From e5e920d178f771793e7e0ebbc0e81610edf5bf1d Mon Sep 17 00:00:00 2001
From: Georgia Garcia <georgia.garcia@canonical.com>
Date: Mon, 20 Mar 2023 12:28:53 -0300
Subject: [PATCH] parser: add parser support for io_uring mediation

io_uring rules have the following format:

io_uring [<access_mode>] [<label>],
access_mode := 'sqpoll'|'override_creds'
label := 'label' '=' <target label>

Signed-off-by: Georgia Garcia <georgia.garcia@canonical.com>
---
 .gitignore             |   1 +
 parser/Makefile        |   7 +-
 parser/io_uring.cc     | 141 +++++++++++++++++++++++++++++++++++++++++
 parser/io_uring.h      |  56 ++++++++++++++++
 parser/parser.h        |   1 +
 parser/parser_common.c |   1 +
 parser/parser_lex.l    |  17 +++--
 parser/parser_main.c   |   3 +
 parser/parser_misc.c   |   3 +
 parser/parser_regex.c  |   4 ++
 parser/parser_yacc.y   |  42 ++++++++++++
 11 files changed, 269 insertions(+), 7 deletions(-)
 create mode 100644 parser/io_uring.cc
 create mode 100644 parser/io_uring.h

diff --git a/.gitignore b/.gitignore
index bac42bf27..b7c913981 100644
--- a/.gitignore
+++ b/.gitignore
@@ -60,6 +60,7 @@ parser/ptrace.o
 parser/rule.o
 parser/signal.o
 parser/userns.o
+parser/io_uring.o
 parser/*.7
 parser/*.5
 parser/*.8
diff --git a/parser/Makefile b/parser/Makefile
index c91794dd2..3280ce528 100644
--- a/parser/Makefile
+++ b/parser/Makefile
@@ -102,11 +102,11 @@ SRCS = parser_common.c parser_include.c parser_interface.c parser_lex.c \
        parser_alias.c common_optarg.c lib.c network.c \
        mount.cc dbus.cc profile.cc rule.cc signal.cc ptrace.cc \
        af_rule.cc af_unix.cc policy_cache.c default_features.c userns.cc \
-       mqueue.cc
+       mqueue.cc io_uring.cc
 STATIC_HDRS = af_rule.h af_unix.h capability.h common_optarg.h dbus.h \
        file_cache.h immunix.h lib.h mount.h network.h parser.h \
        parser_include.h parser_version.h policy_cache.h policydb.h \
-       profile.h ptrace.h rule.h signal.h userns.h mqueue.h
+       profile.h ptrace.h rule.h signal.h userns.h mqueue.h io_uring.h
 
 SPECIAL_HDRS = parser_yacc.h unit_test.h base_cap_names.h
 GENERATED_HDRS = af_names.h generated_af_names.h \
@@ -318,6 +318,9 @@ userns.o: userns.cc $(HDRS)
 mqueue.o: mqueue.cc $(HDRS)
 	$(CXX) $(EXTRA_CFLAGS) -c -o $@ $<
 
