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[2604:1380:45d1:ec00::1]) by mx.google.com with ESMTPS id n22-20020a05622a11d600b00436a4002263si1798567qtk.45.2024.04.12.17.57.51 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Apr 2024 17:57:52 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel+bounces-143466-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1; Authentication-Results: mx.google.com; dkim=pass header.i=@linux.microsoft.com header.s=default header.b="g/8I5Lky"; arc=pass (i=1 spf=pass spfdomain=linux.microsoft.com dkim=pass dkdomain=linux.microsoft.com dmarc=pass fromdomain=linux.microsoft.com); spf=pass (google.com: domain of linux-kernel+bounces-143466-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) smtp.mailfrom="linux-kernel+bounces-143466-linux.lists.archive=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linux.microsoft.com Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ny.mirrors.kernel.org (Postfix) with ESMTPS id CB3A81C211BF for ; Sat, 13 Apr 2024 00:57:51 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 9BB9BD52F; Sat, 13 Apr 2024 00:56:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="g/8I5Lky" Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 0DDFA4C65; Sat, 13 Apr 2024 00:56:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712969768; cv=none; b=YjLN0RtCg4rPO8JBxawyTeGdBVPn8BO5qSrhWbq6ekVxW0Y/gFH0OKxz3y0qTLGp9o1sc7KE2qSVSlr/StUb5x/t7/+E+G+8UwZuFb3q3iHWk153WaigdxAHWHqOiTsJ+sdebBf66sLerE4+VQSn3zfzOPnFBGKDWNmJt6lF8VQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712969768; c=relaxed/simple; bh=nmkyFigrESt5meL78P8f9ZlNuQbg784iYQTAk7ofsX0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References; b=otIkQZenzobN6p0gJCgN0yIz9/RN6P1FqBEcLv1KAi5AeJ5i6gKu5OMdhPiZvT/JCahcGJYo2P0s+MrPe4I7rjyPE1bu60c+NlEcKyQlvaRu/XtjecX8eFVDWmO1aMgg7N0B7+/OGUOwrDf94q27K2iNH3/Y/DDbwLd7U3h6q1Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=g/8I5Lky; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Received: by linux.microsoft.com (Postfix, from userid 1052) id 9113D20F2698; Fri, 12 Apr 2024 17:56:05 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 9113D20F2698 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1712969765; bh=MlCl+KBewXwlYqFug9hrqebz9OAnTL5nlpVNvzqco6E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g/8I5LkyoM+h1wNZyWHlkvqi+N8vS8ypUJOV2WejwsnOtMsHVUbXh1AkJzDAsTORJ rZL6L9XyJ8ggCsLPUswfVmpu4kLl3t44KkC8xOePh22ehI+48o/nEgf11OeIlxM9WJ ecQYjIUIfiMdHko9FmOPOXOlgSXXTej1vp63b6c4= From: Fan Wu To: corbet@lwn.net, zohar@linux.ibm.com, jmorris@namei.org, serge@hallyn.com, tytso@mit.edu, ebiggers@kernel.org, axboe@kernel.dk, agk@redhat.com, snitzer@kernel.org, eparis@redhat.com, paul@paul-moore.com Cc: linux-doc@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, fsverity@lists.linux.dev, linux-block@vger.kernel.org, dm-devel@lists.linux.dev, audit@vger.kernel.org, linux-kernel@vger.kernel.org, Deven Bowers , Fan Wu Subject: [PATCH v17 02/21] ipe: add policy parser Date: Fri, 12 Apr 2024 17:55:45 -0700 Message-Id: <1712969764-31039-3-git-send-email-wufan@linux.microsoft.