d/freebsd-nq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

fusefs: fix a race condition in the allow_other test

Browse Source 
The test could occasionally hang if the parent's SIGUSR2 signal arrived
before the child had pause()d.  Using POSIX semaphores precludes that
possibility.

Sponsored by:	The FreeBSD Foundation
This commit is contained in:
Alan Somers 2019-03-27 00:24:57 +00:00
parent fd2749f25d
commit 13eaa5fadc
1 changed files with 21 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
tests/sys/fs/fusefs/allow_other.cc
View File

@ -35,10 +35,11 @@
extern "C" { extern "C" {
#include <sys/types.h> #include <sys/types.h>
#include <sys/mman.h>
#include <sys/wait.h> #include <sys/wait.h>
#include <fcntl.h> #include <fcntl.h>
#include <pwd.h> #include <pwd.h>
#include <signal.h> #include <semaphore.h>
} }
#include "mockfs.hh" #include "mockfs.hh"
@ -101,12 +102,17 @@ TEST_F(AllowOther, allowed)
uint64_t ino = 42; uint64_t ino = 42;
int fd; int fd;
pid_t child; pid_t child;
sem_t *sem;
int mprot = PROT_READ | PROT_WRITE;
int mflags = MAP_ANON | MAP_SHARED;
signal(SIGUSR2, sighandler); sem = (sem_t*)mmap(NULL, sizeof(*sem), mprot, mflags, -1, 0);
ASSERT_NE(NULL, sem) << strerror(errno);
ASSERT_EQ(0, sem_init(sem, 1, 0)) << strerror(errno);
if ((child = fork()) == 0) { if ((child = fork()) == 0) {
/* In child */ /* In child */
pause(); ASSERT_EQ(0, sem_wait(sem)) << strerror(errno);
/* Drop privileges before accessing */ /* Drop privileges before accessing */
if (0 != setreuid(-1, m_uid)) { if (0 != setreuid(-1, m_uid)) {
@ -122,6 +128,8 @@ TEST_F(AllowOther, allowed)
/* Deliberately leak fd */ /* Deliberately leak fd */
} else if (child > 0) { } else if (child > 0) {
int child_status;
/* /*
* In parent. Cleanup must happen here, because it's still * In parent. Cleanup must happen here, because it's still
* privileged. * privileged.
@ -134,8 +142,7 @@ TEST_F(AllowOther, allowed)
expect_getattr(ino, 0); expect_getattr(ino, 0);
m_mock->m_child_pid = child; m_mock->m_child_pid = child;
/* Signal the child process to go */ /* Signal the child process to go */
kill(child, SIGUSR2); ASSERT_EQ(0, sem_post(sem)) << strerror(errno);
int child_status;
wait(&child_status); wait(&child_status);
ASSERT_EQ(0, WEXITSTATUS(child_status)); ASSERT_EQ(0, WEXITSTATUS(child_status));
@ -149,12 +156,17 @@ TEST_F(NoAllowOther, disallowed)
const char FULLPATH[] = "mountpoint/some_file.txt"; const char FULLPATH[] = "mountpoint/some_file.txt";
int fd; int fd;
pid_t child; pid_t child;
sem_t *sem;
int mprot = PROT_READ | PROT_WRITE;
int mflags = MAP_ANON | MAP_SHARED;
signal(SIGUSR2, sighandler); sem = (sem_t*)mmap(NULL, sizeof(*sem), mprot, mflags, -1, 0);
ASSERT_NE(NULL, sem) << strerror(errno);
ASSERT_EQ(0, sem_init(sem, 1, 0)) << strerror(errno);
if ((child = fork()) == 0) { if ((child = fork()) == 0) {
/* In child */ /* In child */
pause(); ASSERT_EQ(0, sem_wait(sem)) << strerror(errno);
/* Drop privileges before accessing */ /* Drop privileges before accessing */
if (0 != setreuid(-1, m_uid)) { if (0 != setreuid(-1, m_uid)) {
@ -180,7 +192,7 @@ TEST_F(NoAllowOther, disallowed)
*/ */
m_mock->m_child_pid = child; m_mock->m_child_pid = child;
/* Signal the child process to go */ /* Signal the child process to go */
kill(child, SIGUSR2); ASSERT_EQ(0, sem_post(sem)) << strerror(errno);
int child_status; int child_status;
wait(&child_status); wait(&child_status);