From: Piotr Sawicki <p.sawicki2@partner.samsung.com>
Date: Mon, 23 Oct 2017 07:04:14 +0000 (+0200)
Subject: Make changing of shm file mode thread safe
X-Git-Tag: submit/tizen_4.0/20171024.152729~9
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=refs%2Fchanges%2F24%2F157124%2F4;p=platform%2Fcore%2Fsecurity%2Ftef-simulator.git

Make changing of shm file mode thread safe

Change-Id: Id7b07a203878fdf16414c3b3fae281918671d345
---

diff --git a/TEECLib/src/teec_api.c b/TEECLib/src/teec_api.c
index a84aac7..0860520 100644
--- a/TEECLib/src/teec_api.c
+++ b/TEECLib/src/teec_api.c
@@ -41,6 +41,7 @@
 
 #define SHM_MAX_ID				INT32_MAX
 #define SHM_NAME_TEMPLATE		"/teec_shm%d"
+#define SHM_FILE_MODE			0660
 /*-----------------------------------------------------------------------------
  *  Globals
  *-----------------------------------------------------------------------------*/
@@ -98,23 +99,27 @@ static int32_t allocateSharedMemory(TEEC_SharedMemory *shm) {
 	int fd_shm = -1;
 	int res;
 
-	mode_t origMask = umask(0);
-
 	do {
 		res = snprintf(shm_name, sizeof(shm_name), SHM_NAME_TEMPLATE, memKey);
 		if (res == sizeof(shm_name)) {
-			umask(origMask);
 			LOGE(TEEC_LIB, "the shm object name is too long");
 			return TEEC_ERROR_GENERIC;
 		}
 
-		fd_shm = shm_open(shm_name, O_RDWR | O_CREAT | O_EXCL, 0660);
+		fd_shm = shm_open(shm_name, O_RDWR | O_CREAT | O_EXCL, SHM_FILE_MODE);
 		if (fd_shm >= 0) {
+			res = fchmod(fd_shm, SHM_FILE_MODE);
+			if (res == -1) {
+				close(fd_shm);
+				shm_unlink(shm_name);
+				LOGE(TEEC_LIB, "Cannot change permission of the %s shared memory file, error: %s",
+				     shm_name, strerror(errno));
+				return TEEC_ERROR_GENERIC;
+			}
 			break;
 		}
 
 		if (errno != EEXIST) {
-			umask(origMask);
 			LOGE(TEEC_LIB, "Cannot create shared memory object, error: %s", strerror(errno));
 			return TEEC_ERROR_GENERIC;
 		}
@@ -122,8 +127,6 @@ static int32_t allocateSharedMemory(TEEC_SharedMemory *shm) {
 		memKey++;
 	} while (memKey < SHM_MAX_ID);
 
-	umask(origMask);
-
 	if (memKey == SHM_MAX_ID) {
 		LOGE(TEEC_LIB, "Cannot find free shared memory slot");
 		return TEEC_ERROR_GENERIC;