From 62e644c79d558d9f93bbc64b172145aff38ce8e0 Mon Sep 17 00:00:00 2001
From: John Johansen <john.johansen@canonical.com>
Date: Fri, 9 Jun 2017 16:55:04 -0700
Subject: [PATCH 59/65] apparmor: move exec domain mediation to using labels
Git-commit: 93c98a484c4900f0d2c65c16466d45f90ea5b175
Patch-mainline: v4.13-rc1
References: FATE#323500
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
---
security/apparmor/domain.c | 850 ++++++++++++++++++++++++++++------------
security/apparmor/include/lib.h | 87 +++-
2 files changed, 678 insertions(+), 259 deletions(-)
diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c
index 896bca01828e..cb8509373ea3 100644
--- a/security/apparmor/domain.c
+++ b/security/apparmor/domain.c
@@ -87,42 +87,236 @@ static int may_change_ptraced_domain(struct aa_label *to_label,
return error;
}
+/**** TODO: dedup to aa_label_match - needs perm and dfa, merging
+ * specifically this is an exact copy of aa_label_match except
+ * aa_compute_perms is replaced with aa_compute_fperms
+ * and policy.dfa with file.dfa
+ ****/
+/* match a profile and its associated ns component if needed
+ * Assumes visibility test has already been done.
+ * If a subns profile is not to be matched should be prescreened with
+ * visibility test.
+ */
+static inline unsigned int match_component(struct aa_profile *profile,
+ struct aa_profile *tp,
+ bool stack, unsigned int state)
+{
+ const char *ns_name;
+
+ if (stack)
+ state = aa_dfa_match(profile->file.dfa, state, "&");
+ if (profile->ns == tp->ns)
+ return aa_dfa_match(profile->file.dfa, state, tp->base.hname);
+
+ /* try matching with namespace name and then profile */
+ ns_name = aa_ns_name(profile->ns, tp->ns, true);
+ state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
+ state = aa_dfa_match(profile->file.dfa, state, ns_name);
+ state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
+ return aa_dfa_match(profile->file.dfa, state, tp->base.hname);
+}
+
+/**
+ * label_compound_match - find perms for full compound label
+ * @profile: profile to find perms for
+ * @label: label to check access permissions for
+ * @stack: whether this is a stacking request
+ * @start: state to start match in
+ * @subns: whether to do permission checks on components in a subns
+ * @request: permissions to request
+ * @perms: perms struct to set
+ *
+ * Returns: 0 on success else ERROR
+ *
+ * For the label A//&B//&C this does the perm match for A//&B//&C
+ * @perms should be preinitialized with allperms OR a previous permission
+ * check to be stacked.
+ */
+static int label_compound_match(struct aa_profile *profile,
+ struct aa_label *label, bool stack,
+ unsigned int state, bool subns, u32 request,
+ struct aa_perms *perms)
+{
+ struct aa_profile *tp;
+ struct label_it i;
+ struct path_cond cond = { };
+
+ /* find first subcomponent that is visible */
+ label_for_each(i, label, tp) {
+ if (!aa_ns_visible(profile->ns, tp->ns, subns))
+ continue;
+ state = match_component(profile, tp, stack, state);
+ if (!state)
+ goto fail;
+ goto next;
+ }
+
+ /* no component visible */
+ *perms = allperms;
+ return 0;
+
+next:
+ label_for_each_cont(i, label, tp) {
+ if (!aa_ns_visible(profile->ns, tp->ns, subns))
+ continue;
+ state = aa_dfa_match(profile->file.dfa, state, "//&");
+ state = match_component(profile, tp, false, state);
+ if (!state)
+ goto fail;
+ }
+ *perms = aa_compute_fperms(profile->file.dfa, state, &cond);
+ aa_apply_modes_to_perms(profile, perms);
+ if ((perms->allow & request) != request)
+ return -EACCES;
+
+ return 0;
+
+fail:
+ *perms = nullperms;
+ return -EACCES;
+}
+
+/**
+ * label_components_match - find perms for all subcomponents of a label
+ * @profile: profile to find perms for
+ * @label: label to check access permissions for
+ * @stack: whether this is a stacking request
+ * @start: state to start match in
+ * @subns: whether to do permission checks on components in a subns
+ * @request: permissions to request
+ * @perms: an initialized perms struct to add accumulation to
+ *
+ * Returns: 0 on success else ERROR
+ *
+ * For the label A//&B//&C this does the perm match for each of A and B and C
+ * @perms should be preinitialized with allperms OR a previous permission
+ * check to be stacked.
