From: James Carter <jwcart2@gmail.com>
To: Ondrej Mosnacek <omosnace@redhat.com>
Cc: "SElinux list" <selinux@vger.kernel.org>,
"Dominick Grift" <dominick.grift@defensec.nl>,
"Christian Göttsche" <cgzones@googlemail.com>
Subject: Re: [PATCH userspace v2 2/2] libsepol,checkpolicy: add support for self keyword in type transitions
Date: Thu, 28 Apr 2022 15:23:34 -0400 [thread overview]
Message-ID: <CAP+JOzTpJ4XROVjo9-rOmh97rwiEOp2YPxXSuUOQtLbRWX0kGg@mail.gmail.com> (raw)
In-Reply-To: <20220426105118.506847-3-omosnace@redhat.com>
On Wed, Apr 27, 2022 at 6:14 AM Ondrej Mosnacek <omosnace@redhat.com> wrote:
>
> With the addition of the anon_inode class in the kernel, 'self'
> transition rules became useful, but haven't been implemented.
>
> This patch implements the self keyword in all 'typetransition'
> statements at the TE language level and adds the support to the module
> policydb format. Note that changing the kernel policydb format is not
> necessary at all, as type transitions are always expanded in the kernel
> policydb.
>
These patches also cause "self" to be allowed in type change and type
member rules as well. That is fine, but it should be stated.
Another comment below.
> Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
> ---
> checkpolicy/policy_define.c | 42 ++++++++++++-
> libsepol/include/sepol/policydb/policydb.h | 4 +-
> libsepol/src/expand.c | 69 ++++++++++++++--------
> libsepol/src/link.c | 1 +
> libsepol/src/module_to_cil.c | 30 ++++++----
> libsepol/src/policydb.c | 33 +++++++++--
> libsepol/src/policydb_validate.c | 4 ++
> libsepol/src/write.c | 19 ++++--
> 8 files changed, 153 insertions(+), 49 deletions(-)
>
> diff --git a/checkpolicy/policy_define.c b/checkpolicy/policy_define.c
> index 16b78346..7e328edc 100644
> --- a/checkpolicy/policy_define.c
> +++ b/checkpolicy/policy_define.c
> @@ -1634,6 +1634,15 @@ static int define_compute_type_helper(int which, avrule_t ** rule)
> }
> add = 1;
> while ((id = queue_remove(id_queue))) {
> + if (strcmp(id, "self") == 0) {
> + free(id);
> + if (add == 0) {
> + yyerror("-self is not supported");
> + goto bad;
> + }
> + avrule->flags |= RULE_SELF;
> + continue;
> + }
> if (set_types(&avrule->ttypes, id, &add, 0))
> goto bad;
> }
> @@ -3300,7 +3309,7 @@ int define_filename_trans(void)
> type_datum_t *typdatum;
> uint32_t otype;
> unsigned int c, s, t;
> - int add, rc;
> + int add, self, rc;
>
> if (pass == 1) {
> /* stype */
> @@ -3333,8 +3342,18 @@ int define_filename_trans(void)
> goto bad;
> }
>
> - add =1;
> + self = 0;
> + add = 1;
> while ((id = queue_remove(id_queue))) {
> + if (strcmp(id, "self") == 0) {
> + free(id);
> + if (add == 0) {
> + yyerror("-self is not supported");
> + goto bad;
> + }
> + self = 1;
> + continue;
> + }
> if (set_types(&ttypes, id, &add, 0))
> goto bad;
> }
> @@ -3396,6 +3415,24 @@ int define_filename_trans(void)
> goto bad;
> }
> }
> + if (self) {
> + rc = policydb_filetrans_insert(
> + policydbp, s+1, s+1, c+1, name,
> + NULL, otype, NULL
> + );
