From ff1f855804cdbbb6db7b9b6df6cab783d1a40d66 Mon Sep 17 00:00:00 2001 From: Rijo Thomas Date: Wed, 4 Nov 2020 11:56:09 +0530 Subject: [PATCH 1/2] tee: amdtee: fix memory leak due to reset of global shm list The driver maintains a list of shared memory buffers along with their mapped buffer id's in a global linked list. These buffers need to be unmapped after use by the user-space client. The global shared memory list is initialized to zero entries in the function amdtee_open(). This clearing of list entries can be a source for memory leak on secure side if the global linked list previously held some mapped buffer entries allocated from another TEE context. Fix potential memory leak issue by moving global shared memory list to AMD-TEE driver context data structure. Fixes: 757cc3e9ff1d ("tee: add AMD-TEE driver") Reviewed-by: Devaraj Rangasamy Signed-off-by: Rijo Thomas Signed-off-by: Jens Wiklander --- drivers/tee/amdtee/amdtee_private.h | 7 +++---- drivers/tee/amdtee/core.c | 18 +++++++++++------- 2 files changed, 14 insertions(+), 11 deletions(-) diff --git a/drivers/tee/amdtee/amdtee_private.h b/drivers/tee/amdtee/amdtee_private.h index d7f798c3394b..97df16a17285 100644 --- a/drivers/tee/amdtee/amdtee_private.h +++ b/drivers/tee/amdtee/amdtee_private.h @@ -64,9 +64,12 @@ struct amdtee_session { /** * struct amdtee_context_data - AMD-TEE driver context data * @sess_list: Keeps track of sessions opened in current TEE context + * @shm_list: Keeps track of buffers allocated and mapped in current TEE + * context */ struct amdtee_context_data { struct list_head sess_list; + struct list_head shm_list; }; struct amdtee_driver_data { @@ -89,10 +92,6 @@ struct amdtee_shm_data { u32 buf_id; }; -struct amdtee_shm_context { - struct list_head shmdata_list; -}; - #define LOWER_TWO_BYTE_MASK 0x0000FFFF /** diff --git a/drivers/tee/amdtee/core.c b/drivers/tee/amdtee/core.c index 27b4cd77d0db..ce61c68ec58c 100644 --- a/drivers/tee/amdtee/core.c +++ b/drivers/tee/amdtee/core.c @@ -20,7 +20,6 @@ static struct amdtee_driver_data *drv_data; static DEFINE_MUTEX(session_list_mutex); -static struct amdtee_shm_context shmctx; static void amdtee_get_version(struct tee_device *teedev, struct tee_ioctl_version_data *vers) @@ -42,7 +41,7 @@ static int amdtee_open(struct tee_context *ctx) return -ENOMEM; INIT_LIST_HEAD(&ctxdata->sess_list); - INIT_LIST_HEAD(&shmctx.shmdata_list); + INIT_LIST_HEAD(&ctxdata->shm_list); ctx->data = ctxdata; return 0; @@ -152,10 +151,11 @@ static struct amdtee_session *find_session(struct amdtee_context_data *ctxdata, u32 get_buffer_id(struct tee_shm *shm) { - u32 buf_id = 0; + struct amdtee_context_data *ctxdata = shm->ctx->data; struct amdtee_shm_data *shmdata; + u32 buf_id = 0; - list_for_each_entry(shmdata, &shmctx.shmdata_list, shm_node) + list_for_each_entry(shmdata, &ctxdata->shm_list, shm_node) if (shmdata->kaddr == shm->kaddr) { buf_id = shmdata->buf_id; break; @@ -333,8 +333,9 @@ int amdtee_close_session(struct tee_context *ctx, u32 session) int amdtee_map_shmem(struct tee_shm *shm) { - struct shmem_desc shmem; + struct amdtee_context_data *ctxdata; struct amdtee_shm_data *shmnode; + struct shmem_desc shmem; int rc, count; u32 buf_id; @@ -362,7 +363,8 @@ int amdtee_map_shmem(struct tee_shm *shm) shmnode->kaddr = shm->kaddr; shmnode->buf_id = buf_id; - list_add(&shmnode->shm_node, &shmctx.shmdata_list); + ctxdata = shm->ctx->data; + list_add(&shmnode->shm_node, &ctxdata->shm_list); pr_debug("buf_id :[%x] kaddr[%p]\n", shmnode->buf_id, shmnode->kaddr); @@ -371,6 +373,7 @@ int amdtee_map_shmem(struct tee_shm *shm) void amdtee_unmap_shmem(struct tee_shm *shm) { + struct amdtee_context_data *ctxdata; struct amdtee_shm_data *shmnode; u32 buf_id; @@ -381,7 +384,8 @@ void amdtee_unmap_shmem(struct tee_shm *shm) /* Unmap the shared memory from TEE */ handle_unmap_shmem(buf_id); - list_for_each_entry(shmnode, &shmctx.shmdata_list, shm_node) + ctxdata = shm->ctx->data; + list_for_each_entry(shmnode, &ctxdata->shm_list, shm_node) if (buf_id == shmnode->buf_id) { list_del(&shmnode->shm_node); kfree(shmnode); From be353be27874f40837327d9a39e3ad2149ab66d3 Mon Sep 17 00:00:00 2001 From: Rijo Thomas Date: Wed, 4 Nov 2020 11:56:10 +0530 Subject: [PATCH 2/2] tee: amdtee: synchronize access to shm list Synchronize access to shm or shared memory buffer list to prevent race conditions due to concurrent updates to shared shm list by multiple threads. Fixes: 757cc3e9ff1d ("tee: add AMD-TEE driver") Reviewed-by: Devaraj Rangasamy Signed-off-by: Rijo Thomas Signed-off-by: Jens Wiklander --- drivers/tee/amdtee/amdtee_private.h | 1 + drivers/tee/amdtee/core.c | 8 ++++++++ 2 files changed, 9 insertions(+) diff --git a/drivers/tee/amdtee/amdtee_private.h b/drivers/tee/amdtee/amdtee_private.h index 97df16a17285..337c8d82f74e 100644 --- a/drivers/tee/amdtee/amdtee_private.h +++ b/drivers/tee/amdtee/amdtee_private.h @@ -70,6 +70,7 @@ struct amdtee_session { struct amdtee_context_data { struct list_head sess_list; struct list_head shm_list; + struct mutex shm_mutex; /* synchronizes access to @shm_list */ }; struct amdtee_driver_data { diff --git a/drivers/tee/amdtee/core.c b/drivers/tee/amdtee/core.c index ce61c68ec58c..8a6a8f30bb42 100644 --- a/drivers/tee/amdtee/core.c +++ b/drivers/tee/amdtee/core.c @@ -42,6 +42,7 @@ static int amdtee_open(struct tee_context *ctx) INIT_LIST_HEAD(&ctxdata->sess_list); INIT_LIST_HEAD(&ctxdata->shm_list); + mutex_init(&ctxdata->shm_mutex); ctx->data = ctxdata; return 0; @@ -85,6 +86,7 @@ static void amdtee_release(struct tee_context *ctx) list_del(&sess->list_node); release_session(sess); } + mutex_destroy(&ctxdata->shm_mutex); kfree(ctxdata); ctx->data = NULL; @@ -155,11 +157,13 @@ u32 get_buffer_id(struct tee_shm *shm) struct amdtee_shm_data *shmdata; u32 buf_id = 0; + mutex_lock(&ctxdata->shm_mutex); list_for_each_entry(shmdata, &ctxdata->shm_list, shm_node) if (shmdata->kaddr == shm->kaddr) { buf_id = shmdata->buf_id; break; } + mutex_unlock(&ctxdata->shm_mutex); return buf_id; } @@ -364,7 +368,9 @@ int amdtee_map_shmem(struct tee_shm *shm) shmnode->kaddr = shm->kaddr; shmnode->buf_id = buf_id; ctxdata = shm->ctx->data; + mutex_lock(&ctxdata->shm_mutex); list_add(&shmnode->shm_node, &ctxdata->shm_list); + mutex_unlock(&ctxdata->shm_mutex); pr_debug("buf_id :[%x] kaddr[%p]\n", shmnode->buf_id, shmnode->kaddr); @@ -385,12 +391,14 @@ void amdtee_unmap_shmem(struct tee_shm *shm) handle_unmap_shmem(buf_id); ctxdata = shm->ctx->data; + mutex_lock(&ctxdata->shm_mutex); list_for_each_entry(shmnode, &ctxdata->shm_list, shm_node) if (buf_id == shmnode->buf_id) { list_del(&shmnode->shm_node); kfree(shmnode); break; } + mutex_unlock(&ctxdata->shm_mutex); } int amdtee_invoke_func(struct tee_context *ctx,