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fix: dyload open close failed 

本次提交修复内核加载器，异常情况分支的一个bug：mksh通过exec命令（mksh内置命令
，正常情况下，该命令成功执行会复用mksh进程空间，拉起新的指定进程）。但是如果
进程没有成功加载的情况下，内核加载器的异常分支会错误释放mksh的fd句柄。最终导致
下次拉起其他进程时（fork + exec方式），新的进程会继承fd，映射了早就释放的sysfd
，此时的sysfd可能已经被复用，issue场景下这个sysfd被加载过程中打开的libc.so占用
，exec时会释放procfd->sysfd(错误的映射关系)，最终新进程libc.so被关闭。
导致内核崩溃。

close #I452Z7

Signed-off-by: Guangyao Ma <guangyao.ma@outlook.com>
Change-Id: Ifca809f88b5ffcfb879dc5520d1f6adf5cf92bcd
This commit is contained in:
Guangyao Ma 2021-08-31 16:56:21 +08:00
parent 5f970888ef
commit 5e87d8c183
2 changed files with 33 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
kernel/extended/dynload/include/los_load_elf.h
View File

@ -89,7 +89,7 @@ typedef struct {
LD_ELF_EHDR elfEhdr;
LD_ELF_PHDR *elfPhdr;
UINT32 fileLen;
INT32 fd;
INT32 procfd;
} ELFInfo;
typedef struct {

