Merge 446d4138ed into 81401f37f2

vendor.mod

@@ -26,7 +26,7 @@ require (
 	github.com/mattn/go-runewidth v0.0.15
 	github.com/moby/patternmatcher v0.6.0
 	github.com/moby/swarmkit/v2 v2.0.0-20241017191044-e8ecf83ee08e
-	github.com/moby/sys/capability v0.3.0
+	github.com/moby/sys/capability v0.4.0
 	github.com/moby/sys/sequential v0.6.0
 	github.com/moby/sys/signal v0.7.1
 	github.com/moby/term v0.5.0

vendor.sum

@@ -168,8 +168,8 @@ github.com/moby/patternmatcher v0.6.0 h1:GmP9lR19aU5GqSSFko+5pRqHi+Ohk1O69aFiKkV
 github.com/moby/patternmatcher v0.6.0/go.mod h1:hDPoyOpDY7OrrMDLaYoY3hf52gNCR/YOUYxkhApJIxc=
 github.com/moby/swarmkit/v2 v2.0.0-20241017191044-e8ecf83ee08e h1:1yC8fRqStY6NirU/swI74fsrHvZVMbtxsHcvl8YpzDg=
 github.com/moby/swarmkit/v2 v2.0.0-20241017191044-e8ecf83ee08e/go.mod h1:mTTGIAz/59OGZR5Qe+QByIe3Nxc+sSuJkrsStFhr6Lg=
-github.com/moby/sys/capability v0.3.0 h1:kEP+y6te0gEXIaeQhIi0s7vKs/w0RPoH1qPa6jROcVg=
+github.com/moby/sys/capability v0.4.0 h1:4D4mI6KlNtWMCM1Z/K0i7RV1FkX+DBDHKVJpCndZoHk=
-github.com/moby/sys/capability v0.3.0/go.mod h1:4g9IK291rVkms3LKCDOoYlnV8xKwoDTpIrNEE35Wq0I=
+github.com/moby/sys/capability v0.4.0/go.mod h1:4g9IK291rVkms3LKCDOoYlnV8xKwoDTpIrNEE35Wq0I=
 github.com/moby/sys/sequential v0.6.0 h1:qrx7XFUd/5DxtqcoH1h438hF5TmOvzC/lspjy7zgvCU=
 github.com/moby/sys/sequential v0.6.0/go.mod h1:uyv8EUTrca5PnDsdMGXhZe6CCe8U/UiTWd+lL+7b/Ko=
 github.com/moby/sys/signal v0.7.1 h1:PrQxdvxcGijdo6UXXo/lU/TvHUWyPhj7UOpSo8tuvk0=

vendor/github.com/moby/sys/capability/.codespellrc

@@ -1,3 +0,0 @@
-[codespell]
-skip = ./.git
-ignore-words-list = nd

vendor/github.com/moby/sys/capability/.golangci.yml

@@ -1,6 +0,0 @@
-linters:
-  enable:
-    - unconvert
-    - unparam
-    - gofumpt
-    - errorlint

vendor/github.com/moby/sys/capability/CHANGELOG.md

@@ -5,6 +5,30 @@ from https://github.com/syndtr/gocapability/commit/42c35b4376354fd5.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.4.0] - 2024-11-11
+
+### Added
+* New separate API for ambient ([GetAmbient], [SetAmbient], [ResetAmbient])
+  and bound ([GetBound], [DropBound]) capabilities, modelled after libcap. (#176)
+
+### Fixed
+* [Apply] now returns an error if called for non-zero `pid`. Before this change,
+  it could silently change some capabilities of the current process, instead of
+  the one identified by the `pid`. (#168, #174)
+* Fixed tests that change capabilities to be run in a separate process. (#173)
+* Other improvements in tests. (#169, #170)
+
+### Changed
+* Use raw syscalls (which are slightly faster). (#176)
+* Most tests are now limited to testing the public API of the package. (#162)
+* Simplify parsing /proc/*pid*/status, add a test case. (#162)
+* Optimize the number of syscall to set ambient capabilities in Apply
+  by clearing them first; add a test case. (#163, #164)
+* Better documentation for [Apply], [NewFile], [NewFile2], [NewPid], [NewPid2]. (#175)
+
+### Removed
+* `.golangci.yml` and `.codespellrc` are no longer part of the package. (#158)
+
 ## [0.3.0] - 2024-09-25
 
