[AppArmor 39/44] AppArmor: Profile loading and manipulation, pathname matching

[jjohansen]

Pathname matching, transition table loading, profile loading and
manipulation.

Signed-off-by: John Johansen <jjohansen@xxxxxxx>
Signed-off-by: Andreas Gruenbacher <agruen@xxxxxxx>

---
 security/apparmor/match.c            |  248 ++++++++++++++
 security/apparmor/match.h            |   83 ++++
 security/apparmor/module_interface.c |  589 +++++++++++++++++++++++++++++++++++
 3 files changed, 920 insertions(+)

--- /dev/null
+++ b/security/apparmor/match.c
@@ -0,0 +1,248 @@
+/*
+ *	Copyright (C) 2007 Novell/SUSE
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License as
+ *	published by the Free Software Foundation, version 2 of the
+ *	License.
+ *
+ *	Regular expression transition table matching
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include "apparmor.h"
+#include "match.h"
+
+static struct table_header *unpack_table(void *blob, size_t bsize)
+{
+	struct table_header *table = NULL;
+	struct table_header th;
+	size_t tsize;
+
+	if (bsize < sizeof(struct table_header))
+		goto out;
+
+	th.td_id = be16_to_cpu(*(u16 *) (blob));
+	th.td_flags = be16_to_cpu(*(u16 *) (blob + 2));
+	th.td_lolen = be32_to_cpu(*(u32 *) (blob + 8));
+	blob += sizeof(struct table_header);
+
+	if (!(th.td_flags == YYTD_DATA16 || th.td_flags == YYTD_DATA32 ||
+		th.td_flags == YYTD_DATA8))
+		goto out;
+
+	tsize = table_size(th.td_lolen, th.td_flags);
+	if (bsize < tsize)
+		goto out;
+
+	table = kmalloc(tsize, GFP_KERNEL);
+	if (table) {
+		*table = th;
+		if (th.td_flags == YYTD_DATA8)
+			UNPACK_ARRAY(table->td_data, blob, th.td_lolen,
+				     u8, byte_to_byte);
+		else if (th.td_flags == YYTD_DATA16)
+			UNPACK_ARRAY(table->td_data, blob, th.td_lolen,
+				     u16, be16_to_cpu);
+		else
+			UNPACK_ARRAY(table->td_data, blob, th.td_lolen,
+				     u32, be32_to_cpu);
+	}
+
+out:
+	return table;
+}
+
+int unpack_dfa(struct aa_dfa *dfa, void *blob, size_t size)
+{
+	int hsize, i;
+	int error = -ENOMEM;
+
+	/* get dfa table set header */
+	if (size < sizeof(struct table_set_header))
+		goto fail;
+
+	if (ntohl(*(u32 *)blob) != YYTH_MAGIC)
+		goto fail;
+
+	hsize = ntohl(*(u32 *)(blob + 4));
+	if (size < hsize)
+		goto fail;
+
+	blob += hsize;
+	size -= hsize;
+
+	error = -EPROTO;
+	while (size > 0) {
+		struct table_header *table;
+		table = unpack_table(blob, size);
+		if (!table)
+			goto fail;
+
+		switch(table->td_id) {
+		case YYTD_ID_ACCEPT:
+		case YYTD_ID_BASE:
+			dfa->tables[table->td_id - 1] = table;
+			if (table->td_flags != YYTD_DATA32)
+				goto fail;
+			break;
+		case YYTD_ID_DEF:
+		case YYTD_ID_NXT:
+		case YYTD_ID_CHK:
+			dfa->tables[table->td_id - 1] = table;
+			if (table->td_flags != YYTD_DATA16)
+				goto fail;
+			break;
+		case YYTD_ID_EC:
+			dfa->tables[table->td_id - 1] = table;
+			if (table->td_flags != YYTD_DATA8)
+				goto fail;
+			break;
+		default:
+			kfree(table);
+			goto fail;
+		}
+
+		blob += table_size(table->td_lolen, table->td_flags);
+		size -= table_size(table->td_lolen, table->td_flags);
+	}
+
+	return 0;
+
+fail:
+	for (i = 0; i < ARRAY_SIZE(dfa->tables); i++) {
+		if (dfa->tables[i]) {
+			kfree(dfa->tables[i]);
+			dfa->tables[i] = NULL;
+		}
+	}
+	return error;
+}
+
+/**
+ * verify_dfa - verify that all the transitions and states in the dfa tables
+ *              are in bounds.
