From: serge@hallyn.com (Serge E. Hallyn) To: linux-security-module@vger.kernel.org Subject: [PATCH V3 01/10] capabilities: factor out cap_bprm_set_creds privileged root Date: Thu, 24 Aug 2017 10:42:08 -0500 [thread overview] Message-ID: <20170824154208.GA10515@mail.hallyn.com> (raw) In-Reply-To: <63333a7ed7e3ce62e3142b5e34ee942f3874a0d6.1503459890.git.rgb@redhat.com> Quoting Richard Guy Briggs (rgb at redhat.com): > Factor out the case of privileged root from the function > cap_bprm_set_creds() to make the latter easier to read and analyse. > > Suggested-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> > Signed-off-by: Richard Guy Briggs <rgb@redhat.com> > --- > security/commoncap.c | 62 +++++++++++++++++++++++++++---------------------- > 1 files changed, 34 insertions(+), 28 deletions(-) > > diff --git a/security/commoncap.c b/security/commoncap.c > index 78b3783..b7fbf77 100644 > --- a/security/commoncap.c > +++ b/security/commoncap.c > @@ -481,6 +481,38 @@ static int get_file_caps(struct linux_binprm *bprm, bool *effective, bool *has_c > return rc; > } > > +void handle_privileged_root(struct linux_binprm *bprm, bool has_cap, bool *effective, kuid_t root_uid) > +{ > + const struct cred *old = current_cred(); > + struct cred *new = bprm->cred; > + > + if (issecure(SECURE_NOROOT)) > + return; > + /* > + * If the legacy file capability is set, then don't set privs > + * for a setuid root binary run by a non-root user. Do set it > + * for a root user just to cause least surprise to an admin. > + */ > + if (has_cap && !uid_eq(new->uid, root_uid) && uid_eq(new->euid, root_uid)) { > + warn_setuid_and_fcaps_mixed(bprm->filename); > + return; > + } > + /* > + * To support inheritance of root-permissions and suid-root > + * executables under compatibility mode, we override the > + * capability sets for the file. > + * > + * If only the real uid is 0, we do not set the effective bit. > + */ > + if (uid_eq(new->euid, root_uid) || uid_eq(new->uid, root_uid)) { > + /* pP' = (cap_bset & ~0) | (pI & ~0) */ > + new->cap_permitted = cap_combine(old->cap_bset, > + old->cap_inheritable); > + } > + if (uid_eq(new->euid, root_uid)) > + *effective = true; > +} > + > /** > * cap_bprm_set_creds - Set up the proposed credentials for execve(). > * @bprm: The execution parameters, including the proposed creds > @@ -493,46 +525,20 @@ int cap_bprm_set_creds(struct linux_binprm *bprm) > { > const struct cred *old = current_cred(); > struct cred *new = bprm->cred; > - bool effective, has_cap = false, is_setid; > + bool effective = false, has_cap = false, is_setid; > int ret; > kuid_t root_uid; > > if (WARN_ON(!cap_ambient_invariant_ok(old))) > return -EPERM; > > - effective = false; > ret = get_file_caps(bprm, &effective, &has_cap); > if (ret < 0) > return ret; > > root_uid = make_kuid(new->user_ns, 0); > > - if (!issecure(SECURE_NOROOT)) { > - /* > - * If the legacy file capability is set, then don't set privs > - * for a setuid root binary run by a non-root user. Do set it > - * for a root user just to cause least surprise to an admin. > - */ > - if (has_cap && !uid_eq(new->uid, root_uid) && uid_eq(new->euid, root_uid)) { > - warn_setuid_and_fcaps_mixed(bprm->filename); > - goto skip; > - } > - /* > - * To support