+io_uring.o: io_uring.cc $(HDRS)
+	$(CXX) $(EXTRA_CFLAGS) -c -o $@ $<
+
 parser_version.h: Makefile
 	@echo \#define PARSER_VERSION \"$(VERSION)\" > .ver
 	@mv -f .ver $@
diff --git a/parser/io_uring.cc b/parser/io_uring.cc
new file mode 100644
index 000000000..aef4b8899
--- /dev/null
+++ b/parser/io_uring.cc
@@ -0,0 +1,141 @@
+/*
+ *   Copyright (c) 2023
+ *   Canonical Ltd. (All rights reserved)
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of version 2 of the GNU General Public
+ *   License published by the Free Software Foundation.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, contact or Canonical Ltd.
+ */
+
+#include "parser.h"
+#include "profile.h"
+#include "io_uring.h"
+
+#include <iomanip>
+#include <string>
+#include <iostream>
+#include <sstream>
+
+void io_uring_rule::move_conditionals(struct cond_entry *conds)
+{
+	struct cond_entry *cond_ent;
+
+	list_for_each(conds, cond_ent) {
+		/* disallow keyword 'in' (list) */
+		if (!cond_ent->eq)
+			yyerror("keyword \"in\" is not allowed in io_uring rules\n");
+
+		if (list_len(cond_ent->vals) > 1)
+			yyerror("io_uring conditional \"%s\" only supports a single value\n",
+				cond_ent->name);
+
+		if (strcmp(cond_ent->name, "label") == 0) {
+			move_conditional_value("io_uring", &label, cond_ent);
+		} else {
+			yyerror("invalid io_uring conditional \"%s\"\n",
+				cond_ent->name);
+		}
+	}
+}
+
+io_uring_rule::io_uring_rule(perms_t perms_p, struct cond_entry *conds, struct cond_entry *ring_conds):
+	perms_rule_t(AA_CLASS_IO_URING), label(NULL)
+{
+	if (perms_p) {
+		if (perms_p & ~AA_VALID_IO_URING_PERMS) {
+			yyerror("perms contains invalid permissions for io_uring\n");
+		}
+		perms = perms_p;
+
+	} else {
+		/* default to all perms */
+		perms = AA_VALID_IO_URING_PERMS;
+	}
+	move_conditionals(conds);
+	move_conditionals(ring_conds);
+	free_cond_list(conds);
+	free_cond_list(ring_conds);
+}
+
+ostream &io_uring_rule::dump(ostream &os)
+{
+	class_rule_t::dump(os);
+
+	if (perms != AA_VALID_IO_URING_PERMS) {
+		os << " ( ";
+
+		if (perms & AA_IO_URING_OVERRIDE_CREDS)
+			os << "override_creds ";
+		if (perms & AA_IO_URING_SQPOLL)
+			os << " sqpoll ";
+
+		os << ")";
+	}
+
+	if (label)
+		os << " label=" << label;
+
+	os << ",\n";
+
+	return os;
+}
+
+
+int io_uring_rule::expand_variables(void)
+{
+	return 0;
+}
+
+void io_uring_rule::warn_once(const char *name)
+{
+	rule_t::warn_once(name, "io_uring rules not enforced");
+}
+
+int io_uring_rule::gen_policy_re(Profile &prof)
+{
+	std::ostringstream buffer;
+	std::string buf, labelbuf;
+
+	if (!features_supports_io_uring) {
+		warn_once(prof.name);
+		return RULE_NOT_SUPPORTED;
+	}
+
+	buffer << "\\x" << std::setfill('0') << std::setw(2) << std::hex << AA_CLASS_IO_URING;
+	buf = buffer.str();
+
+	if (label) {
+		if (!convert_entry(labelbuf, label))
+			goto fail;
+		buffer << labelbuf;
+	} else {
+		buffer << default_match_pattern;
+	}
+
+	if (perms & AA_VALID_IO_URING_PERMS) {
+		if (!prof.policy.rules->add_rule(buf.c_str(), rule_mode == RULE_DENY, perms,
+						 audit == AUDIT_FORCE ? perms : 0,
+						 dfaflags))
+			goto fail;
+
+		if (perms & AA_IO_URING_OVERRIDE_CREDS) {
+			buf = buffer.str(); /* update buf to have label */
+			if (!prof.policy.rules->add_rule(buf.c_str(), rule_mode == RULE_DENY,
+							 perms, audit == AUDIT_FORCE ? perms : 0,
+							 dfaflags))
+				goto fail;
+		}
+
+	}
+	return RULE_OK;
+fail:
+	return RULE_ERROR;
+}
diff --git a/parser/io_uring.h b/parser/io_uring.h
new file mode 100644
index 000000000..7644403c7
--- /dev/null
+++ b/parser/io_uring.h
@@ -0,0 +1,56 @@
+/*
+ *   Copyright (c) 2023
+ *   Canonical Ltd. (All rights reserved)
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of version 2 of the GNU General Public
+ *   License published by the Free Software Foundation.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, contact or Canonical Ltd.
+ */
+
+#ifndef __AA_IO_URING_H
+#define __AA_IO_URING_H
+
+#include "parser.h"
+
+#define AA_IO_URING_OVERRIDE_CREDS AA_MAY_APPEND
+#define AA_IO_URING_SQPOLL AA_MAY_CREATE
+
+#define AA_VALID_IO_URING_PERMS (AA_IO_URING_OVERRIDE_CREDS | \
+				 AA_IO_URING_SQPOLL)
+
+class io_uring_rule: public perms_rule_t {
+	void move_conditionals(struct cond_entry *conds);
+public:
+	char *label;
+
+	io_uring_rule(perms_t perms, struct cond_entry *conds, struct cond_entry *ring_conds);
+	virtual ~io_uring_rule()
+	{
+		free(label);
+	};
+
+	virtual bool valid_prefix(const prefixes &p, const char *&error) {
+		if (p.owner) {
+			error = _("owner prefix not allowed on io_uring rules");
+			return false;
+		}
+		return true;
+	};
+
+	virtual ostream &dump(ostream &os);
+	virtual int expand_variables(void);
+	virtual int gen_policy_re(Profile &prof);
+
+protected:
+	virtual void warn_once(const char *name) override;
+};
+
+#endif /* __AA_IO_URING_H */
diff --git a/parser/parser.h b/parser/parser.h
index a115ff92a..0399db8be 100644
--- a/parser/parser.h
+++ b/parser/parser.h
@@ -353,6 +353,7 @@ extern int features_supports_domain_xattr;
 extern int features_supports_userns;
 extern int features_supports_posix_mqueue;
 extern int features_supports_sysv_mqueue;
+extern int features_supports_io_uring;
 extern int kernel_supports_oob;
 extern int conf_verbose;
 extern int conf_quiet;
diff --git a/parser/parser_common.c b/parser/parser_common.c
index 3f798ecfc..75b637e19 100644
--- a/parser/parser_common.c
+++ b/parser/parser_common.c
@@ -81,6 +81,7 @@ int features_supports_domain_xattr = 0;	/* x attachment cond */
 int features_supports_userns = 0;	/* kernel supports user namespace */
 int features_supports_posix_mqueue = 0;	/* kernel supports mqueue rules */
 int features_supports_sysv_mqueue = 0;	/* kernel supports mqueue rules */
+int features_supports_io_uring = 0;	/* kernel supports io_uring rules */
 int kernel_supports_oob = 0;		/* out of band transitions */
 int conf_verbose = 0;
 int conf_quiet = 0;
diff --git a/parser/parser_lex.l b/parser/parser_lex.l
index 1a07ca91c..8abc47b4c 100644
--- a/parser/parser_lex.l
+++ b/parser/parser_lex.l
@@ -329,6 +329,7 @@ GT		>
 %x ABI_MODE
 %x USERNS_MODE
 %x MQUEUE_MODE
+%x IOURING_MODE
 