+ * @dfa: dfa to test
+ *
+ * assumes dfa has gone through the verification done by unpacking
+ */
+int verify_dfa(struct aa_dfa *dfa)
+{
+	size_t i, state_count, trans_count;
+	int error = -EPROTO;
+
+	/* check that required tables exist */
+	if (!(dfa->tables[YYTD_ID_ACCEPT -1 ] &&
+	      dfa->tables[YYTD_ID_DEF - 1] &&
+	      dfa->tables[YYTD_ID_BASE - 1] &&
+	      dfa->tables[YYTD_ID_NXT - 1] &&
+	      dfa->tables[YYTD_ID_CHK - 1]))
+		goto out;
+
+	/* accept.size == default.size == base.size */
+	state_count = dfa->tables[YYTD_ID_BASE - 1]->td_lolen;
+	if (!(state_count == dfa->tables[YYTD_ID_DEF - 1]->td_lolen &&
+	      state_count == dfa->tables[YYTD_ID_ACCEPT - 1]->td_lolen))
+		goto out;
+
+	/* next.size == chk.size */
+	trans_count = dfa->tables[YYTD_ID_NXT - 1]->td_lolen;
+	if (trans_count != dfa->tables[YYTD_ID_CHK - 1]->td_lolen)
+		goto out;
+
+	/* if equivalence classes then its table size must be 256 */
+	if (dfa->tables[YYTD_ID_EC - 1] &&
+	    dfa->tables[YYTD_ID_EC - 1]->td_lolen != 256)
+		goto out;
+
+	for (i = 0; i < state_count; i++) {
+		if (DEFAULT_TABLE(dfa)[i] >= state_count)
+			goto out;
+		if (BASE_TABLE(dfa)[i] >= trans_count + 256)
+			goto out;
+	}
+
+	for (i = 0; i < trans_count ; i++) {
+		if (NEXT_TABLE(dfa)[i] >= state_count)
+			goto out;
+		if (CHECK_TABLE(dfa)[i] >= state_count)
+			goto out;
+	}
+
+	/* verify accept permissions */
+	for (i = 0; i < state_count; i++) {
+		int mode = ACCEPT_TABLE(dfa)[i];
+
+		if (mode & ~AA_VALID_PERM_MASK)
+			goto out;
+
+		/* if MAY_EXEC, exactly one exec modifier must be set */
+		if (mode & MAY_EXEC) {
+			mode &= AA_EXEC_MODIFIERS;
+			if (mode & (mode - 1))
+				goto out;
+		}
+	}
+
+	error = 0;
+out:
+	return error;
+}
+
+struct aa_dfa *aa_match_alloc(void)
+{
+	return kzalloc(sizeof(struct aa_dfa), GFP_KERNEL);
+}
+
+void aa_match_free(struct aa_dfa *dfa)
+{
+	if (dfa) {
+		int i;
+
+		for (i = 0; i < ARRAY_SIZE(dfa->tables); i++)
+			kfree(dfa->tables[i]);
+	}
+	kfree(dfa);
+}
+
+/**
+ * aa_dfa_match - match @path against @dfa starting in @state
+ * @dfa: the dfa to match @path against
+ * @state: the state to start matching in
+ * @path: the path to match against the dfa
+ *
+ * aa_dfa_match will match the full path length and return the state it
+ * finished matching in. The final state is used to look up the accepting
+ * label.
+ */
+unsigned int aa_dfa_match(struct aa_dfa *dfa, const char *str)
+{
+	u16 *def = DEFAULT_TABLE(dfa);
+	u32 *base = BASE_TABLE(dfa);
+	u16 *next = NEXT_TABLE(dfa);
+	u16 *check = CHECK_TABLE(dfa);
+	unsigned int state = 1, pos;
+
+	/* current state is <state>, matching character *str */
+	if (dfa->tables[YYTD_ID_EC - 1]) {
+		u8 *equiv = EQUIV_TABLE(dfa);
+		while (*str) {
+			pos = base[state] + equiv[(u8)*str++];
+			if (check[pos] == state)
+				state = next[pos];
+			else
+				state = def[state];
+		}
+	} else {
+		while (*str) {
+			pos = base[state] + (u8)*str++;
+			if (check[pos] == state)
+				state = next[pos];
+			else
+				state = def[state];
+		}
+	}
+	return ACCEPT_TABLE(dfa)[state];
+}
--- /dev/null
+++ b/security/apparmor/match.h
@@ -0,0 +1,83 @@
+/*
+ *	Copyright (C) 2007 Novell/SUSE
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License as
+ *	published by the Free Software Foundation, version 2 of the
+ *	License.