+ */
+static int label_components_match(struct aa_profile *profile,
+ struct aa_label *label, bool stack,
+ unsigned int start, bool subns, u32 request,
+ struct aa_perms *perms)
+{
+ struct aa_profile *tp;
+ struct label_it i;
+ struct aa_perms tmp;
+ struct path_cond cond = { };
+ unsigned int state = 0;
+
+ /* find first subcomponent to test */
+ label_for_each(i, label, tp) {
+ if (!aa_ns_visible(profile->ns, tp->ns, subns))
+ continue;
+ state = match_component(profile, tp, stack, start);
+ if (!state)
+ goto fail;
+ goto next;
+ }
+
+ /* no subcomponents visible - no change in perms */
+ return 0;
+
+next:
+ tmp = aa_compute_fperms(profile->file.dfa, state, &cond);
+ aa_apply_modes_to_perms(profile, &tmp);
+ aa_perms_accum(perms, &tmp);
+ label_for_each_cont(i, label, tp) {
+ if (!aa_ns_visible(profile->ns, tp->ns, subns))
+ continue;
+ state = match_component(profile, tp, stack, start);
+ if (!state)
+ goto fail;
+ tmp = aa_compute_fperms(profile->file.dfa, state, &cond);
+ aa_apply_modes_to_perms(profile, &tmp);
+ aa_perms_accum(perms, &tmp);
+ }
+
+ if ((perms->allow & request) != request)
+ return -EACCES;
+
+ return 0;
+
+fail:
+ *perms = nullperms;
+ return -EACCES;
+}
+
+/**
+ * label_match - do a multi-component label match
+ * @profile: profile to match against (NOT NULL)
+ * @label: label to match (NOT NULL)
+ * @stack: whether this is a stacking request
+ * @state: state to start in
+ * @subns: whether to match subns components
+ * @request: permission request
+ * @perms: Returns computed perms (NOT NULL)
+ *
+ * Returns: the state the match finished in, may be the none matching state
+ */
+static int label_match(struct aa_profile *profile, struct aa_label *label,
+ bool stack, unsigned int state, bool subns, u32 request,
+ struct aa_perms *perms)
+{
+ int error;
+
+ *perms = nullperms;
+ error = label_compound_match(profile, label, stack, state, subns,
+ request, perms);
+ if (!error)
+ return error;
+
+ *perms = allperms;
+ return label_components_match(profile, label, stack, state, subns,
+ request, perms);
+}
+
+/******* end TODO: dedup *****/
+
/**
* change_profile_perms - find permissions for change_profile
* @profile: the current profile (NOT NULL)
- * @ns: the namespace being switched to (NOT NULL)
- * @name: the name of the profile to change to (NOT NULL)
+ * @target: label to transition to (NOT NULL)
+ * @stack: whether this is a stacking request
* @request: requested perms
* @start: state to start matching in
*
+ *
* Returns: permission set
+ *
+ * currently only matches full label A//&B//&C or individual components A, B, C
+ * not arbitrary combinations. Eg. A//&B, C
*/
-static struct aa_perms change_profile_perms(struct aa_profile *profile,
- struct aa_ns *ns,
- const char *name, u32 request,
- unsigned int start)
+static int change_profile_perms(struct aa_profile *profile,
+ struct aa_label *target, bool stack,
+ u32 request, unsigned int start,
+ struct aa_perms *perms)
+{
+ if (profile_unconfined(profile)) {
+ perms->allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
+ perms->audit = perms->quiet = perms->kill = 0;
+ return 0;
+ }
+
+ /* TODO: add profile in ns screening */
+ return label_match(profile, target, stack, start, true, request, perms);
+}
+
+static struct aa_perms change_profile_perms_wrapper(struct aa_profile *profile,
+ struct aa_profile *target,
+ u32 request,
+ unsigned int start)
{
struct aa_perms perms;
- struct path_cond cond = { };
- unsigned int state;
if (profile_unconfined(profile)) {
perms.allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
perms.audit = perms.quiet = perms.kill = 0;
return perms;
- } else if (!profile->file.dfa) {
- return nullperms;
- } else if ((ns == profile->ns)) {
- /* try matching against rules with out namespace prepended */
- aa_str_perms(profile->file.dfa, start, name, &cond, &perms);
- if (COMBINED_PERM_MASK(perms) & request)
- return perms;
}
- /* try matching with namespace name and then profile */
- state = aa_dfa_match(profile->file.dfa, start, ns->base.name);
- state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
- aa_str_perms(profile->file.dfa, state, name, &cond, &perms);
+ if (change_profile_perms(profile, &target->label, false, request,
+ start, &perms))
+ return nullperms;
return perms;
}
@@ -173,10 +367,10 @@ static struct aa_profile *__attach_match(const char *name,
* @list: list to search (NOT NULL)
* @name: the executable name to match against (NOT NULL)
*
- * Returns: profile or NULL if no match found
+ * Returns: label or NULL if no match found
*/
-static struct aa_profile *find_attach(struct aa_ns *ns,
- struct list_head *list, const char *name)
+static struct aa_label *find_attach(struct aa_ns *ns, struct list_head *list,
+ const char *name)
{
struct aa_profile *profile;
@@ -184,49 +378,7 @@ static struct aa_profile *find_attach(struct aa_ns *ns,
profile = aa_get_profile(__attach_match(name, list));
rcu_read_unlock();
- return profile;
-}
-
-/**
- * separate_fqname - separate the namespace and profile names
- * @fqname: the fqname name to split (NOT NULL)
- * @ns_name: the namespace name if it exists (NOT NULL)
- *
- * This is the xtable equivalent routine of aa_split_fqname. It finds the
- * split in an xtable fqname which contains an embedded \0 instead of a :
- * if a namespace is specified. This is done so the xtable is constant and
- * isn't re-split on every lookup.