 %%
 
@@ -341,7 +342,7 @@ GT		>
 	}
 %}
 
-<INITIAL,SUB_ID_WS,INCLUDE,INCLUDE_EXISTS,LIST_VAL_MODE,EXTCOND_MODE,LIST_COND_VAL,LIST_COND_PAREN_VAL,LIST_COND_MODE,EXTCONDLIST_MODE,ASSIGN_MODE,NETWORK_MODE,CHANGE_PROFILE_MODE,RLIMIT_MODE,MOUNT_MODE,DBUS_MODE,SIGNAL_MODE,PTRACE_MODE,UNIX_MODE,ABI_MODE,USERNS_MODE,MQUEUE_MODE>{
+<INITIAL,SUB_ID_WS,INCLUDE,INCLUDE_EXISTS,LIST_VAL_MODE,EXTCOND_MODE,LIST_COND_VAL,LIST_COND_PAREN_VAL,LIST_COND_MODE,EXTCONDLIST_MODE,ASSIGN_MODE,NETWORK_MODE,CHANGE_PROFILE_MODE,RLIMIT_MODE,MOUNT_MODE,DBUS_MODE,SIGNAL_MODE,PTRACE_MODE,UNIX_MODE,ABI_MODE,USERNS_MODE,MQUEUE_MODE,IOURING_MODE>{
 	{WS}+	{  DUMP_PREPROCESS; /* Ignoring whitespace */ }
 }
 
