validate_user_datum(margs->handle, d, margs->flavors, margs->mls);
+	return validate_user_datum(margs->handle, d, margs->flavors, margs->policy);
 }
 
 static int validate_bool_datum(sepol_handle_t *handle, cond_bool_datum_t *boolean, validate_t flavors[])
@@ -689,7 +689,7 @@ static int validate_datum(__attribute__ ((unused))hashtab_key_t k, hashtab_datum
 
 static int validate_datum_array_entries(sepol_handle_t *handle, policydb_t *p, validate_t flavors[])
 {
-	map_arg_t margs = { flavors, handle, p->mls };
+	map_arg_t margs = { flavors, handle, p };
 
 	if (hashtab_map(p->p_commons.table, validate_common_datum_wrapper, &margs))
 		goto bad;
-- 
2.36.1

Re: [PATCH] libsepol: fix validation of user declarations in modules

[Christian Göttsche]

On Wed, 8 Jun 2022 at 21:16, Nicolas Iooss <nicolas.iooss@m4x.org> wrote:
>
> On Tue, Jun 7, 2022 at 5:02 PM Christian Göttsche
> <cgzones@googlemail.com> wrote:
> >
> > Users are allowed to be declared in modules. Modules do not get expanded
> > leaving the `struct user_datum` members `exp_range` and `exp_dfltlevel`
> > empty.
> > Do no validate the expanded range and level for modular polices.
> >
> > Reported-by: bauen1 <j2468h@gmail.com>
> > Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
> > ---
> >  libsepol/src/policydb_validate.c | 12 ++++++------
> >  1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/libsepol/src/policydb_validate.c b/libsepol/src/policydb_validate.c
> > index da18282b..99d4eb7f 100644
> > --- a/libsepol/src/policydb_validate.c
> > +++ b/libsepol/src/policydb_validate.c
> > @@ -18,7 +18,7 @@ typedef struct validate {
> >  typedef struct map_arg {
> >         validate_t *flavors;
> >         sepol_handle_t *handle;
> > -       int mls;
> > +       policydb_t *policy;
> >  } map_arg_t;
>
> Hello,
> As the policy is not modified, could this pointer be "const policydb_t
> *policy;"? (And the last parameter of validate_user_datum be "const
> policydb_t *p"). On the other hand, as policydb_validate.c does not
> use any const pointer, feel free to disregard my comment.
>

Since policydb_validate.c does not use const pointer at all yet I
followed that style.
I might prepare a patch to constify all pointers and refactor the
logging mechanism,
since I like to add validation into the kernel to avoid crashes like
[1], especially
if SELinux gets namespace support [2].


[1]: https://github.com/SELinuxProject/selinux-testsuite/issues/76
[2]: https://patchwork.kernel.org/project/selinux/list/?series=632975

> This patch nevertheless looks good to me too.
> Thanks!
> Nicolas
>

Re: [PATCH] libsepol: fix validation of user declarations in modules

[James Carter]

On Wed, Jun 8, 2022 at 2:41 PM James Carter <jwcart2@gmail.com> wrote:
>
> On Tue, Jun 7, 2022 at 11:54 AM Christian Göttsche
> <cgzones@googlemail.com> wrote:
> >
> > Users are allowed to be declared in modules. Modules do not get expanded
> > leaving the `struct user_datum` members `exp_range` and `exp_dfltlevel`
> > empty.
> > Do no validate the expanded range and level for modular polices.
> >
> > Reported-by: bauen1 <j2468h@gmail.com>
> > Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
>
> Acked-by: James Carter <jwcart2@gmail.com>
>
Merged.
Thanks,
Jim

> > ---
> >  libsepol/src/policydb_validate.c | 12 ++++++------
> >  1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/libsepol/src/policydb_validate.c b/libsepol/src/policydb_validate.c
> > index da18282b..99d4eb7f 100644
> > --- a/libsepol/src/policydb_validate.c
> > +++ b/libsepol/src/policydb_validate.c
> > @@ -18,7 +18,7 @@ typedef struct validate {
> >  typedef struct map_arg {
> >         validate_t *flavors;
> >         sepol_handle_t *handle;
> > -       int mls;
> > +       policydb_t *policy;
> >  } map_arg_t;
> >
> >  static int create_gap_ebitmap(char **val_to_name, uint32_t nprim, ebitmap_t *gaps)
> > @@ -571,7 +571,7 @@ static int validate_mls_range(mls_range_t *range, validate_t *sens, validate_t *
> >         return -1;
> >  }
> >
> > -static int validate_user_datum(sepol_handle_t *handle, user_datum_t *user, validate_t flavors[], int mls)
> > +static int validate_user_datum(sepol_handle_t *handle, user_datum_t *user, validate_t flavors[], policydb_t *p)
> >  {
> >         if (validate_value(user->s.value, &flavors[SYM_USERS]))
> >                 goto bad;
> > @@ -581,9 +581,9 @@ static int validate_user_datum(sepol_handle_t *handle, user_datum_t *user, valid
> >                 goto bad;
> >         if (validate_mls_semantic_level(&user->dfltlevel, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
> >                 goto bad;
> > -       if (mls && validate_mls_range(&user->exp_range, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
> > +       if (p->mls && p->policy_type != POLICY_MOD && validate_mls_range(&user->exp_range, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
> >                 goto bad;
> > -       if (mls && validate_mls_level(&user->exp_dfltlevel, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
> > +       if (p->mls && p->policy_type != POLICY_MOD && validate_mls_level(&user->exp_dfltlevel, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
> >                 goto bad;
> >         if (user->bounds && validate_value(user->bounds, &flavors[SYM_USERS]))
> >                 goto bad;
> > @@ -599,7 +599,7 @@ static int validate_user_datum_wrapper(__attribute__((unused)) hashtab_key_t k,
> >  {
> >         map_arg_t *margs = args;
> >
> > -       return validate_user_datum(margs->handle, d, margs->flavors, margs->mls);
> > +       return validate_user_datum(margs->handle, d, margs->flavors, margs->policy);
> >  }
> >
> >  static int validate_bool_datum(sepol_handle_t *handle, cond_bool_datum_t *boolean, validate_t flavors[])
> > @@ -689,7 +689,7 @@ static int validate_datum(__attribute__ ((unused))hashtab_key_t k, hashtab_datum
> >
> >  static int validate_datum_array_entries(sepol_handle_t *handle, policydb_t *p, validate_t flavors[])
> >  {
> > -       map_arg_t margs = { flavors, handle, p->mls };
> > +       map_arg_t margs = { flavors, handle, p };
> >
> >         if (hashtab_map(p->p_commons.table, validate_common_datum_wrapper, &margs))
> >                 goto bad;
> > --
> > 2.36.1
> >