> + if (rc != SEPOL_OK) {
> + if (rc == SEPOL_EEXIST) {
> + yyerror2("duplicate filename transition for: filename_trans %s %s %s:%s",
> + name,
> + policydbp->p_type_val_to_name[s],
> + policydbp->p_type_val_to_name[s],
> + policydbp->p_class_val_to_name[c]);
> + goto bad;
> + }
> + yyerror("out of memory");
> + goto bad;
> + }
> + }
> }
>
> /* Now add the real rule since we didn't find any duplicates */
> @@ -3418,6 +3455,7 @@ int define_filename_trans(void)
> }
> ftr->tclass = c + 1;
> ftr->otype = otype;
> + ftr->flags = self ? RULE_SELF : 0;
> }
>
> free(name);
> diff --git a/libsepol/include/sepol/policydb/policydb.h b/libsepol/include/sepol/policydb/policydb.h
> index 4bf9f05d..de0068a6 100644
> --- a/libsepol/include/sepol/policydb/policydb.h
> +++ b/libsepol/include/sepol/policydb/policydb.h
> @@ -314,6 +314,7 @@ typedef struct role_allow_rule {
> } role_allow_rule_t;
>
> typedef struct filename_trans_rule {
> + uint32_t flags; /* may have RULE_SELF set */
> type_set_t stypes;
> type_set_t ttypes;
> uint32_t tclass;
> @@ -781,9 +782,10 @@ extern int policydb_set_target_platform(policydb_t *p, int platform);
> #define MOD_POLICYDB_VERSION_XPERMS_IOCTL 18
> #define MOD_POLICYDB_VERSION_INFINIBAND 19
> #define MOD_POLICYDB_VERSION_GLBLUB 20
> +#define MOD_POLICYDB_VERSION_SELF_TYPETRANS 21
>
> #define MOD_POLICYDB_VERSION_MIN MOD_POLICYDB_VERSION_BASE
> -#define MOD_POLICYDB_VERSION_MAX MOD_POLICYDB_VERSION_GLBLUB
> +#define MOD_POLICYDB_VERSION_MAX MOD_POLICYDB_VERSION_SELF_TYPETRANS
>
> #define POLICYDB_CONFIG_MLS 1
>
> diff --git a/libsepol/src/expand.c b/libsepol/src/expand.c
> index 7316124f..8d19850e 100644
> --- a/libsepol/src/expand.c
> +++ b/libsepol/src/expand.c
> @@ -1407,6 +1407,40 @@ static int copy_role_trans(expand_state_t * state, role_trans_rule_t * rules)
> return 0;
> }
>
> +static int expand_filename_trans_helper(expand_state_t *state,
> + filename_trans_rule_t *rule,
> + unsigned int s, unsigned int t)
> +{
> + uint32_t mapped_otype, present_otype;
> + int rc;
> +
> + mapped_otype = state->typemap[rule->otype - 1];
> +
> + rc = policydb_filetrans_insert(
> + state->out, s + 1, t + 1,
> + rule->tclass, rule->name,
> + NULL, mapped_otype, &present_otype
> + );
> + if (rc == SEPOL_EEXIST) {
> + /* duplicate rule, ignore */
> + if (present_otype == mapped_otype)
> + return 0;
> +
> + ERR(state->handle, "Conflicting name-based type_transition %s %s:%s \"%s\": %s vs %s",
> + state->out->p_type_val_to_name[s],
> + state->out->p_type_val_to_name[t],
> + state->out->p_class_val_to_name[rule->tclass - 1],
> + rule->name,
> + state->out->p_type_val_to_name[present_otype - 1],
> + state->out->p_type_val_to_name[mapped_otype - 1]);
> + return -1;
> + } else if (rc < 0) {
> + ERR(state->handle, "Out of memory!");
> + return -1;
> + }
> + return 0;
> +}
> +
> static int expand_filename_trans(expand_state_t *state, filename_trans_rule_t *rules)
> {
> unsigned int i, j;
> @@ -1417,8 +1451,6 @@ static int expand_filename_trans(expand_state_t *state, filename_trans_rule_t *r
