From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 29FA8C2D0D2 for ; Wed, 25 Dec 2019 00:03:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 00528206D7 for ; Wed, 25 Dec 2019 00:03:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=yahoo.com header.i=@yahoo.com header.b="T4gN+n4o" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726330AbfLYADU (ORCPT ); Tue, 24 Dec 2019 19:03:20 -0500 Received: from sonic313-15.consmr.mail.ne1.yahoo.com ([66.163.185.38]:42284 "EHLO sonic313-15.consmr.mail.ne1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726325AbfLYADU (ORCPT ); Tue, 24 Dec 2019 19:03:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1577232196; bh=bywCGGumEasJ7z5/nI4xVR7i1z8dhO2rCAtskFh94TI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From:Subject; b=T4gN+n4oD70mkJs0pBsS4y60xC+4ba6Hde+1JXhT1Ok2Mdk5TmCC9NMjZCZYRp2hEoj8forxsQ09Hn7KT2cLe245LXTv1G0nXEUH9rZGZwcq1VSHQmDXnYubiwAk59XlATOTdKdhsJSXBxVZ4dQuFLafCaQwKXoKb+5uaBuyNkxB0YFcDvEGO7IZWcu8WSHfoQjUnCWjOF/ndv0yDrkw3X+zV/E8GBbs4iKiDvn6nsi37AVUMU15ngl0Xx/GLiKOY/Rfj24bexWpSxfQgj1XnCWQy1zpu/Fs3F8zI1Yoi37sBH7AodPDvxgllyKZkDpBraCIR/aSvakug4EWCnSlKg== X-YMail-OSG: 9dvIcFYVM1kYTHPwYRWh6uThHikXYXxx9AuzCPa9auVHynM__MMb1UO1F1Ud7hF QnEBAd9oEO7L_YfjsO5GPSXt82tR6VAKTuP1QKS9LeIrTtIuBBjkOS3NZdG0vxtH_NYQRskwYNHm R4PXR5JMlhyxSOLz96uKnofSyfUHy24J7gjUAwBLj04urvY1XNYo.rM4m6aYgp.vWKw6lKBFXfke IZecN9oxdT79k.mWMh4LiqU_BWqdvZXE6rvCkhavOzGn2iF3M5p5M_f5zq.p7Ri9ETldfMWdvFqE DyJjhkeLGBo23b0Us84Hy.0F6u7.i3VOx9DpfvtbGQKS2mlsIKhzcQbK3OFOy5dBSHodxzTXHqwq l8tckxfNB3fzcx7FGbu7kECebcKLo3268_D3rEud.JFeG9J66jAIWvgIGPwyPlGdKf1mPh13uLIL 7Ra36PJP1JpCDRLarb_LgmnWekn4doAuWdgUpYOvfWtxeYSUs54XjjC0DzjzyCvqD8laJVys5azS vcnH3elSNXAKlhdE_migdr7sMl5etw2PEfzNsUcC2ABf6jCEnAkechp8QcpnThD_OQaRcdGPiuwU aQGjTs.N8zDleSxdUF27XXMIqACShBIdJkoVsFWcy8ckVU58Q5rPwPNW14r9WPrHRSurxBTzRv.M rDP10QLuyiOKF8hxY5CF2g20wt8JLJugRwG2WTd9y0QUjbHoSVAkyXJl3GXs63dMu34XeafHv1QV E8oBS2ww0g9K2NW7wrYed0aqMTAPUaotWEIg1K2eAta6LoSnSMeMmS3zq1quvsjobaSLW5hRQzPZ nPXX87NOfcwSZ._qQ6Wsk_H5y0sPy46My97MvsBSZpzYf8QEY2ieUFVlCNhBmq8JTEQdCvfY_eae 3qQAanK7qDI16YF5SdeA4B6h83nvCSV4BfnX.PvuudEzQ1D41._1Y06lPEcyyPouf5fsi0FfMONB fFv9b4bqLk2PJmo.oXy79WahcqDU_CA5kxmjcxvBPA1gAAJhWXLBPZKRD1rUZElvTW9.KmKgBVxO MskcrL3reYWc3T_ab6aybtLUi30cJQtAw0Z3lRb4fGIrPdNTPxwT6abwTyGeMXWj7tjd2zQjhF7j sF.0UPdvwrv_5x31mJN_DPmFv9s2s8BZ5VQ.CjomomsNyEFJ.0vsbto8trv0XL_Xy6pZM.ukM1il 4WYVA.r_MhqysGuIqTwNxcl5PFpgWuVp1RTzAPOzq0o7_AYTokg.6Y4y_FyyCsu6CjR.pDWbYtZS mljDBGalevaov_tkj.GI7tcbx5GNgXeWLv_yz6yf485B1IBQQGy4bW0sE.h6e.CKLxjZZ4_sqEW8 UGtQZHTM94E3.tvW65fvG3m5q5ka6KXyZSIm3RozhSaCUFkiQ8oPLsyaDPR_iiCj0FLhDbBlb70. nDQGVNypR0zZkRuhFPRL4ix8xZXIPfVmxiBVOOPOHE5IujTJNn74WieKVchK8y1a0LqcrRXM- Received: from sonic.gate.mail.ne1.yahoo.com by sonic313.consmr.mail.ne1.yahoo.com with HTTP; Wed, 25 Dec 2019 00:03:16 +0000 Received: by smtp427.mail.ne1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID aedf02fec9fe6bb4a4ffd9636b4dac63; Wed, 25 Dec 2019 00:03:12 +0000 (UTC) From: Casey Schaufler To: casey.schaufler@intel.com, jmorris@namei.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org Cc: casey@schaufler-ca.com, keescook@chromium.org, john.johansen@canonical.com, penguin-kernel@i-love.sakura.ne.jp, paul@paul-moore.com, sds@tycho.nsa.gov Subject: [PATCH v13 23/25] NET: Add SO_PEERCONTEXT for multiple LSMs Date: Tue, 24 Dec 2019 15:59:37 -0800 Message-Id: <20191224235939.7483-24-casey@schaufler-ca.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191224235939.7483-1-casey@schaufler-ca.com> References: <20191224235939.7483-1-casey@schaufler-ca.