- *
- * Either the profile or namespace name may be optional but if the namespace
- * is specified the profile name termination must be present. This results
- * in the following possible encodings:
- * profile_name\0
- * :ns_name\0profile_name\0
- * :ns_name\0\0
- *
- * NOTE: the xtable fqname is pre-validated at load time in unpack_trans_table
- *
- * Returns: profile name if it is specified else NULL
- */
-static const char *separate_fqname(const char *fqname, const char **ns_name)
-{
- const char *name;
-
- if (fqname[0] == ':') {
- /* In this case there is guaranteed to be two \0 terminators
- * in the string. They are verified at load time by
- * by unpack_trans_table
- */
- *ns_name = fqname + 1; /* skip : */
- name = *ns_name + strlen(*ns_name) + 1;
- if (!*name)
- name = NULL;
- } else {
- *ns_name = NULL;
- name = fqname;
- }
-
- return name;
+ return profile ? &profile->label : NULL;
}
static const char *next_name(int xtype, const char *name)
@@ -238,295 +390,477 @@ static const char *next_name(int xtype, const char *name)
* x_table_lookup - lookup an x transition name via transition table
* @profile: current profile (NOT NULL)
* @xindex: index into x transition table
+ * @name: returns: name tested to find label (NOT NULL)
*
- * Returns: refcounted profile, or NULL on failure (MAYBE NULL)
+ * Returns: refcounted label, or NULL on failure (MAYBE NULL)
*/
-static struct aa_profile *x_table_lookup(struct aa_profile *profile, u32 xindex)
+static struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex,
+ const char **name)
{
- struct aa_profile *new_profile = NULL;
- struct aa_ns *ns = profile->ns;
+ struct aa_label *label = NULL;
u32 xtype = xindex & AA_X_TYPE_MASK;
int index = xindex & AA_X_INDEX_MASK;
- const char *name;
- /* index is guaranteed to be in range, validated at load time */
- for (name = profile->file.trans.table[index]; !new_profile && name;
- name = next_name(xtype, name)) {
- struct aa_ns *new_ns;
- const char *xname = NULL;
+ AA_BUG(!name);
- new_ns = NULL;
+ /* index is guaranteed to be in range, validated at load time */
+ /* TODO: move lookup parsing to unpack time so this is a straight
+ * index into the resultant label
+ */
+ for (*name = profile->file.trans.table[index]; !label && *name;
+ *name = next_name(xtype, *name)) {
if (xindex & AA_X_CHILD) {
+ struct aa_profile *new_profile;
/* release by caller */
- new_profile = aa_find_child(profile, name);
+ new_profile = aa_find_child(profile, *name);
+ if (new_profile)
+ label = &new_profile->label;
continue;
- } else if (*name == ':') {
- /* switching namespace */
- const char *ns_name;
- xname = name = separate_fqname(name, &ns_name);
- if (!xname)
- /* no name so use profile name */
- xname = profile->base.hname;
- if (*ns_name == '@') {
- /* TODO: variable support */
- ;
- }
- /* released below */
- new_ns = aa_find_ns(ns, ns_name);
- if (!new_ns)
- continue;
- } else if (*name == '@') {
- /* TODO: variable support */
- continue;
- } else {
- /* basic namespace lookup */
- xname = name;
}
-
- /* released by caller */
- new_profile = aa_lookup_profile(new_ns ? new_ns : ns, xname);
- aa_put_ns(new_ns);
+ label = aa_label_parse(&profile->label, *name, GFP_ATOMIC,
+ true, false);
+ if (IS_ERR(label))
+ label = NULL;
}
/* released by caller */
- return new_profile;
+
+ return label;
}
/**
- * x_to_profile - get target profile for a given xindex
+ * x_to_label - get target label for a given xindex
* @profile: current profile (NOT NULL)
* @name: name to lookup (NOT NULL)
* @xindex: index into x transition table
+ * @lookupname: returns: name used in lookup if one was specified (NOT NULL)
*
- * find profile for a transition index
+ * find label for a transition index
*
- * Returns: refcounted profile or NULL if not found available
+ * Returns: refcounted label or NULL if not found available