 ### Added
@@ -63,14 +87,24 @@ This is an initial release since the fork.
  * Removed init function so programs that use this package start faster. [#6]
  * Removed `CAP_LAST_CAP` (use [LastCap] instead). [#6]
 
-<!-- Doc links. -->
+<!-- Doc links (please keep sorted). -->
 [Apply]: https://pkg.go.dev/github.com/moby/sys/capability#Capabilities.Apply
+[DropBound]: https://pkg.go.dev/github.com/moby/sys/capability#DropBound
+[GetAmbient]: https://pkg.go.dev/github.com/moby/sys/capability#GetAmbient
+[GetBound]: https://pkg.go.dev/github.com/moby/sys/capability#GetBound
 [LastCap]: https://pkg.go.dev/github.com/moby/sys/capability#LastCap
-[List]: https://pkg.go.dev/github.com/moby/sys/capability#List
 [ListKnown]: https://pkg.go.dev/github.com/moby/sys/capability#ListKnown
 [ListSupported]: https://pkg.go.dev/github.com/moby/sys/capability#ListSupported
+[List]: https://pkg.go.dev/github.com/moby/sys/capability#List
+[NewFile2]: https://pkg.go.dev/github.com/moby/sys/capability#NewFile2
+[NewFile]: https://pkg.go.dev/github.com/moby/sys/capability#NewFile
+[NewPid2]: https://pkg.go.dev/github.com/moby/sys/capability#NewPid2
+[NewPid]: https://pkg.go.dev/github.com/moby/sys/capability#NewPid
+[ResetAmbient]: https://pkg.go.dev/github.com/moby/sys/capability#ResetAmbient
+[SetAmbient]: https://pkg.go.dev/github.com/moby/sys/capability#SetAmbient
 
 <!-- Minor releases. -->
+[0.4.0]: https://github.com/moby/sys/releases/tag/capability%2Fv0.4.0
 [0.3.0]: https://github.com/moby/sys/releases/tag/capability%2Fv0.3.0
 [0.2.0]: https://github.com/moby/sys/releases/tag/capability%2Fv0.2.0
 [0.1.1]: https://github.com/kolyshkin/capability/compare/v0.1.0...v0.1.1

vendor/github.com/moby/sys/capability/capability.go

@@ -56,16 +56,16 @@ type Capabilities interface {
 	// outstanding changes.
 	Load() error
 
-	// Apply apply the capabilities settings, so all changes will take
+	// Apply apply the capabilities settings, so all changes made by
-	// effect.
+	// [Set], [Unset], [Fill], or [Clear] will take effect.
 	Apply(kind CapType) error
 }
 
 // NewPid initializes a new [Capabilities] object for given pid when
 // it is nonzero, or for the current process if pid is 0.
 //
-// Deprecated: Replace with [NewPid2] followed by [Capabilities.Load].
+// Deprecated: replace with [NewPid2] followed by optional [Capabilities.Load]
-// For example, replace:
+// (only if needed). For example, replace:
 //
 //	c, err := NewPid(0)
 //	if err != nil {
@@ -93,16 +93,16 @@ func NewPid(pid int) (Capabilities, error) {
 
 // NewPid2 initializes a new [Capabilities] object for given pid when
 // it is nonzero, or for the current process if pid is 0. This
-// does not load the process's current capabilities; to do that you
+// does not load the process's current capabilities; if needed,
-// must call [Capabilities.Load] explicitly.
+// call [Capabilities.Load].
 func NewPid2(pid int) (Capabilities, error) {
 	return newPid(pid)
 }
 