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: The getsockopt SO_PEERSEC provides the LSM based security information for a single module, but for reasons of backward compatibility cannot include the information for multiple modules. A new option SO_PEERCONTEXT is added to report the security "context" of multiple modules using a "compound" format lsm1\0value\0lsm2\0value\0 This is expected to be used by system services, including dbus-daemon. The exact format of a compound context has been the subject of considerable debate. This format was suggested by Simon McVittie, a dbus maintainer with a significant stake in the format being usable. Signed-off-by: Casey Schaufler cc: netdev@vger.kernel.org cc: linux-api@vger.kernel.org --- Documentation/security/lsm.rst | 15 ++++ arch/alpha/include/uapi/asm/socket.h | 1 + arch/mips/include/uapi/asm/socket.h | 1 + arch/parisc/include/uapi/asm/socket.h | 1 + arch/sparc/include/uapi/asm/socket.h | 1 + include/linux/lsm_hooks.h | 9 +- include/linux/security.h | 10 ++- include/uapi/asm-generic/socket.h | 1 + net/core/sock.c | 7 +- security/apparmor/lsm.c | 20 ++--- security/security.c | 115 +++++++++++++++++++++++--- security/selinux/hooks.c | 20 ++--- security/smack/smack_lsm.c | 31 +++---- 13 files changed, 170 insertions(+), 62 deletions(-) diff --git a/Documentation/security/lsm.rst b/Documentation/security/lsm.rst index aadf47c808c0..77cc326a52cc 100644 --- a/Documentation/security/lsm.rst +++ b/Documentation/security/lsm.rst @@ -199,3 +199,18 @@ capability-related fields: - ``fs/nfsd/auth.c``::c:func:`nfsd_setuser()` - ``fs/proc/array.c``::c:func:`task_cap()` + +LSM External Interfaces +======================= + +The LSM infrastructure does not generally provide external interfaces. +The individual security modules provide what external interfaces they +require. The infrastructure does provide two interfaces for the special +case where multiple security modules provide a process context. This +is provided in compound context format. + +- `lsm1\0value\0lsm2\0value\0` + +The special file ``/proc/pid/attr/context`` provides the security +context of the identified process. The socket option SO_PEERCONTEXT +provides the security context of a packet. diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h index de6c4df61082..b26fb34e4226 100644 --- a/arch/alpha/include/uapi/asm/socket.h +++ b/arch/alpha/include/uapi/asm/socket.h @@ -123,6 +123,7 @@ #define SO_SNDTIMEO_NEW 67 #define SO_DETACH_REUSEPORT_BPF 68 +#define SO_PEERCONTEXT 69 #if !defined(__KERNEL__) diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h index d0a9ed2ca2d6..10e03507b1ed 100644 --- a/arch/mips/include/uapi/asm/socket.h +++ b/arch/mips/include/uapi/asm/socket.h @@ -134,6 +134,7 @@ #define SO_SNDTIMEO_NEW 67 #define SO_DETACH_REUSEPORT_BPF 68 +#define SO_PEERCONTEXT 69 #if !defined(__KERNEL__) diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h index 10173c32195e..e11df59a84d1 100644 --- a/arch/parisc/include/uapi/asm/socket.h +++ b/arch/parisc/include/uapi/asm/socket.h @@ -115,6 +115,7 @@ #define SO_SNDTIMEO_NEW 0x4041 #define SO_DETACH_REUSEPORT_BPF 0x4042 +#define SO_PEERCONTEXT 0x4043 #if !defined(__KERNEL__) diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h index 8029b681fc7c..5b41ef778040 100644 --- a/arch/sparc/include/uapi/asm/socket.h +++ b/arch/sparc/include/uapi/asm/socket.h @@ -116,6 +116,7 @@ #define SO_SNDTIMEO_NEW 0x0045 #define SO_DETACH_REUSEPORT_BPF 0x0047 +#define SO_PEERCONTEXT 0x0048 #if !defined(__KERNEL__) diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 