On 04/13/2011 11:23 AM, Steve Lawrence wrote:
> Thanks for the patch. This solves the problem, but I'm still seeing
> issues that seems related to support of older version of policy when
> using role_transition with non-process classes. I'm now seeing an mls
> range overflow error:
>
> libsepol.role_trans_write: Discarding role_transition rules for security
> class other than "process"
> libsepol.mls_read_range_helper: range overflow
> libsepol.context_read_and_validate: error reading MLS range of context
> libsepol.policydb_to_image: new policy image is invalid
>
> I'm still looking into it, but I'm not too familiar this part of the code.
>
>
> On 04/12/2011 05:11 PM, Eric Paris wrote:
>> Although the role trans code had support to handle the kernel policy
>> when the version was less that roletrans such support was not in the
>> module read/write code. This patch adds proper support for role trans
>> in modules.
>>
>> Signed-off-by: Eric Paris <eparis@xxxxxxxxxx>
>> ---
>> libsepol/src/policydb.c | 14 ++++++++++----
>> libsepol/src/write.c | 37 ++++++++++++++++++++++++++++++++-----
>> 2 files changed, 42 insertions(+), 9 deletions(-)
>>
>> diff --git a/libsepol/src/policydb.c b/libsepol/src/policydb.c
>> index 2ecb636..6d8ff91 100644
>> --- a/libsepol/src/policydb.c
>> +++ b/libsepol/src/policydb.c
>> @@ -3033,7 +3033,8 @@ int avrule_read_list(policydb_t * p, avrule_t ** avrules,
>> return 0;
>> }
>>
>> -static int role_trans_rule_read(role_trans_rule_t ** r, struct policy_file *fp)
>> +static int role_trans_rule_read(policydb_t *p, role_trans_rule_t ** r,
>> + struct policy_file *fp)
>> {
>> uint32_t buf[1], nel;
>> unsigned int i;
>> @@ -3064,8 +3065,13 @@ static int role_trans_rule_read(role_trans_rule_t ** r, struct policy_file *fp)
>> if (type_set_read(&tr->types, fp))
>> return -1;
>>
>> - if (ebitmap_read(&tr->classes, fp))
>> - return -1;
>> + if (p->policyvers >= MOD_POLICYDB_VERSION_ROLETRANS) {
>> + if (ebitmap_read(&tr->classes, fp))
>> + return -1;
>> + } else {
>> + if (ebitmap_set_bit(&tr->classes, SECCLASS_PROCESS - 1, 1))
>> + return -1;
>> + }
>>
>> rc = next_entry(buf, fp, sizeof(uint32_t));
>> if (rc < 0)
>> @@ -3258,7 +3264,7 @@ static int avrule_decl_read(policydb_t * p, avrule_decl_t * decl,
>> decl->enabled = le32_to_cpu(buf[1]);
>> if (cond_read_list(p, &decl->cond_list, fp) == -1 ||
>> avrule_read_list(p, &decl->avrules, fp) == -1 ||
>> - role_trans_rule_read(&decl->role_tr_rules, fp) == -1 ||
>> + role_trans_rule_read(p, &decl->role_tr_rules, fp) == -1 ||
>> role_allow_rule_read(&decl->role_allow_rules, fp) == -1) {
>> return -1;
>> }
>> diff --git a/libsepol/src/write.c b/libsepol/src/write.c
>> index c4f5035..78b3aa6 100644
>> --- a/libsepol/src/write.c
>> +++ b/libsepol/src/write.c
>> @@ -1482,26 +1482,53 @@ static int avrule_write_list(avrule_t * avrules, struct policy_file *fp)
>> return POLICYDB_SUCCESS;
>> }
>>
>> -static int role_trans_rule_write(role_trans_rule_t * t, struct policy_file *fp)
>> +static int only_process(ebitmap_t *in)
>> +{
>> + unsigned int i;
>> + ebitmap_node_t *node;
>> +
>> + ebitmap_for_each_bit(in, node, i) {
>> + if (ebitmap_node_get_bit(node, i) &&
>> + i != SECCLASS_PROCESS - 1)
>> + return 0;
>> + }
>> + return 1;
>> +}
>> +
>> +static int role_trans_rule_write(policydb_t *p, role_trans_rule_t * t,
>> + struct policy_file *fp)
>> {
>> int nel = 0;
>> size_t items;
>> uint32_t buf[1];
>> role_trans_rule_t *tr;
>> + int warned = 0;
>> + int new_role = p->policyvers >= MOD_POLICYDB_VERSION_ROLETRANS;
>>
>> for (tr = t; tr; tr = tr->next)
>> - nel++;
>> + if (new_role || only_process(&tr->classes))
>> + nel++;
>> +
>> buf[0] = cpu_to_le32(nel);
>> items = put_entry(buf, sizeof(uint32_t), 1, fp);
>> if (items != 1)
>> return POLICYDB_ERROR;
>> for (tr = t; tr; tr = tr->next) {
>> + if (!new_role && !only_process(&tr->classes)) {
>> + if (!warned)
>> + WARN(fp->handle, "Discarding role_transition "
>> + "rules for security classes other than "
>> + "\"process\"");
>> + warned = 1;
>> + continue;
>> + }
>> if (role_set_write(&tr->roles, fp))
>> return POLICYDB_ERROR;
>> if (type_set_write(&tr->types, fp))
>> return POLICYDB_ERROR;
>> - if (ebitmap_write(&tr->classes, fp))
>> - return POLICYDB_ERROR;
>> + if (new_role)
>> + if (ebitmap_write(&tr->classes, fp))
>> + return POLICYDB_ERROR;
>> buf[0] = cpu_to_le32(tr->new_role);
>> items = put_entry(buf, sizeof(uint32_t), 1, fp);
>> if (items != 1)
>> @@ -1636,7 +1663,7 @@ static int avrule_decl_write(avrule_decl_t * decl, int num_scope_syms,
>> }
>> if (cond_write_list(p, decl->cond_list, fp) == -1 ||
>> avrule_write_list(decl->avrules, fp) == -1 ||
>> - role_trans_rule_write(decl->role_tr_rules, fp) == -1 ||
>> + role_trans_rule_write(p, decl->role_tr_rules, fp) == -1 ||
>> role_allow_rule_write(decl->role_allow_rules, fp) == -1) {
>> return POLICYDB_ERROR;
>> }
>
>
> --
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I think the below patch fixes the problem I was seeing. Some rules were
getting discarded in role_trans_write during a policy downgrade, but the
count was not being decreased. This fix is similar to your fix in
role_trans_rule_write.
---
diff --git a/libsepol/src/write.c b/libsepol/src/write.c
index 78b3aa6..3a9c35a 100644
--- a/libsepol/src/write.c
+++ b/libsepol/src/write.c
@@ -474,7 +474,9 @@ static int role_trans_write(policydb_t *p, struct
policy_file *fp)
nel = 0;
for (tr = r; tr; tr = tr->next)
- nel++;
+ if(new_roletr || tr->class == SECCLASS_PROCESS)
+ nel++;
+
buf[0] = cpu_to_le32(nel);
items = put_entry(buf, sizeof(uint32_t), 1, fp);
if (items != 1)
--
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