@@ -615,7 +616,12 @@ GT		>
 	{ARROW}		{ RETURN_TOKEN(TOK_ARROW); }
 }
 
-<MOUNT_MODE,DBUS_MODE,SIGNAL_MODE,PTRACE_MODE,UNIX_MODE,MQUEUE_MODE>{
+<IOURING_MODE>{
+	override_creds { RETURN_TOKEN(TOK_OVERRIDE_CREDS); }
+	sqpoll { RETURN_TOKEN(TOK_SQPOLL); }
+}
+
+<MOUNT_MODE,DBUS_MODE,SIGNAL_MODE,PTRACE_MODE,UNIX_MODE,MQUEUE_MODE,IOURING_MODE>{
 	({IDS_NOEQ}|{LABEL}|{QUOTED_ID}) {
 		yylval.id = processid(yytext, yyleng);
 		RETURN_TOKEN(TOK_ID);
@@ -749,7 +755,7 @@ include/{WS}	{
 	PUSH_AND_RETURN(state, token);
 }
 
-<INITIAL,NETWORK_MODE,RLIMIT_MODE,CHANGE_PROFILE_MODE,MOUNT_MODE,DBUS_MODE,SIGNAL_MODE,PTRACE_MODE,UNIX_MODE,ABI_MODE,USERNS_MODE,MQUEUE_MODE>{
+<INITIAL,NETWORK_MODE,RLIMIT_MODE,CHANGE_PROFILE_MODE,MOUNT_MODE,DBUS_MODE,SIGNAL_MODE,PTRACE_MODE,UNIX_MODE,ABI_MODE,USERNS_MODE,MQUEUE_MODE,IOURING_MODE>{
 	{END_OF_RULE}	{
 		if (YY_START != INITIAL)
 			POP_NODUMP();
@@ -757,14 +763,14 @@ include/{WS}	{
 	}
 }
 
-<INITIAL,SUB_ID_WS,INCLUDE,INCLUDE_EXISTS,LIST_VAL_MODE,EXTCOND_MODE,LIST_COND_VAL,LIST_COND_PAREN_VAL,LIST_COND_MODE,EXTCONDLIST_MODE,NETWORK_MODE,CHANGE_PROFILE_MODE,RLIMIT_MODE,MOUNT_MODE,DBUS_MODE,SIGNAL_MODE,PTRACE_MODE,UNIX_MODE,ABI_MODE,USERNS_MODE,MQUEUE_MODE>{
+<INITIAL,SUB_ID_WS,INCLUDE,INCLUDE_EXISTS,LIST_VAL_MODE,EXTCOND_MODE,LIST_COND_VAL,LIST_COND_PAREN_VAL,LIST_COND_MODE,EXTCONDLIST_MODE,NETWORK_MODE,CHANGE_PROFILE_MODE,RLIMIT_MODE,MOUNT_MODE,DBUS_MODE,SIGNAL_MODE,PTRACE_MODE,UNIX_MODE,ABI_MODE,USERNS_MODE,MQUEUE_MODE,IOURING_MODE>{
 	\r?\n	{
 		DUMP_PREPROCESS;
 		current_lineno++;
 	}
 }
 