 // NewFile initializes a new Capabilities object for given file path.
 //
-// Deprecated: Replace with [NewFile2] followed by [Capabilities.Load].
+// Deprecated: replace with [NewFile2] followed by optional [Capabilities.Load]
-// For example, replace:
+// (only if needed). For example, replace:
 //
 //	c, err := NewFile(path)
 //	if err != nil {
@@ -130,7 +130,7 @@ func NewFile(path string) (Capabilities, error) {
 
 // NewFile2 creates a new initialized [Capabilities] object for given
 // file path. This does not load the process's current capabilities;
-// to do that you must call [Capabilities.Load] explicitly.
+// if needed, call [Capabilities.Load].
 func NewFile2(path string) (Capabilities, error) {
 	return newFile(path)
 }
@@ -142,3 +142,35 @@ func NewFile2(path string) (Capabilities, error) {
 func LastCap() (Cap, error) {
 	return lastCap()
 }
+
+// GetAmbient determines if a specific ambient capability is raised in the
+// calling thread.
+func GetAmbient(c Cap) (bool, error) {
+	return getAmbient(c)
+}
+
+// SetAmbient raises or lowers specified ambient capabilities for the calling
+// thread. To complete successfully, the prevailing effective capability set
+// must have a raised CAP_SETPCAP. Further, to raise a specific ambient
+// capability the inheritable and permitted sets of the calling thread must
+// already contain the specified capability.
+func SetAmbient(raise bool, caps ...Cap) error {
+	return setAmbient(raise, caps...)
+}
+
+// ResetAmbient resets all of the ambient capabilities for the calling thread
+// to their lowered value.
+func ResetAmbient() error {
+	return resetAmbient()
+}
+
+// GetBound determines if a specific bounding capability is raised in the
+// calling thread.
+func GetBound(c Cap) (bool, error) {
+	return getBound(c)
+}
+
+// DropBound lowers the specified bounding set capability.
+func DropBound(caps ...Cap) error {
+	return dropBound(caps...)
+}

vendor/github.com/moby/sys/capability/capability_linux.go

@@ -117,6 +117,13 @@ func newPid(pid int) (c Capabilities, retErr error) {
 	return
 }
 
+func ignoreEINVAL(err error) error {
+	if errors.Is(err, syscall.EINVAL) {
+		err = nil
+	}
+	return err
+}
+
 type capsV3 struct {
 	hdr     capHeader
 	data    [2]capData
@@ -307,15 +314,15 @@ func (c *capsV3) Load() (err error) {
 			}
 			break
 		}
-		if strings.HasPrefix(line, "CapB") {
+		if val, ok := strings.CutPrefix(line, "CapBnd:\t"); ok {
-			_, err = fmt.Sscanf(line[4:], "nd:  %08x%08x", &c.bounds[1], &c.bounds[0])
+			_, err = fmt.Sscanf(val, "%08x%08x", &c.bounds[1], &c.bounds[0])
 			if err != nil {
 				break
 			}
 			continue
 		}
-		if strings.HasPrefix(line, "CapA") {
+		if val, ok := strings.CutPrefix(line, "CapAmb:\t"); ok {
-			_, err = fmt.Sscanf(line[4:], "mb:  %08x%08x", &c.ambient[1], &c.ambient[0])
+			_, err = fmt.Sscanf(val, "%08x%08x", &c.ambient[1], &c.ambient[0])
 			if err != nil {
 				break
 			}
@@ -327,7 +334,10 @@ func (c *capsV3) Load() (err error) {
 	return
 }
 
-func (c *capsV3) Apply(kind CapType) (err error) {
+func (c *capsV3) Apply(kind CapType) error {
+	if c.hdr.pid != 0 {
+		return errors.New("unable to modify capabilities of another process")
+	}
 	last, err := LastCap()
 	if err != nil {
 		return err
@@ -336,21 +346,17 @@ func (c *capsV3) Apply(kind CapType) (err error) {
 		var data [2]capData
 		err = capget(&c.hdr, &data[0])
 		if err != nil {
-			return
+			return err
 		}
 		if (1<<uint(CAP_SETPCAP))&data[0].effective != 0 {
 			for i := Cap(0); i <= last; i++ {
 				if c.Get(BOUNDING, i) {
 					continue
 				}
-				err = prctl(syscall.PR_CAPBSET_DROP, uintptr(i), 0, 0, 0)
-				if err != nil {
 				// Ignore EINVAL since the capability may not be supported in this system.
-					if err == syscall.EINVAL { //nolint:errorlint // Errors from syscall are bare.
+				err = ignoreEINVAL(dropBound(i))
-						err = nil
+				if err != nil {
-						continue
+					return err
-					}
-					return
 				}
 			}
 		}
@@ -359,29 +365,73 @@ func (c *capsV3) Apply(kind CapType) (err error) {
 	if kind&CAPS == CAPS {
 		err = capset(&c.hdr, &c.data[0])
 		if err != nil {
-			return
+			return err
 		}
 	}
 