>
> cur_rule = rules;
> while (cur_rule) {
> - uint32_t mapped_otype, present_otype;
> -
> ebitmap_init(&stypes);
> ebitmap_init(&ttypes);
>
> @@ -1434,32 +1466,21 @@ static int expand_filename_trans(expand_state_t *state, filename_trans_rule_t *r
> return -1;
> }
>
> - mapped_otype = state->typemap[cur_rule->otype - 1];
>
> ebitmap_for_each_positive_bit(&stypes, snode, i) {
> ebitmap_for_each_positive_bit(&ttypes, tnode, j) {
> - rc = policydb_filetrans_insert(
> - state->out, i + 1, j + 1,
> - cur_rule->tclass, cur_rule->name,
> - NULL, mapped_otype, &present_otype
> + rc = expand_filename_trans_helper(
> + state, cur_rule, i, j
> );
> - if (rc == SEPOL_EEXIST) {
> - /* duplicate rule, ignore */
> - if (present_otype == mapped_otype)
> - continue;
> -
> - ERR(state->handle, "Conflicting name-based type_transition %s %s:%s \"%s\": %s vs %s",
> - state->out->p_type_val_to_name[i],
> - state->out->p_type_val_to_name[j],
> - state->out->p_class_val_to_name[cur_rule->tclass - 1],
> - cur_rule->name,
> - state->out->p_type_val_to_name[present_otype - 1],
> - state->out->p_type_val_to_name[mapped_otype - 1]);
> - return -1;
> - } else if (rc < 0) {
> - ERR(state->handle, "Out of memory!");
> - return -1;
> - }
> + if (rc)
> + return rc;
> + }
> + if (cur_rule->flags & RULE_SELF) {
> + rc = expand_filename_trans_helper(
> + state, cur_rule, i, i
> + );
> + if (rc)
> + return rc;
> }
> }
>
> diff --git a/libsepol/src/link.c b/libsepol/src/link.c
> index ecfb5786..7e8313cb 100644
> --- a/libsepol/src/link.c
> +++ b/libsepol/src/link.c
> @@ -1482,6 +1482,7 @@ static int copy_filename_trans_list(filename_trans_rule_t * list,
>
> new_rule->tclass = module->map[SYM_CLASSES][cur->tclass - 1];
> new_rule->otype = module->map[SYM_TYPES][cur->otype - 1];
> + new_rule->flags = cur->flags;
>
> cur = cur->next;
> }
> diff --git a/libsepol/src/module_to_cil.c b/libsepol/src/module_to_cil.c
> index 156a74a2..0e211c93 100644
> --- a/libsepol/src/module_to_cil.c
> +++ b/libsepol/src/module_to_cil.c
> @@ -1608,20 +1608,30 @@ static int filename_trans_to_cil(int indent, struct policydb *pdb, struct filena
> goto exit;
> }
>
> - ts = &rule->ttypes;
> - rc = process_typeset(pdb, ts, attr_list, &ttypes, &num_ttypes);
> - if (rc != 0) {
> - goto exit;
> - }
> -
> - for (stype = 0; stype < num_stypes; stype++) {
> - for (ttype = 0; ttype < num_ttypes; ttype++) {
> - cil_println(indent, "(typetransition %s %s %s \"%s\" %s)",
> - stypes[stype], ttypes[ttype],
> + if (rule->flags & RULE_SELF) {
> + for (stype = 0; stype < num_stypes; stype++) {
> + cil_println(indent, "(typetransition %s self %s \"%s\" %s)",
> + stypes[stype],
> pdb->p_class_val_to_name[rule->tclass - 1],
> rule->name,
> pdb->p_type_val_to_name[rule->otype - 1]);
> }
> + } else {
> + ts = &rule->ttypes;
> + rc = process_typeset(pdb, ts, attr_list, &ttypes, &num_ttypes);
> + if (rc != 0) {
> + goto exit;
> + }
> +
> + for (stype = 0; stype < num_stypes; stype++) {