-<INITIAL,SUB_ID,SUB_ID_WS,SUB_VALUE,LIST_VAL_MODE,EXTCOND_MODE,LIST_COND_VAL,LIST_COND_PAREN_VAL,LIST_COND_MODE,EXTCONDLIST_MODE,ASSIGN_MODE,NETWORK_MODE,CHANGE_PROFILE_MODE,MOUNT_MODE,DBUS_MODE,SIGNAL_MODE,PTRACE_MODE,UNIX_MODE,RLIMIT_MODE,INCLUDE,INCLUDE_EXISTS,ABI_MODE,USERNS_MODE,MQUEUE_MODE>{
+<INITIAL,SUB_ID,SUB_ID_WS,SUB_VALUE,LIST_VAL_MODE,EXTCOND_MODE,LIST_COND_VAL,LIST_COND_PAREN_VAL,LIST_COND_MODE,EXTCONDLIST_MODE,ASSIGN_MODE,NETWORK_MODE,CHANGE_PROFILE_MODE,MOUNT_MODE,DBUS_MODE,SIGNAL_MODE,PTRACE_MODE,UNIX_MODE,RLIMIT_MODE,INCLUDE,INCLUDE_EXISTS,ABI_MODE,USERNS_MODE,MQUEUE_MODE,IOURING_MODE>{
 	(.|\n)	{
 		DUMP_PREPROCESS;
 		/* Something we didn't expect */
@@ -801,4 +807,5 @@ unordered_map<int, string> state_names = {
 	STATE_TABLE_ENT(ABI_MODE),
 	STATE_TABLE_ENT(USERNS_MODE),
 	STATE_TABLE_ENT(MQUEUE_MODE),
+	STATE_TABLE_ENT(IOURING_MODE),
 };
diff --git a/parser/parser_main.c b/parser/parser_main.c
index b1731bed8..64cbe4654 100644
--- a/parser/parser_main.c
+++ b/parser/parser_main.c
@@ -950,6 +950,9 @@ void set_supported_features()
 	features_supports_sysv_mqueue = features_intersect(kernel_features,
 						      policy_features,
 						      "ipc/sysv_mqueue");
+	features_supports_io_uring = features_intersect(kernel_features,
+							policy_features,
+							"io_uring");
 }
 
 static bool do_print_cache_dir(aa_features *features, int dirfd, const char *path)
diff --git a/parser/parser_misc.c b/parser/parser_misc.c
index 960d4977c..651b4ce98 100644
--- a/parser/parser_misc.c
+++ b/parser/parser_misc.c
@@ -124,6 +124,9 @@ static struct keyword_table keyword_table[] = {
 	{"mqueue",		TOK_MQUEUE},
 	{"delete",		TOK_DELETE},
 	{"open",		TOK_OPEN},
+	{"io_uring",		TOK_IO_URING},
+	{"override_creds",	TOK_OVERRIDE_CREDS},
+	{"sqpoll",		TOK_SQPOLL},
 
 	/* terminate */
 	{NULL, 0}
diff --git a/parser/parser_regex.c b/parser/parser_regex.c
index f5df1635d..db1b775b3 100644
--- a/parser/parser_regex.c
+++ b/parser/parser_regex.c
@@ -942,6 +942,7 @@ static const char *mediates_net_unix = CLASS_SUB_STR(AA_CLASS_NET, AF_UNIX);
 static const char *mediates_ns = CLASS_STR(AA_CLASS_NS);
 static const char *mediates_posix_mqueue = CLASS_STR(AA_CLASS_POSIX_MQUEUE);
 static const char *mediates_sysv_mqueue = CLASS_STR(AA_CLASS_SYSV_MQUEUE);
+static const char *mediates_io_uring = CLASS_STR(AA_CLASS_IO_URING);
 
 int process_profile_policydb(Profile *prof)
 {
@@ -993,6 +994,9 @@ int process_profile_policydb(Profile *prof)
 	if (features_supports_sysv_mqueue &&
 	    !prof->policy.rules->add_rule(mediates_sysv_mqueue, 0, AA_MAY_READ, 0, dfaflags))
 		goto out;
+	if (features_supports_io_uring &&
+	    !prof->policy.rules->add_rule(mediates_io_uring, 0, AA_MAY_READ, 0, dfaflags))
+		goto out;
 
