Date: Wed, 1 May 2019 00:00:49 +0000 (UTC) From: Alan Somers <asomers@FreeBSD.org> To: src-committers@freebsd.org, svn-src-projects@freebsd.org Subject: svn commit: r346979 - in projects/fuse2: sys/fs/fuse tests/sys/fs/fusefs Message-ID: <201905010000.x4100nVs085078@repo.freebsd.org>
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Author: asomers Date: Wed May 1 00:00:49 2019 New Revision: 346979 URL: https://svnweb.freebsd.org/changeset/base/346979 Log: fusefs: fix some permission checks with -o default_permissions When mounted with -o default_permissions fusefs is supposed to validate all permissions in the kernel, not the file system. This commit fixes two permissions that I had previously overlooked. * Only root may chown a file * Non-root users may only chgrp a file to a group to which they belong PR: 216391 Sponsored by: The FreeBSD Foundation Modified: projects/fuse2/sys/fs/fuse/fuse_vnops.c projects/fuse2/tests/sys/fs/fusefs/default_permissions.cc projects/fuse2/tests/sys/fs/fusefs/utils.cc projects/fuse2/tests/sys/fs/fusefs/utils.hh Modified: projects/fuse2/sys/fs/fuse/fuse_vnops.c ============================================================================== --- projects/fuse2/sys/fs/fuse/fuse_vnops.c Tue Apr 30 23:53:54 2019 (r346978) +++ projects/fuse2/sys/fs/fuse/fuse_vnops.c Wed May 1 00:00:49 2019 (r346979) @@ -1518,14 +1518,20 @@ fuse_vnop_setattr(struct vop_setattr_args *ap) struct thread *td = curthread; struct fuse_dispatcher fdi; struct fuse_setattr_in *fsai; + struct mount *mp; pid_t pid = td->td_proc->p_pid; - + struct fuse_data *data; + int dataflags; int err = 0; enum vtype vtyp; int sizechanged = 0; uint64_t newsize = 0; accmode_t accmode = 0; + mp = vnode_mount(vp); + data = fuse_get_mpdata(mp); + dataflags = data->dataflags; + if (fuse_isdeadfs(vp)) { return ENXIO; } @@ -1535,11 +1541,28 @@ fuse_vnop_setattr(struct vop_setattr_args *ap) fsai->valid = 0; if (vap->va_uid != (uid_t)VNOVAL) { + if (dataflags & FSESS_DEFAULT_PERMISSIONS) { + /* Only root may change a file's owner */ + err = priv_check_cred(cred, PRIV_VFS_CHOWN); + if (err) + return err; + } fsai->uid = vap->va_uid; fsai->valid |= FATTR_UID; accmode |= VADMIN; } if (vap->va_gid != (gid_t)VNOVAL) { + if (dataflags & FSESS_DEFAULT_PERMISSIONS && + !groupmember(vap->va_gid, cred)) + { + /* + * Non-root users may only chgrp to one of their own + * groups + */ + err = priv_check_cred(cred, PRIV_VFS_CHOWN); + if (err) + return err; + } fsai->gid = vap->va_gid; fsai->valid |= FATTR_GID; accmode |= VADMIN; Modified: projects/fuse2/tests/sys/fs/fusefs/default_permissions.cc ============================================================================== --- projects/fuse2/tests/sys/fs/fusefs/default_permissions.cc Tue Apr 30 23:53:54 2019 (r346978) +++ projects/fuse2/tests/sys/fs/fusefs/default_permissions.cc Wed May 1 00:00:49 2019 (r346979) @@ -69,7 +69,7 @@ virtual void SetUp() { public: void expect_getattr(uint64_t ino, mode_t mode, uint64_t attr_valid, int times, - uid_t uid = 0) + uid_t uid = 0, gid_t gid = 0) { EXPECT_CALL(*m_mock, process( ResultOf([=](auto in) { @@ -84,19 +84,22 @@ void expect_getattr(uint64_t ino, mode_t mode, uint64_ out->body.attr.attr.mode = mode; out->body.attr.attr.size = 0; out->body.attr.attr.uid = uid; + out->body.attr.attr.uid = gid; out->body.attr.attr_valid = attr_valid; }))); } void expect_lookup(const char *relpath, uint64_t ino, mode_t mode, - uint64_t attr_valid, uid_t uid = 0) + uint64_t attr_valid, uid_t uid = 0, gid_t gid = 0) { - FuseTest::expect_lookup(relpath, ino, mode, 0, 1, attr_valid, uid); + FuseTest::expect_lookup(relpath, ino, mode, 0, 1, attr_valid, uid, gid); } }; class Access: public DefaultPermissions {}; +class Chown: public DefaultPermissions {}; +class Chgrp: public DefaultPermissions {}; class Lookup: public DefaultPermissions {}; class Open: public DefaultPermissions {}; class Setattr: public DefaultPermissions {}; @@ -252,6 +255,105 @@ TEST_F(Access, ok) */ ASSERT_EQ(0, access(FULLPATH, access_mode)) << strerror(errno); +} + +/* Only root may change a file's