diff options
author | Dean Deng <deandeng@google.com> | 2020-06-24 19:20:58 -0700 |
---|---|---|
committer | gVisor bot <gvisor-bot@google.com> | 2020-06-24 19:22:12 -0700 |
commit | b5e814445a4db5df7f4f58027422a5dba97ea766 (patch) | |
tree | f079641b8c9a859d7662cd78a30113b7aa7fe654 /test | |
parent | ac6f7b600bb6fe2e0c9171d24c0da2cc29388397 (diff) |
Fix procfs bugs in vfs2.
- Support writing on proc/[pid]/{uid,gid}map
- Return EIO for writing to static files.
Updates #2923.
PiperOrigin-RevId: 318188503
Diffstat (limited to 'test')
-rw-r--r-- | test/syscalls/BUILD | 2 | ||||
-rw-r--r-- | test/syscalls/linux/proc.cc | 49 |
2 files changed, 49 insertions, 2 deletions
diff --git a/test/syscalls/BUILD b/test/syscalls/BUILD index 39c1f79ad..23123006f 100644 --- a/test/syscalls/BUILD +++ b/test/syscalls/BUILD @@ -479,6 +479,7 @@ syscall_test( syscall_test( size = "medium", test = "//test/syscalls/linux:proc_test", + vfs2 = "True", ) syscall_test( @@ -498,6 +499,7 @@ syscall_test( syscall_test( test = "//test/syscalls/linux:proc_pid_uid_gid_map_test", + vfs2 = "True", ) syscall_test( diff --git a/test/syscalls/linux/proc.cc b/test/syscalls/linux/proc.cc index e77e9820e..d6b875dbf 100644 --- a/test/syscalls/linux/proc.cc +++ b/test/syscalls/linux/proc.cc @@ -754,8 +754,53 @@ TEST(ProcCpuinfo, RequiredFieldsArePresent) { } } -TEST(ProcCpuinfo, DeniesWrite) { - EXPECT_THAT(open("/proc/cpuinfo", O_WRONLY), SyscallFailsWithErrno(EACCES)); +TEST(ProcCpuinfo, DeniesWriteNonRoot) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_FOWNER))); + + // Do setuid in a separate thread so that after finishing this test, the + // process can still open files the test harness created before starting this + // test. Otherwise, the files are created by root (UID before the test), but + // cannot be opened by the `uid` set below after the test. After calling + // setuid(non-zero-UID), there is no way to get root privileges back. + ScopedThread([&] { + // Use syscall instead of glibc setuid wrapper because we want this setuid + // call to only apply to this task. POSIX threads, however, require that all + // threads have the same UIDs, so using the setuid wrapper sets all threads' + // real UID. + // Also drops capabilities. + constexpr int kNobody = 65534; + EXPECT_THAT(syscall(SYS_setuid, kNobody), SyscallSucceeds()); + EXPECT_THAT(open("/proc/cpuinfo", O_WRONLY), SyscallFailsWithErrno(EACCES)); + // TODO(gvisor.dev/issue/1193): Properly support setting size attributes in + // kernfs. + if (!IsRunningOnGvisor() || IsRunningWithVFS1()) { + EXPECT_THAT(truncate("/proc/cpuinfo", 123), + SyscallFailsWithErrno(EACCES)); + } + }); +} + +// With root privileges, it is possible to open /proc/cpuinfo with write mode, +// but all write operations will return EIO. +TEST(ProcCpuinfo, DeniesWriteRoot) { + // VFS1 does not behave differently for root/non-root. + SKIP_IF(IsRunningWithVFS1()); + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_FOWNER))); + + int fd; + EXPECT_THAT(fd = open("/proc/cpuinfo", O_WRONLY), SyscallSucceeds()); + if (fd > 0) { + EXPECT_THAT(write(fd, "x", 1), SyscallFailsWithErrno(EIO)); + EXPECT_THAT(pwrite(fd, "x", 1, 123), SyscallFailsWithErrno(EIO)); + } + // TODO(gvisor.dev/issue/1193): Properly support setting size attributes in + // kernfs. + if (!IsRunningOnGvisor() || IsRunningWithVFS1()) { + if (fd > 0) { + EXPECT_THAT(ftruncate(fd, 123), SyscallFailsWithErrno(EIO)); + } + EXPECT_THAT(truncate("/proc/cpuinfo", 123), SyscallFailsWithErrno(EIO)); + } } // Sanity checks that uptime is present. |