 	if (prof->policy.rules->rule_count > 0) {
 		int xmatch_len = 0;
diff --git a/parser/parser_yacc.y b/parser/parser_yacc.y
index 91a4ffaff..ca1105ace 100644
--- a/parser/parser_yacc.y
+++ b/parser/parser_yacc.y
@@ -146,6 +146,9 @@ bool check_x_qualifier(struct cod_entry *entry, const char *&errror);
 %token TOK_USERNS
 %token TOK_MQUEUE
 %token TOK_DELETE
+%token TOK_IO_URING
+%token TOK_OVERRIDE_CREDS
+%token TOK_SQPOLL
 
  /* rlimits */
 %token TOK_RLIMIT
@@ -183,6 +186,7 @@ bool check_x_qualifier(struct cod_entry *entry, const char *&errror);
 	#include "af_unix.h"
 	#include "userns.h"
 	#include "mqueue.h"
+	#include "io_uring.h"
 }
 
 %union {
@@ -201,6 +205,7 @@ bool check_x_qualifier(struct cod_entry *entry, const char *&errror);
 	unix_rule *unix_entry;
 	userns_rule *userns_entry;
 	mqueue_rule *mqueue_entry;
+	io_uring_rule *io_uring_entry;
 	prefix_rule_t *prefix_entry;
 
 	flagvals flags;
@@ -293,6 +298,10 @@ bool check_x_qualifier(struct cod_entry *entry, const char *&errror);
 %type <fperms>  mqueue_perms
 %type <fperms>	opt_mqueue_perm
 %type <mqueue_entry>	mqueue_rule
+%type <fperms>	io_uring_perm
+%type <fperms>	io_uring_perms
+%type <fperms>	opt_io_uring_perm
+%type <io_uring_entry>	io_uring_rule
 %%
 
 
@@ -783,6 +792,7 @@ prefix_rule : mnt_rule { $$ = $1; }
 	| unix_rule { $$ = $1; }
 	| userns_rule { $$ = $1; }
 	| mqueue_rule { $$ = $1; }
+	| io_uring_rule { $$ = $1; }
 
 rules:  rules opt_prefix prefix_rule
 	{
@@ -1558,6 +1568,38 @@ mqueue_rule: TOK_MQUEUE opt_mqueue_perm opt_conds TOK_END_OF_RULE
 		$$ = ent;
 	}
 
+io_uring_perm: TOK_VALUE
+	{
+		if (strcmp($1, "override_creds") == 0)
+			$$ = AA_IO_URING_OVERRIDE_CREDS;
+		else if (strcmp($1, "sqpoll") == 0)
+			$$ = AA_IO_URING_SQPOLL;
+		else
+			$$ = 0;
+
+		if ($1)
+			free($1);
+	}
+	| TOK_OVERRIDE_CREDS { $$ = AA_IO_URING_OVERRIDE_CREDS; }
+	| TOK_SQPOLL { $$ = AA_IO_URING_SQPOLL; }
+
+io_uring_perms: { /* nothing */ $$ = 0; }
+	| io_uring_perms io_uring_perm { $$ = $1 | $2; }
+	| io_uring_perms TOK_COMMA io_uring_perm { $$ = $1 | $3; }
+
+opt_io_uring_perm: { /* nothing */ $$ = 0; }
+	| io_uring_perm { $$ = $1; }
+	| TOK_OPENPAREN io_uring_perms TOK_CLOSEPAREN { $$ = $2; }
+
+io_uring_rule: TOK_IO_URING opt_io_uring_perm opt_conds opt_cond_list TOK_END_OF_RULE
+	{
+		io_uring_rule *ent;
+		ent = new io_uring_rule($2, $3, $4.list);
+		if (!ent)
+			yyerror(_("Memory allocation error."));
+		$$ = ent;
+	}
+
 hat_start: TOK_CARET {}
 	| TOK_HAT {}