2bf82e1cf347..2ae10e7f81a7 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -880,8 +880,8 @@ * SO_GETPEERSEC. For tcp sockets this can be meaningful if the * socket is associated with an ipsec SA. * @sock is the local socket. - * @optval userspace memory where the security state is to be copied. - * @optlen userspace int where the module should copy the actual length + * @optval memory where the security state is to be copied. + * @optlen int where the module should copy the actual length * of the security state. * @len as input is the maximum length to copy to userspace provided * by the caller. @@ -1724,9 +1724,8 @@ union security_list_options { int (*socket_setsockopt)(struct socket *sock, int level, int optname); int (*socket_shutdown)(struct socket *sock, int how); int (*socket_sock_rcv_skb)(struct sock *sk, struct sk_buff *skb); - int (*socket_getpeersec_stream)(struct socket *sock, - char __user *optval, - int __user *optlen, unsigned len); + int (*socket_getpeersec_stream)(struct socket *sock, char **optval, + int *optlen, unsigned len); int (*socket_getpeersec_dgram)(struct socket *sock, struct sk_buff *skb, u32 *secid); int (*sk_alloc_security)(struct sock *sk, int family, gfp_t priority); diff --git a/include/linux/security.h b/include/linux/security.h index d7af2bbbc878..26967055a002 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -178,6 +178,7 @@ struct lsmblob { #define LSMBLOB_NOT_NEEDED -3 /* Slot not requested */ #define LSMBLOB_DISPLAY -4 /* Use the "display" slot */ #define LSMBLOB_FIRST -5 /* Use the default "display" slot */ +#define LSMBLOB_COMPOUND -6 /* A compound "display" */ /** * lsmblob_init - initialize an lsmblob structure. @@ -1396,7 +1397,8 @@ int security_socket_setsockopt(struct socket *sock, int level, int optname); int security_socket_shutdown(struct socket *sock, int how); int security_sock_rcv_skb(struct sock *sk, struct sk_buff *skb); int security_socket_getpeersec_stream(struct socket *sock, char __user *optval, - int __user *optlen, unsigned len); + int __user *optlen, unsigned len, + int display); int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, struct lsmblob *blob); int security_sk_alloc(struct sock *sk, int family, gfp_t priority); @@ -1530,8 +1532,10 @@ static inline int security_sock_rcv_skb(struct sock *sk, return 0; } -static inline int security_socket_getpeersec_stream(struct socket *sock, char __user *optval, - int __user *optlen, unsigned len) +static inline int security_socket_getpeersec_stream(struct socket *sock, + char __user *optval, + int __user *optlen, + unsigned len, int display) { return -ENOPROTOOPT; } diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h index 77f7c1638eb1..e3a853d53705 100644 --- a/include/uapi/asm-generic/socket.h +++ b/include/uapi/asm-generic/socket.h @@ -118,6 +118,7 @@ #define SO_SNDTIMEO_NEW 67 #define SO_DETACH_REUSEPORT_BPF 68 +#define SO_PEERCONTEXT 69 #if !defined(__KERNEL__) diff --git a/net/core/sock.c b/net/core/sock.c index 043db3ce023e..63b7eda81a90 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1411,7 +1411,12 @@ int sock_getsockopt(struct socket *sock, int level, int optname, break; case SO_PEERSEC: - return security_socket_getpeersec_stream(sock, optval, optlen, len); + return security_socket_getpeersec_stream(sock, optval, optlen, + len, LSMBLOB_DISPLAY); + + case SO_PEERCONTEXT: + return security_socket_getpeersec_stream(sock, optval, optlen, + len, LSMBLOB_COMPOUND); case SO_MARK: v.val = sk->sk_mark; diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index 