From 2a764b529ae57bed61da2c90ff132b9fec97f80b Mon Sep 17 00:00:00 2001 From: Luis Ressel Date: Tue, 25 Jul 2017 15:13:41 -0400 Subject: selinux: Assign proper class to PF_UNIX/SOCK_RAW sockets For PF_UNIX, SOCK_RAW is synonymous with SOCK_DGRAM (cf. net/unix/af_unix.c). This is a tad obscure, but libpcap uses it. Signed-off-by: Luis Ressel Acked-by: Stephen Smalley Signed-off-by: Paul Moore --- security/selinux/hooks.c | 1 + 1 file changed, 1 insertion(+) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 33fd061305c4..00ad46e166f6 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1303,6 +1303,7 @@ static inline u16 socket_type_to_security_class(int family, int type, int protoc case SOCK_SEQPACKET: return SECCLASS_UNIX_STREAM_SOCKET; case SOCK_DGRAM: + case SOCK_RAW: return SECCLASS_UNIX_DGRAM_SOCKET; } break; -- cgit v1.2.3 From af63f4193f9fbbbac50fc766417d74735afd87ef Mon Sep 17 00:00:00 2001 From: Stephen Smalley Date: Mon, 31 Jul 2017 10:12:46 -0400 Subject: selinux: Generalize support for NNP/nosuid SELinux domain transitions As systemd ramps up enabling NNP (NoNewPrivileges) for system services, it is increasingly breaking SELinux domain transitions for those services and their descendants. systemd enables NNP not only for services whose unit files explicitly specify NoNewPrivileges=yes but also for services whose unit files specify any of the following options in combination with running without CAP_SYS_ADMIN (e.g. specifying User= or a CapabilityBoundingSet= without CAP_SYS_ADMIN): SystemCallFilter=, SystemCallArchitectures=, RestrictAddressFamilies=, RestrictNamespaces=, PrivateDevices=, ProtectKernelTunables=, ProtectKernelModules=, MemoryDenyWriteExecute=, or RestrictRealtime= as per the systemd.exec(5) man page. The end result is bad for the security of both SELinux-disabled and SELinux-enabled systems. Packagers have to turn off these options in the unit files to preserve SELinux domain transitions. For users who choose to disable SELinux, this means that they miss out on at least having the systemd-supported protections. For users who keep SELinux enabled, they may still be missing out on some protections because it isn't necessarily guaranteed that the SELinux policy for that service provides the same protections in all cases. commit 7b0d0b40cd78 ("selinux: Permit bounded transitions under NO_NEW_PRIVS or NOSUID.") allowed bounded transitions under NNP in order to support limited usage for sandboxing programs. However, defining typebounds for all of the affected service domains is impractical to implement in policy, since typebounds requires us to ensure that each domain is allowed everything all of its descendant domains are allowed, and this has to be repeated for the entire chain of domain transitions. There is no way to clone all allow rules from descendants to their ancestors in policy currently, and doing so would be undesirable even if it were practical, as it requires leaking permissions to objects and operations into ancestor domains that could weaken their own security in order to allow them to the descendants (e.g. if a descendant requires execmem permission, then so do all of its ancestors; if a descendant requires execute permission to a file, then so do all of its ancestors; if a descendant requires read to a symbolic link or temporary file, then so do all of its ancestors...). SELinux domains are intentionally not hierarchical / bounded in this manner normally, and making them so would undermine their protections and least privilege. We have long had a similar tension with SELinux transitions and nosuid mounts, albeit not as severe. Users often have had to choose between retaining nosuid on a mount and allowing SELinux domain transitions on files within those mounts. This likewise leads to unfortunate tradeoffs in security. Decouple NNP/nosuid from SELinux transitions, so that we don't have to make a choice between them. Introduce a nnp_nosuid_transition policy capability that enables transitions under NNP/nosuid to be based on a permission (nnp_transition for NNP; nosuid_transition for nosuid) between the old and new contexts in addition to the current support for bounded transitions. Domain transitions can then be allowed in policy without requiring the parent to be a strict superset of all of its children. With this change, systemd unit files can be left unmodified from upstream. SELinux-disabled and SELinux-enabled users will benefit from retaining any of the systemd-provided protections. SELinux policy will only need to be adapted to enable the new policy capability and to allow the new permissions between domain pairs as appropriate. NB: Allowing nnp_transition between two contexts opens up the potential for the old context to subvert the new context by installing seccomp filters before the execve. Allowing nosuid_transition between two contexts opens up the potential for a context