net: Fix memory leak in the proto_register function

If the slub allocator is used, kmem_cache_create() may merge two or more
kmem_cache's into one but the cache name pointer is not updated and
kmem_cache_name() is no longer guaranteed to return the pointer passed
to the former function. This patch stores the kmalloc'ed pointers in the
corresponding request_sock_ops and timewait_sock_ops structures.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 19 deletions

diff --git a/net/core/sock.c b/net/core/sock.c
index 341e39456952..edf7220889a4 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2035,9 +2035,6 @@ static inline void release_proto_idx(struct proto *prot)
 
 int proto_register(struct proto *prot, int alloc_slab)
 {
-        char *request_sock_slab_name = NULL;
-        char *timewait_sock_slab_name;
-
         if (alloc_slab) {
                 prot->slab = kmem_cache_create(prot->name, prot->obj_size, 0,
                                                SLAB_HWCACHE_ALIGN, NULL);
@@ -2051,12 +2048,12 @@ int proto_register(struct proto *prot, int alloc_slab)
                 if (prot->rsk_prot != NULL) {
                         static const char mask[] = "request_sock_%s";
 
-                        request_sock_slab_name = kmalloc(strlen(prot->name) + sizeof(mask) - 1, GFP_KERNEL);
-                        if (request_sock_slab_name == NULL)
+                        prot->rsk_prot->slab_name = kmalloc(strlen(prot->name) + sizeof(mask) - 1, GFP_KERNEL);
+                        if (prot->rsk_prot->slab_name == NULL)
                                 goto out_free_sock_slab;
 
-                        sprintf(request_sock_slab_name, mask, prot->name);
-                        prot->rsk_prot->slab = kmem_cache_create(request_sock_slab_name,
+                        sprintf(prot->rsk_prot->slab_name, mask, prot->name);
+                        prot->rsk_prot->slab = kmem_cache_create(prot->rsk_prot->slab_name,
                                                                  prot->rsk_prot->obj_size, 0,
                                                                  SLAB_HWCACHE_ALIGN, NULL);
 
@@ -2070,14 +2067,14 @@ int proto_register(struct proto *prot, int alloc_slab)
                 if (prot->twsk_prot != NULL) {
                         static const char mask[] = "tw_sock_%s";
 
-                        timewait_sock_slab_name = kmalloc(strlen(prot->name) + sizeof(mask) - 1, GFP_KERNEL);
+                        prot->twsk_prot->twsk_slab_name = kmalloc(strlen(prot->name) + sizeof(mask) - 1, GFP_KERNEL);
 
-                        if (timewait_sock_slab_name == NULL)
+                        if (prot->twsk_prot->twsk_slab_name == NULL)
                                 goto out_free_request_sock_slab;
 
-                        sprintf(timewait_sock_slab_name, mask, prot->name);
+                        sprintf(prot->twsk_prot->twsk_slab_name, mask, prot->name);
                         prot->twsk_prot->twsk_slab =
-                                kmem_cache_create(timewait_sock_slab_name,
+                                kmem_cache_create(prot->twsk_prot->twsk_slab_name,
                                                   prot->twsk_prot->twsk_obj_size,
                                                   0, SLAB_HWCACHE_ALIGN,
                                                   NULL);
@@ -2093,14 +2090,14 @@ int proto_register(struct proto *prot, int alloc_slab)
         return 0;
 
 out_free_timewait_sock_slab_name:
-        kfree(timewait_sock_slab_name);
+        kfree(prot->twsk_prot->twsk_slab_name);
 out_free_request_sock_slab:
         if (prot->rsk_prot && prot->rsk_prot->slab) {
                 kmem_cache_destroy(prot->rsk_prot->slab);
                 prot->rsk_prot->slab = NULL;
         }
 out_free_request_sock_slab_name:
-        kfree(request_sock_slab_name);
+        kfree(prot->rsk_prot->slab_name);
 out_free_sock_slab:
         kmem_cache_destroy(prot->slab);
         prot->slab = NULL;
@@ -2123,18 +2120,14 @@ void proto_unregister(struct proto *prot)
         }
 
         if (prot->rsk_prot != NULL && prot->rsk_prot->slab != NULL) {
-                const char *name = kmem_cache_name(prot->rsk_prot->slab);
-
                 kmem_cache_destroy(prot->rsk_prot->slab);
-                kfree(name);
+                kfree(prot->rsk_prot->slab_name);
                 prot->rsk_prot->slab = NULL;
         }
 
         if (prot->twsk_prot != NULL && prot->twsk_prot->twsk_slab != NULL) {
-                const char *name = kmem_cache_name(prot->twsk_prot->twsk_slab);
-
                 kmem_cache_destroy(prot->twsk_prot->twsk_slab);
-                kfree(name);
+                kfree(prot->twsk_prot->twsk_slab_name);
                 prot->twsk_prot->twsk_slab = NULL;
         }
 }