+ *
+ *	AppArmor submodule (match) prototypes
+ */
+
+#ifndef __MATCH_H
+#define __MATCH_H
+
+/**
+ * The format used for transition tables is based on the GNU flex table
+ * file format (--tables-file option; see Table File Format in the flex
+ * info pages and the flex sources for documentation). The magic number
+ * used in the header is 0x1B5E783D insted of 0xF13C57B1 though, because
+ * the YY_ID_CHK (check) and YY_ID_DEF (default) tables are used
+ * slightly differently (see the apparmor-parser package).
+ */
+
+#define YYTH_MAGIC	0x1B5E783D
+
+struct table_set_header {
+	u32		th_magic;	/* YYTH_MAGIC */
+	u32		th_hsize;
+	u32		th_ssize;
+	u16		th_flags;
+	char		th_version[];
+};
+
+#define	YYTD_ID_ACCEPT	1
+#define YYTD_ID_BASE	2
+#define YYTD_ID_CHK	3
+#define YYTD_ID_DEF	4
+#define YYTD_ID_EC	5
+#define YYTD_ID_META	6
+#define YYTD_ID_NXT	8
+
+
+#define YYTD_DATA8	1
+#define YYTD_DATA16	2
+#define YYTD_DATA32	4
+
+struct table_header {
+	u16		td_id;
+	u16		td_flags;
+	u32		td_hilen;
+	u32		td_lolen;
+	char		td_data[];
+};
+
+#define DEFAULT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_DEF - 1]->td_data))
+#define BASE_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_BASE - 1]->td_data))
+#define NEXT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_NXT - 1]->td_data))
+#define CHECK_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_CHK - 1]->td_data))
+#define EQUIV_TABLE(DFA) ((u8 *)((DFA)->tables[YYTD_ID_EC - 1]->td_data))
+#define ACCEPT_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT - 1]->td_data))
+
+struct aa_dfa {
+	struct table_header *tables[YYTD_ID_NXT];
+};
+
+#define byte_to_byte(X) (X)
+
+#define UNPACK_ARRAY(TABLE, BLOB, LEN, TYPE, NTOHX) \
+	do { \
+		typeof(LEN) __i; \
+		TYPE *__t = (TYPE *) TABLE; \
+		TYPE *__b = (TYPE *) BLOB; \
+		for (__i = 0; __i < LEN; __i++) { \
+			__t[__i] = NTOHX(__b[__i]); \
+		} \
+	} while (0)
+
+static inline size_t table_size(size_t len, size_t el_size)
+{
+	return ALIGN(sizeof(struct table_header) + len * el_size, 8);
+}
+
+#endif /* __MATCH_H */
--- /dev/null
+++ b/security/apparmor/module_interface.c
@@ -0,0 +1,589 @@
+/*
+ *	Copyright (C) 1998-2007 Novell/SUSE
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License as
+ *	published by the Free Software Foundation, version 2 of the
+ *	License.
+ *
+ *	AppArmor userspace policy interface
+ */
+
+#include <asm/unaligned.h>
+
+#include "apparmor.h"
+#include "inline.h"
+
+/*
+ * This mutex is used to synchronize profile adds, replacements, and
+ * removals: we only allow one of these operations at a time.
+ * We do not use the profile list lock here in order to avoid blocking
+ * exec during those operations.  (Exec involves a profile list lookup
+ * for named-profile transitions.)
+ */
+DEFINE_MUTEX(aa_interface_lock);
+
+/*
+ * The AppArmor interface treats data as a type byte followed by the
+ * actual data.  The interface has the notion of a a named entry
+ * which has a name (AA_NAME typecode followed by name string) followed by
+ * the entries typecode and data.  Named types allow for optional
+ * elements and extensions to be added and tested for without breaking
+ * backwards compatability.
+ */
+
+enum aa_code {
+	AA_U8,
+	AA_U16,
+	AA_U32,
+	AA_U64,
+	AA_NAME,	/* same as string except it is items name */
+	AA_STRING,
+	AA_BLOB,
+	AA_STRUCT,
+	AA_STRUCTEND,
+	AA_LIST,
+	AA_LISTEND,
+};
+
+/*
+ * aa_ext is the read of the buffer containing the serialized profile.  The
+ * data is copied into a kernel buffer in apparmorfs and then handed off to
+ * the unpack routines.