transition to occur on a file from an untrusted filesystem (e.g. removable media or remote filesystem). Use with care. Signed-off-by: Stephen Smalley Signed-off-by: Paul Moore --- security/selinux/hooks.c | 47 ++++++++++++++++++++++++++++++++--------------- 1 file changed, 32 insertions(+), 15 deletions(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 00ad46e166f6..04b8e1082c9a 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2318,6 +2318,7 @@ static int check_nnp_nosuid(const struct linux_binprm *bprm, int nnp = (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS); int nosuid = !mnt_may_suid(bprm->file->f_path.mnt); int rc; + u32 av; if (!nnp && !nosuid) return 0; /* neither NNP nor nosuid */ @@ -2326,24 +2327,40 @@ static int check_nnp_nosuid(const struct linux_binprm *bprm, return 0; /* No change in credentials */ /* - * The only transitions we permit under NNP or nosuid - * are transitions to bounded SIDs, i.e. SIDs that are - * guaranteed to only be allowed a subset of the permissions - * of the current SID. + * If the policy enables the nnp_nosuid_transition policy capability, + * then we permit transitions under NNP or nosuid if the + * policy allows the corresponding permission between + * the old and new contexts. */ - rc = security_bounded_transition(old_tsec->sid, new_tsec->sid); - if (rc) { - /* - * On failure, preserve the errno values for NNP vs nosuid. - * NNP: Operation not permitted for caller. - * nosuid: Permission denied to file. - */ + if (selinux_policycap_nnp_nosuid_transition) { + av = 0; if (nnp) - return -EPERM; - else - return -EACCES; + av |= PROCESS2__NNP_TRANSITION; + if (nosuid) + av |= PROCESS2__NOSUID_TRANSITION; + rc = avc_has_perm(old_tsec->sid, new_tsec->sid, + SECCLASS_PROCESS2, av, NULL); + if (!rc) + return 0; } - return 0; + + /* + * We also permit NNP or nosuid transitions to bounded SIDs, + * i.e. SIDs that are guaranteed to only be allowed a subset + * of the permissions of the current SID. + */ + rc = security_bounded_transition(old_tsec->sid, new_tsec->sid); + if (!rc) + return 0; + + /* + * On failure, preserve the errno values for NNP vs nosuid. + * NNP: Operation not permitted for caller. + * nosuid: Permission denied to file. + */ + if (nnp) + return -EPERM; + return -EACCES; } static int selinux_bprm_set_creds(struct linux_binprm *bprm) -- cgit v1.2.3 From 7efbb60b455115f6027e76c45ec548436115f72c Mon Sep 17 00:00:00 2001 From: Stephen Smalley Date: Thu, 17 Aug 2017 13:32:36 -0400 Subject: selinux: update my email address Update my email address since epoch.ncsc.mil no longer exists. MAINTAINERS and CREDITS are already correct. Signed-off-by: Stephen Smalley Signed-off-by: Paul Moore --- security/selinux/hooks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 04b8e1082c9a..2bd7b824b7f5 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3,7 +3,7 @@ * * This file contains the SELinux hook function implementations. * - * Authors: Stephen Smalley, + * Authors: Stephen Smalley, * Chris Vance, * Wayne Salamon, * James Morris -- cgit v1.2.3 From 901ef845fa2469c211ce3b1e955d9e7245ab5d50 Mon Sep 17 00:00:00 2001 From: Antonio Murdaca Date: Thu, 9 Feb 2017 17:02:42 +0100 Subject: selinux: allow per-file labeling for cgroupfs This patch allows genfscon per-file labeling for cgroupfs. For instance, this allows to label the "release_agent" file within each cgroup mount and limit writes to it. Signed-off-by: Antonio Murdaca [PM: subject line and merge tweaks] Signed-off-by: Paul Moore --- security/selinux/hooks.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 2bd7b824b7f5..f803fdcde9cf 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -815,7 +815,9 @@ static int selinux_set_mnt_opts(struct super_block *sb, if (!strcmp(sb->s_type->name, "debugfs") || !strcmp(sb->s_type->name, "tracefs") || !strcmp(sb->s_type->name, "sysfs") || - !strcmp(sb->s_type->name, "pstore")) + !strcmp(sb->s_type->name, "pstore") || + !strcmp(sb->s_type->name, "cgroup") || + !strcmp(sb->s_type->name, "cgroup2")) sbsec->flags |= SE_SBGENFS; if (!sbsec->behavior) { -- cgit v1.2.3 From 0c3014f22dec0e1d14c8298551bfb6434638bdd9 Mon Sep 17 00:00:00 2001 From: Arvind Yadav Date: Sat, 26 Aug 2017 16:17:35 +0530 Subject: selinux: constify nf_hook_ops nf_hook_ops are not supposed to change at runtime. nf_register_net_hooks and nf_unregister_net_hooks are working with const nf_hook_ops. So mark the non-const nf_hook_ops structs as const. Signed-off-by: Arvind Yadav Signed-off-by: Paul Moore --- security/selinux/hooks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index f803fdcde9cf..45943e18da8b 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -6550,7 +6550,7 @@ security_initcall(selinux_init); #if defined(CONFIG_NETFILTER) -static struct nf_hook_ops selinux_nf_ops[] = { +static const struct nf_hook_ops selinux_nf_ops[] = { { .hook = selinux_ipv4_postroute, .pf = NFPROTO_IPV4, -- cgit v1.2.3