From patchwork Fri Jun 24 23:29:57 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Casey Schaufler X-Patchwork-Id: 9198253 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 991046075F for ; Fri, 24 Jun 2016 23:30:20 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8725B284DF for ; Fri, 24 Jun 2016 23:30:20 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 792B4284E5; Fri, 24 Jun 2016 23:30:20 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 80028284DF for ; Fri, 24 Jun 2016 23:30:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751298AbcFXX36 (ORCPT ); Fri, 24 Jun 2016 19:29:58 -0400 Received: from nm3-vm0.bullet.mail.bf1.yahoo.com ([98.139.212.154]:54986 "EHLO nm3-vm0.bullet.mail.bf1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751209AbcFXX36 (ORCPT ); Fri, 24 Jun 2016 19:29:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1466810996; bh=JOsCQc2QcFc+4LFWWOMz8S8Uk2cWEH+7nYa+NMsKxAs=; h=Subject:To:References:Cc:From:Date:In-Reply-To:From:Subject; b=RvTDRyXtyM2f5BZimFb8SXsgvn6KUbo/YIAxusgch+zQjySVSBqtnM9KkGf3J3cPcoIBBHif4UiZHORZJ9+2+T4j5v6dkFd6JgFqkkE1eeNi+xqjza1vLWDTic6UjmD5JWBMr+wWm1OH9RmvnYU+RY2QInTiBcX1FxaFbee8rO/GPFWNsE0mqvE+F4Qqub8IbU1aiVUDmzaj7RuR+fyYHhXEN42pM+2ctSIMjfazyuPT0rOBw3Y3mXVyBQZzA+b40WskHIQvfAGTFItuhSvjdukjswUQYinANlJ6LTItZ5t+3xZLZpWcILQVplHC3PQzAkqEZhoLjS2/cbOyJltMHg== Received: from [98.139.170.182] by nm3.bullet.mail.bf1.yahoo.com with NNFMP; 24 Jun 2016 23:29:56 -0000 Received: from [98.139.211.203] by tm25.bullet.mail.bf1.yahoo.com with NNFMP; 24 Jun 2016 23:29:56 -0000 Received: from [127.0.0.1] by smtp212.mail.bf1.yahoo.com with NNFMP; 24 Jun 2016 23:29:56 -0000 X-Yahoo-Newman-Id: 479374.1257.bm@smtp212.mail.bf1.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: n7.n168VM1lDNalWSn5NBtH4k8.YWgQjo1jD2bRCaD8J3bS 1y5t8T6S1PIz1v10mLkKTEfaOmqiQ0b.VaHLOJco8k5j0hiZdkE9K5PZ_ASx t9wEDeOyVh4bfn7V4MhDpUQMJT88va9zb73Ti9k2fOA6cgiE7JbYQmtugsR4 h89RY3iS0wkeDngJ3z.JLDSiz4RHxFSlEP5_6k.sPZBLF1u5dddQ899c9fN0 bnsuqCG.Ko1hLmgYuD9hjcM.3bFjRdGJ2Wkl1WfjAfnMHjA_GwzJi.E7Proi 7axhIVTLuoOXgV19AQJMEVl74ECftxpB2zjPfYb9s1w1CN3RD2bPnyeczCXh XvoTjJ5WQp07oRXCpY9fnDPPhGWuGhqA2o1JkXRTTH9Ll4M0Dz.fFY9VaYdQ wEaAVRTGK27Iu.CUA.juONlvGhqTVPQY4Ci4ylnh4lNeEg3_V_HzItPXnK5N LGbNgJFPaj.uEc7Lf8__fgAJxoGvWatze_1gV8erNYyy36u38FMuG_Oo.6Rd _Y5DHS70JbZmkml1Mf1IKFft01dYXpf5CUl75BGBDCF0vVwe7kIN62IqMFHY vA3p5M.iAyCDb_PdE.33TC9w- X-Yahoo-SMTP: OIJXglSswBDfgLtXluJ6wiAYv6_cnw-- Subject: [PATCH v4 3/3] LSM: Add context interface for proc attrs To: Paul Moore , Kees Cook References: <599d0a80-0838-2baa-8ee2-7eefafc10cec@schaufler-ca.com> <4263259c-7fc4-58e4-a86d-7ba92abe510a@schaufler-ca.com> <587c9d63-bd39-5781-a7b6-6add2f63c72e@schaufler-ca.com> Cc: LSM , James Morris , John Johansen , Stephen Smalley , Tetsuo Handa , LKLM From: Casey Schaufler Message-ID: <56dc3195-dccb-cd2d-0de0-320f9c4b3672@schaufler-ca.com> Date: Fri, 24 Jun 2016 16:29:57 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: <587c9d63-bd39-5781-a7b6-6add2f63c72e@schaufler-ca.com> Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Subject: [PATCH v4 3/3] LSM: Add context interface for proc attrs The /proc/.../attr/current interface is used by all three Linux security modules (SELinux, Smack and AppArmor) to report and modify the process security attribute. This is all fine when there is exactly one of these modules active and the userspace code knows which it module it is. It would require a major change to the "current" interface to provide information about more than one set of process security attributes. Instead, a "context" attribute is added, which identifies the security module that the information applies to. The format is: lsmname='context-value' When multiple concurrent modules are supported the /proc/.../attr/context interface will include the data for all of the active modules. lsmname1='context-value1',lsmname2='context-value2' The module specific subdirectories under attr contain context entries that report the information for that specific module in the same format. Signed-off-by: Casey Schaufler Acked-by: Paul Moore Acked-by: John Johansen Signed-off-by: Casey Schaufler Acked-by: John Johansen Acked-by: Paul Moore Acked-by: Kees Cook --- Documentation/security/LSM.txt | 8 +++ fs/proc/base.c | 4 ++ security/apparmor/lsm.c | 35 +++++++++++-- security/security.c | 108 +++++++++++++++++++++++++++++++++++++++++ security/selinux/hooks.c | 20 +++++++- security/smack/smack_lsm.c | 20 ++++---- 6 files changed, 180 insertions(+), 15 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/Documentation/security/LSM.txt b/Documentation/security/LSM.txt index 125c489..af3eb11 100644 --- a/Documentation/security/LSM.txt +++ b/Documentation/security/LSM.txt @@ -36,6 +36,14 @@ for SELinux would be in /proc/.../attr/selinux. Using the files found directly in /proc/.../attr (e.g. current) should be avoided. These files remain as legacy interfaces. +The files named "context" in the attr directories contain the +same information as the "current" files, but formatted to +identify the module it comes from. + +if selinux is the active security module: + /proc/self/attr/context could contain selinux='unconfined_t' + /proc/self/attr/selinux/context could contain selinux='unconfined_t' + Based on https://lkml.org/lkml/2007/10/26/215, a new LSM is accepted into the kernel when its intent (a description of what it tries to protect against and in what cases one would expect to diff --git a/fs/proc/base.c b/fs/proc/base.c index 182bc28..df94f26 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2532,6 +2532,7 @@ static const struct pid_entry selinux_attr_dir_stuff[] = { ATTR("selinux", "fscreate", S_IRUGO|S_IWUGO), ATTR("selinux", "keycreate", S_IRUGO|S_IWUGO), ATTR("selinux", "sockcreate", S_IRUGO|S_IWUGO), + ATTR("selinux", "context", S_IRUGO|S_IWUGO), }; LSM_DIR_OPS(selinux); #endif @@ -2539,6 +2540,7 @@ LSM_DIR_OPS(selinux); #ifdef CONFIG_SECURITY_SMACK static const struct pid_entry smack_attr_dir_stuff[] = { ATTR("smack", "current", S_IRUGO|S_IWUGO), + ATTR("smack", "context", S_IRUGO|S_IWUGO), }; LSM_DIR_OPS(smack); #endif @@ -2548,6 +2550,7 @@ static const struct pid_entry apparmor_attr_dir_stuff[] = { ATTR("apparmor", "current", S_IRUGO|S_IWUGO), ATTR("apparmor", "prev", S_IRUGO), ATTR("apparmor", "exec", S_IRUGO|S_IWUGO), + ATTR("apparmor", "context", S_IRUGO|S_IWUGO), }; LSM_DIR_OPS(apparmor); #endif @@ -2559,6 +2562,7 @@ static const struct pid_entry attr_dir_stuff[] = { ATTR(NULL, "fscreate", S_IRUGO|S_IWUGO), ATTR(NULL, "keycreate", S_IRUGO|S_IWUGO), ATTR(NULL, "sockcreate", S_IRUGO|S_IWUGO), + ATTR(NULL, "context", S_IRUGO|S_IWUGO), #ifdef CONFIG_SECURITY_SELINUX DIR("selinux", S_IRUGO|S_IXUGO, proc_selinux_attr_dir_inode_ops, proc_selinux_attr_dir_ops), diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index fb0fb03..5cac15f 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -476,9 +476,13 @@ static int apparmor_getprocattr(struct task_struct *task, char *name, const struct cred *cred = get_task_cred(task); struct aa_task_cxt *cxt = cred_cxt(cred); struct aa_profile *profile = NULL; + char *vp; + char *np; if (strcmp(name, "current") == 0) profile = aa_get_newest_profile(cxt->profile); + else if (strcmp(name, "context") == 0) + profile = aa_get_newest_profile(cxt->profile); else if (strcmp(name, "prev") == 0 && cxt->previous) profile = aa_get_newest_profile(cxt->previous); else if (strcmp(name, "exec") == 0 && cxt->onexec) @@ -486,9 +490,29 @@ static int apparmor_getprocattr(struct task_struct *task, char *name, else error = -EINVAL; - if (profile) - error = aa_getprocattr(profile, value); + if (profile == NULL) + goto put_out; + + error = aa_getprocattr(profile, &vp); + if (error < 0) + goto put_out; + + if (strcmp(name, "context") == 0) { + *value = kasprintf(GFP_KERNEL, "apparmor='%s'", vp); + if (*value == NULL) { + error = -ENOMEM; + goto put_out; + } + np = strchr(*value, '\n'); + if (np != NULL) { + np[0] = '\''; + np[1] = '\0'; + } + error = strlen(*value); + } else + *value = vp; +put_out: aa_put_profile(profile); put_cred(cred); @@ -530,7 +554,7 @@ static int apparmor_setprocattr(struct task_struct *task, char *name, return -EINVAL; arg_size = size - (args - (char *) value); - if (strcmp(name, "current") == 0) { + if (strcmp(name, "current") == 0 || strcmp(name, "context") == 0) { if (strcmp(command, "changehat") == 0) { error = aa_setprocattr_changehat(args, arg_size, !AA_DO_TEST); @@ -552,7 +576,10 @@ static int apparmor_setprocattr(struct task_struct *task, char *name, else goto fail; } else - /* only support the "current" and "exec" process attributes */ + /* + * only support the "current", context and "exec" + * process attributes + */ return -EINVAL; if (!error) diff --git a/security/security.c b/security/security.c index 1e9cb55..f97f0d9 100644 --- a/security/security.c +++ b/security/security.c @@ -1186,8 +1186,47 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name, char **value) { struct security_hook_list *hp; + char *vp; + char *cp = NULL; int rc = -EINVAL; + int trc; + /* + * "context" requires work here in addition to what + * the modules provide. + */ + if (strcmp(name, "context") == 0) { + *value = NULL; + list_for_each_entry(hp, + &security_hook_heads.getprocattr, list) { + if (lsm != NULL && strcmp(lsm, hp->lsm)) + continue; + trc = hp->hook.getprocattr(p, "context", &vp); + if (trc == -ENOENT) + continue; + if (trc <= 0) { + kfree(*value); + return trc; + } + rc = trc; + if (*value == NULL) { + *value = vp; + } else { + cp = kasprintf(GFP_KERNEL, "%s,%s", *value, vp); + if (cp == NULL) { + kfree(*value); + kfree(vp); + return -ENOMEM; + } + kfree(*value); + kfree(vp); + *value = cp; + } + } + if (rc > 0) + return strlen(*value); + return rc; + } list_for_each_entry(hp, &security_hook_heads.getprocattr, list) { if (lsm != NULL && strcmp(lsm, hp->lsm)) @@ -1204,7 +1243,76 @@ int security_setprocattr(struct task_struct *p, const char *lsm, char *name, { struct security_hook_list *hp; int rc = -EINVAL; + char *local; + char *cp; + int slen; + int failed = 0; + + /* + * If lsm is NULL look at all the modules to find one + * that processes name. If lsm is not NULL only look at + * that module. + * + * "context" is handled directly here. + */ + if (strcmp(name, "context") == 0) { + /* + * First verify that the input is acceptable. + * lsm1='v1'lsm2='v2'lsm3='v3' + * + * A note on the use of strncmp() below. + * The check is for the substring at the beginning of cp. + * The kzalloc of size + 1 ensures a terminated string. + */ + local = kzalloc(size + 1, GFP_KERNEL); + memcpy(local, value, size); + cp = local; + list_for_each_entry(hp, &security_hook_heads.setprocattr, + list) { + if (lsm != NULL && strcmp(lsm, hp->lsm)) + continue; + if (cp[0] == ',') { + if (cp == local) + goto free_out; + cp++; + } + slen = strlen(hp->lsm); + if (strncmp(cp, hp->lsm, slen)) + goto free_out; + cp += slen; + if (cp[0] != '=' || cp[1] != '\'' || cp[2] == '\'') + goto free_out; + for (cp += 2; cp[0] != '\''; cp++) + if (cp[0] == '\0') + goto free_out; + cp++; + } + cp = local; + list_for_each_entry(hp, &security_hook_heads.setprocattr, + list) { + if (lsm != NULL && strcmp(lsm, hp->lsm)) + continue; + if (cp[0] == ',') + cp++; + cp += strlen(hp->lsm) + 2; + for (slen = 0; cp[slen] != '\''; slen++) + ; + cp[slen] = '\0'; + + rc = hp->hook.setprocattr(p, "context", cp, slen); + if (rc < 0) + failed = rc; + cp += slen + 1; + } + if (failed != 0) + rc = failed; + else + rc = size; +free_out: + kfree(local); + return rc; + } list_for_each_entry(hp, &security_hook_heads.setprocattr, list) { if (lsm != NULL && strcmp(lsm, hp->lsm)) continue; diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index ed3a757..6397721 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -5711,6 +5711,8 @@ static int selinux_getprocattr(struct task_struct *p, if (!strcmp(name, "current")) sid = __tsec->sid; + else if (!strcmp(name, "context")) + sid = __tsec->sid; else if (!strcmp(name, "prev")) sid = __tsec->osid; else if (!strcmp(name, "exec")) @@ -5728,7 +5730,19 @@ static int selinux_getprocattr(struct task_struct *p, if (!sid) return 0; - error = security_sid_to_context(sid, value, &len); + if (strcmp(name, "context")) { + error = security_sid_to_context(sid, value, &len); + } else { + char *vp; + + error = security_sid_to_context(sid, &vp, &len); + if (!error) { + *value = kasprintf(GFP_KERNEL, "selinux='%s'", vp); + if (*value == NULL) + error = -ENOMEM; + } + } + if (error) return error; return len; @@ -5768,6 +5782,8 @@ static int selinux_setprocattr(struct task_struct *p, error = current_has_perm(p, PROCESS__SETSOCKCREATE); else if (!strcmp(name, "current")) error = current_has_perm(p, PROCESS__SETCURRENT); + else if (!strcmp(name, "context")) + error = current_has_perm(p, PROCESS__SETCURRENT); else error = -EINVAL; if (error) @@ -5827,7 +5843,7 @@ static int selinux_setprocattr(struct task_struct *p, tsec->keycreate_sid = sid; } else if (!strcmp(name, "sockcreate")) { tsec->sockcreate_sid = sid; - } else if (!strcmp(name, "current")) { + } else if (!strcmp(name, "current") || !strcmp(name, "context")) { error = -EINVAL; if (sid == 0) goto abort_change; diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 3577009..92e66f8 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -3574,18 +3574,20 @@ static int smack_getprocattr(struct task_struct *p, char *name, char **value) { struct smack_known *skp = smk_of_task_struct(p); char *cp; - int slen; - if (strcmp(name, "current") != 0) + if (strcmp(name, "current") == 0) { + cp = kstrdup(skp->smk_known, GFP_KERNEL); + if (cp == NULL) + return -ENOMEM; + } else if (strcmp(name, "context") == 0) { + cp = kasprintf(GFP_KERNEL, "smack='%s'", skp->smk_known); + if (cp == NULL) + return -ENOMEM; + } else return -EINVAL; - cp = kstrdup(skp->smk_known, GFP_KERNEL); - if (cp == NULL) - return -ENOMEM; - - slen = strlen(cp); *value = cp; - return slen; + return strlen(cp); } /** @@ -3622,7 +3624,7 @@ static int smack_setprocattr(struct task_struct *p, char *name, if (value == NULL || size == 0 || size >= SMK_LONGLABEL) return -EINVAL; - if (strcmp(name, "current") != 0) + if (strcmp(name, "current") != 0 && strcmp(name, "context") != 0) return -EINVAL; skp = smk_import_entry(value, size);