inheritance of root-permissions and suid-root > - * executables under compatibility mode, we override the > - * capability sets for the file. > - * > - * If only the real uid is 0, we do not set the effective bit. > - */ > - if (uid_eq(new->euid, root_uid) || uid_eq(new->uid, root_uid)) { > - /* pP' = (cap_bset & ~0) | (pI & ~0) */ > - new->cap_permitted = cap_combine(old->cap_bset, > - old->cap_inheritable); > - } > - if (uid_eq(new->euid, root_uid)) > - effective = true; > - } > -skip: > + 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)) > -- > 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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From: "Serge E. Hallyn" <serge@hallyn.com> To: Richard Guy Briggs <rgb@redhat.com> Cc: linux-security-module@vger.kernel.org, linux-audit@redhat.com, Andy Lutomirski <luto@kernel.org>, "Serge E. Hallyn" <serge.hallyn@ubuntu.com>, Kees Cook <keescook@chromium.org>, James Morris <james.l.morris@oracle.com>, Eric Paris <eparis@redhat.com>, Paul Moore <pmoore@redhat.com>, Steve Grubb <sgrubb@redhat.com> Subject: Re: [PATCH V3 01/10] capabilities: factor out cap_bprm_set_creds privileged root Date: Thu, 24 Aug 2017 10:42:08 -0500 [thread overview] Message-ID: <20170824154208.GA10515@mail.hallyn.com> (raw) In-Reply-To: <63333a7ed7e3ce62e3142b5e34ee942f3874a0d6.1503459890.git.rgb@redhat.com> Quoting Richard Guy Briggs (rgb@redhat.com): > Factor out the case of privileged root from the function > cap_bprm_set_creds() to make the latter easier to read and analyse. > > Suggested-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> > Signed-off-by: Richard Guy Briggs <rgb@redhat.com> > --- > security/commoncap.c | 62 +++++++++++++++++++++++++++---------------------- > 1 files changed, 34 insertions(+), 28 deletions(-) > > diff --git a/security/commoncap.c b/security/commoncap.c > index 78b3783..b7fbf77 100644 > --- a/security/commoncap.c > +++ b/security/commoncap.c > @@ -481,6 +481,38 @@ static int get_file_caps(struct linux_binprm *bprm, bool *effective, bool *has_c > return rc; > } > > +void handle_privileged_root(struct linux_binprm *bprm, bool has_cap, bool *effective, kuid_t root_uid) > +{ > + const struct cred *old = current_cred(); > + struct cred *new = bprm->cred; > + > + if (issecure(SECURE_NOROOT)) > + return; > + /* > + * If the legacy file capability is set, then don't set privs > + * for a setuid root binary run by a non-root user. Do set it > + * for a root user just to cause least surprise to an admin. > + */ > + if (has_cap && !uid_eq(new->uid, root_uid) && uid_eq(new->euid, root_uid)) { > + warn_setuid_and_fcaps_mixed(bprm->filename); > + return; > + } > + /* > + * To support inheritance of root-permissions and suid-root > + * executables under compatibility mode, we override the > + * capability sets for the file. > + * > + * If only the real uid is 0, we do not set the effective bit. > + */ > + if (uid_eq(new->euid, root_uid) || uid_eq(new->uid, root_uid)) { > + /* pP' = (cap_bset & ~0) | (pI & ~0) */ > + new->cap_permitted = cap_combine(old->cap_bset, > + old->cap_inheritable); > + } > + if (uid_eq(new->euid, root_uid)) > + *effective = true; > +} > + > /** > * cap_bprm_set_creds - Set up the proposed credentials for