feat: 支持AT_RANDOM以增强用户态栈保护能力

背景：不开地址随机化时，用户态栈CANARY值是固定值
方案：支持AT_RANDOM，CANARY从AT_RANDOM获取随机值以增强用户态栈保护能力

close #I4CB8M

Signed-off-by: Haryslee <lihao189@huawei.com>
Change-Id: I28cef09f7016a5096e2096d4f6aa72722fcf1fd7

kernel/extended/dynload/include/los_load_elf.h

@@ -79,6 +79,7 @@ extern "C" {
 #endif
 
 #define STACK_ALIGN_SIZE                    0x10
+#define RANDOM_VECTOR_SIZE                  1
 
 /* The permissions on sections in the program header. */
 #define PF_R                                0x4
@@ -99,23 +100,22 @@ typedef struct {
     CHAR         *execName;
     INT32        argc;
     INT32        envc;
-    CHAR *const  *argv;
+    CHAR * const  *argv;
-    CHAR *const  *envp;
+    CHAR * const  *envp;
     UINTPTR      stackTop;
     UINTPTR      stackTopMax;
     UINTPTR      stackBase;
     UINTPTR      stackParamBase;
     UINT32       stackSize;
     INT32        stackProt;
+    UINTPTR      argStart;
     UINTPTR      loadAddr;
     UINTPTR      elfEntry;
     UINTPTR      topOfMem;
     UINTPTR      oldFiles;
     LosVmSpace   *newSpace;
     LosVmSpace   *oldSpace;
-#ifdef LOSCFG_ASLR
     INT32        randomDevFD;
-#endif
 } ELFLoadInfo;
 
 STATIC INLINE BOOL OsIsBadUserAddress(VADDR_T vaddr)

kernel/extended/dynload/src/los_load_elf.c

@@ -789,12 +789,10 @@ STATIC INT32 OsSetArgParams(ELFLoadInfo *loadInfo, CHAR *const *argv, CHAR *cons
     UINT32 vmFlags;
     INT32 ret;
 
-#ifdef LOSCFG_ASLR
     loadInfo->randomDevFD = open("/dev/urandom", O_RDONLY);
     if (loadInfo->randomDevFD < 0) {
         PRINT_ERR("%s: open /dev/urandom failed\n", __FUNCTION__);
     }
-#endif
 
     (VOID)OsGetStackProt(loadInfo);
     if (((UINT32)loadInfo->stackProt & (PROT_READ | PROT_WRITE)) != (PROT_READ | PROT_WRITE)) {
@@ -831,13 +829,13 @@ STATIC INT32 OsSetArgParams(ELFLoadInfo *loadInfo, CHAR *const *argv, CHAR *cons
     if (ret != LOS_OK) {
         return ret;
     }
+    loadInfo->argStart = loadInfo->topOfMem;
 
     return LOS_OK;
 }
 
 STATIC INT32 OsPutParamToStack(ELFLoadInfo *loadInfo, const UINTPTR *auxVecInfo, INT32 vecIndex)
 {
-    UINTPTR argStart = loadInfo->topOfMem;
     UINTPTR *topMem = (UINTPTR *)ROUNDDOWN(loadInfo->topOfMem, sizeof(UINTPTR));
     UINTPTR *argsPtr = NULL;
     INT32 items = (loadInfo->argc + 1) + (loadInfo->envc + 1) + 1;
@@ -858,8 +856,8 @@ STATIC INT32 OsPutParamToStack(ELFLoadInfo *loadInfo, const UINTPTR *auxVecInfo,
 
     argsPtr++;
 
