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authorLinus Torvalds <torvalds@linux-foundation.org>2020-01-04 19:28:30 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-01-04 19:28:30 -0800
commita125bcda2d0aee1d98b51c167aca60fb312572aa (patch)
treebee33879981c1225109bd0f1253803be21a663be
parentc420ddda506b80ec2686e405698d37fafeea3b7a (diff)
parent8c62ed27a12c00e3db1c9f04bc0f272bdbb06734 (diff)
Merge tag 'apparmor-pr-2020-01-04' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor
Pull apparmor fixes from John Johansen: - performance regression: only get a label reference if the fast path check fails - fix aa_xattrs_match() may sleep while holding a RCU lock - fix bind mounts aborting with -ENOMEM * tag 'apparmor-pr-2020-01-04' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor: apparmor: fix aa_xattrs_match() may sleep while holding a RCU lock apparmor: only get a label reference if the fast path check fails apparmor: fix bind mounts aborting with -ENOMEM
-rw-r--r--security/apparmor/apparmorfs.c2
-rw-r--r--security/apparmor/domain.c82
-rw-r--r--security/apparmor/file.c12
-rw-r--r--security/apparmor/mount.c2
-rw-r--r--security/apparmor/policy.c4
5 files changed, 55 insertions, 47 deletions
diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c
index 09996f2552ee..47aff8700547 100644
--- a/security/apparmor/apparmorfs.c
+++ b/security/apparmor/apparmorfs.c
@@ -623,7 +623,7 @@ static __poll_t ns_revision_poll(struct file *file, poll_table *pt)
void __aa_bump_ns_revision(struct aa_ns *ns)
{
- ns->revision++;
+ WRITE_ONCE(ns->revision, ns->revision + 1);
wake_up_interruptible(&ns->wait);
}
diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c
index 9be7ccb8379e..6ceb74e0f789 100644
--- a/security/apparmor/domain.c
+++ b/security/apparmor/domain.c
@@ -317,6 +317,7 @@ static int aa_xattrs_match(const struct linux_binprm *bprm,
if (!bprm || !profile->xattr_count)
return 0;
+ might_sleep();
/* transition from exec match to xattr set */
state = aa_dfa_null_transition(profile->xmatch, state);
@@ -361,10 +362,11 @@ out:
}
/**
- * __attach_match_ - find an attachment match
+ * find_attach - do attachment search for unconfined processes
* @bprm - binprm structure of transitioning task
- * @name - to match against (NOT NULL)
+ * @ns: the current namespace (NOT NULL)
* @head - profile list to walk (NOT NULL)
+ * @name - to match against (NOT NULL)
* @info - info message if there was an error (NOT NULL)
*
* Do a linear search on the profiles in the list. There is a matching
@@ -374,12 +376,11 @@ out:
*
* Requires: @head not be shared or have appropriate locks held
*
- * Returns: profile or NULL if no match found
+ * Returns: label or NULL if no match found
*/
-static struct aa_profile *__attach_match(const struct linux_binprm *bprm,
- const char *name,
- struct list_head *head,
- const char **info)
+static struct aa_label *find_attach(const struct linux_binprm *bprm,
+ struct aa_ns *ns, struct list_head *head,
+ const char *name, const char **info)
{
int candidate_len = 0, candidate_xattrs = 0;
bool conflict = false;
@@ -388,6 +389,8 @@ static struct aa_profile *__attach_match(const struct linux_binprm *bprm,
AA_BUG(!name);
AA_BUG(!head);
+ rcu_read_lock();
+restart:
list_for_each_entry_rcu(profile, head, base.list) {
if (profile->label.flags & FLAG_NULL &&
&profile->label == ns_unconfined(profile->ns))
@@ -413,16 +416,32 @@ static struct aa_profile *__attach_match(const struct linux_binprm *bprm,
perm = dfa_user_allow(profile->xmatch, state);
/* any accepting state means a valid match. */
if (perm & MAY_EXEC) {
- int ret;
+ int ret = 0;
if (count < candidate_len)
continue;
- ret = aa_xattrs_match(bprm, profile, state);
- /* Fail matching if the xattrs don't match */
- if (ret < 0)
- continue;
-
+ if (bprm && profile->xattr_count) {
+ long rev = READ_ONCE(ns->revision);
+
+ if (!aa_get_profile_not0(profile))
+ goto restart;
+ rcu_read_unlock();
+ ret = aa_xattrs_match(bprm, profile,
+ state);
+ rcu_read_lock();
+ aa_put_profile(profile);
+ if (rev !=
+ READ_ONCE(ns->revision))
+ /* policy changed */
+ goto restart;
+ /*