16b992235c11..34edfd29c32f 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -1078,10 +1078,8 @@ static struct aa_label *sk_peer_label(struct sock *sk) * * Note: for tcp only valid if using ipsec or cipso on lan */ -static int apparmor_socket_getpeersec_stream(struct socket *sock, - char __user *optval, - int __user *optlen, - unsigned int len) +static int apparmor_socket_getpeersec_stream(struct socket *sock, char **optval, + int *optlen, unsigned int len) { char *name; int slen, error = 0; @@ -1101,17 +1099,11 @@ static int apparmor_socket_getpeersec_stream(struct socket *sock, if (slen < 0) { error = -ENOMEM; } else { - if (slen > len) { + if (slen > len) error = -ERANGE; - } else if (copy_to_user(optval, name, slen)) { - error = -EFAULT; - goto out; - } - if (put_user(slen, optlen)) - error = -EFAULT; -out: - kfree(name); - + else + *optval = name; + *optlen = slen; } done: diff --git a/security/security.c b/security/security.c index 6d05222aac9c..80539dfd0245 100644 --- a/security/security.c +++ b/security/security.c @@ -723,6 +723,42 @@ static void __init lsm_early_task(struct task_struct *task) panic("%s: Early task alloc failed.\n", __func__); } +/** + * append_ctx - append a lsm/context pair to a compound context + * @ctx: the existing compound context + * @ctxlen: size of the old context, including terminating nul byte + * @lsm: new lsm name, nul terminated + * @new: new context, possibly nul terminated + * @newlen: maximum size of @new + * + * replace @ctx with a new compound context, appending @newlsm and @new + * to @ctx. On exit the new data replaces the old, which is freed. + * @ctxlen is set to the new size, which includes a trailing nul byte. + * + * Returns 0 on success, -ENOMEM if no memory is available. + */ +static int append_ctx(char **ctx, int *ctxlen, const char *lsm, char *new, + int newlen) +{ + char *final; + int llen; + + llen = strlen(lsm) + 1; + newlen = strnlen(new, newlen) + 1; + + final = kzalloc(*ctxlen + llen + newlen, GFP_KERNEL); + if (final == NULL) + return -ENOMEM; + if (*ctxlen) + memcpy(final, *ctx, *ctxlen); + memcpy(final + *ctxlen, lsm, llen); + memcpy(final + *ctxlen + llen, new, newlen); + kfree(*ctx); + *ctx = final; + *ctxlen = *ctxlen + llen + newlen; + return 0; +} + /* * Hook list operation macros. * @@ -2164,8 +2200,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value, hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) { if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm)) continue; - if (lsm == NULL && *display != LSMBLOB_INVALID && - *display != hp->lsmid->slot) + if (lsm == NULL && display != NULL && + *display != LSMBLOB_INVALID && *display != hp->lsmid->slot) continue; return hp->hook.setprocattr(name, value, size); } @@ -2245,12 +2281,21 @@ void security_release_secctx(struct lsmcontext *cp) { struct security_hook_list *hp; + if (cp->slot == LSMBLOB_INVALID) + return; + + if (cp->slot == LSMBLOB_COMPOUND) { + kfree(cp->context); + goto clear_out; + } + hlist_for_each_entry(hp, &security_hook_heads.release_secctx, list) if (cp->slot == hp->lsmid->slot) { hp->hook.release_secctx(cp->context, cp->len); break; } +clear_out: memset(cp, 0, sizeof(*cp)); } EXPORT_SYMBOL(security_release_secctx); @@ -2383,17 +2428,67 @@ int security_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) EXPORT_SYMBOL(security_sock_rcv_skb); int security_socket_getpeersec_stream(struct socket *sock, char __user *optval, - int __user *optlen, unsigned len) + int __user *optlen, unsigned len, + int display) { - int display = lsm_task_display(current); struct security_hook_list *hp; + char *final = NULL; + char *cp; + int rc = 0; + unsigned finallen = 0; + unsigned clen = 0; - hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_stream, - list) - if (display == LSMBLOB_INVALID || display == hp->lsmid->slot) - return hp->hook.socket_getpeersec_stream(sock, optval, - optlen, len); - return -ENOPROTOOPT; + switch (display) { + case LSMBLOB_DISPLAY: + rc = -ENOPROTOOPT; + display = lsm_task_display(current); + hlist_for_each_entry(hp, + &security_hook_heads.socket_getpeersec_stream, + list) + if (display == LSMBLOB_INVALID || + display == hp->lsmid->slot) { + rc = hp->hook.socket_getpeersec_stream(sock, + &final, &finallen, len); + break; + } + break; + case LSMBLOB_COMPOUND: + /* + * A compound context, in the form [lsm\0value\0]... + */ + hlist_for_each_entry(hp, + &security_hook_heads.socket_getpeersec_stream, + list) { + rc = hp->hook.socket_getpeersec_stream(sock, &cp, &clen, + len); + if (rc == -EINVAL || rc == -ENOPROTOOPT) { + rc = 0; + continue; + } + if (rc) { + kfree(final); + return rc; + } + rc = append_ctx(&final, &finallen, hp->lsmid->lsm, + cp, clen); + } + if (final == NULL) + return -EINVAL; + break; + default: + return -EINVAL; + } + + if (finallen > len) + rc = -ERANGE; + else if (copy_to_user(optval, final, finallen)) + rc = -EFAULT; + + if (put_user(finallen, optlen)) + rc = -EFAULT; + + kfree(final); + return rc; } int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index cd4743331800..c3e6fd3f8c56 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -5056,10 +5056,8 @@ static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) return err; } -static int selinux_socket_getpeersec_stream(struct socket *sock, - char __user *optval, - int __user *optlen, - unsigned int len) +static int selinux_socket_getpeersec_stream(struct socket *sock, char **optval, + int *optlen, unsigned int len) { int err = 0; char *scontext; @@ -5079,18 +5077,12 @@ static int selinux_socket_getpeersec_stream(struct socket *sock, if (err) return err; - if (scontext_len > len) { + if (scontext_len > len) err = -ERANGE; - goto out_len; - } - - if (copy_to_user(optval, scontext, scontext_len)) - err = -EFAULT; + else + *optval = scontext; -out_len: - if (put_user(scontext_len, optlen)) - err = -EFAULT; - kfree(scontext); + *optlen = scontext_len; return err; } diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 9ce67e03ac49..316c5faf9053 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -3957,28 +3957,29 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) * * returns zero on success, an error code otherwise */ -static int smack_socket_getpeersec_stream(struct socket *sock, - char __user *optval, - int __user *optlen, unsigned len) +static int smack_socket_getpeersec_stream(struct socket *sock, char **optval, + int *optlen, unsigned len) { - struct socket_smack *ssp; - char *rcp = ""; - int slen = 1; + struct socket_smack *ssp = smack_sock(sock->sk); + char *rcp; + int slen; int rc = 0; - ssp = smack_sock(sock->sk); - if (ssp->smk_packet != NULL) { - rcp = ssp->smk_packet->smk_known; - slen = strlen(rcp) + 1; + if (ssp->smk_packet == NULL) { + *optlen = 0; + return -EINVAL; } + rcp = ssp->smk_packet->smk_known; + slen = strlen(rcp) + 1; if (slen > len) rc = -ERANGE; - else if (copy_to_user(optval, rcp, slen) != 0) - rc = -EFAULT; - - if (put_user(slen, optlen) != 0) - rc = -EFAULT; + else { + *optval = kstrdup(rcp, GFP_KERNEL); + if (*optval == NULL) + rc = -ENOMEM; + } + *optlen = slen; return rc; } -- 2.20.1