execve(). > * @bprm: The execution parameters, including the proposed creds > @@ -493,46 +525,20 @@ int cap_bprm_set_creds(struct linux_binprm *bprm) > { > const struct cred *old = current_cred(); > struct cred *new = bprm->cred; > - bool effective, has_cap = false, is_setid; > + bool effective = false, has_cap = false, is_setid; > int ret; > kuid_t root_uid; > > if (WARN_ON(!cap_ambient_invariant_ok(old))) > return -EPERM; > > - effective = false; > ret = get_file_caps(bprm, &effective, &has_cap); > if (ret < 0) > return ret; > > root_uid = make_kuid(new->user_ns, 0); > > - if (!issecure(SECURE_NOROOT)) { > - /* > - * If the legacy file capability is set, then don't set privs > - * for a setuid root binary run by a non-root user. Do set it > - * for a root user just to cause least surprise to an admin. > - */ > - if (has_cap && !uid_eq(new->uid, root_uid) && uid_eq(new->euid, root_uid)) { > - warn_setuid_and_fcaps_mixed(bprm->filename); > - goto skip; > - } > - /* > - * To support inheritance of root-permissions and suid-root > - * executables under compatibility mode, we override the > - * capability sets for the file. > - * > - * If only the real uid is 0, we do not set the effective bit. > - */ > - if (uid_eq(new->euid, root_uid) || uid_eq(new->uid, root_uid)) { > - /* pP' = (cap_bset & ~0) | (pI & ~0) */ > - new->cap_permitted = cap_combine(old->cap_bset, > - old->cap_inheritable); > - } > - if (uid_eq(new->euid, root_uid)) > - effective = true; > - } > -skip: > + 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)) > -- > 1.7.1
next prev parent reply other threads:[~2017-08-24 15:42 UTC|newest] Thread overview: 114+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-08-23 10:12 [PATCH V3 00/10] capabilities: do not audit log BPRM_FCAPS on set*id Richard Guy Briggs 2017-08-23 10:12 ` Richard Guy Briggs 2017-08-23 10:12 ` [PATCH V3 01/10] capabilities: factor out cap_bprm_set_creds privileged root Richard Guy Briggs 2017-08-23 10:12 ` Richard Guy Briggs 2017-08-24 15:42 ` Serge E. Hallyn [this message] 2017-08-24 15:42 ` Serge E. Hallyn 2017-08-25 5:55 ` James Morris 2017-08-25 5:55 ` James Morris 2017-08-25 10:49 ` Richard Guy Briggs 2017-08-25 10:49 ` Richard Guy Briggs 2017-08-23 10:12 ` [PATCH V3 02/10] capabilities: intuitive names for cap gain status Richard Guy Briggs 2017-08-23 10:12 ` Richard Guy Briggs 2017-08-24 16:03 ` Serge E. Hallyn 2017-08-24 16:03 ` Serge E. Hallyn 2017-08-24 16:19 ` Richard Guy Briggs 2017-08-24 16:19 ` Richard Guy Briggs 2017-08-24 16:37 ` Serge E. Hallyn 2017-08-24 16:37 ` Serge E. Hallyn 2017-08-24 19:06 ` Kees Cook 2017-08-24 19:06 ` Kees Cook 2017-08-24 21:17 ` Paul Moore 2017-08-24 21:17 ` Paul Moore 2017-08-28 9:19 ` Richard Guy Briggs 2017-08-28 9:19 ` Richard Guy Briggs 2017-08-28 11:08 ` Richard Guy Briggs 2017-08-28 11:08 ` Richard Guy Briggs 2017-09-01 10:18 ` Richard Guy Briggs 2017-09-01 10:18 ` Richard Guy Briggs 2017-09-02 5:37 ` Serge E. Hallyn 2017-09-02 5:37 ` Serge E. Hallyn 2017-09-04 6:57 ` Richard Guy Briggs 2017-09-04 6:57 ` Richard Guy Briggs 2017-09-05 6:45 ` Richard Guy Briggs 2017-09-05 6:45 ` Richard Guy Briggs 2017-08-25 5:56 ` James Morris 2017-08-25 5:56 ` James Morris 2017-08-25 15:08 ` Andy Lutomirski 2017-08-25 15:08 ` Andy