*/
-static struct aa_profile *x_to_profile(struct aa_profile *profile,
- const char *name, u32 xindex)
+static struct aa_label *x_to_label(struct aa_profile *profile,
+ const char *name, u32 xindex,
+ const char **lookupname,
+ const char **info)
{
- struct aa_profile *new_profile = NULL;
+ struct aa_label *new = NULL;
struct aa_ns *ns = profile->ns;
u32 xtype = xindex & AA_X_TYPE_MASK;
+ const char *stack = NULL;
switch (xtype) {
case AA_X_NONE:
/* fail exec unless ix || ux fallback - handled by caller */
- return NULL;
+ *lookupname = NULL;
+ break;
+ case AA_X_TABLE:
+ /* TODO: fix when perm mapping done at unload */
+ stack = profile->file.trans.table[xindex & AA_X_INDEX_MASK];
+ if (*stack != '&') {
+ /* released by caller */
+ new = x_table_lookup(profile, xindex, lookupname);
+ stack = NULL;
+ break;
+ }
+ /* fall through to X_NAME */
case AA_X_NAME:
if (xindex & AA_X_CHILD)
/* released by caller */
- new_profile = find_attach(ns, &profile->base.profiles,
- name);
+ new = find_attach(ns, &profile->base.profiles,
+ name);
else
/* released by caller */
- new_profile = find_attach(ns, &ns->base.profiles,
- name);
- break;
- case AA_X_TABLE:
- /* released by caller */
- new_profile = x_table_lookup(profile, xindex);
+ new = find_attach(ns, &ns->base.profiles,
+ name);
+ *lookupname = name;
break;
}
+ if (!new) {
+ if (xindex & AA_X_INHERIT) {
+ /* (p|c|n)ix - don't change profile but do
+ * use the newest version
+ */
+ *info = "ix fallback";
+ /* no profile && no error */
+ new = aa_get_newest_label(&profile->label);
+ } else if (xindex & AA_X_UNCONFINED) {
+ new = aa_get_newest_label(ns_unconfined(profile->ns));
+ *info = "ux fallback";
+ }
+ }
+
+ if (new && stack) {
+ /* base the stack on post domain transition */
+ struct aa_label *base = new;
+
+ new = aa_label_parse(base, stack, GFP_ATOMIC, true, false);
+ if (IS_ERR(new))
+ new = NULL;
+ aa_put_label(base);
+ }
+
/* released by caller */
- return new_profile;
+ return new;
}
-/**
- * apparmor_bprm_set_creds - set the new creds on the bprm struct
- * @bprm: binprm for the exec (NOT NULL)
- *
- * Returns: %0 or error on failure
- */
-int apparmor_bprm_set_creds(struct linux_binprm *bprm)
+static struct aa_label *profile_transition(struct aa_profile *profile,
+ const struct linux_binprm *bprm,
+ char *buffer, struct path_cond *cond,
+ bool *secure_exec)
{
- struct aa_task_ctx *ctx;
- struct aa_label *label;
- struct aa_profile *profile, *new_profile = NULL;
- struct aa_ns *ns;
- char *buffer = NULL;
- unsigned int state;
+ struct aa_label *new = NULL;
+ const char *info = NULL, *name = NULL, *target = NULL;
+ unsigned int state = profile->file.start;
struct aa_perms perms = {};
- struct path_cond cond = {
- file_inode(bprm->file)->i_uid,
- file_inode(bprm->file)->i_mode
- };
- const char *name = NULL, *info = NULL;
+ bool nonewprivs = false;
int error = 0;
- if (bprm->cred_prepared)
- return 0;
-
- ctx = cred_ctx(bprm->cred);
- AA_BUG(!ctx);
-
- label = aa_get_newest_label(ctx->label);
- profile = labels_profile(label);
-
- /* buffer freed below, name is pointer into buffer */
- get_buffers(buffer);
- /*
- * get the namespace from the replacement profile as replacement
- * can change the namespace
- */
- ns = profile->ns;
- state = profile->file.start;
+ AA_BUG(!profile);
+ AA_BUG(!bprm);
+ AA_BUG(!buffer);
error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
&name, &info, profile->disconnected);
if (error) {
if (profile_unconfined(profile) ||
- (profile->label.flags & FLAG_IX_ON_NAME_ERROR))
+ (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
+ AA_DEBUG("name lookup ix on error");
error = 0;
+ new = aa_get_newest_label(&profile->label);
+ }
name = bprm->filename;
goto audit;
}
- /* Test for onexec first as onexec directives override other
- * x transitions.