+ */
+struct aa_ext {
+	void *start;
+	void *end;
+	void *pos;	/* pointer to current position in the buffer */
+	u32 version;
+};
+
+static inline int aa_inbounds(struct aa_ext *e, size_t size)
+{
+	return (size <= e->end - e->pos);
+}
+
+/**
+ * aa_u16_chunck - test and do bounds checking for a u16 size based chunk
+ * @e: serialized data read head
+ * @chunk: start address for chunk of data
+ *
+ * return the size of chunk found with the read head at the end of
+ * the chunk.
+ */
+static size_t aa_is_u16_chunk(struct aa_ext *e, char **chunk)
+{
+	void *pos = e->pos;
+	size_t size = 0;
+
+	if (!aa_inbounds(e, sizeof(u16)))
+		goto fail;
+	size = le16_to_cpu(get_unaligned((u16 *)e->pos));
+	e->pos += sizeof(u16);
+	if (!aa_inbounds(e, size))
+		goto fail;
+	*chunk = e->pos;
+	e->pos += size;
+	return size;
+
+fail:
+	e->pos = pos;
+	return 0;
+}
+
+static inline int aa_is_X(struct aa_ext *e, enum aa_code code)
+{
+	if (!aa_inbounds(e, 1))
+		return 0;
+	if (*(u8 *) e->pos != code)
+		return 0;
+	e->pos++;
+	return 1;
+}
+
+/**
+ * aa_is_nameX - check is the next element is of type X with a name of @name
+ * @e: serialized data extent information
+ * @code: type code
+ * @name: name to match to the serialized element.
+ *
+ * check that the next serialized data element is of type X and has a tag
+ * name @name.  If @name is specified then there must be a matching
+ * name element in the stream.  If @name is NULL any name element will be
+ * skipped and only the typecode will be tested.
+ * returns 1 on success (both type code and name tests match) and the read
+ * head is advanced past the headers
+ * returns %0 if either match failes, the read head does not move
+ */
+static int aa_is_nameX(struct aa_ext *e, enum aa_code code, const char *name)
+{
+	void *pos = e->pos;
+	/*
+	 * Check for presence of a tagname, and if present name size
+	 * AA_NAME tag value is a u16.
+	 */
+	if (aa_is_X(e, AA_NAME)) {
+		char *tag;
+		size_t size = aa_is_u16_chunk(e, &tag);
+		/* if a name is specified it must match. otherwise skip tag */
+		if (name && (!size || strcmp(name, tag)))
+			goto fail;
+	} else if (name) {
+		/* if a name is specified and there is no name tag fail */
+		goto fail;
+	}
+
+	/* now check if type code matches */
+	if (aa_is_X(e, code))
+		return 1;
+
+fail:
+	e->pos = pos;
+	return 0;
+}
+
+static int aa_is_u32(struct aa_ext *e, u32 *data, const char *name)
+{
+	void *pos = e->pos;
+	if (aa_is_nameX(e, AA_U32, name)) {
+		if (!aa_inbounds(e, sizeof(u32)))
+			goto fail;
+		if (data)
+			*data = le32_to_cpu(get_unaligned((u32 *)e->pos));
+		e->pos += sizeof(u32);
+		return 1;
+	}
+fail:
+	e->pos = pos;
+	return 0;
+}
+
+static size_t aa_is_blob(struct aa_ext *e, char **blob, const char *name)
+{
+	void *pos = e->pos;
+	if (aa_is_nameX(e, AA_BLOB, name)) {
+		u32 size;
+		if (!aa_inbounds(e, sizeof(u32)))
+			goto fail;
+		size = le32_to_cpu(get_unaligned((u32 *)e->pos));
+		e->pos += sizeof(u32);
+		if (aa_inbounds(e, (size_t) size)) {
+			* blob = e->pos;
+			e->pos += size;
+			return size;
+		}
+	}
+fail:
+	e->pos = pos;
+	return 0;
+}
+
+static int aa_is_dynstring(struct aa_ext *e, char **string, const char *name)
+{
+	char *src_str;
+	size_t size = 0;
+	void *pos = e->pos;
+	*string = NULL;
+	if (aa_is_nameX(e, AA_STRING, name) &&
+	    (size = aa_is_u16_chunk(e, &src_str))) {
+		char *str;
+		if (!(str = kmalloc(size, GFP_KERNEL)))
+			goto fail;
+		memcpy(str, src_str, size);
+		*string = str;
+	}
+
+	return size;
+
+fail:
+	e->pos = pos;
+	return 0;
+}
+
+/**
+ * aa_unpack_dfa - unpack a file rule dfa
+ * @e: serialized data extent information
+ *
+ * returns dfa or ERR_PTR
+ */
+struct aa_dfa *aa_unpack_dfa(struct aa_ext *e)
+{
+	char *blob = NULL;
+	size_t size, error = 0;
+	struct aa_dfa *dfa = NULL;
+
+	size = aa_is_blob(e, &blob, "aadfa");
+	if (size) {
+		dfa = aa_match_alloc();
+		if (dfa) {
+			/*
+			 * The dfa is aligned with in the blob to 8 bytes
+			 * from the beginning of the stream.