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1712969764-31039-1-git-send-email-wufan@linux.microsoft.com> References: <1712969764-31039-1-git-send-email-wufan@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: From: Deven Bowers IPE's interpretation of the what the user trusts is accomplished through its policy. IPE's design is to not provide support for a single trust provider, but to support multiple providers to enable the end-user to choose the best one to seek their needs. This requires the policy to be rather flexible and modular so that integrity providers, like fs-verity, dm-verity, dm-integrity, or some other system, can plug into the policy with minimal code changes. Signed-off-by: Deven Bowers Signed-off-by: Fan Wu --- v2: + Split evaluation loop, access control hooks, and evaluation loop from policy parser and userspace interface to pass mailing list character limit v3: + Move policy load and activation audit event to 03/12 + Fix a potential panic when a policy failed to load. + use pr_warn for a failure to parse instead of an audit record + Remove comments from headers + Add lockdep assertions to ipe_update_active_policy and ipe_activate_policy + Fix up warnings with checkpatch --strict + Use file_ns_capable for CAP_MAC_ADMIN for securityfs nodes. + Use memdup_user instead of kzalloc+simple_write_to_buffer. + Remove strict_parse command line parameter, as it is added by the sysctl command line. + Prefix extern variables with ipe_ v4: + Remove securityfs to reverse-dependency + Add SHA1 reverse dependency. + Add versioning scheme for IPE properties, and associated interface to query the versioning scheme. + Cause a parser to always return an error on unknown syntax. + Remove strict_parse option + Change active_policy interface from sysctl, to securityfs, and change scheme. v5: + Cause an error if a default action is not defined for each operation. + Minor function renames v6: + No changes v7: + Further split parser and userspace interface into two separate commits, for easier review. + Refactor policy parser to make code cleaner via introducing a more modular design, for easier extension of policy, and easier review. v8: + remove unnecessary pr_info emission on parser loading + add explicit newline to the pr_err emitted when a parser fails to load. v9: + switch to match table to parse policy + remove quote syntax and KERNEL_READ operation v10: + Fix memory leaks in parser + Fix typos and change code styles v11: + Fix code style issues v12: + Add __always_unused to an unused parameter + Simplify error case handling v13: + No changes v14: + No changes v15: + No changes v16: + No changes v17: + Add years to license header + Fix code and documentation style issues --- security/ipe/Makefile | 2 + security/ipe/policy.c | 103 ++++++++ security/ipe/policy.h | 83 ++++++ security/ipe/policy_parser.c | 495 +++++++++++++++++++++++++++++++++++ security/ipe/policy_parser.h | 11 + 5 files changed, 694 insertions(+) create mode 100644 security/ipe/policy.c create mode 100644 security/ipe/policy.h create mode 100644 security/ipe/policy_parser.c create mode 100644 security/ipe/policy_parser.h diff --git a/security/ipe/Makefile b/security/ipe/Makefile index 5486398a69e9..3093de1afd3e 100644 --- a/security/ipe/Makefile +++ b/security/ipe/Makefile @@ -7,3 +7,5 @@ obj-$(CONFIG_SECURITY_IPE) += \ ipe.o \ + policy.o \ + policy_parser.o \ diff --git a/security/ipe/policy.c b/security/ipe/policy.c new file mode 100644 index 000000000000..dd7b5b79903a --- /dev/null +++ b/security/ipe/policy.c @@ -0,0 +1,103 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#include +#include + +#include "ipe.h" +#include "policy.h" +#include "policy_parser.h" + +/** + * ipe_free_policy() - Deallocate a given IPE policy. + * @p: Supplies the policy to free. + * + * Safe to call on IS_ERR/NULL. + */ +void ipe_free_policy(struct ipe_policy *p) +{ + if (IS_ERR_OR_NULL(p)) + return; + + ipe_free_parsed_policy(p->parsed); + /* + * p->text is allocated only when p->pkcs7 is not NULL + * otherwise it points to the plaintext data inside