- */
if (profile_unconfined(profile)) {
- /* unconfined task */
- if (ctx->onexec)
- /* change_profile on exec already been granted */
- new_profile = labels_profile(aa_get_label(ctx->onexec));
- else
- new_profile = find_attach(ns, &ns->base.profiles, name);
- if (!new_profile)
- goto cleanup;
- /*
- * NOTE: Domain transitions from unconfined are allowed
- * even when no_new_privs is set because this aways results
- * in a further reduction of permissions.
- */
- goto apply;
+ new = find_attach(profile->ns, &profile->ns->base.profiles,
+ name);
+ if (new) {
+ AA_DEBUG("unconfined attached to new label");
+ return new;
+ }
+ AA_DEBUG("unconfined exec no attachment");
+ return aa_get_newest_label(&profile->label);
}
/* find exec permissions for name */
- state = aa_str_perms(profile->file.dfa, state, name, &cond, &perms);
- if (ctx->onexec) {
- struct aa_perms cp;
- info = "change_profile onexec";
- new_profile = labels_profile(aa_get_newest_label(ctx->onexec));
- if (!(perms.allow & AA_MAY_ONEXEC))
- goto audit;
-
- /* test if this exec can be paired with change_profile onexec.
- * onexec permission is linked to exec with a standard pairing
- * exec\0change_profile
- */
- state = aa_dfa_null_transition(profile->file.dfa, state);
- cp = change_profile_perms(profile, labels_ns(ctx->onexec),
- labels_profile(ctx->onexec)->base.name,
- AA_MAY_ONEXEC, state);
-
- if (!(cp.allow & AA_MAY_ONEXEC))
- goto audit;
- goto apply;
- }
-
+ state = aa_str_perms(profile->file.dfa, state, name, cond, &perms);
if (perms.allow & MAY_EXEC) {
/* exec permission determine how to transition */
- new_profile = x_to_profile(profile, name, perms.xindex);
- if (!new_profile) {
- if (perms.xindex & AA_X_INHERIT) {
- /* (p|c|n)ix - don't change profile but do
- * use the newest version, which was picked
- * up above when getting profile
- */
- info = "ix fallback";
- new_profile = aa_get_profile(profile);
- goto x_clear;
- } else if (perms.xindex & AA_X_UNCONFINED) {
- new_profile = aa_get_newest_profile(ns->unconfined);
- info = "ux fallback";
- } else {
- error = -EACCES;
- info = "profile not found";
- /* remove MAY_EXEC to audit as failure */
- perms.allow &= ~MAY_EXEC;
- }
+ new = x_to_label(profile, name, perms.xindex, &target, &info);
+ if (new && new->proxy == profile->label.proxy && info) {
+ /* hack ix fallback - improve how this is detected */
+ goto audit;
+ } else if (!new) {
+ error = -EACCES;
+ info = "profile transition not found";
+ /* remove MAY_EXEC to audit as failure */
+ perms.allow &= ~MAY_EXEC;
}
} else if (COMPLAIN_MODE(profile)) {
- /* no exec permission - are we in learning mode */
- new_profile = aa_new_null_profile(profile, false, name,
- GFP_ATOMIC);
+ /* no exec permission - learning mode */
+ struct aa_profile *new_profile = aa_new_null_profile(profile,
+ false, name,
+ GFP_ATOMIC);
if (!new_profile) {
error = -ENOMEM;
info = "could not create null profile";
- } else
+ } else {
error = -EACCES;
+ new = &new_profile->label;
+ }
perms.xindex |= AA_X_UNSAFE;
} else
/* fail exec */
error = -EACCES;
- /*
- * Policy has specified a domain transition, if no_new_privs then
- * fail the exec.
+ if (!new)
+ goto audit;
+
+ /* Policy has specified a domain transitions. if no_new_privs and
+ * confined and not transitioning to the current domain fail.
+ *
+ * NOTE: Domain transitions from unconfined and to stritly stacked
+ * subsets are allowed even when no_new_privs is set because this
+ * aways results in a further reduction of permissions.