+			 */
+			size_t sz = blob - (char *) e->start;
+			size_t pad = ALIGN(sz, 8) - sz;
+			error = unpack_dfa(dfa, blob + pad, size - pad);
+			if (!error)
+				error = verify_dfa(dfa);
+		} else {
+			error = -ENOMEM;
+		}
+
+		if (error) {
+			aa_match_free(dfa);
+			dfa = ERR_PTR(error);
+		}
+	}
+
+	return dfa;
+}
+
+/**
+ * aa_unpack_profile - unpack a serialized profile
+ * @e: serialized data extent information
+ * @operation: operation profile is being unpacked for
+ */
+static struct aa_profile *aa_unpack_profile(struct aa_ext *e,
+					    const char *operation)
+{
+	struct aa_profile *profile = NULL;
+	struct aa_audit sa;
+
+	int error = -EPROTO;
+
+	profile = alloc_aa_profile();
+	if (!profile)
+		return ERR_PTR(-ENOMEM);
+
+	/* check that we have the right struct being passed */
+	if (!aa_is_nameX(e, AA_STRUCT, "profile"))
+		goto fail;
+	if (!aa_is_dynstring(e, &profile->name, NULL))
+		goto fail;
+
+	/* per profile debug flags (complain, audit) */
+	if (!aa_is_nameX(e, AA_STRUCT, "flags"))
+		goto fail;
+	if (!aa_is_u32(e, NULL, NULL))
+		goto fail;
+	if (!aa_is_u32(e, &(profile->flags.complain), NULL))
+		goto fail;
+	if (!aa_is_u32(e, &(profile->flags.audit), NULL))
+		goto fail;
+	if (!aa_is_nameX(e, AA_STRUCTEND, NULL))
+		goto fail;
+
+	if (!aa_is_u32(e, &(profile->capabilities), NULL))
+		goto fail;
+
+	/* get file rules */
+	profile->file_rules = aa_unpack_dfa(e);
+	if (IS_ERR(profile->file_rules)) {
+		error = PTR_ERR(profile->file_rules);
+		profile->file_rules = NULL;
+		goto fail;
+	}
+
+	if (!aa_is_nameX(e, AA_STRUCTEND, NULL))
+		goto fail;
+
+	return profile;
+
+fail:
+	memset(&sa, 0, sizeof(sa));
+	sa.operation = operation;
+	sa.gfp_mask = GFP_KERNEL;
+	sa.name = profile && profile->name ? profile->name : "unknown";
+	sa.info = "failed to unpack profile";
+	aa_audit_status(NULL, &sa);
+
+	if (profile)
+		free_aa_profile(profile);
+
+	return ERR_PTR(error);
+}
+
+/**
+ * aa_verify_head - unpack serialized stream header
+ * @e: serialized data read head
+ * @operation: operation header is being verified for
+ *
+ * returns error or 0 if header is good
+ */
+static int aa_verify_header(struct aa_ext *e, const char *operation)
+{
+	/* get the interface version */
+	if (!aa_is_u32(e, &e->version, "version")) {
+		struct aa_audit sa;
+		memset(&sa, 0, sizeof(sa));
+		sa.operation = operation;
+		sa.gfp_mask = GFP_KERNEL;
+		sa.info = "invalid profile format";
+		aa_audit_status(NULL, &sa);
+		return -EPROTONOSUPPORT;
+	}
+
+	/* check that the interface version is currently supported */
+	if (e->version != 3) {
+		struct aa_audit sa;
+		memset(&sa, 0, sizeof(sa));
+		sa.operation = operation;
+		sa.gfp_mask = GFP_KERNEL;
+		sa.info = "unsupported interface version";
+		aa_audit_status(NULL, &sa);
+		return -EPROTONOSUPPORT;
+	}
+	return 0;
+}
+
+/**
+ * aa_add_profile - Unpack and add a new profile to the profile list
+ * @data: serialized data stream
+ * @size: size of the serialized data stream
+ */
+ssize_t aa_add_profile(void *data, size_t size)