> + for (ttype = 0; ttype < num_ttypes; ttype++) {
> + cil_println(indent, "(typetransition %s %s %s \"%s\" %s)",
> + stypes[stype], ttypes[ttype],
> + pdb->p_class_val_to_name[rule->tclass - 1],
> + rule->name,
> + pdb->p_type_val_to_name[rule->otype - 1]);
> + }
> + }
> }
>
> names_destroy(&stypes, &num_stypes);
> diff --git a/libsepol/src/policydb.c b/libsepol/src/policydb.c
> index 7c99571f..fc260eb6 100644
> --- a/libsepol/src/policydb.c
> +++ b/libsepol/src/policydb.c
> @@ -327,6 +327,13 @@ static const struct policydb_compat_info policydb_compat[] = {
> .ocon_num = OCON_IBENDPORT + 1,
> .target_platform = SEPOL_TARGET_SELINUX,
> },
> + {
> + .type = POLICY_BASE,
> + .version = MOD_POLICYDB_VERSION_SELF_TYPETRANS,
> + .sym_num = SYM_NUM,
> + .ocon_num = OCON_IBENDPORT + 1,
> + .target_platform = SEPOL_TARGET_SELINUX,
> + },
> {
> .type = POLICY_MOD,
> .version = MOD_POLICYDB_VERSION_BASE,
> @@ -446,7 +453,13 @@ static const struct policydb_compat_info policydb_compat[] = {
> .ocon_num = 0,
> .target_platform = SEPOL_TARGET_SELINUX,
> },
> -
> + {
> + .type = POLICY_MOD,
> + .version = MOD_POLICYDB_VERSION_SELF_TYPETRANS,
> + .sym_num = SYM_NUM,
> + .ocon_num = 0,
> + .target_platform = SEPOL_TARGET_SELINUX,
> + },
> };
>
> #if 0
> @@ -3822,10 +3835,11 @@ static int role_allow_rule_read(role_allow_rule_t ** r, struct policy_file *fp)
> return 0;
> }
>
> -static int filename_trans_rule_read(filename_trans_rule_t ** r, struct policy_file *fp)
> +static int filename_trans_rule_read(policydb_t *p, filename_trans_rule_t **r,
> + struct policy_file *fp)
> {
> - uint32_t buf[2], nel;
> - unsigned int i, len;
> + uint32_t buf[3], nel, i, len;
> + unsigned int entries;
> filename_trans_rule_t *ftr, *lftr;
> int rc;
>
> @@ -3870,11 +3884,18 @@ static int filename_trans_rule_read(filename_trans_rule_t ** r, struct policy_fi
> if (type_set_read(&ftr->ttypes, fp))
> return -1;
>
> - rc = next_entry(buf, fp, sizeof(uint32_t) * 2);
> + if (p->policyvers >= MOD_POLICYDB_VERSION_SELF_TYPETRANS)
> + entries = 3;
> + else
> + entries = 2;
> +
> + rc = next_entry(buf, fp, sizeof(uint32_t) * entries);
> if (rc < 0)
> return -1;
> ftr->tclass = le32_to_cpu(buf[0]);
> ftr->otype = le32_to_cpu(buf[1]);
> + if (p->policyvers >= MOD_POLICYDB_VERSION_SELF_TYPETRANS)
> + ftr->flags = le32_to_cpu(buf[2]);
> }
>
> return 0;
> @@ -3977,7 +3998,7 @@ static int avrule_decl_read(policydb_t * p, avrule_decl_t * decl,
> }
>
> if (p->policyvers >= MOD_POLICYDB_VERSION_FILENAME_TRANS &&
> - filename_trans_rule_read(&decl->filename_trans_rules, fp))
> + filename_trans_rule_read(p, &decl->filename_trans_rules, fp))
> return -1;
>
> if (p->policyvers >= MOD_POLICYDB_VERSION_RANGETRANS &&
> diff --git a/libsepol/src/policydb_validate.c b/libsepol/src/policydb_validate.c
> index 13d9480d..da18282b 100644
> --- a/libsepol/src/policydb_validate.c
> +++ b/libsepol/src/policydb_validate.c
> @@ -1184,6 +1184,10 @@ static int validate_filename_trans_rules(sepol_handle_t *handle, filename_trans_
> goto bad;