*/
- if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) {
+ if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
+ !profile_unconfined(profile) &&
+ !aa_label_is_subset(new, &profile->label)) {
error = -EPERM;
- goto cleanup;
+ info = "no new privs";
+ nonewprivs = true;
+ perms.allow &= ~MAY_EXEC;
+ goto audit;
+ }
+
+ if (!(perms.xindex & AA_X_UNSAFE)) {
+ if (DEBUG_ON) {
+ dbg_printk("apparmor: scrubbing environment variables"
+ " for %s profile=", name);
+ aa_label_printk(new, GFP_ATOMIC);
+ dbg_printk("\n");
+ }
+ *secure_exec = true;
}
- if (!new_profile)
+audit:
+ aa_audit_file(profile, &perms, OP_EXEC, MAY_EXEC, name, target, new,
+ cond->uid, info, error);
+ if (!new || nonewprivs) {
+ aa_put_label(new);
+ return ERR_PTR(error);
+ }
+
+ return new;
+}
+
+static int profile_onexec(struct aa_profile *profile, struct aa_label *onexec,
+ bool stack, const struct linux_binprm *bprm,
+ char *buffer, struct path_cond *cond,
+ bool *secure_exec)
+{
+ unsigned int state = profile->file.start;
+ struct aa_perms perms = {};
+ const char *xname = NULL, *info = "change_profile onexec";
+ int error = -EACCES;
+
+ AA_BUG(!profile);
+ AA_BUG(!onexec);
+ AA_BUG(!bprm);
+ AA_BUG(!buffer);
+
+ if (profile_unconfined(profile)) {
+ /* change_profile on exec already granted */
+ /*
+ * NOTE: Domain transitions from unconfined are allowed
+ * even when no_new_privs is set because this aways results
+ * in a further reduction of permissions.
+ */
+ return 0;
+ }
+
+ error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
+ &xname, &info, profile->disconnected);
+ if (error) {
+ if (profile_unconfined(profile) ||
+ (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
+ AA_DEBUG("name lookup ix on error");
+ error = 0;
+ }
+ xname = bprm->filename;
goto audit;
+ }
+
+ /* find exec permissions for name */
+ state = aa_str_perms(profile->file.dfa, state, xname, cond, &perms);
+ if (!(perms.allow & AA_MAY_ONEXEC)) {
+ info = "no change_onexec valid for executable";
+ goto audit;
+ }
+ /* test if this exec can be paired with change_profile onexec.
+ * onexec permission is linked to exec with a standard pairing
+ * exec\0change_profile
+ */
+ state = aa_dfa_null_transition(profile->file.dfa, state);
+ error = change_profile_perms(profile, onexec, stack, AA_MAY_ONEXEC,
+ state, &perms);
+ if (error) {
+ perms.allow &= ~AA_MAY_ONEXEC;
+ goto audit;
+ }
+ /* Policy has specified a domain transitions. if no_new_privs and
+ * confined and not transitioning to the current domain fail.
+ *
+ * NOTE: Domain transitions from unconfined and to stritly stacked
+ * subsets are allowed even when no_new_privs is set because this
+ * aways results in a further reduction of permissions.
+ */
+ if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
+ !profile_unconfined(profile) &&
+ !aa_label_is_subset(onexec, &profile->label)) {
+ error = -EPERM;
+ info = "no new privs";
+ perms.allow &= ~AA_MAY_ONEXEC;
+ goto audit;
+ }
+
+ if (!(perms.xindex & AA_X_UNSAFE)) {
+ if (DEBUG_ON) {
+ dbg_printk("apparmor: scrubbing environment "
+ "variables for %s label=", xname);
+ aa_label_printk(onexec, GFP_ATOMIC);
+ dbg_printk("\n");
+ }
+ *secure_exec = true;
+ }
+
+audit:
+ return aa_audit_file(profile, &perms, OP_EXEC, AA_MAY_ONEXEC, xname,
+ NULL, onexec, cond->uid, info, error);
+}
+
+/* ensure none ns domain transitions are correctly applied with onexec */
+
+static struct aa_label *handle_onexec(struct aa_label *label,
+ struct aa_label *onexec, bool stack,
+ const struct linux_binprm *bprm,
+ char *buffer, struct path_cond *cond,
+ bool *unsafe)
+{
+ struct aa_profile *profile;
+ struct aa_label *new;
+ int error;
+
+ AA_BUG(!label);
+ AA_BUG(!onexec);
+ AA_BUG(!bprm);
+ AA_BUG(!buffer);
+
+ if (!stack) {
+ error = fn_for_each_in_ns(label, profile,
+ profile_onexec(profile, onexec, stack,
+ bprm, buffer, cond, unsafe));
+ if (error)
