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apparmor: group dfa policydb unpacking

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There are currently three policydb rule groupings (xmatch, file,
policydb) that each do their own slightly different thing. Group them
into a single routine and unify.

This extends/unifies dfa features by
- all dfas are allowed having an optional start field
- all dfas are allowed having a string/transition table

Signed-off-by: John Johansen <john.johansen@canonical.com>
This commit is contained in:
John Johansen 2022-07-18 16:53:17 -07:00
parent a0792e2ced
commit ad596ea74e
1 changed files with 63 additions and 38 deletions
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101
security/apparmor/policy_unpack.c
View File

@ -648,6 +648,54 @@ fail:
return false;
}
static int unpack_pdb(struct aa_ext *e, struct aa_policydb *policy,
bool required_dfa, bool required_trans,
const char **info)
{
int i;
policy->dfa = unpack_dfa(e);
if (IS_ERR(policy->dfa)) {
int error = PTR_ERR(policy->dfa);
policy->dfa = NULL;
*info = "failed to unpack - dfa";
return error;
} else if (!policy->dfa) {
if (required_dfa) {
*info = "missing required dfa";
return -EPROTO;
}
goto out;
}
/*
* only unpack the following if a dfa is present
*
* sadly start was given different names for file and policydb
* but since it is optional we can try both
*/
if (!unpack_u32(e, &policy->start[0], "start"))
/* default start state */
policy->start[0] = DFA_START;
if (!unpack_u32(e, &policy->start[AA_CLASS_FILE], "dfa_start")) {
/* default start state for xmatch and file dfa */
policy->start[AA_CLASS_FILE] = DFA_START;
} /* setup class index */
for (i = AA_CLASS_FILE + 1; i <= AA_CLASS_LAST; i++) {
policy->start[i] = aa_dfa_next(policy->dfa, policy->start[0],
i);
}
if (!unpack_trans_table(e, &policy->trans) && required_trans) {
*info = "failed to unpack profile transition table";
return -EPROTO;
}
/* TODO: move compat mapping here, requires dfa merging first */
out:
return 0;
}
static u32 strhash(const void *data, u32 len, u32 seed)
{
const char * const *key = data;
@ -679,7 +727,7 @@ static struct aa_profile *unpack_profile(struct aa_ext *e, char **ns_name)
struct rhashtable_params params = { 0 };
char *key = NULL;
struct aa_data *data;
int i, error = -EPROTO;
int error = -EPROTO;
kernel_cap_t tmpcap;
u32 tmp;
@ -714,13 +762,10 @@ static struct aa_profile *unpack_profile(struct aa_ext *e, char **ns_name)
(void) unpack_str(e, &profile->attach, "attach");
/* xmatch is optional and may be NULL */
profile->xmatch.dfa = unpack_dfa(e);
if (IS_ERR(profile->xmatch.dfa)) {
error = PTR_ERR(profile->xmatch.dfa);
profile->xmatch.dfa = NULL;
info = "bad xmatch";
error = unpack_pdb(e, &profile->xmatch, false, false, &info);
if (error)
goto fail;
}
/* neither xmatch_len not xmatch_perms are optional if xmatch is set */
if (profile->xmatch.dfa) {
if (!unpack_u32(e, &tmp, NULL)) {
@ -838,25 +883,16 @@ static struct aa_profile *unpack_profile(struct aa_ext *e, char **ns_name)
if (unpack_nameX(e, AA_STRUCT, "policydb")) {
/* generic policy dfa - optional and may be NULL */
info = "failed to unpack policydb";
profile->policy.dfa = unpack_dfa(e);
if (IS_ERR(profile->policy.dfa)) {
error = PTR_ERR(profile->policy.dfa);
profile->policy.dfa = NULL;
error = unpack_pdb(e, &profile->policy, true, false, &info);
if (error)
goto fail;
} else if (!profile->policy.dfa) {
error = -EPROTO;
goto fail;
}
if (!unpack_u32(e, &profile->policy.start[0], "start"))
/* default start state */
profile->policy.start[0] = DFA_START;
/* setup class index */
for (i = AA_CLASS_FILE; i <= AA_CLASS_LAST; i++) {
profile->policy.start[i] =
aa_dfa_next(profile->policy.dfa,
profile->policy.start[0],
i);
}
/* Fixup: drop when we get rid of start array */
if (aa_dfa_next(profile->policy.dfa, profile->policy.start[0],
AA_CLASS_FILE))
profile->policy.start[AA_CLASS_FILE] =
aa_dfa_next(profile->policy.dfa,
profile->policy.start[0],
AA_CLASS_FILE);
if (!unpack_nameX(e, AA_STRUCTEND, NULL))
goto fail;
if (aa_compat_map_policy(&profile->policy, e->version)) {
@ -867,25 +903,14 @@ static struct aa_profile *unpack_profile(struct aa_ext *e, char **ns_name)
profile->policy.dfa = aa_get_dfa(nulldfa);
/* get file rules */
profile->file.dfa = unpack_dfa(e);
if (IS_ERR(profile->file.dfa)) {
error = PTR_ERR(profile->file.dfa);
profile->file.dfa = NULL;
info = "failed to unpack profile file rules";
error = unpack_pdb(e, &profile->file, false, true, &info);
if (error) {
goto fail;
} else if (profile->file.dfa) {
if (!unpack_u32(e, &profile->file.start[AA_CLASS_FILE],
"dfa_start"))
/* default start state */
profile->file.start[AA_CLASS_FILE] = DFA_START;
if (aa_compat_map_file(&profile->file)) {
info = "failed to remap file permission table";
goto fail;
}
if (!unpack_trans_table(e, &profile->file.trans)) {
info = "failed to unpack profile transition table";
goto fail;
}
} else if (profile->policy.dfa &&
profile->policy.start[AA_CLASS_FILE]) {
profile->file.dfa = aa_get_dfa(profile->policy.dfa);