Lutomirski 2017-08-25 18:47 ` Serge E. Hallyn 2017-08-25 18:47 ` Serge E. Hallyn 2017-08-23 10:12 ` [PATCH V3 03/10] capabilities: rename has_cap to has_fcap Richard Guy Briggs 2017-08-23 10:12 ` Richard Guy Briggs 2017-08-24 16:10 ` Serge E. Hallyn 2017-08-24 16:10 ` Serge E. Hallyn 2017-08-25 5:56 ` James Morris 2017-08-25 5:56 ` James Morris 2017-08-23 10:12 ` [PATCH V3 04/10] capabilities: use root_priveleged inline to clarify logic Richard Guy Briggs 2017-08-23 10:12 ` Richard Guy Briggs 2017-08-24 16:14 ` Serge E. Hallyn 2017-08-24 16:14 ` Serge E. Hallyn 2017-08-25 5:58 ` James Morris 2017-08-25 5:58 ` James Morris 2017-08-28 12:03 ` Richard Guy Briggs 2017-08-28 12:03 ` Richard Guy Briggs 2017-08-31 14:49 ` Serge E. Hallyn 2017-08-31 14:49 ` Serge E. Hallyn 2017-08-23 10:12 ` [PATCH V3 05/10] capabilities: use intuitive names for id changes Richard Guy Briggs 2017-08-23 10:12 ` Richard Guy Briggs 2017-08-24 16:17 ` Serge E. Hallyn 2017-08-24 16:17 ` Serge E. Hallyn 2017-08-25 5:59 ` James Morris 2017-08-25 5:59 ` James Morris 2017-08-25 15:06 ` Andy Lutomirski 2017-08-25 15:06 ` Andy Lutomirski 2017-08-25 18:51 ` Serge E. Hallyn 2017-08-25 18:51 ` Serge E. Hallyn 2017-08-25 19:45 ` Andy Lutomirski 2017-08-25 19:45 ` Andy Lutomirski 2017-08-25 20:06 ` Serge E. Hallyn 2017-08-25 20:06 ` Serge E. Hallyn 2017-08-28 1:32 ` James Morris 2017-08-28 1:32 ` James Morris 2017-08-28 9:12 ` Richard Guy Briggs 2017-08-28 9:12 ` Richard Guy Briggs 2017-08-28 20:12 ` Andy Lutomirski 2017-08-28 20:12 ` Andy Lutomirski 2017-08-23 10:12 ` [PATCH V3 06/10] capabilities: move audit log decision to function Richard Guy Briggs 2017-08-23 10:12 ` Richard Guy Briggs 2017-08-24 16:18 ` Serge E. Hallyn 2017-08-24 16:18 ` Serge E. Hallyn 2017-08-25 6:01 ` James Morris 2017-08-25 6:01 ` James Morris 2017-08-23 10:12 ` [PATCH V3 07/10] capabilities: remove a layer of conditional logic Richard Guy Briggs 2017-08-23 10:12 ` Richard Guy Briggs 2017-08-24 16:20 ` Serge E. Hallyn 2017-08-24 16:20 ` Serge E. Hallyn 2017-08-25 5:47 ` James Morris 2017-08-25 5:47 ` James Morris 2017-08-25 15:11 ` Andy Lutomirski 2017-08-25 15:11 ` Andy Lutomirski 2017-08-25 18:53 ` Serge E. Hallyn 2017-08-25 18:53 ` Serge E. Hallyn 2017-08-23 10:12 ` [PATCH V3 08/10] capabilities: invert logic for clarity Richard Guy Briggs 2017-08-23 10:12 ` Richard Guy Briggs 2017-08-24 16:23 ` Serge E. Hallyn 2017-08-24 16:23 ` Serge E. Hallyn 2017-08-25 5:47 ` James Morris 2017-08-25 5:47 ` James Morris 2017-08-23 10:13 ` [PATCH V3 09/10] capabilities: fix logic for effective root or real root Richard Guy Briggs 2017-08-23 10:13 ` Richard Guy Briggs 2017-08-24 16:29 ` Serge E. Hallyn 2017-08-24 16:29 ` Serge E. Hallyn 2017-08-24 16:44 ` Richard Guy Briggs 2017-08-24 16:44 ` Richard Guy Briggs 2017-08-24 16:47 ` Serge E. Hallyn 2017-08-24 16:47 ` Serge E. Hallyn 2017-08-25 5:48 ` James Morris 2017-08-25 5:48 ` James Morris 2017-08-23 10:13 ` [PATCH V3 10/10] capabilities: audit log other surprising conditions Richard Guy Briggs 2017-08-23 10:13 ` Richard Guy Briggs 2017-08-24 16:35 ` Serge E. Hallyn 2017-08-24 16:35 ` Serge E. Hallyn 2017-08-25 5:50 ` James Morris 2017-08-25 5:50 ` James Morris
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