+ return ERR_PTR(error);
+ new = fn_label_build_in_ns(label, profile, GFP_ATOMIC,
+ aa_get_newest_label(onexec),
+ profile_transition(profile, bprm, buffer,
+ cond, unsafe));
+
+ } else {
+ /* TODO: determine how much we want to losen this */
+ error = fn_for_each_in_ns(label, profile,
+ profile_onexec(profile, onexec, stack, bprm,
+ buffer, cond, unsafe));
+ if (error)
+ return ERR_PTR(error);
+ new = fn_label_build_in_ns(label, profile, GFP_ATOMIC,
+ aa_label_merge(&profile->label, onexec,
+ GFP_ATOMIC),
+ profile_transition(profile, bprm, buffer,
+ cond, unsafe));
+ }
+
+ if (new)
+ return new;
+
+ /* TODO: get rid of GLOBAL_ROOT_UID */
+ error = fn_for_each_in_ns(label, profile,
+ aa_audit_file(profile, &nullperms, OP_CHANGE_ONEXEC,
+ AA_MAY_ONEXEC, bprm->filename, NULL,
+ onexec, GLOBAL_ROOT_UID,
+ "failed to build target label", -ENOMEM));
+ return ERR_PTR(error);
+}
+
+/**
+ * apparmor_bprm_set_creds - set the new creds on the bprm struct
+ * @bprm: binprm for the exec (NOT NULL)
+ *
+ * Returns: %0 or error on failure
+ *
+ * TODO: once the other paths are done see if we can't refactor into a fn
+ */
+int apparmor_bprm_set_creds(struct linux_binprm *bprm)
+{
+ struct aa_task_ctx *ctx;
+ struct aa_label *label, *new = NULL;
+ struct aa_profile *profile;
+ char *buffer = NULL;
+ const char *info = NULL;
+ int error = 0;
+ bool unsafe = false;
+ struct path_cond cond = {
+ file_inode(bprm->file)->i_uid,
+ file_inode(bprm->file)->i_mode
+ };
+
+ if (bprm->cred_prepared)
+ return 0;
+
+ ctx = cred_ctx(bprm->cred);
+ AA_BUG(!ctx);
+
+ label = aa_get_newest_label(ctx->label);
+
+ /* buffer freed below, name is pointer into buffer */
+ get_buffers(buffer);
+ /* Test for onexec first as onexec override other x transitions. */
+ if (ctx->onexec)
+ new = handle_onexec(label, ctx->onexec, ctx->token,
+ bprm, buffer, &cond, &unsafe);
+ else
+ new = fn_label_build(label, profile, GFP_ATOMIC,
+ profile_transition(profile, bprm, buffer,
+ &cond, &unsafe));
+
+ AA_BUG(!new);
+ if (IS_ERR(new)) {
+ error = PTR_ERR(new);
+ goto done;
+ } else if (!new) {
+ error = -ENOMEM;
+ goto done;
+ }
+
+ /* TODO: Add ns level no_new_privs subset test */
if (bprm->unsafe & LSM_UNSAFE_SHARE) {
/* FIXME: currently don't mediate shared state */
;
}
- if (bprm->unsafe & LSM_UNSAFE_PTRACE) {
- error = may_change_ptraced_domain(&new_profile->label, &info);
+ if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) {
+ /* TODO: test needs to be profile of label to new */
+ error = may_change_ptraced_domain(new, &info);
if (error)
goto audit;
}
- /* Determine if secure exec is needed.
- * Can be at this point for the following reasons:
- * 1. unconfined switching to confined
- * 2. confined switching to different confinement
- * 3. confined switching to unconfined
- *
- * Cases 2 and 3 are marked as requiring secure exec
- * (unless policy specified "unsafe exec")
- *
- * bprm->unsafe is used to cache the AA_X_UNSAFE permission
- * to avoid having to recompute in secureexec
- */
- if (!(perms.xindex & AA_X_UNSAFE)) {
- AA_DEBUG("scrubbing environment variables for %s profile=%s\n",
- name, new_profile->base.hname);
+ if (unsafe) {
+ if (DEBUG_ON) {
+ dbg_printk("scrubbing environment variables for %s "
+ "label=", bprm->filename);
+ aa_label_printk(new, GFP_ATOMIC);
+ dbg_printk("\n");
+ }
bprm->unsafe |= AA_SECURE_X_NEEDED;
}
-apply:
- /* when transitioning profiles clear unsafe personality bits */
- bprm->per_clear |= PER_CLEAR_ON_SETID;
-x_clear:
+ if (label->proxy != new->proxy) {
+ /* when transitioning clear unsafe personality bits */
+ if (DEBUG_ON) {
+ dbg_printk("apparmor: clearing unsafe personality "
+ "bits. %s label=", bprm->filename);
+ aa_label_printk(new, GFP_ATOMIC);
+ dbg_printk("\n");
+ }
+ bprm->per_clear |= PER_CLEAR_ON_SETID;
+ }
aa_put_label(ctx->label);
- /* transfer new profile reference will be released when ctx is freed */
