Commit c140dcd1 authored by John Johansen's avatar John Johansen
Browse files

apparmor: make str table more generic and be able to have multiple entries 



The strtable is currently limited to a single entry string on unpack
even though domain has the concept of multiple entries within it. Make
this a reality as it will be used for tags and more advanced domain
transitions.

Reviewed-by: default avatarGeorgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: default avatarJohn Johansen <john.johansen@canonical.com>
parent 6fc367bf

security/apparmor/domain.c

+1 −1
Original line number Diff line number Diff line
@@ -529,7 +529,7 @@ struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex, 
	/* TODO: move lookup parsing to unpack time so this is a straight

	 *       index into the resultant label

	 */

	for (next = rules->file->trans.table[index]; next;

	for (next = rules->file->trans.table[index].strs; next;

	     next = next_name(xtype, next)) {

		const char *lookup = (*next == '&') ? next + 1 : next;

		*name = next;

security/apparmor/include/lib.h

+9 −2
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ extern struct aa_dfa *stacksplitdfa; 
#define DEBUG_DOMAIN 4

#define DEBUG_POLICY 8

#define DEBUG_INTERFACE 0x10

#define DEBUG_UNPACK 0x40



#define DEBUG_ALL 0x1f		/* update if new DEBUG_X added */

#define DEBUG_PARSE_ERROR (-1)
@@ -119,13 +120,19 @@ static inline bool path_mediated_fs(struct dentry *dentry) 
	return !(dentry->d_sb->s_flags & SB_NOUSER);

}



struct aa_str_table_ent {

	int count;

	int size;

	char *strs;

};



struct aa_str_table {

	int size;

	char **table;

	struct aa_str_table_ent *table;

};



void aa_free_str_table(struct aa_str_table *table);

bool aa_resize_str_table(struct aa_str_table *t, int newsize, gfp_t gfp);

void aa_destroy_str_table(struct aa_str_table *table);



struct counted_str {

	struct kref count;

security/apparmor/lib.c

+6 −5
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ static struct val_table_ent debug_values_table[] = { 
	{ "domain", DEBUG_DOMAIN },

	{ "policy", DEBUG_POLICY },

	{ "interface", DEBUG_INTERFACE },

	{ "unpack", DEBUG_UNPACK },

	{ NULL, 0 }

};
@@ -118,7 +119,7 @@ int aa_print_debug_params(char *buffer) 


bool aa_resize_str_table(struct aa_str_table *t, int newsize, gfp_t gfp)

{

	char **n;

	struct aa_str_table_ent *n;

	int i;



	if (t->size == newsize)
@@ -129,7 +130,7 @@ bool aa_resize_str_table(struct aa_str_table *t, int newsize, gfp_t gfp) 
	for (i = 0; i < min(t->size, newsize); i++)

		n[i] = t->table[i];

	for (; i < t->size; i++)

		kfree_sensitive(t->table[i]);

		kfree_sensitive(t->table[i].strs);

	if (newsize > t->size)

		memset(&n[t->size], 0, (newsize-t->size)*sizeof(*n));

	kfree_sensitive(t->table);
@@ -140,10 +141,10 @@ bool aa_resize_str_table(struct aa_str_table *t, int newsize, gfp_t gfp) 
}



/**

 * aa_free_str_table - free entries str table

 * aa_destroy_str_table - free entries str table

 * @t: the string table to free  (MAYBE NULL)

 */

void aa_free_str_table(struct aa_str_table *t)

void aa_destroy_str_table(struct aa_str_table *t)

{

	int i;
@@ -152,7 +153,7 @@ void aa_free_str_table(struct aa_str_table *t) 
			return;



		for (i = 0; i < t->size; i++)

			kfree_sensitive(t->table[i]);

			kfree_sensitive(t->table[i].strs);

		kfree_sensitive(t->table);

		t->table = NULL;

		t->size = 0;

security/apparmor/policy.c

+1 −1
Original line number Diff line number Diff line
@@ -104,7 +104,7 @@ static void aa_free_pdb(struct aa_policydb *pdb) 
	if (pdb) {

		aa_put_dfa(pdb->dfa);

		kvfree(pdb->perms);

		aa_free_str_table(&pdb->trans);

		aa_destroy_str_table(&pdb->trans);

		kfree(pdb);

	}

}

security/apparmor/policy_unpack.c

+73 −37
Original line number Diff line number Diff line
@@ -450,20 +450,72 @@ static struct aa_dfa *unpack_dfa(struct aa_ext *e, int flags) 
	return dfa;

}



static int process_strs_entry(char *str, int size, bool multi)

{

	int c = 1;



	if (size <= 0)

		return -1;

	if (multi) {

		if (size < 2)

			return -2;

		/* multi ends with double \0 */

		if (str[size - 2])

			return -3;

	}



	char *save = str;

	char *pos = str;

	char *end = multi ? str + size - 2 : str + size - 1;

	/* count # of internal \0 */

	while (str < end) {

		if (str == pos) {

			/* starts with ... */

			if (!*str) {

				AA_DEBUG(DEBUG_UNPACK,

					 "starting with null save=%lu size %d c=%d",

					 str - save, size, c);

				return -4;