+{
+	struct aa_profile *profile = NULL;
+	struct aa_ext e = {
+		.start = data,
+		.end = data + size,
+		.pos = data
+	};
+	ssize_t error = aa_verify_header(&e, "profile_load");
+	if (error)
+		return error;
+
+	profile = aa_unpack_profile(&e, "profile_load");
+	if (IS_ERR(profile))
+		return PTR_ERR(profile);
+
+	mutex_lock(&aa_interface_lock);
+	write_lock(&profile_list_lock);
+	if (__aa_find_profile(profile->name, &profile_list)) {
+		/* A profile with this name exists already. */
+		write_unlock(&profile_list_lock);
+		mutex_unlock(&aa_interface_lock);
+		aa_put_profile(profile);
+		return -EEXIST;
+	}
+	list_add(&profile->list, &profile_list);
+	write_unlock(&profile_list_lock);
+	mutex_unlock(&aa_interface_lock);
+
+	return size;
+}
+
+/**
+ * task_replace - replace a task's profile
+ * @task: task to replace profile on
+ * @new_cxt: new aa_task_context to do replacement with
+ * @new_profile: new profile
+ */
+static inline void task_replace(struct task_struct *task,
+				struct aa_task_context *new_cxt,
+				struct aa_profile *new_profile)
+{
+	struct aa_task_context *cxt = aa_task_context(task);
+
+	AA_DEBUG("%s: replacing profile for task %d "
+		 "profile=%s (%p)\n",
+		 __FUNCTION__,
+		 cxt->task->pid,
+		 cxt->profile->name, cxt->profile);
+
+	aa_change_task_context(task, new_cxt, new_profile, cxt->cookie,
+			       cxt->previous_profile);
+}
+
+/**
+ * aa_replace_profile - replace a profile on the profile list
+ * @udata: serialized data stream
+ * @size: size of the serialized data stream
+ *
+ * unpack and replace a profile on the profile list and uses of that profile
+ * by any aa_task_context.  If the profile does not exist on the profile list
+ * it is added.  Return %0 or error.
+ */
+ssize_t aa_replace_profile(void *udata, size_t size)
+{
+	struct aa_profile *old_profile, *new_profile;
+	struct aa_task_context *new_cxt;
+	struct aa_ext e = {
+		.start = udata,
+		.end = udata + size,
+		.pos = udata
+	};
+	ssize_t error = aa_verify_header(&e, "profile_replace");
+	if (error)
+		return error;
+
+	new_profile = aa_unpack_profile(&e, "profile_replace");
+	if (IS_ERR(new_profile))
+		return PTR_ERR(new_profile);
+
+	mutex_lock(&aa_interface_lock);
+	write_lock(&profile_list_lock);
+	old_profile = __aa_find_profile(new_profile->name, &profile_list);
+	if (old_profile) {
+		lock_profile(old_profile);
+		old_profile->isstale = 1;
+		unlock_profile(old_profile);
+		list_del_init(&old_profile->list);
+	}
+	list_add(&new_profile->list, &profile_list);
+	write_unlock(&profile_list_lock);
+
+	if (!old_profile)
+		goto out;
+
+	/*
+	 * Replacement needs to allocate a new aa_task_context for each
+	 * task confined by old_profile.  To do this the profile locks
+	 * are only held when the actual switch is done per task.  While
+	 * looping to allocate a new aa_task_context the old_task list
+	 * may get shorter if tasks exit/change their profile but will
+	 * not get longer as new task will not use old_profile detecting
+	 * that is stale.
