From dd8e19456d60a519de1852ae4b1be7d62690d2e0 Mon Sep 17 00:00:00 2001 From: Elena Reshetova Date: Fri, 20 Oct 2017 10:23:41 +0300 Subject: [PATCH] drivers, net, mlx5: convert fs_node.refcount from atomic_t to refcount_t atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable fs_node.refcount is used as pure reference counter. Convert it to refcount_t and fix up the operations. Suggested-by: Kees Cook Reviewed-by: David Windsor Reviewed-by: Hans Liljestrand Signed-off-by: Elena Reshetova Signed-off-by: David S. Miller --- .../net/ethernet/mellanox/mlx5/core/fs_core.c | 28 +++++++++---------- .../net/ethernet/mellanox/mlx5/core/fs_core.h | 3 +- 2 files changed, 16 insertions(+), 15 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c index f77e496f7053..c7fa1389bace 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c @@ -188,7 +188,7 @@ static void tree_init_node(struct fs_node *node, void (*del_hw_func)(struct fs_node *), void (*del_sw_func)(struct fs_node *)) { - atomic_set(&node->refcount, 1); + refcount_set(&node->refcount, 1); INIT_LIST_HEAD(&node->list); INIT_LIST_HEAD(&node->children); init_rwsem(&node->lock); @@ -200,7 +200,7 @@ static void tree_init_node(struct fs_node *node, static void tree_add_node(struct fs_node *node, struct fs_node *parent) { if (parent) - atomic_inc(&parent->refcount); + refcount_inc(&parent->refcount); node->parent = parent; /* Parent is the root */ @@ -212,7 +212,7 @@ static void tree_add_node(struct fs_node *node, struct fs_node *parent) static int tree_get_node(struct fs_node *node) { - return atomic_add_unless(&node->refcount, 1, 0); + return refcount_inc_not_zero(&node->refcount); } static void nested_down_read_ref_node(struct fs_node *node, @@ -220,7 +220,7 @@ static void nested_down_read_ref_node(struct fs_node *node, { if (node) { down_read_nested(&node->lock, class); - atomic_inc(&node->refcount); + refcount_inc(&node->refcount); } } @@ -229,7 +229,7 @@ static void nested_down_write_ref_node(struct fs_node *node, { if (node) { down_write_nested(&node->lock, class); - atomic_inc(&node->refcount); + refcount_inc(&node->refcount); } } @@ -237,19 +237,19 @@ static void down_write_ref_node(struct fs_node *node) { if (node) { down_write(&node->lock); - atomic_inc(&node->refcount); + refcount_inc(&node->refcount); } } static void up_read_ref_node(struct fs_node *node) { - atomic_dec(&node->refcount); + refcount_dec(&node->refcount); up_read(&node->lock); } static void up_write_ref_node(struct fs_node *node) { - atomic_dec(&node->refcount); + refcount_dec(&node->refcount); up_write(&node->lock); } @@ -257,7 +257,7 @@ static void tree_put_node(struct fs_node *node) { struct fs_node *parent_node = node->parent; - if (atomic_dec_and_test(&node->refcount)) { + if (refcount_dec_and_test(&node->refcount)) { if (node->del_hw_func) node->del_hw_func(node); if (parent_node) { @@ -280,8 +280,8 @@ static void tree_put_node(struct fs_node *node) static int tree_remove_node(struct fs_node *node) { - if (atomic_read(&node->refcount) > 1) { - atomic_dec(&node->refcount); + if (refcount_read(&node->refcount) > 1) { + refcount_dec(&node->refcount); return -EEXIST; } tree_put_node(node); @@ -1184,7 +1184,7 @@ static void destroy_flow_handle(struct fs_fte *fte, int i) { for (; --i >= 0;) { - if (atomic_dec_and_test(&handle->rule[i]->node.refcount)) { + if (refcount_dec_and_test(&handle->rule[i]->node.refcount)) { fte->dests_size--; list_del(&handle->rule[i]->node.list); kfree(handle->rule[i]); @@ -1215,7 +1215,7 @@ create_flow_handle(struct fs_fte *fte, if (dest) { rule = find_flow_rule(fte, dest + i); if (rule) { - atomic_inc(&rule->node.refcount); + refcount_inc(&rule->node.refcount); goto rule_found; } } @@ -1466,7 +1466,7 @@ static struct mlx5_flow_handle *add_rule_fg(struct mlx5_flow_group *fg, trace_mlx5_fs_set_fte(fte, false); for (i = 0; i < handle->num_rules; i++) { - if (atomic_read(&handle->rule[i]->node.refcount) == 1) { + if (refcount_read(&handle->rule[i]->node.refcount) == 1) { tree_add_node(&handle->rule[i]->node, &fte->node); trace_mlx5_fs_add_rule(handle->rule[i]); } diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.h b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.h index 80f6f3c714c8..397d24a621a4 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.h @@ -33,6 +33,7 @@ #ifndef _MLX5_FS_CORE_ #define _MLX5_FS_CORE_ +#include #include #include @@ -84,7 +85,7 @@ struct fs_node { struct fs_node *root; /* lock the node for writing and traversing */ struct rw_semaphore lock; - atomic_t refcount; + refcount_t refcount; bool active; void (*del_hw_func)(struct fs_node *); void (*del_sw_func)(struct fs_node *); -- 2.30.2