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Diffstat (limited to 'security/apparmor/lsm.c')
-rw-r--r--security/apparmor/lsm.c111
1 files changed, 84 insertions, 27 deletions
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 8f7ffc51ad86..3e0cfdebee45 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -48,8 +48,13 @@
/* Flag indicating whether initialization completed */
int apparmor_initialized;
-DEFINE_PER_CPU(struct aa_buffers, aa_buffers);
+union aa_buffer {
+ struct list_head list;
+ char buffer[1];
+};
+static LIST_HEAD(aa_global_buffers);
+static DEFINE_SPINLOCK(aa_buffers_lock);
/*
* LSM hook functions
@@ -1422,6 +1427,7 @@ static int param_set_aauint(const char *val, const struct kernel_param *kp)
return -EPERM;
error = param_set_uint(val, kp);
+ aa_g_path_max = max_t(uint32_t, aa_g_path_max, sizeof(union aa_buffer));
pr_info("AppArmor: buffer size set to %d bytes\n", aa_g_path_max);
return error;
@@ -1565,6 +1571,48 @@ static int param_set_mode(const char *val, const struct kernel_param *kp)
return 0;
}
+char *aa_get_buffer(void)
+{
+ union aa_buffer *aa_buf;
+ bool try_again = true;
+
+retry:
+ spin_lock(&aa_buffers_lock);
+ if (!list_empty(&aa_global_buffers)) {
+ aa_buf = list_first_entry(&aa_global_buffers, union aa_buffer,
+ list);
+ list_del(&aa_buf->list);
+ spin_unlock(&aa_buffers_lock);
+ return &aa_buf->buffer[0];
+ }
+ spin_unlock(&aa_buffers_lock);
+
+ aa_buf = kmalloc(aa_g_path_max, GFP_KERNEL | __GFP_RETRY_MAYFAIL |
+ __GFP_NOWARN);
+ if (!aa_buf) {
+ if (try_again) {
+ try_again = false;
+ goto retry;
+ }
+ pr_warn_once("AppArmor: Failed to allocate a memory buffer.\n");
+ return NULL;
+ }
+ return &aa_buf->buffer[0];
+}
+
+void aa_put_buffer(char *buf)
+{
+ union aa_buffer *aa_buf;
+
+ if (!buf)
+ return;
+ aa_buf = container_of(buf, union aa_buffer, buffer[0]);
+
+ spin_lock(&aa_buffers_lock);
+ list_add(&aa_buf->list, &aa_global_buffers);
+ spin_unlock(&aa_buffers_lock);
+}
+
/*
* AppArmor init functions
*/
@@ -1585,38 +1633,48 @@ static int __init set_init_ctx(void)
static void destroy_buffers(void)
{
- u32 i, j;
+ union aa_buffer *aa_buf;
- for_each_possible_cpu(i) {
- for_each_cpu_buffer(j) {
- kfree(per_cpu(aa_buffers, i).buf[j]);
- per_cpu(aa_buffers, i).buf[j] = NULL;
- }
+ spin_lock(&aa_buffers_lock);
+ while (!list_empty(&aa_global_buffers)) {
+ aa_buf = list_first_entry(&aa_global_buffers, union aa_buffer,
+ list);
+ list_del(&aa_buf->list);
+ spin_unlock(&aa_buffers_lock);
+ kfree(aa_buf);
+ spin_lock(&aa_buffers_lock);
}
+ spin_unlock(&aa_buffers_lock);
}
static int __init alloc_buffers(void)
{
- u32 i, j;
-
- for_each_possible_cpu(i) {
- for_each_cpu_buffer(j) {
- char *buffer;
-
- if (cpu_to_node(i) > num_online_nodes())
- /* fallback to kmalloc for offline nodes */
- buffer = kmalloc(aa_g_path_max, GFP_KERNEL);
- else
- buffer = kmalloc_node(aa_g_path_max, GFP_KERNEL,
- cpu_to_node(i));
- if (!buffer) {
- destroy_buffers();
- return -ENOMEM;
- }
- per_cpu(aa_buffers, i).buf[j] = buffer;
+ union aa_buffer *aa_buf;
+ int i, num;
+
+ /*
+ * A function may require two buffers at once. Usually the buffers are
+ * used for a short period of time and are shared. On UP kernel buffers
+ * two should be enough, with more CPUs it is possible that more
+ * buffers will be used simultaneously. The preallocated pool may grow.
+ * This preallocation has also the side-effect that AppArmor will be
+ * disabled early at boot if aa_g_path_max is extremly high.
+ */
+ if (num_online_cpus() > 1)
+ num = 4;
+ else
+ num = 2;
+
+ for (i = 0; i < num; i++) {
+
+ aa_buf = kmalloc(aa_g_path_max, GFP_KERNEL |
+ __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
+ if (!aa_buf) {
+ destroy_buffers();
+ return -ENOMEM;
}
+ aa_put_buffer(&aa_buf->buffer[0]);
}
-
return 0;
}
@@ -1781,7 +1839,7 @@ static int __init apparmor_init(void)
error = alloc_buffers();
if (error) {
AA_ERROR("Unable to allocate work buffers\n");
- goto buffers_out;
+ goto alloc_out;
}
error = set_init_ctx();
@@ -1806,7 +1864,6 @@ static int __init apparmor_init(void)
buffers_out:
destroy_buffers();
-
alloc_out:
aa_destroy_aafs();
aa_teardown_dfa_engine();