Re: [PATCH v2] libsepol: fix validation of user declarations in non-base modules

[James Carter]

On Thu, Jun 9, 2022 at 4:27 AM Christian Göttsche
<cgzones@googlemail.com> wrote:
>
> Users may be declared in non-base modules, which do not get expanded,
> leaving the `struct user_datum` members `exp_range` and `exp_dfltlevel`
> empty.
> Skip validation of the expanded range and level for non-base module
> polices.
>
> Reported-by: bauen1 <j2468h@gmail.com>
> Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
> ---
> v2:
>    - update commit description and fix typos

Sorry, I didn't see this patch before I applied the first one.
Jim

> ---
>  libsepol/src/policydb_validate.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/libsepol/src/policydb_validate.c b/libsepol/src/policydb_validate.c
> index da18282b..99d4eb7f 100644
> --- a/libsepol/src/policydb_validate.c
> +++ b/libsepol/src/policydb_validate.c
> @@ -18,7 +18,7 @@ typedef struct validate {
>  typedef struct map_arg {
>         validate_t *flavors;
>         sepol_handle_t *handle;
> -       int mls;
> +       policydb_t *policy;
>  } map_arg_t;
>
>  static int create_gap_ebitmap(char **val_to_name, uint32_t nprim, ebitmap_t *gaps)
> @@ -571,7 +571,7 @@ static int validate_mls_range(mls_range_t *range, validate_t *sens, validate_t *
>         return -1;
>  }
>
> -static int validate_user_datum(sepol_handle_t *handle, user_datum_t *user, validate_t flavors[], int mls)
> +static int validate_user_datum(sepol_handle_t *handle, user_datum_t *user, validate_t flavors[], policydb_t *p)
>  {
>         if (validate_value(user->s.value, &flavors[SYM_USERS]))
>                 goto bad;
> @@ -581,9 +581,9 @@ static int validate_user_datum(sepol_handle_t *handle, user_datum_t *user, valid
>                 goto bad;
>         if (validate_mls_semantic_level(&user->dfltlevel, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
>                 goto bad;
> -       if (mls && validate_mls_range(&user->exp_range, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
> +       if (p->mls && p->policy_type != POLICY_MOD && validate_mls_range(&user->exp_range, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
>                 goto bad;
> -       if (mls && validate_mls_level(&user->exp_dfltlevel, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
> +       if (p->mls && p->policy_type != POLICY_MOD && validate_mls_level(&user->exp_dfltlevel, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
>                 goto bad;
>         if (user->bounds && validate_value(user->bounds, &flavors[SYM_USERS]))
>                 goto bad;
> @@ -599,7 +599,7 @@ static int validate_user_datum_wrapper(__attribute__((unused)) hashtab_key_t k,
>  {
>         map_arg_t *margs = args;
>
> -       return validate_user_datum(margs->handle, d, margs->flavors, margs->mls);
> +       return validate_user_datum(margs->handle, d, margs->flavors, margs->policy);
>  }
>
>  static int validate_bool_datum(sepol_handle_t *handle, cond_bool_datum_t *boolean, validate_t flavors[])
> @@ -689,7 +689,7 @@ static int validate_datum(__attribute__ ((unused))hashtab_key_t k, hashtab_datum
>
>  static int validate_datum_array_entries(sepol_handle_t *handle, policydb_t *p, validate_t flavors[])
>  {
> -       map_arg_t margs = { flavors, handle, p->mls };
> +       map_arg_t margs = { flavors, handle, p };
>
>         if (hashtab_map(p->p_commons.table, validate_common_datum_wrapper, &margs))
>                 goto bad;
> --
> 2.36.1
>