the pkcs7 + */ + if (!p->pkcs7) + kfree(p->text); + kfree(p->pkcs7); + kfree(p); +} + +static int set_pkcs7_data(void *ctx, const void *data, size_t len, + size_t asn1hdrlen __always_unused) +{ + struct ipe_policy *p = ctx; + + p->text = (const char *)data; + p->textlen = len; + + return 0; +} + +/** + * ipe_new_policy() - Allocate and parse an ipe_policy structure. + * + * @text: Supplies a pointer to the plain-text policy to parse. + * @textlen: Supplies the length of @text. + * @pkcs7: Supplies a pointer to a pkcs7-signed IPE policy. + * @pkcs7len: Supplies the length of @pkcs7. + * + * @text/@textlen Should be NULL/0 if @pkcs7/@pkcs7len is set. + * + * Return: + * * a pointer to the ipe_policy structure - Success + * * %-EBADMSG - Policy is invalid + * * %-ENOMEM - Out of memory (OOM) + * * %-ERANGE - Policy version number overflow + * * %-EINVAL - Policy version parsing error + */ +struct ipe_policy *ipe_new_policy(const char *text, size_t textlen, + const char *pkcs7, size_t pkcs7len) +{ + struct ipe_policy *new = NULL; + int rc = 0; + + new = kzalloc(sizeof(*new), GFP_KERNEL); + if (!new) + return ERR_PTR(-ENOMEM); + + if (!text) { + new->pkcs7len = pkcs7len; + new->pkcs7 = kmemdup(pkcs7, pkcs7len, GFP_KERNEL); + if (!new->pkcs7) { + rc = -ENOMEM; + goto err; + } + + rc = verify_pkcs7_signature(NULL, 0, new->pkcs7, pkcs7len, NULL, + VERIFYING_UNSPECIFIED_SIGNATURE, + set_pkcs7_data, new); + if (rc) + goto err; + } else { + new->textlen = textlen; + new->text = kstrdup(text, GFP_KERNEL); + if (!new->text) { + rc = -ENOMEM; + goto err; + } + } + + rc = ipe_parse_policy(new); + if (rc) + goto err; + + return new; +err: + ipe_free_policy(new); + return ERR_PTR(rc); +} diff --git a/security/ipe/policy.h b/security/ipe/policy.h new file mode 100644 index 000000000000..8292ffaaff12 --- /dev/null +++ b/security/ipe/policy.h @@ -0,0 +1,83 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ +#ifndef _IPE_POLICY_H +#define _IPE_POLICY_H + +#include +#include + +enum ipe_op_type { + IPE_OP_EXEC = 0, + IPE_OP_FIRMWARE, + IPE_OP_KERNEL_MODULE, + IPE_OP_KEXEC_IMAGE, + IPE_OP_KEXEC_INITRAMFS, + IPE_OP_POLICY, + IPE_OP_X509, + __IPE_OP_MAX, +}; + +#define IPE_OP_INVALID __IPE_OP_MAX + +enum ipe_action_type { + IPE_ACTION_ALLOW = 0, + IPE_ACTION_DENY, + __IPE_ACTION_MAX +}; + +#define IPE_ACTION_INVALID __IPE_ACTION_MAX + +enum ipe_prop_type { + __IPE_PROP_MAX +}; + +#define IPE_PROP_INVALID __IPE_PROP_MAX + +struct ipe_prop { + struct list_head next; + enum ipe_prop_type type; + void *value; +}; + +struct ipe_rule { + enum ipe_op_type op; + enum ipe_action_type action; + struct list_head props; + struct list_head next; +}; + +struct ipe_op_table { + struct list_head rules; + enum ipe_action_type default_action; +}; + +struct ipe_parsed_policy { + const char *name; + struct { + u16 major; + u16 minor; + u16 rev; + } version; + + enum ipe_action_type global_default_action; + + struct ipe_op_table rules[__IPE_OP_MAX]; +}; + +struct ipe_policy { + const char *pkcs7; + size_t pkcs7len; + + const char *text; + size_t textlen; + + struct ipe_parsed_policy *parsed; +}; + +struct ipe_policy *ipe_new_policy(const char *text, size_t textlen, + const char *pkcs7, size_t pkcs7len); +void ipe_free_policy(struct ipe_policy *pol); + +#endif /* _IPE_POLICY_H */ diff --git a/security/ipe/policy_parser.c b/security/ipe/policy_parser.c new file mode 100644 index 000000000000..32064262348a --- /dev/null +++ b/security/ipe/policy_parser.c @@ -0,0 +1,495 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#include +#include +#include +#include +#include + +#include "policy.h" +#include "policy_parser.h" + +#define START_COMMENT '#' +#define IPE_POLICY_DELIM " \t" +#define IPE_LINE_DELIM "\n\r" + +/** + * new_parsed_policy() - Allocate and initialize a parsed policy. + * + * Return: + * * a pointer to the ipe_parsed_policy structure - Success + * * %-ENOMEM - Out of memory (OOM) + */ +static struct ipe_parsed_policy *new_parsed_policy(void) +{ + struct ipe_parsed_policy *p = NULL; + struct ipe_op_table *t = NULL; + size_t i = 0; + + p = kzalloc(sizeof(*p), GFP_KERNEL); + if (!p) + return ERR_PTR(-ENOMEM); + + p->global_default_action = IPE_ACTION_INVALID; + + for (i = 0; i < ARRAY_SIZE(p->rules); ++i) { + t = &p->rules[i]; + + t->default_action = IPE_ACTION_INVALID; + INIT_LIST_HEAD(&t->rules); + } + + return p; +} + +/** + * remove_comment() - Truncate all chars following START_COMMENT in a string. + * + * @line: Supplies a policy line string for preprocessing. + */ +static void remove_comment(char *line) +{ + line = strchr(line, START_COMMENT); + + if (line) + *line = '\0'; +} + +/** + * remove_trailing_spaces() - Truncate all trailing spaces in a string. + * + * @line: Supplies a policy line string for preprocessing. + * + * Return: The length of truncated string. + */ +static size_t remove_trailing_spaces(char *line) +{ + size_t i = 0; + + i = strlen(line); + while (i > 0 && isspace(line[i - 1])) + i--; + + line[i] = '\0'; + + return i; +} + +/** + * parse_version() - Parse policy version. + * @ver: Supplies a version string to be parsed. + * @p: Supplies the partial parsed policy. + * + * Return: + * * %0 - Success + * * %-EBADMSG - Version string is invalid + * * %-ERANGE - Version number overflow + * * %-EINVAL - Parsing error + */ +static int parse_version(char *ver, struct ipe_parsed_policy *p) +{ + u16 *const cv[] = { &p->version.major, &p->version.minor, &p->version.rev }; + size_t sep_count = 0; + char *token; + int rc = 0; + + while ((token = strsep(&ver, ".")) != NULL) { + /* prevent overflow */ + if (sep_count >= ARRAY_SIZE(cv)) + return -EBADMSG; + + rc = kstrtou16(token, 10, cv[sep_count]); + if (rc) + return rc; + + ++sep_count; + } + + /* prevent underflow */ + if (sep_count != ARRAY_SIZE(cv)) + return -EBADMSG; + + return 0; +} + +enum header_opt { + IPE_HEADER_POLICY_NAME = 0, + IPE_HEADER_POLICY_VERSION, + __IPE_HEADER_MAX +}; + +static const match_table_t header_tokens = { + {IPE_HEADER_POLICY_NAME, "policy_name=%s"}, + {IPE_HEADER_POLICY_VERSION, "policy_version=%s"}, + {__IPE_HEADER_MAX, NULL} +}; + +/** + * parse_header() - Parse policy header information. + * @line: Supplies header line to be parsed. + * @p: Supplies the partial parsed policy. + * + * Return: + * * %0 - Success + * * %-EBADMSG - Header string is invalid + * * %-ENOMEM - Out of memory (OOM) + * * %-ERANGE - Version number overflow + * * %-EINVAL - Version parsing error + */ +static int parse_header(char *line, struct ipe_parsed_policy *p) +{ + substring_t args[MAX_OPT_ARGS]; + char *t, *ver = NULL; + size_t idx = 0; + int rc = 0; + + while ((t = strsep(&line, IPE_POLICY_DELIM)) != NULL) { + int token; + + if (*t == '\0') + continue; + if (idx >= __IPE_HEADER_MAX) { + rc = -EBADMSG; + goto out; + } + + token = match_token(t, header_tokens, args); + if (token != idx) { + rc = -EBADMSG; + goto out; + } + + switch (token) { + case IPE_HEADER_POLICY_NAME: + p->name = match_strdup(&args[0]); + if (!p->name) + rc = -ENOMEM; + break; + case IPE_HEADER_POLICY_VERSION: + ver = match_strdup(&args[0]); + if (!ver) { + rc = -ENOMEM; + break; + } + rc = parse_version(ver, p); + break; + default: + rc = -EBADMSG; + } + if (rc) + goto out; + ++idx; + } + + if (idx != __IPE_HEADER_MAX) + rc = -EBADMSG; + +out: + kfree(ver); + return rc; +} + +/** + * token_default() - Determine if the given token is "DEFAULT". + * @token: Supplies the token string to be compared. + * + * Return: + * * %false - The token is not "DEFAULT" + * * %true - The token is "DEFAULT" + */ +static bool token_default(char *token) +{ + return !strcmp(token, "DEFAULT"); +} + +/** + * free_rule() - Free the supplied ipe_rule struct. + * @r: Supplies the ipe_rule struct to be freed. + * + * Free a ipe_rule struct @r. Note @r must be removed from any lists before + * calling this function. + */ +static void free_rule(struct ipe_rule *r) +{ + struct ipe_prop *p, *t; + + if (IS_ERR_OR_NULL(r)) + return; + + list_for_each_entry_safe(p, t, &r->props, next) { + list_del(&p->next); + kfree(p); + } + + kfree(r); +} + +static const match_table_t operation_tokens = { + {IPE_OP_EXEC, "op=EXECUTE"}, + {IPE_OP_FIRMWARE, "op=FIRMWARE"}, + {IPE_OP_KERNEL_MODULE, "op=KMODULE"}, + {IPE_OP_KEXEC_IMAGE, "op=KEXEC_IMAGE"}, + {IPE_OP_KEXEC_INITRAMFS, "op=KEXEC_INITRAMFS"}, + {IPE_OP_POLICY, "op=POLICY"}, + {IPE_OP_X509, "op=X509_CERT"}, + {IPE_OP_INVALID, NULL} +}; + +/** + * parse_operation() - Parse the operation type given a token string. + * @t: Supplies the token string to be parsed. + * + * Return: The parsed operation type. + */ +static enum ipe_op_type parse_operation(char *t) +{ + substring_t args[MAX_OPT_ARGS]; + + return match_token(t, operation_tokens, args); +} + +static const match_table_t action_tokens = { + {IPE_ACTION_ALLOW, "action=ALLOW"}, + {IPE_ACTION_DENY, "action=DENY"}, + {IPE_ACTION_INVALID, NULL} +}; + +/** + * parse_action() - Parse the action type given a token string. + * @t: Supplies the token string to be parsed. + * + * Return: The parsed action type. + */ +static enum ipe_action_type parse_action(char *t) +{ + substring_t args[MAX_OPT_ARGS]; + + return match_token(t, action_tokens, args); +} + +/** + * parse_property() - Parse a rule property given a token string. + * @t: Supplies the token string to be parsed. + * @r: Supplies the ipe_rule the parsed property will be associated with. + * + * This is a placeholder. The actual function will be introduced in the + * latter commits. + * + * Return: + * * %0 - Success + * * %-ENOMEM - Out of memory (OOM) + * * %-EBADMSG - The supplied token cannot be parsed + */ +static int parse_property(char *t, struct ipe_rule *r) +{ + return -EBADMSG; +} + +/** + * parse_rule() - parse a policy rule line. + * @line: Supplies rule line to be parsed. + * @p: Supplies the partial parsed policy. + * + * Return: + * * 0 - Success + * * %-ENOMEM - Out of memory (OOM) + * * %-EBADMSG - Policy syntax error + */ +static int parse_rule(char *line, struct ipe_parsed_policy *p) +{ + enum ipe_action_type action = IPE_ACTION_INVALID; + enum ipe_op_type op = IPE_OP_INVALID; + bool is_default_rule = false; + struct ipe_rule *r = NULL; + bool first_token = true; + bool op_parsed = false; + int rc = 0; + char *t; + + r = kzalloc(sizeof(*r), GFP_KERNEL); + if (!r) + return -ENOMEM; + + INIT_LIST_HEAD(&r->next); + INIT_LIST_HEAD(&r->props); + + while (t = strsep(&line, IPE_POLICY_DELIM), line) { + if (*t == '\0') + continue; + if (first_token && token_default(t)) { + is_default_rule = true; + } else { + if (!op_parsed) { + op = parse_operation(t); + if (op == IPE_OP_INVALID) + rc = -EBADMSG; + else + op_parsed = true; + } else { + rc = parse_property(t, r); + } + } + + if (rc) + goto err; + first_token = false; + } + + action = parse_action(t); + if (action == IPE_ACTION_INVALID) { + rc = -EBADMSG; + goto err; + } + + if (is_default_rule) { + if (!list_empty(&r->props)) { + rc = -EBADMSG; + } else if (op == IPE_OP_INVALID) { + if (p->global_default_action != IPE_ACTION_INVALID) + rc = -EBADMSG; + else + p->global_default_action = action; + } else { + if (p->rules[op].default_action != IPE_ACTION_INVALID) + rc = -EBADMSG; + else + p->rules[op].default_action = action; + } + } else if (op != IPE_OP_INVALID && action != IPE_ACTION_INVALID) { + r->op = op; + r->action = action; + } else { + rc = -EBADMSG; + } + + if (rc) + goto err; + if (!is_default_rule) + list_add_tail(&r->next, &p->rules[op].rules); + else + free_rule(r); + + return rc; +err: + free_rule(r); + return rc; +} + +/** + * ipe_free_parsed_policy() - free a parsed policy structure. + * @p: Supplies the parsed policy. + */ +void ipe_free_parsed_policy(struct ipe_parsed_policy *p) +{ + struct ipe_rule *pp, *t; + size_t i = 0; + + if (IS_ERR_OR_NULL(p)) + return; + + for (i = 0; i < ARRAY_SIZE(p->rules); ++i) + list_for_each_entry_safe(pp, t, &p->rules[i].rules, next) { + list_del(&pp->next); + free_rule(pp); + } + + kfree(p->name); + kfree(p); +} + +/** + * validate_policy() - validate a parsed policy. + * @p: Supplies the fully parsed policy. + * + * Given a policy structure that was just parsed, validate that all + * operations have their default rules or a global default rule is set. + * + * Return: + * * %0 - Success + * * %-EBADMSG - Policy is invalid + */ +static int validate_policy(const struct ipe_parsed_policy *p) +{ + size_t i = 0; + + if (p->global_default_action != IPE_ACTION_INVALID) + return 0; + + for (i = 0; i < ARRAY_SIZE(p->rules); ++i) { + if (p->rules[i].default_action == IPE_ACTION_INVALID) + return -EBADMSG; + } + + return 0; +} + +/** + * ipe_parse_policy() - Given a string, parse the string into an IPE policy. + * @p: partially filled ipe_policy structure to populate with the result. + * it must have text and textlen set. + * + * Return: + * * %0 - Success + * * %-EBADMSG - Policy is invalid + * * %-ENOMEM - Out of Memory + * * %-ERANGE - Policy version number overflow + * * %-EINVAL - Policy version parsing error + */ +int ipe_parse_policy(struct ipe_policy *p) +{ + struct ipe_parsed_policy *pp = NULL; + char *policy = NULL, *dup = NULL; + bool header_parsed = false; + char *line = NULL; + size_t len; + int rc = 0; + + if (!p->textlen) + return -EBADMSG; + + policy = kmemdup_nul(p->text, p->textlen, GFP_KERNEL); + if (!policy) + return -ENOMEM; + dup = policy; + + pp = new_parsed_policy(); + if (IS_ERR(pp)) { + rc = PTR_ERR(pp); + goto out; + } + + while ((line = strsep(&policy, IPE_LINE_DELIM)) != NULL) { + remove_comment(line); + len = remove_trailing_spaces(line); + if (!len) + continue; + + if (!header_parsed) { + rc = parse_header(line, pp); + if (rc) + goto err; + header_parsed = true; + } else { + rc = parse_rule(line, pp); + if (rc) + goto err; + } + } + + if (!header_parsed || validate_policy(pp)) { + rc = -EBADMSG; + goto err; + } + + p->parsed = pp; + +out: + kfree(dup); + return rc; +err: + ipe_free_parsed_policy(pp); + goto out; +} diff --git a/security/ipe/policy_parser.h b/security/ipe/policy_parser.h new file mode 100644 index 000000000000..62b6209019a2 --- /dev/null +++ b/security/ipe/policy_parser.h @@ -0,0 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ +#ifndef _IPE_POLICY_PARSER_H +#define _IPE_POLICY_PARSER_H + +int ipe_parse_policy(struct ipe_policy *p); +void ipe_free_parsed_policy(struct ipe_parsed_policy *p); + +#endif /* _IPE_POLICY_PARSER_H */ -- 2.44.0