- ctx->label = &new_profile->label;
- new_profile = NULL;
+ /* transfer reference, released when ctx is freed */
+ ctx->label = new;
- /* clear out all temporary/transitional state from the context */
+done:
+ /* clear out temporary/transitional state from the context */
aa_clear_task_ctx_trans(ctx);
-audit:
- error = aa_audit_file(profile, &perms, OP_EXEC, MAY_EXEC, name,
- new_profile ? new_profile->base.hname : NULL,
- new_profile ? &new_profile->label : NULL,
- cond.uid, info, error);
-
-cleanup:
- aa_put_profile(new_profile);
aa_put_label(label);
put_buffers(buffer);
return error;
+
+audit:
+ error = fn_for_each(label, profile,
+ aa_audit_file(profile, &nullperms, OP_EXEC, MAY_EXEC,
+ bprm->filename, NULL, new,
+ file_inode(bprm->file)->i_uid, info,
+ error));
+ aa_put_label(new);
+ goto done;
}
/**
@@ -778,8 +1112,8 @@ int aa_change_profile(const char *fqname, int flags)
}
}
- perms = change_profile_perms(profile, target->ns, target->base.hname,
- request, profile->file.start);
+ perms = change_profile_perms_wrapper(profile, target, request,
+ profile->file.start);
if (!(perms.allow & request)) {
error = -EACCES;
goto audit;
diff --git a/security/apparmor/include/lib.h b/security/apparmor/include/lib.h
index 593877d38088..436b3a722357 100644
--- a/security/apparmor/include/lib.h
+++ b/security/apparmor/include/lib.h
@@ -211,4 +211,89 @@ bool aa_policy_init(struct aa_policy *policy, const char *prefix,
const char *name, gfp_t gfp);
void aa_policy_destroy(struct aa_policy *policy);
-#endif /* AA_LIB_H */
+
+/*
+ * fn_label_build - abstract out the build of a label transition
+ * @L: label the transition is being computed for
+ * @P: profile parameter derived from L by this macro, can be passed to FN
+ * @GFP: memory allocation type to use
+ * @FN: fn to call for each profile transition. @P is set to the profile
+ *
+ * Returns: new label on success
+ * ERR_PTR if build @FN fails
+ * NULL if label_build fails due to low memory conditions
+ *
+ * @FN must return a label or ERR_PTR on failure. NULL is not allowed
+ */
+#define fn_label_build(L, P, GFP, FN) \
+({ \
+ __label__ __cleanup, __done; \
+ struct aa_label *__new_; \
+ \
+ if ((L)->size > 1) { \
+ /* TODO: add cache of transitions already done */ \
+ struct label_it __i; \
+ int __j, __k, __count; \
+ DEFINE_VEC(label, __lvec); \
+ DEFINE_VEC(profile, __pvec); \
+ if (vec_setup(label, __lvec, (L)->size, (GFP))) { \
+ __new_ = NULL; \
+ goto __done; \
+ } \
+ __j = 0; \
+ label_for_each(__i, (L), (P)) { \
+ __new_ = (FN); \
+ AA_BUG(!__new_); \
+ if (IS_ERR(__new_)) \
+ goto __cleanup; \
+ __lvec[__j++] = __new_; \
+ } \
+ for (__j = __count = 0; __j < (L)->size; __j++) \
+ __count += __lvec[__j]->size; \
+ if (!vec_setup(profile, __pvec, __count, (GFP))) { \
+ for (__j = __k = 0; __j < (L)->size; __j++) { \
+ label_for_each(__i, __lvec[__j], (P)) \
+ __pvec[__k++] = aa_get_profile(P); \
+ } \
+ __count -= aa_vec_unique(__pvec, __count, 0); \
+ if (__count > 1) { \
+ __new_ = aa_vec_find_or_create_label(__pvec,\
+ __count, (GFP)); \
+ /* only fails if out of Mem */ \
+ if (!__new_) \
+ __new_ = NULL; \
+ } else \
+ __new_ = aa_get_label(&__pvec[0]->label); \
+ vec_cleanup(profile, __pvec, __count); \
+ } else \
+ __new_ = NULL; \
+__cleanup: \
+ vec_cleanup(label, __lvec, (L)->size); \
+ } else { \
+ (P) = labels_profile(L); \
+ __new_ = (FN); \
+ } \
+__done: \
+ if (!__new_) \
+ AA_DEBUG("label build failed\n"); \
+ (__new_); \
+})
+
+
+#define __fn_build_in_ns(NS, P, NS_FN, OTHER_FN) \
+({ \
+ struct aa_label *__new; \
+ if ((P)->ns != (NS)) \
+ __new = (OTHER_FN); \
+ else \
+ __new = (NS_FN); \
+ (__new); \
+})
+
+#define fn_label_build_in_ns(L, P, GFP, NS_FN, OTHER_FN) \
+({ \
+ fn_label_build((L), (P), (GFP), \
+ __fn_build_in_ns(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \
+})
+
+#endif /* __AA_LIB_H */
--
2.12.3