48
kernel/extended/dynload/src/los_load_elf.c
View File

@ -62,6 +62,20 @@ static int OsELFOpen(const CHAR *fileName, INT32 oflags)
}
AssociateSystemFd(procFd, ret);
return procFd;
}
static int OsELFClose(int procFd)
{
int ret;
/* Process procfd convert to system global procfd */
int sysfd = DisassociateProcessFd(procFd);
ret = close(sysfd);
if (ret < 0) {
AssociateSystemFd(procFd, sysfd);
return -get_errno();
}
FreeProcessFd(procFd);
return ret;
}
@ -95,10 +109,11 @@ STATIC INT32 OsGetFileLength(UINT32 *fileLen, const CHAR *fileName)
return LOS_OK;
}
STATIC INT32 OsReadELFInfo(INT32 fd, UINT8 *buffer, size_t readSize, off_t offset)
STATIC INT32 OsReadELFInfo(INT32 procfd, UINT8 *buffer, size_t readSize, off_t offset)
{
ssize_t byteNum;
off_t returnPos;
INT32 fd = GetAssociatedSystemFd(procfd);
if (readSize > 0) {
returnPos = lseek(fd, offset, SEEK_SET);
@ -172,8 +187,8 @@ STATIC VOID OsLoadInit(ELFLoadInfo *loadInfo)
#else
loadInfo->oldFiles = NULL;
#endif
loadInfo->execInfo.fd = INVALID_FD;
loadInfo->interpInfo.fd = INVALID_FD;
loadInfo->execInfo.procfd = INVALID_FD;
loadInfo->interpInfo.procfd = INVALID_FD;
}
STATIC INT32 OsReadEhdr(const CHAR *fileName, ELFInfo *elfInfo, BOOL isExecFile)
@ -190,17 +205,17 @@ STATIC INT32 OsReadEhdr(const CHAR *fileName, ELFInfo *elfInfo, BOOL isExecFile)
PRINT_ERR("%s[%d], Failed to open ELF file: %s!\n", __FUNCTION__, __LINE__, fileName);
return ret;
}
elfInfo->fd = ret;
elfInfo->procfd = ret;
#ifdef LOSCFG_DRIVERS_TZDRIVER
if (isExecFile) {
ret = fs_getfilep(elfInfo->fd, &OsCurrProcessGet()->execFile);
ret = fs_getfilep(GetAssociatedSystemFd(elfInfo->procfd), &OsCurrProcessGet()->execFile);
if (ret) {
PRINT_ERR("%s[%d], Failed to get struct file %s!\n", __FUNCTION__, __LINE__, fileName);
}
}
#endif
ret = OsReadELFInfo(elfInfo->fd, (UINT8 *)&elfInfo->elfEhdr, sizeof(LD_ELF_EHDR), 0);
ret = OsReadELFInfo(elfInfo->procfd, (UINT8 *)&elfInfo->elfEhdr, sizeof(LD_ELF_EHDR), 0);
if (ret != LOS_OK) {
PRINT_ERR("%s[%d]\n", __FUNCTION__, __LINE__);
return -EIO;
@ -240,7 +255,7 @@ STATIC INT32 OsReadPhdrs(ELFInfo *elfInfo, BOOL isExecFile)
return -ENOMEM;
}
ret = OsReadELFInfo(elfInfo->fd, (UINT8 *)elfInfo->elfPhdr, size, elfEhdr->elfPhoff);
ret = OsReadELFInfo(elfInfo->procfd, (UINT8 *)elfInfo->elfPhdr, size, elfEhdr->elfPhoff);
if (ret != LOS_OK) {
(VOID)LOS_MemFree(m_aucSysMem0, elfInfo->elfPhdr);
elfInfo->elfPhdr = NULL;
@ -281,7 +296,7 @@ STATIC INT32 OsReadInterpInfo(ELFLoadInfo *loadInfo)
return -ENOMEM;
}
ret = OsReadELFInfo(loadInfo->execInfo.fd, (UINT8 *)elfInterpName, elfPhdr->fileSize, elfPhdr->offset);
ret = OsReadELFInfo(loadInfo->execInfo.procfd, (UINT8 *)elfInterpName, elfPhdr->fileSize, elfPhdr->offset);
if (ret != LOS_OK) {
PRINT_ERR("%s[%d]\n", __FUNCTION__, __LINE__);
ret = -EIO;
@ -466,13 +481,14 @@ STATIC INT32 OsSetBss(const LD_ELF_PHDR *elfPhdr, INT32 fd, UINTPTR bssStart, UI
return LOS_OK;
}
STATIC INT32 OsMmapELFFile(INT32 fd, const LD_ELF_PHDR *elfPhdr, const LD_ELF_EHDR *elfEhdr, UINTPTR *elfLoadAddr,
STATIC INT32 OsMmapELFFile(INT32 procfd, const LD_ELF_PHDR *elfPhdr, const LD_ELF_EHDR *elfEhdr, UINTPTR *elfLoadAddr,
UINT32 mapSize, UINTPTR *loadBase)
{
const LD_ELF_PHDR *elfPhdrTemp = elfPhdr;
UINTPTR vAddr, mapAddr, bssStart;
UINT32 bssEnd, elfProt, elfFlags;
INT32 ret, i;
INT32 fd = GetAssociatedSystemFd(procfd);
for (i = 0; i < elfEhdr->elfPhNum; ++i, ++elfPhdrTemp) {
if (elfPhdrTemp->type != LD_PT_LOAD) {
@ -538,7 +554,7 @@ STATIC INT32 OsLoadInterpBinary(const ELFLoadInfo *loadInfo, UINTPTR *interpMapB
return -EINVAL;
}
ret = OsMmapELFFile(loadInfo->interpInfo.fd, loadInfo->interpInfo.elfPhdr, &loadInfo->interpInfo.elfEhdr,
ret = OsMmapELFFile(loadInfo->interpInfo.procfd, loadInfo->interpInfo.elfPhdr, &loadInfo->interpInfo.elfEhdr,
interpMapBase, mapSize, &loadBase);
if (ret != LOS_OK) {
PRINT_ERR("%s[%d]\n", __FUNCTION__, __LINE__);
@ -898,14 +914,14 @@ STATIC INT32 OsLoadELFSegment(ELFLoadInfo *loadInfo)
}
}
ret = OsMmapELFFile(loadInfo->execInfo.fd, loadInfo->execInfo.elfPhdr, &loadInfo->execInfo.elfEhdr,
ret = OsMmapELFFile(loadInfo->execInfo.procfd, loadInfo->execInfo.elfPhdr, &loadInfo->execInfo.elfEhdr,
&loadInfo->loadAddr, mapSize, &loadBase);
if (ret != LOS_OK) {
PRINT_ERR("%s[%d]\n", __FUNCTION__, __LINE__);
return ret;
}
if (loadInfo->interpInfo.fd != INVALID_FD) {
if (loadInfo->interpInfo.procfd != INVALID_FD) {
ret = OsLoadInterpBinary(loadInfo, &interpMapBase);
if (ret != LOS_OK) {
return ret;
@ -961,12 +977,12 @@ STATIC VOID OsDeInitLoadInfo(ELFLoadInfo *loadInfo)
STATIC VOID OsDeInitFiles(ELFLoadInfo *loadInfo)
{
if (loadInfo->execInfo.fd != INVALID_FD) {
(VOID)close(loadInfo->execInfo.fd);
if (loadInfo->execInfo.procfd != INVALID_FD) {
(VOID)OsELFClose(loadInfo->execInfo.procfd);
}
if (loadInfo->interpInfo.fd != INVALID_FD) {
(VOID)close(loadInfo->interpInfo.fd);
if (loadInfo->interpInfo.procfd != INVALID_FD) {
(VOID)OsELFClose(loadInfo->interpInfo.procfd);
}
#ifdef LOSCFG_FS_VFS
delete_files_snapshot((struct files_struct *)loadInfo->oldFiles);