 	if kind&AMBS == AMBS {
-		for i := Cap(0); i <= last; i++ {
-			action := pr_CAP_AMBIENT_LOWER
-			if c.Get(AMBIENT, i) {
-				action = pr_CAP_AMBIENT_RAISE
-			}
-			err = prctl(pr_CAP_AMBIENT, action, uintptr(i), 0, 0)
-			if err != nil {
 		// Ignore EINVAL as not supported on kernels before 4.3
-				if err == syscall.EINVAL { //nolint:errorlint // Errors from syscall are bare.
+		err = ignoreEINVAL(resetAmbient())
-					err = nil
+		if err != nil {
+			return err
+		}
+		for i := Cap(0); i <= last; i++ {
+			if !c.Get(AMBIENT, i) {
 				continue
 			}
-				return
+			// Ignore EINVAL as not supported on kernels before 4.3
+			err = ignoreEINVAL(setAmbient(true, i))
+			if err != nil {
+				return err
 			}
 		}
 	}
 
-	return
+	return nil
+}
+
+func getAmbient(c Cap) (bool, error) {
+	res, err := prctlRetInt(pr_CAP_AMBIENT, pr_CAP_AMBIENT_IS_SET, uintptr(c))
+	if err != nil {
+		return false, err
+	}
+	return res > 0, nil
+}
+
+func setAmbient(raise bool, caps ...Cap) error {
+	op := pr_CAP_AMBIENT_RAISE
+	if !raise {
+		op = pr_CAP_AMBIENT_LOWER
+	}
+	for _, val := range caps {
+		err := prctl(pr_CAP_AMBIENT, op, uintptr(val))
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func resetAmbient() error {
+	return prctl(pr_CAP_AMBIENT, pr_CAP_AMBIENT_CLEAR_ALL, 0)
+}
+
+func getBound(c Cap) (bool, error) {
+	res, err := prctlRetInt(syscall.PR_CAPBSET_READ, uintptr(c), 0)
+	if err != nil {
+		return false, err
+	}
+	return res > 0, nil
+}
+
+func dropBound(caps ...Cap) error {
+	for _, val := range caps {
+		err := prctl(syscall.PR_CAPBSET_DROP, uintptr(val), 0)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
 }
 
 func newFile(path string) (c Capabilities, err error) {

vendor/github.com/moby/sys/capability/capability_noop.go

@@ -24,3 +24,23 @@ func newFile(_ string) (Capabilities, error) {
 func lastCap() (Cap, error) {
 	return -1, errNotSup
 }
+
+func getAmbient(_ Cap) (bool, error) {
+	return false, errNotSup
+}
+
+func setAmbient(_ bool, _ ...Cap) error {
+	return errNotSup
+}
+
+func resetAmbient() error {
+	return errNotSup
+}
+
+func getBound(_ Cap) (bool, error) {
+	return false, errNotSup
+}
+
+func dropBound(_ ...Cap) error {
+	return errNotSup
+}

vendor/github.com/moby/sys/capability/enum.go

@@ -316,7 +316,7 @@ func ListKnown() []Cap {
 	return list()
 }
 
-// ListSupported retuns the list of all capabilities known to the package,
+// ListSupported returns the list of all capabilities known to the package,
 // except those that are not supported by the currently running Linux kernel.
 func ListSupported() ([]Cap, error) {
 	last, err := LastCap()

