From 762e4761cc4edd92108f6836ad1933c7158b8be8 Mon Sep 17 00:00:00 2001 From: gVisor bot Date: Tue, 11 Feb 2020 11:08:28 -0800 Subject: Move Align{Up,Down} into binary package. PiperOrigin-RevId: 294477647 --- pkg/binary/binary.go | 10 ++++++++++ pkg/sentry/socket/control/control.go | 26 ++++++++------------------ pkg/sentry/socket/netfilter/extensions.go | 7 +------ pkg/sentry/socket/netlink/message.go | 15 ++++----------- pkg/sentry/strace/BUILD | 1 - pkg/sentry/strace/socket.go | 7 +++---- 6 files changed, 26 insertions(+), 40 deletions(-) diff --git a/pkg/binary/binary.go b/pkg/binary/binary.go index 631785f7b..25065aef9 100644 --- a/pkg/binary/binary.go +++ b/pkg/binary/binary.go @@ -254,3 +254,13 @@ func WriteUint64(w io.Writer, order binary.ByteOrder, num uint64) error { _, err := w.Write(buf) return err } + +// AlignUp rounds a length up to an alignment. align must be a power of 2. +func AlignUp(length int, align uint) int { + return (length + int(align) - 1) & ^(int(align) - 1) +} + +// AlignDown rounds a length down to an alignment. align must be a power of 2. +func AlignDown(length int, align uint) int { + return length & ^(int(align) - 1) +} diff --git a/pkg/sentry/socket/control/control.go b/pkg/sentry/socket/control/control.go index 00265f15b..6145a7fc3 100644 --- a/pkg/sentry/socket/control/control.go +++ b/pkg/sentry/socket/control/control.go @@ -189,7 +189,7 @@ func putUint32(buf []byte, n uint32) []byte { // putCmsg writes a control message header and as much data as will fit into // the unused capacity of a buffer. func putCmsg(buf []byte, flags int, msgType uint32, align uint, data []int32) ([]byte, int) { - space := AlignDown(cap(buf)-len(buf), 4) + space := binary.AlignDown(cap(buf)-len(buf), 4) // We can't write to space that doesn't exist, so if we are going to align // the available space, we must align down. @@ -282,19 +282,9 @@ func PackCredentials(t *kernel.Task, creds SCMCredentials, buf []byte, flags int return putCmsg(buf, flags, linux.SCM_CREDENTIALS, align, c) } -// AlignUp rounds a length up to an alignment. align must be a power of 2. -func AlignUp(length int, align uint) int { - return (length + int(align) - 1) & ^(int(align) - 1) -} - -// AlignDown rounds a down to an alignment. align must be a power of 2. -func AlignDown(length int, align uint) int { - return length & ^(int(align) - 1) -} - // alignSlice extends a slice's length (up to the capacity) to align it. func alignSlice(buf []byte, align uint) []byte { - aligned := AlignUp(len(buf), align) + aligned := binary.AlignUp(len(buf), align) if aligned > cap(buf) { // Linux allows unaligned data if there isn't room for alignment. // Since there isn't room for alignment, there isn't room for any @@ -377,7 +367,7 @@ func PackControlMessages(t *kernel.Task, cmsgs socket.ControlMessages, buf []byt // cmsgSpace is equivalent to CMSG_SPACE in Linux. func cmsgSpace(t *kernel.Task, dataLen int) int { - return linux.SizeOfControlMessageHeader + AlignUp(dataLen, t.Arch().Width()) + return linux.SizeOfControlMessageHeader + binary.AlignUp(dataLen, t.Arch().Width()) } // CmsgsSpace returns the number of bytes needed to fit the control messages @@ -437,7 +427,7 @@ func Parse(t *kernel.Task, socketOrEndpoint interface{}, buf []byte) (socket.Con case linux.SOL_SOCKET: switch h.Type { case linux.SCM_RIGHTS: - rightsSize := AlignDown(length, linux.SizeOfControlMessageRight) + rightsSize := binary.AlignDown(length, linux.SizeOfControlMessageRight) numRights := rightsSize / linux.SizeOfControlMessageRight if len(fds)+numRights > linux.SCM_MAX_FD { @@ -448,7 +438,7 @@ func Parse(t *kernel.Task, socketOrEndpoint interface{}, buf []byte) (socket.Con fds = append(fds, int32(usermem.ByteOrder.Uint32(buf[j:j+linux.SizeOfControlMessageRight]))) } - i += AlignUp(length, width) + i += binary.AlignUp(length, width) case linux.SCM_CREDENTIALS: if length < linux.SizeOfControlMessageCredentials { @@ -462,7 +452,7 @@ func Parse(t *kernel.Task, socketOrEndpoint interface{}, buf []byte) (socket.Con return socket.ControlMessages{}, err } cmsgs.Unix.Credentials = scmCreds - i += AlignUp(length, width) + i += binary.AlignUp(length, width) default: // Unknown message type. @@ -476,7 +466,7 @@ func Parse(t *kernel.Task, socketOrEndpoint interface{}, buf []byte) (socket.Con } cmsgs.IP.HasTOS = true binary.Unmarshal(buf[i:i+linux.SizeOfControlMessageTOS], usermem.ByteOrder, &cmsgs.IP.TOS) - i += AlignUp(length, width) + i += binary.AlignUp(length, width) default: return socket.ControlMessages{}, syserror.EINVAL @@ -489,7 +479,7 @@ func Parse(t *kernel.Task, socketOrEndpoint