+ * Fail matching if the xattrs don't
+ * match
+ */
+ if (ret < 0)
+ continue;
+ }
/*
* TODO: allow for more flexible best match
*
@@ -445,43 +464,28 @@ static struct aa_profile *__attach_match(const struct linux_binprm *bprm,
candidate_xattrs = ret;
conflict = false;
}
- } else if (!strcmp(profile->base.name, name))
+ } else if (!strcmp(profile->base.name, name)) {
/*
* old exact non-re match, without conditionals such
* as xattrs. no more searching required
*/
- return profile;
+ candidate = profile;
+ goto out;
+ }
}
- if (conflict) {
- *info = "conflicting profile attachments";
+ if (!candidate || conflict) {
+ if (conflict)
+ *info = "conflicting profile attachments";
+ rcu_read_unlock();
return NULL;
}
- return candidate;
-}
-
-/**
- * find_attach - do attachment search for unconfined processes
- * @bprm - binprm structure of transitioning task
- * @ns: the current namespace (NOT NULL)
- * @list: list to search (NOT NULL)
- * @name: the executable name to match against (NOT NULL)
- * @info: info message if there was an error
- *
- * Returns: label or NULL if no match found
- */
-static struct aa_label *find_attach(const struct linux_binprm *bprm,
- struct aa_ns *ns, struct list_head *list,
- const char *name, const char **info)
-{
- struct aa_profile *profile;
-
- rcu_read_lock();
- profile = aa_get_profile(__attach_match(bprm, name, list, info));
+out:
+ candidate = aa_get_newest_profile(candidate);
rcu_read_unlock();
- return profile ? &profile->label : NULL;
+ return &candidate->label;
}
static const char *next_name(int xtype, const char *name)
diff --git a/security/apparmor/file.c b/security/apparmor/file.c
index fe2ebe5e865e..f1caf3674e1c 100644
--- a/security/apparmor/file.c
+++ b/security/apparmor/file.c
@@ -618,8 +618,7 @@ int aa_file_perm(const char *op, struct aa_label *label, struct file *file,
fctx = file_ctx(file);
rcu_read_lock();
- flabel = aa_get_newest_label(rcu_dereference(fctx->label));
- rcu_read_unlock();
+ flabel = rcu_dereference(fctx->label);
AA_BUG(!flabel);
/* revalidate access, if task is unconfined, or the cached cred
@@ -631,9 +630,13 @@ int aa_file_perm(const char *op, struct aa_label *label, struct file *file,
*/
denied = request & ~fctx->allow;
if (unconfined(label) || unconfined(flabel) ||
- (!denied && aa_label_is_subset(flabel, label)))
+ (!denied && aa_label_is_subset(flabel, label))) {
+ rcu_read_unlock();
goto done;
+ }
+ flabel = aa_get_newest_label(flabel);
+ rcu_read_unlock();
/* TODO: label cross check */
if (file->f_path.mnt && path_mediated_fs(file->f_path.dentry))
@@ -643,8 +646,9 @@ int aa_file_perm(const char *op, struct aa_label *label, struct file *file,
else if (S_ISSOCK(file_inode(file)->i_mode))
error = __file_sock_perm(op, label, flabel, file, request,
denied);
-done:
aa_put_label(flabel);
+
+done:
return error;
}
diff --git a/security/apparmor/mount.c b/security/apparmor/mount.c
index 4ed6688f9d40..e0828ee7a345 100644
--- a/security/apparmor/mount.c
+++ b/security/apparmor/mount.c
@@ -442,7 +442,7 @@ int aa_bind_mount(struct aa_label *label, const struct path *path,
buffer = aa_get_buffer(false);
old_buffer = aa_get_buffer(false);
error = -ENOMEM;
- if (!buffer || old_buffer)
+ if (!buffer || !old_buffer)
goto out;
error = fn_for_each_confined(label, profile,
diff --git a/security/apparmor/policy.c b/security/apparmor/policy.c
index 03104830c913..269f2f53c0b1 100644
--- a/security/apparmor/policy.c
+++ b/security/apparmor/policy.c
@@ -1125,8 +1125,8 @@ ssize_t aa_remove_profiles(struct aa_ns *policy_ns, struct aa_label *subj,
if (!name) {
/* remove namespace - can only happen if fqname[0] == ':' */
mutex_lock_nested(&ns->parent->lock, ns->level);
- __aa_remove_ns(ns);
__aa_bump_ns_revision(ns);
+ __aa_remove_ns(ns);
mutex_unlock(&ns->parent->lock);
} else {
/* remove profile */
@@ -1138,9 +1138,9 @@ ssize_t aa_remove_profiles(struct aa_ns *policy_ns, struct aa_label *subj,
goto fail_ns_lock;
}
name = profile->base.hname;
+ __aa_bump_ns_revision(ns);
__remove_profile(profile);
__aa_labelset_update_subtree(ns);
- __aa_bump_ns_revision(ns);
mutex_unlock(&ns->lock);
}