+	 */
+	do {
+		new_cxt = aa_alloc_task_context(GFP_KERNEL | __GFP_NOFAIL);
+
+		lock_both_profiles(old_profile, new_profile);
+		if (!list_empty(&old_profile->task_contexts)) {
+			struct task_struct *task =
+				list_entry(old_profile->task_contexts.next,
+					   struct aa_task_context, list)->task;
+			task_lock(task);
+			task_replace(task, new_cxt, new_profile);
+			task_unlock(task);
+			new_cxt = NULL;
+		}
+		unlock_both_profiles(old_profile, new_profile);
+	} while (!new_cxt);
+	aa_free_task_context(new_cxt);
+	aa_put_profile(old_profile);
+
+out:
+	mutex_unlock(&aa_interface_lock);
+	return size;
+}
+
+/**
+ * aa_remove_profile - remove a profile from the system
+ * @name: name of the profile to remove
+ * @size: size of the name
+ *
+ * remove a profile from the profile list and all aa_task_context references
+ * to said profile.
+ */
+ssize_t aa_remove_profile(const char *name, size_t size)
+{
+	struct aa_profile *profile;
+
+	mutex_lock(&aa_interface_lock);
+	write_lock(&profile_list_lock);
+	profile = __aa_find_profile(name, &profile_list);
+	if (!profile) {
+		write_unlock(&profile_list_lock);
+		mutex_unlock(&aa_interface_lock);
+		return -ENOENT;
+	}
+
+	/* Remove the profile from each task context it is on. */
+	lock_profile(profile);
+	profile->isstale = 1;
+	aa_unconfine_tasks(profile);
+	unlock_profile(profile);
+
+	/* Release the profile itself. */
+	list_del_init(&profile->list);
+	aa_put_profile(profile);
+	write_unlock(&profile_list_lock);
+	mutex_unlock(&aa_interface_lock);
+
+	return size;
+}
+
+/**
+ * free_aa_profile_kref - free aa_profile by kref (called by aa_put_profile)
+ * @kr: kref callback for freeing of a profile
+ */
+void free_aa_profile_kref(struct kref *kref)
+{
+	struct aa_profile *p=container_of(kref, struct aa_profile, count);
+
+	free_aa_profile(p);
+}
+
+/**
+ * alloc_aa_profile - allocate, initialize and return a new profile
+ * Returns NULL on failure.
+ */
+struct aa_profile *alloc_aa_profile(void)
+{
+	struct aa_profile *profile;
+
+	profile = kzalloc(sizeof(*profile), GFP_KERNEL);
+	AA_DEBUG("%s(%p)\n", __FUNCTION__, profile);
+	if (profile) {
+		INIT_LIST_HEAD(&profile->list);
+		kref_init(&profile->count);
+		INIT_LIST_HEAD(&profile->task_contexts);
+		spin_lock_init(&profile->lock);
+	}
+	return profile;
+}
+
+/**
+ * free_aa_profile - free a profile
+ * @profile: the profile to free
+ *
+ * Free a profile, its hats and null_profile. All references to the profile,
+ * its hats and null_profile must have been put.
+ *
+ * If the profile was referenced from a task context, free_aa_profile() will
+ * be called from an rcu callback routine, so we must not sleep here.
+ */
+void free_aa_profile(struct aa_profile *profile)
+{
+	AA_DEBUG("%s(%p)\n", __FUNCTION__, profile);
+
+	if (!profile)
+		return;
+
+	/* profile is still on global profile list -- invalid */
+	if (!list_empty(&profile->list)) {
+		AA_ERROR("%s: internal error, "
+			 "profile '%s' still on global list\n",
+			 __FUNCTION__,
+			 profile->name);
+		BUG();
+	}
+
+	aa_match_free(profile->file_rules);
+
+	if (profile->name) {
+		AA_DEBUG("%s: %s\n", __FUNCTION__, profile->name);
+		kfree(profile->name);
+	}
+
+	kfree(profile);
+}
+
+/**
+ * aa_unconfine_tasks - remove tasks on a profile's task context list
+ * @profile: profile to remove tasks from
+ *
+ * Assumes that @profile lock is held.
+ */
+void aa_unconfine_tasks(struct aa_profile *profile)
+{
+	while (!list_empty(&profile->task_contexts)) {
+		struct task_struct *task =
+			list_entry(profile->task_contexts.next,
+				   struct aa_task_context, list)->task;
+		task_lock(task);
+		aa_change_task_context(task, NULL, NULL, 0, NULL);
+		task_unlock(task);
+	}
+}

-- 
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