mdbx-posix: safeguard for DB corruption in case FD <= STDERR_FILENO.

Resolve https://github.com/erthink/libmdbx/issues/144

Change-Id: Ic3467338d494b021fa0d1863c8227976d0a2bcd5
This commit is contained in:
Leonid Yuriev 2020-12-05 22:03:18 +03:00
parent 338de2e1fb
commit d116e7235a
2 changed files with 50 additions and 0 deletions

View File

@ -360,6 +360,7 @@ eacces
EAFNOSUPPORT
EAGAIN
EB
EBADF
EBADFD
EBADSIGN
EBUSY
@ -1033,6 +1034,7 @@ nocache
NOCANDO
nocheckloglevel
NOCORE
NOCTTY
nodedata
NODEFAULTLIB
nodekey

View File

@ -532,6 +532,10 @@ MDBX_INTERNAL_FUNC int mdbx_removefile(const char *pathname) {
#endif
}
#if !(defined(_WIN32) || defined(_WIN64))
static bool is_valid_fd(int fd) { return !(isatty(fd) < 0 && errno == EBADF); }
#endif /*! Windows */
MDBX_INTERNAL_FUNC int mdbx_removedirectory(const char *pathname) {
#if defined(_WIN32) || defined(_WIN64)
const size_t wlen = mbstowcs(nullptr, pathname, INT_MAX);
@ -670,6 +674,20 @@ MDBX_INTERNAL_FUNC int mdbx_openfile(const enum mdbx_openfile_purpose purpose,
flags |= O_CLOEXEC;
#endif /* O_CLOEXEC */
/* Safeguard for https://github.com/erthink/libmdbx/issues/144 */
#if STDIN_FILENO == 0 && STDOUT_FILENO == 1 && STDERR_FILENO == 2
int stub_fd0 = -1, stub_fd1 = -1, stub_fd2 = -1;
static const char dev_null[] = "/dev/null";
if (!is_valid_fd(STDIN_FILENO))
stub_fd0 = open(dev_null, O_RDONLY | O_NOCTTY);
if (!is_valid_fd(STDOUT_FILENO))
stub_fd1 = open(dev_null, O_WRONLY | O_NOCTTY);
if (!is_valid_fd(STDERR_FILENO))
stub_fd2 = open(dev_null, O_WRONLY | O_NOCTTY);
#else
#error "Unexpected or unsupported UNIX or POSIX system"
#endif /* STDIN_FILENO == 0 && STDERR_FILENO == 2 */
*fd = open(pathname, flags, unix_mode_bits);
#if defined(O_DIRECT)
if (*fd < 0 && (flags & O_DIRECT) &&
@ -678,6 +696,35 @@ MDBX_INTERNAL_FUNC int mdbx_openfile(const enum mdbx_openfile_purpose purpose,
*fd = open(pathname, flags, unix_mode_bits);
}
#endif /* O_DIRECT */
/* Safeguard for https://github.com/erthink/libmdbx/issues/144 */
#if STDIN_FILENO == 0 && STDOUT_FILENO == 1 && STDERR_FILENO == 2
if (*fd == STDIN_FILENO) {
assert(stub_fd0 == -1);
*fd = dup(stub_fd0 = *fd);
}
if (*fd == STDOUT_FILENO) {
assert(stub_fd1 == -1);
*fd = dup(stub_fd1 = *fd);
}
if (*fd == STDERR_FILENO) {
assert(stub_fd2 == -1);
*fd = dup(stub_fd2 = *fd);
}
if (stub_fd0 != -1)
close(stub_fd0);
if (stub_fd1 != -1)
close(stub_fd1);
if (stub_fd2 != -1)
close(stub_fd2);
if (*fd >= STDIN_FILENO && *fd <= STDERR_FILENO) {
close(*fd);
return EBADF;
}
#else
#error "Unexpected or unsupported UNIX or POSIX system"
#endif /* STDIN_FILENO == 0 && STDERR_FILENO == 2 */
if (*fd < 0)
return errno;
@ -701,6 +748,7 @@ MDBX_INTERNAL_FUNC int mdbx_closefile(mdbx_filehandle_t fd) {
#if defined(_WIN32) || defined(_WIN64)
return CloseHandle(fd) ? MDBX_SUCCESS : GetLastError();
#else
assert(fd > STDERR_FILENO);
return (close(fd) == 0) ? MDBX_SUCCESS : errno;
#endif
}