> if (validate_value(filename_trans->otype, &flavors[SYM_TYPES]))
> goto bad;
> +
> + /* currently only the RULE_SELF flag can be set */
> + if ((filename_trans->flags & ~RULE_SELF) != 0)
> + goto bad;
> }
>
> return 0;
> diff --git a/libsepol/src/write.c b/libsepol/src/write.c
> index d7ac2b25..5f593c1d 100644
> --- a/libsepol/src/write.c
> +++ b/libsepol/src/write.c
> @@ -1929,11 +1929,12 @@ static int role_allow_rule_write(role_allow_rule_t * r, struct policy_file *fp)
> return POLICYDB_SUCCESS;
> }
>
> -static int filename_trans_rule_write(filename_trans_rule_t * t, struct policy_file *fp)
> +static int filename_trans_rule_write(policydb_t *p, filename_trans_rule_t *t,
> + struct policy_file *fp)
> {
> int nel = 0;
> - size_t items;
> - uint32_t buf[2], len;
> + size_t items, entries;
> + uint32_t buf[3], len;
> filename_trans_rule_t *ftr;
>
> for (ftr = t; ftr; ftr = ftr->next)
The flags field needs to be cleared if the policy version being
written is < MOD_POLICYDB_VERSION_SELF_TYPETRANS.
Something like:
+ if ((p->policyvers < MOD_POLICYDB_VERSION_SELF_TYPETRANS) &&
+ (ftr->flags & RULE_SELF)) {
+ WARN(fp->handle, "Module policy version %u does not support using "
+ "\"self\" in a filename type transition rule", p->policyvers);
+ ftr->flags &= ~RULE_SELF;
+ }
A similar check is needed in avrule_write(), but there needs to be a
check that the rule is an AVRULE_TYPE as well.
Everything else seems to work fine.
Thanks,
Jim
> @@ -1962,9 +1963,15 @@ static int filename_trans_rule_write(filename_trans_rule_t * t, struct policy_fi
>
> buf[0] = cpu_to_le32(ftr->tclass);
> buf[1] = cpu_to_le32(ftr->otype);
> + buf[2] = cpu_to_le32(ftr->flags);
>
> - items = put_entry(buf, sizeof(uint32_t), 2, fp);
> - if (items != 2)
> + if (p->policyvers >= MOD_POLICYDB_VERSION_SELF_TYPETRANS)
> + entries = 3;
> + else
> + entries = 2;
> +
> + items = put_entry(buf, sizeof(uint32_t), entries, fp);
> + if (items != entries)
> return POLICYDB_ERROR;
> }
> return POLICYDB_SUCCESS;
> @@ -2039,7 +2046,7 @@ static int avrule_decl_write(avrule_decl_t * decl, int num_scope_syms,
> }
>
> if (p->policyvers >= MOD_POLICYDB_VERSION_FILENAME_TRANS &&
> - filename_trans_rule_write(decl->filename_trans_rules, fp))
> + filename_trans_rule_write(p, decl->filename_trans_rules, fp))
> return POLICYDB_ERROR;
>
> if (p->policyvers >= MOD_POLICYDB_VERSION_RANGETRANS &&
> --
> 2.35.1
>
next prev parent reply other threads:[~2022-04-28 19:23 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-26 10:51 [PATCH userspace v2 0/2] Support the 'self' keyword in type transitions Ondrej Mosnacek
2022-04-26 10:51 ` [PATCH userspace v2 1/2] libsepol/cil: add support for self " Ondrej Mosnacek
2022-04-26 10:51 ` [PATCH userspace v2 2/2] libsepol,checkpolicy: " Ondrej Mosnacek
2022-04-27 15:22 ` James Carter
2022-04-28 19:23 ` James Carter [this message]
2022-05-06 13:49 ` Ondrej Mosnacek
2022-05-06 15:42 ` James Carter
2022-05-09 9:27 ` Ondrej Mosnacek
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