vendor/github.com/moby/sys/capability/syscall_linux.go

@@ -24,7 +24,7 @@ type capData struct {
 }
 
 func capget(hdr *capHeader, data *capData) (err error) {
-	_, _, e1 := syscall.Syscall(syscall.SYS_CAPGET, uintptr(unsafe.Pointer(hdr)), uintptr(unsafe.Pointer(data)), 0)
+	_, _, e1 := syscall.RawSyscall(syscall.SYS_CAPGET, uintptr(unsafe.Pointer(hdr)), uintptr(unsafe.Pointer(data)), 0)
 	if e1 != 0 {
 		err = e1
 	}
@@ -32,7 +32,7 @@ func capget(hdr *capHeader, data *capData) (err error) {
 }
 
 func capset(hdr *capHeader, data *capData) (err error) {
-	_, _, e1 := syscall.Syscall(syscall.SYS_CAPSET, uintptr(unsafe.Pointer(hdr)), uintptr(unsafe.Pointer(data)), 0)
+	_, _, e1 := syscall.RawSyscall(syscall.SYS_CAPSET, uintptr(unsafe.Pointer(hdr)), uintptr(unsafe.Pointer(data)), 0)
 	if e1 != 0 {
 		err = e1
 	}
@@ -48,14 +48,22 @@ const (
 	pr_CAP_AMBIENT_CLEAR_ALL = uintptr(4)
 )
 
-func prctl(option int, arg2, arg3, arg4, arg5 uintptr) (err error) {
+func prctl(option int, arg2, arg3 uintptr) (err error) {
-	_, _, e1 := syscall.Syscall6(syscall.SYS_PRCTL, uintptr(option), arg2, arg3, arg4, arg5, 0)
+	_, _, e1 := syscall.RawSyscall(syscall.SYS_PRCTL, uintptr(option), arg2, arg3)
 	if e1 != 0 {
 		err = e1
 	}
 	return
 }
 
+func prctlRetInt(option int, arg2, arg3 uintptr) (int, error) {
+	ret, _, err := syscall.RawSyscall(syscall.SYS_PRCTL, uintptr(option), arg2, arg3)
+	if err != 0 {
+		return 0, err
+	}
+	return int(ret), nil
+}
+
 const (
 	vfsXattrName = "security.capability"
 
@@ -92,7 +100,7 @@ func getVfsCap(path string, dest *vfscapData) (err error) {
 	if err != nil {
 		return
 	}
-	r0, _, e1 := syscall.Syscall6(syscall.SYS_GETXATTR, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(_vfsXattrName)), uintptr(unsafe.Pointer(dest)), vfscapDataSizeV2, 0, 0)
+	r0, _, e1 := syscall.RawSyscall6(syscall.SYS_GETXATTR, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(_vfsXattrName)), uintptr(unsafe.Pointer(dest)), vfscapDataSizeV2, 0, 0)
 	if e1 != 0 {
 		if e1 == syscall.ENODATA {
 			dest.version = 2
@@ -145,7 +153,7 @@ func setVfsCap(path string, data *vfscapData) (err error) {
 	} else {
 		return syscall.EINVAL
 	}
-	_, _, e1 := syscall.Syscall6(syscall.SYS_SETXATTR, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(_vfsXattrName)), uintptr(unsafe.Pointer(data)), size, 0, 0)
+	_, _, e1 := syscall.RawSyscall6(syscall.SYS_SETXATTR, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(_vfsXattrName)), uintptr(unsafe.Pointer(data)), size, 0, 0)
 	if e1 != 0 {
 		err = e1
 	}

vendor/modules.txt

@@ -205,7 +205,7 @@ github.com/moby/swarmkit/v2/api/defaults
 github.com/moby/swarmkit/v2/api/genericresource
 github.com/moby/swarmkit/v2/manager/raftselector
 github.com/moby/swarmkit/v2/protobuf/plugin
-# github.com/moby/sys/capability v0.3.0
+# github.com/moby/sys/capability v0.4.0
 ## explicit; go 1.21
 github.com/moby/sys/capability
 # github.com/moby/sys/sequential v0.6.0