-    if ((OsPutUserArgv(&argStart, &argsPtr, loadInfo->argc) != LOS_OK) ||
+    if ((OsPutUserArgv(&loadInfo->argStart, &argsPtr, loadInfo->argc) != LOS_OK) ||
-        (OsPutUserArgv(&argStart, &argsPtr, loadInfo->envc) != LOS_OK)) {
+        (OsPutUserArgv(&loadInfo->argStart, &argsPtr, loadInfo->envc) != LOS_OK)) {
         PRINT_ERR("%s[%d], Failed to put argv or envp to user stack!\n", __FUNCTION__, __LINE__);
         return -EFAULT;
     }
@@ -873,16 +871,46 @@ STATIC INT32 OsPutParamToStack(ELFLoadInfo *loadInfo, const UINTPTR *auxVecInfo,
     return LOS_OK;
 }
 
+STATIC INT32 OsGetRndNum(const ELFLoadInfo *loadInfo, UINT32 *rndVec, UINT32 vecSize)
+{
+    UINT32 randomValue = 0;
+    UINT32 i, ret;
+
+    for (i = 0; i < vecSize; ++i) {
+        ret = read(loadInfo->randomDevFD, &randomValue, sizeof(UINT32));
+        if (ret != sizeof(UINT32)) {
+            return -EIO;
+        }
+        rndVec[i] = randomValue;
+    }
+
+    return LOS_OK;
+}
+
 STATIC INT32 OsMakeArgsStack(ELFLoadInfo *loadInfo, UINTPTR interpMapBase)
 {
     UINTPTR auxVector[AUX_VECTOR_SIZE] = { 0 };
     UINTPTR *auxVecInfo = (UINTPTR *)auxVector;
     INT32 vecIndex = 0;
+    UINT32 rndVec[RANDOM_VECTOR_SIZE];
+    UINTPTR rndVecStart;
     INT32 ret;
 #ifdef LOSCFG_KERNEL_VDSO
     vaddr_t vdsoLoadAddr;
 #endif
 
+    ret = OsGetRndNum(loadInfo, rndVec, sizeof(rndVec));
+    if (ret != LOS_OK) {
+        return ret;
+    }
+    loadInfo->topOfMem -= sizeof(rndVec);
+    rndVecStart = loadInfo->topOfMem;
+
+    ret = LOS_ArchCopyToUser((VOID *)loadInfo->topOfMem, rndVec, sizeof(rndVec));
+    if (ret != 0) {
+        return -EFAULT;
+    }
+
     AUX_VEC_ENTRY(auxVector, vecIndex, AUX_PHDR,   loadInfo->loadAddr + loadInfo->execInfo.elfEhdr.elfPhoff);
     AUX_VEC_ENTRY(auxVector, vecIndex, AUX_PHENT,  sizeof(LD_ELF_PHDR));
     AUX_VEC_ENTRY(auxVector, vecIndex, AUX_PHNUM,  loadInfo->execInfo.elfEhdr.elfPhNum);
@@ -897,7 +925,7 @@ STATIC INT32 OsMakeArgsStack(ELFLoadInfo *loadInfo, UINTPTR interpMapBase)
     AUX_VEC_ENTRY(auxVector, vecIndex, AUX_HWCAP,  0);
     AUX_VEC_ENTRY(auxVector, vecIndex, AUX_CLKTCK, 0);
     AUX_VEC_ENTRY(auxVector, vecIndex, AUX_SECURE, 0);
-    AUX_VEC_ENTRY(auxVector, vecIndex, AUX_RANDOM, 0);
+    AUX_VEC_ENTRY(auxVector, vecIndex, AUX_RANDOM, rndVecStart);
     AUX_VEC_ENTRY(auxVector, vecIndex, AUX_EXECFN, (UINTPTR)loadInfo->execName);
 
 #ifdef LOSCFG_KERNEL_VDSO
@@ -988,9 +1016,7 @@ STATIC VOID OsFlushAspace(ELFLoadInfo *loadInfo)
 
 STATIC VOID OsDeInitLoadInfo(ELFLoadInfo *loadInfo)
 {
-#ifdef LOSCFG_ASLR
     (VOID)close(loadInfo->randomDevFD);
-#endif
 
     if (loadInfo->execInfo.elfPhdr != NULL) {
         (VOID)LOS_MemFree(m_aucSysMem0, loadInfo->execInfo.elfPhdr);