diff options
| author | Richard Guy Briggs <rgb@redhat.com> | 2017-10-12 02:57:06 +0200 |
|---|---|---|
| committer | James Morris <james.l.morris@oracle.com> | 2017-10-20 06:22:43 +0200 |
| commit | 4c7e715fc87b6f8b652363b3515b48b3822c5b5f (patch) | |
| tree | dd6a8ec6b79721e30d0f867ccd207b9836a6de9b /security | |
| parent | capabilities: factor out cap_bprm_set_creds privileged root (diff) | |
| download | linux-4c7e715fc87b6f8b652363b3515b48b3822c5b5f.tar.xz linux-4c7e715fc87b6f8b652363b3515b48b3822c5b5f.zip | |
capabilities: intuitive names for cap gain status
Introduce macros cap_gained, cap_grew, cap_full to make the use of the
negation of is_subset() easier to read and analyse.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Acked-by: Kees Cook <keescook@chromium.org>
Okay-ished-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Diffstat (limited to 'security')
| -rw-r--r-- | security/commoncap.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/security/commoncap.c b/security/commoncap.c index be9bca50c312..4c9af6ef24b6 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -741,6 +741,12 @@ static void handle_privileged_root(struct linux_binprm *bprm, bool has_cap, *effective = true; } +#define __cap_gained(field, target, source) \ + !cap_issubset(target->cap_##field, source->cap_##field) +#define __cap_grew(target, source, cred) \ + !cap_issubset(cred->cap_##target, cred->cap_##source) +#define __cap_full(field, cred) \ + cap_issubset(CAP_FULL_SET, cred->cap_##field) /** * cap_bprm_set_creds - Set up the proposed credentials for execve(). * @bprm: The execution parameters, including the proposed creds @@ -769,10 +775,9 @@ int cap_bprm_set_creds(struct linux_binprm *bprm) handle_privileged_root(bprm, has_cap, &effective, root_uid); /* if we have fs caps, clear dangerous personality flags */ - if (!cap_issubset(new->cap_permitted, old->cap_permitted)) + if (__cap_gained(permitted, new, old)) bprm->per_clear |= PER_CLEAR_ON_SETID; - /* Don't let someone trace a set[ug]id/setpcap binary with the revised * credentials unless they have the appropriate permit. * @@ -780,8 +785,7 @@ int cap_bprm_set_creds(struct linux_binprm *bprm) */ is_setid = !uid_eq(new->euid, old->uid) || !gid_eq(new->egid, old->gid); - if ((is_setid || - !cap_issubset(new->cap_permitted, old->cap_permitted)) && + if ((is_setid || __cap_gained(permitted, new, old)) && ((bprm->unsafe & ~LSM_UNSAFE_PTRACE) || !ptracer_capable(current, new->user_ns))) { /* downgrade; they get no more than they had, and maybe less */ @@ -831,8 +835,8 @@ int cap_bprm_set_creds(struct linux_binprm *bprm) * Number 1 above might fail if you don't have a full bset, but I think * that is interesting information to audit. */ - if (!cap_issubset(new->cap_effective, new->cap_ambient)) { - if (!cap_issubset(CAP_FULL_SET, new->cap_effective) || + if (__cap_grew(effective, ambient, new)) { + if (!__cap_full(effective, new) || !uid_eq(new->euid, root_uid) || !uid_eq(new->uid, root_uid) || issecure(SECURE_NOROOT)) { ret = audit_log_bprm_fcaps(bprm, new, old); @@ -852,7 +856,7 @@ int cap_bprm_set_creds(struct linux_binprm *bprm) bprm->cap_elevated = 1; } else if (!uid_eq(new->uid, root_uid)) { if (effective || - !cap_issubset(new->cap_permitted, new->cap_ambient)) + __cap_grew(permitted, ambient, new)) bprm->cap_elevated = 1; } |