interface{}, buf []byte) (socket.Con } cmsgs.IP.HasTClass = true binary.Unmarshal(buf[i:i+linux.SizeOfControlMessageTClass], usermem.ByteOrder, &cmsgs.IP.TClass) - i += AlignUp(length, width) + i += binary.AlignUp(length, width) default: return socket.ControlMessages{}, syserror.EINVAL diff --git a/pkg/sentry/socket/netfilter/extensions.go b/pkg/sentry/socket/netfilter/extensions.go index 22fd0ebe7..b4b244abf 100644 --- a/pkg/sentry/socket/netfilter/extensions.go +++ b/pkg/sentry/socket/netfilter/extensions.go @@ -72,7 +72,7 @@ func marshalEntryMatch(name string, data []byte) []byte { nflog("marshaling matcher %q", name) // We have to pad this struct size to a multiple of 8 bytes. - size := alignUp(linux.SizeOfXTEntryMatch+len(data), 8) + size := binary.AlignUp(linux.SizeOfXTEntryMatch+len(data), 8) matcher := linux.KernelXTEntryMatch{ XTEntryMatch: linux.XTEntryMatch{ MatchSize: uint16(size), @@ -93,8 +93,3 @@ func unmarshalMatcher(match linux.XTEntryMatch, filter iptables.IPHeaderFilter, } return matchMaker.unmarshal(buf, filter) } - -// alignUp rounds a length up to an alignment. align must be a power of 2. -func alignUp(length int, align uint) int { - return (length + int(align) - 1) & ^(int(align) - 1) -} diff --git a/pkg/sentry/socket/netlink/message.go b/pkg/sentry/socket/netlink/message.go index 4ea252ccb..0899c61d1 100644 --- a/pkg/sentry/socket/netlink/message.go +++ b/pkg/sentry/socket/netlink/message.go @@ -23,18 +23,11 @@ import ( "gvisor.dev/gvisor/pkg/usermem" ) -// alignUp rounds a length up to an alignment. -// -// Preconditions: align is a power of two. -func alignUp(length int, align uint) int { - return (length + int(align) - 1) &^ (int(align) - 1) -} - // alignPad returns the length of padding required for alignment. // // Preconditions: align is a power of two. func alignPad(length int, align uint) int { - return alignUp(length, align) - length + return binary.AlignUp(length, align) - length } // Message contains a complete serialized netlink message. @@ -138,7 +131,7 @@ func (m *Message) Finalize() []byte { // Align the message. Note that the message length in the header (set // above) is the useful length of the message, not the total aligned // length. See net/netlink/af_netlink.c:__nlmsg_put. - aligned := alignUp(len(m.buf), linux.NLMSG_ALIGNTO) + aligned := binary.AlignUp(len(m.buf), linux.NLMSG_ALIGNTO) m.putZeros(aligned - len(m.buf)) return m.buf } @@ -173,7 +166,7 @@ func (m *Message) PutAttr(atype uint16, v interface{}) { m.Put(v) // Align the attribute. - aligned := alignUp(l, linux.NLA_ALIGNTO) + aligned := binary.AlignUp(l, linux.NLA_ALIGNTO) m.putZeros(aligned - l) } @@ -190,7 +183,7 @@ func (m *Message) PutAttrString(atype uint16, s string) { m.putZeros(1) // Align the attribute. - aligned := alignUp(l, linux.NLA_ALIGNTO) + aligned := binary.AlignUp(l, linux.NLA_ALIGNTO) m.putZeros(aligned - l) } diff --git a/pkg/sentry/strace/BUILD b/pkg/sentry/strace/BUILD index 762a946fe..2f39a6f2b 100644 --- a/pkg/sentry/strace/BUILD +++ b/pkg/sentry/strace/BUILD @@ -30,7 +30,6 @@ go_library( "//pkg/seccomp", "//pkg/sentry/arch", "//pkg/sentry/kernel", - "//pkg/sentry/socket/control", "//pkg/sentry/socket/netlink", "//pkg/sentry/socket/netstack", "//pkg/sentry/syscalls/linux", diff --git a/pkg/sentry/strace/socket.go b/pkg/sentry/strace/socket.go index f7ff4573e..51e6d81b2 100644 --- a/pkg/sentry/strace/socket.go +++ b/pkg/sentry/strace/socket.go @@ -22,7 +22,6 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/binary" "gvisor.dev/gvisor/pkg/sentry/kernel" - "gvisor.dev/gvisor/pkg/sentry/socket/control" "gvisor.dev/gvisor/pkg/sentry/socket/netlink" "gvisor.dev/gvisor/pkg/sentry/socket/netstack" slinux "gvisor.dev/gvisor/pkg/sentry/syscalls/linux" @@ -220,13 +219,13 @@ func cmsghdr(t *kernel.Task, addr usermem.Addr, length uint64, maxBytes uint64) if skipData { strs = append(strs, fmt.Sprintf("{level=%s, type=%s, length=%d}", level, typ, h.Length)) - i += control.AlignUp(length, width) + i += binary.AlignUp(length, width) continue } switch h.Type { case linux.SCM_RIGHTS: - rightsSize := control.AlignDown(length, linux.SizeOfControlMessageRight) + rightsSize := binary.AlignDown(length, linux.SizeOfControlMessageRight) numRights := rightsSize / linux.SizeOfControlMessageRight fds := make(linux.ControlMessageRights, numRights) @@ -295,7 +294,7 @@ func cmsghdr(t *kernel.Task, addr usermem.Addr, length uint64, maxBytes uint64) default: panic("unreachable") } - i += control.AlignUp(length, width) + i += binary.AlignUp(length, width) } return fmt.Sprintf("%#x %s", addr, strings.Join(strs, ", ")) -- cgit v1.2.3