			}

			if (isspace(*str))

				return -5;

			if (*str == ':') {

				/* :ns_str\0str\0

				 * first character after : must be valid

				 */

				if (!str[1])

					return -6;

			}

		} else if (!*str) {

			if (*pos == ':')

				*str = ':';

			else

				c++;

			pos = str +  1;

		}

		str++;

	} /* while */



	return c;

}



/**

 * unpack_trans_table - unpack a profile transition table

 * unpack_strs_table - unpack a profile transition table

 * @e: serialized data extent information  (NOT NULL)

 * @name: name of table (MAY BE NULL)

 * @multi: allow multiple strings on a single entry

 * @strs: str table to unpack to (NOT NULL)

 *

 * Returns: true if table successfully unpacked or not present

 */

static bool unpack_trans_table(struct aa_ext *e, struct aa_str_table *strs)

static bool unpack_strs_table(struct aa_ext *e, const char *name, bool multi,

			      struct aa_str_table *strs)

{

	void *saved_pos = e->pos;

	char **table = NULL;

	struct aa_str_table_ent *table = NULL;



	/* exec table is optional */

	if (aa_unpack_nameX(e, AA_STRUCT, "xtable")) {

	if (aa_unpack_nameX(e, AA_STRUCT, name)) {

		u16 size;

		int i;
@@ -475,7 +527,8 @@ static bool unpack_trans_table(struct aa_ext *e, struct aa_str_table *strs) 
			 * for size check here

			 */

			goto fail;

		table = kcalloc(size, sizeof(char *), GFP_KERNEL);

		table = kcalloc(size, sizeof(struct aa_str_table_ent),

				GFP_KERNEL);

		if (!table)

			goto fail;
@@ -483,42 +536,24 @@ static bool unpack_trans_table(struct aa_ext *e, struct aa_str_table *strs) 
		strs->size = size;

		for (i = 0; i < size; i++) {

			char *str;

			int c, j, pos, size2 = aa_unpack_strdup(e, &str, NULL);

			int c, size2 = aa_unpack_strdup(e, &str, NULL);

			/* aa_unpack_strdup verifies that the last character is

			 * null termination byte.

			 */

			if (!size2)

				goto fail;

			table[i] = str;

			/* verify that name doesn't start with space */

			if (isspace(*str))

			c = process_strs_entry(str, size2, multi);

			if (c <= 0) {

				AA_DEBUG(DEBUG_UNPACK, "process_strs %d", c);

				goto fail;



			/* count internal #  of internal \0 */

			for (c = j = 0; j < size2 - 1; j++) {

				if (!str[j]) {

					pos = j;

					c++;

				}

			}

			if (*str == ':') {

				/* first character after : must be valid */

				if (!str[1])

					goto fail;

				/* beginning with : requires an embedded \0,

				 * verify that exactly 1 internal \0 exists

				 * trailing \0 already verified by aa_unpack_strdup

				 *

				 * convert \0 back to : for label_parse

				 */

				if (c == 1)

					str[pos] = ':';

				else if (c > 1)

					goto fail;

			} else if (c)

			if (!multi && c > 1) {

				AA_DEBUG(DEBUG_UNPACK, "!multi && c > 1");

				/* fail - all other cases with embedded \0 */

				goto fail;

			}

			table[i].strs = str;

			table[i].count = c;

			table[i].size = size2;

		}

		if (!aa_unpack_nameX(e, AA_ARRAYEND, NULL))

			goto fail;

		if (!aa_unpack_nameX(e, AA_STRUCTEND, NULL))
@@ -527,7 +562,7 @@ static bool unpack_trans_table(struct aa_ext *e, struct aa_str_table *strs) 
	return true;



fail:

	aa_free_str_table(strs);

	aa_destroy_str_table(strs);

	e->pos = saved_pos;

	return false;

}
@@ -795,13 +830,14 @@ static int unpack_pdb(struct aa_ext *e, struct aa_policydb **policy, 
	 * transition table may be present even when the dfa is

	 * not. For compatibility reasons unpack and discard.

	 */

	if (!unpack_trans_table(e, &pdb->trans) && required_trans) {

	if (!unpack_strs_table(e, "xtable", false, &pdb->trans) &&

	    required_trans) {

		*info = "failed to unpack profile transition table";

		goto fail;

	}



	if (!pdb->dfa && pdb->trans.table)

		aa_free_str_table(&pdb->trans);

		aa_destroy_str_table(&pdb->trans);



	/* TODO:

	 * - move compat mapping here, requires dfa merging first
@@ -1268,7 +1304,7 @@ static bool verify_perms(struct aa_policydb *pdb) 
	}

	/* deal with incorrectly constructed string tables */

	if (xmax == -1) {

		aa_free_str_table(&pdb->trans);

		aa_destroy_str_table(&pdb->trans);

	} else if (pdb->trans.size > xmax + 1) {

		if (!aa_resize_str_table(&pdb->trans, xmax + 1, GFP_KERNEL))

			return false;