From aafa80918a245edcbdaceb1191d749570f1872d0 Mon Sep 17 00:00:00 2001 From: Giuseppe Scrivano Date: Mon, 28 Feb 2022 09:48:52 +0100 Subject: do not set the inheritable capabilities The kernel never sets the inheritable capabilities for a process, they are only set by userspace. Emulate the same behavior. Closes: CVE-2022-27649 Signed-off-by: Giuseppe Scrivano --- pkg/specgen/generate/security.go | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'pkg') diff --git a/pkg/specgen/generate/security.go b/pkg/specgen/generate/security.go index 9c6709905..988c29832 100644 --- a/pkg/specgen/generate/security.go +++ b/pkg/specgen/generate/security.go @@ -146,6 +146,10 @@ func securityConfigureGenerator(s *specgen.SpecGenerator, g *generate.Generator, configSpec := g.Config configSpec.Process.Capabilities.Ambient = []string{} + + // Always unset the inheritable capabilities similarly to what the Linux kernel does + // They are used only when using capabilities with uid != 0. + configSpec.Process.Capabilities.Inheritable = []string{} configSpec.Process.Capabilities.Bounding = caplist user := strings.Split(s.User, ":")[0] @@ -153,7 +157,6 @@ func securityConfigureGenerator(s *specgen.SpecGenerator, g *generate.Generator, if (user == "" && s.UserNS.NSMode != specgen.KeepID) || user == "root" || user == "0" { configSpec.Process.Capabilities.Effective = caplist configSpec.Process.Capabilities.Permitted = caplist - configSpec.Process.Capabilities.Inheritable = caplist } else { mergedCaps, err := capabilities.MergeCapabilities(nil, s.CapAdd, nil) if err != nil { @@ -175,12 +178,12 @@ func securityConfigureGenerator(s *specgen.SpecGenerator, g *generate.Generator, } configSpec.Process.Capabilities.Effective = userCaps configSpec.Process.Capabilities.Permitted = userCaps - configSpec.Process.Capabilities.Inheritable = userCaps // Ambient capabilities were added to Linux 4.3. Set ambient // capabilities only when the kernel supports them. if supportAmbientCapabilities() { configSpec.Process.Capabilities.Ambient = userCaps + configSpec.Process.Capabilities.Inheritable = userCaps } } -- cgit v1.2.3-54-g00ecf