owner */ +TEST_F(Chown, eperm) +{ + const char FULLPATH[] = "mountpoint/some_file.txt"; + const char RELPATH[] = "some_file.txt"; + const uint64_t ino = 42; + const mode_t mode = 0755; + + expect_getattr(1, S_IFDIR | 0755, UINT64_MAX, 1, geteuid()); + expect_lookup(RELPATH, ino, S_IFREG | mode, UINT64_MAX, geteuid()); + EXPECT_CALL(*m_mock, process( + ResultOf([](auto in) { + return (in->header.opcode == FUSE_SETATTR); + }, Eq(true)), + _) + ).Times(0); + + EXPECT_NE(0, chown(FULLPATH, 0, -1)); + EXPECT_EQ(EPERM, errno); +} + +/* non-root users may only chgrp a file to a group they belong to */ +TEST_F(Chgrp, eperm) +{ + const char FULLPATH[] = "mountpoint/some_file.txt"; + const char RELPATH[] = "some_file.txt"; + const uint64_t ino = 42; + const mode_t mode = 0755; + int ngroups = 64; + gid_t groups[ngroups]; + uid_t uid; + gid_t gid, newgid; + int i; + + uid = geteuid(); + gid = getegid(); + getgrouplist(getlogin(), getegid(), groups, &ngroups); + for (newgid = 0; newgid >= 0; newgid++) { + bool belongs = false; + + for (i = 0; i < ngroups; i++) { + if (groups[i] == newgid) + belongs = true; + } + if (!belongs) + break; + } + /* newgid is now a group to which the current user does not belong */ + + expect_getattr(1, S_IFDIR | 0755, UINT64_MAX, 1, uid, gid); + expect_lookup(RELPATH, ino, S_IFREG | mode, UINT64_MAX, uid, gid); + EXPECT_CALL(*m_mock, process( + ResultOf([](auto in) { + return (in->header.opcode == FUSE_SETATTR); + }, Eq(true)), + _) + ).Times(0); + + EXPECT_NE(0, chown(FULLPATH, -1, newgid)); + EXPECT_EQ(EPERM, errno); +} + +TEST_F(Chgrp, ok) +{ + const char FULLPATH[] = "mountpoint/some_file.txt"; + const char RELPATH[] = "some_file.txt"; + const uint64_t ino = 42; + const mode_t mode = 0755; + uid_t uid; + gid_t gid, newgid; + + uid = geteuid(); + gid = 0; + newgid = getegid(); + + expect_getattr(1, S_IFDIR | 0755, UINT64_MAX, 1, uid, gid); + expect_lookup(RELPATH, ino, S_IFREG | mode, UINT64_MAX, uid, gid); + EXPECT_CALL(*m_mock, process( + ResultOf([](auto in) { + return (in->header.opcode == FUSE_SETATTR); + }, Eq(true)), + _) + ).Times(0); + EXPECT_CALL(*m_mock, process( + ResultOf([](auto in) { + return (in->header.opcode == FUSE_SETATTR && + in->header.nodeid == ino); + }, Eq(true)), + _) + ).WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto out) { + SET_OUT_HEADER_LEN(out, attr); + out->body.attr.attr.mode = S_IFREG | mode; + out->body.attr.attr.uid = uid; + out->body.attr.attr.gid = newgid; + }))); + + EXPECT_EQ(0, chown(FULLPATH, -1, newgid)) << strerror(errno); } TEST_F(Create, ok) Modified: projects/fuse2/tests/sys/fs/fusefs/utils.cc ============================================================================== --- projects/fuse2/tests/sys/fs/fusefs/utils.cc Tue Apr 30 23:53:54 2019 (r346978) +++ projects/fuse2/tests/sys/fs/fusefs/utils.cc Wed May 1 00:00:49 2019 (r346979) @@ -175,7 +175,7 @@ void FuseTest::expect_getattr(uint64_t ino, uint64_t s } void FuseTest::expect_lookup(const char *relpath, uint64_t ino, mode_t mode, - uint64_t size, int times, uint64_t attr_valid, uid_t uid) + uint64_t size, int times, uint64_t attr_valid, uid_t uid, gid_t gid) { EXPECT_LOOKUP(1, relpath) .Times(times) @@ -187,6 +187,7 @@ void FuseTest::expect_lookup(const char *relpath, uint out->body.entry.attr_valid = attr_valid; out->body.entry.attr.size = size; out->body.entry.attr.uid = uid; + out->body.entry.attr.gid = gid; }))); } Modified: projects/fuse2/tests/sys/fs/fusefs/utils.hh ============================================================================== --- projects/fuse2/tests/sys/fs/fusefs/utils.hh Tue Apr 30 23:53:54 2019 (r346978) +++ projects/fuse2/tests/sys/fs/fusefs/utils.hh Wed May 1 00:00:49 2019 (r346979) @@ -103,7 +103,7 @@ class FuseTest : public ::testing::Test { */ void expect_lookup(const char *relpath, uint64_t ino, mode_t mode, uint64_t size, int times, uint64_t attr_valid = UINT64_MAX, - uid_t uid = 0); + uid_t uid = 0, gid_t gid = 0); /* * Create an expectation that FUSE_OPEN will be called for the given
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