Merge tag 'apparmor-pr-2018-04-10' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor

Pull apparmor updates from John Johansen:
 "Features:
  - add base infrastructure for socket mediation. ABI bump and
    additional checks to ensure only v8 compliant policy uses socket af
    mediation.
  - improve and cleanup dfa verification
  - improve profile attachment logic
     - improve overlapping expression handling
     - add the xattr matching to the attachment logic
  - improve signal mediation handling with stacked labels
  - improve handling of no_new_privs in a label stack

  Cleanups and changes:
  - use dfa to parse string split
  - bounded version of label_parse
  - proper line wrap nulldfa.in
  - split context out into task and cred naming to better match usage
  - simplify code in aafs

  Bug fixes:
  - fix display of .ns_name for containers
  - fix resource audit messages when auditing peer
  - fix logging of the existence test for signals
  - fix resource audit messages when auditing peer
  - fix display of .ns_name for containers
  - fix an error code in verify_table_headers()
  - fix memory leak on buffer on error exit path
  - fix error returns checks by making size a ssize_t"

* tag 'apparmor-pr-2018-04-10' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor: (36 commits)
  apparmor: fix memory leak on buffer on error exit path
  apparmor: fix dangling symlinks to policy rawdata after replacement
  apparmor: Fix an error code in verify_table_headers()
  apparmor: fix error returns checks by making size a ssize_t
  apparmor: update MAINTAINERS file git and wiki locations
  apparmor: remove POLICY_MEDIATES_SAFE
  apparmor: add base infastructure for socket mediation
  apparmor: improve overlapping domain attachment resolution
  apparmor: convert attaching profiles via xattrs to use dfa matching
  apparmor: Add support for attaching profiles via xattr, presence and value
  apparmor: cleanup: simplify code to get ns symlink name
  apparmor: cleanup create_aafs() error path
  apparmor: dfa split verification of table headers
  apparmor: dfa add support for state differential encoding
  apparmor: dfa move character match into a macro
  apparmor: update domain transitions that are subsets of confinement at nnp
  apparmor: move context.h to cred.h
  apparmor: move task related defines and fns to task.X files
  apparmor: cleanup, drop unused fn __aa_task_is_confined()
  apparmor: cleanup fixup description of aa_replace_profiles
  ...

1 files changed, 352 insertions, 71 deletions

diff --git a/security/apparmor/match.c b/security/apparmor/match.c
index 72c604350e80..280eba082c7b 100644
--- a/security/apparmor/match.c
+++ b/security/apparmor/match.c
@@ -30,6 +30,11 @@ static char nulldfa_src[] = {
 };
 struct aa_dfa *nulldfa;
 
+static char stacksplitdfa_src[] = {
+	#include "stacksplitdfa.in"
+};
+struct aa_dfa *stacksplitdfa;
+
 int aa_setup_dfa_engine(void)
 {
 	int error;
@@ -37,19 +42,31 @@ int aa_setup_dfa_engine(void)
 	nulldfa = aa_dfa_unpack(nulldfa_src, sizeof(nulldfa_src),
 				TO_ACCEPT1_FLAG(YYTD_DATA32) |
 				TO_ACCEPT2_FLAG(YYTD_DATA32));
-	if (!IS_ERR(nulldfa))
-		return 0;
+	if (IS_ERR(nulldfa)) {
+		error = PTR_ERR(nulldfa);
+		nulldfa = NULL;
+		return error;
+	}
 
-	error = PTR_ERR(nulldfa);
-	nulldfa = NULL;
+	stacksplitdfa = aa_dfa_unpack(stacksplitdfa_src,
+				      sizeof(stacksplitdfa_src),
+				      TO_ACCEPT1_FLAG(YYTD_DATA32) |
+				      TO_ACCEPT2_FLAG(YYTD_DATA32));
+	if (IS_ERR(stacksplitdfa)) {
+		aa_put_dfa(nulldfa);
+		nulldfa = NULL;
+		error = PTR_ERR(stacksplitdfa);
+		stacksplitdfa = NULL;
+		return error;
+	}
 
-	return error;
+	return 0;
 }
 
 void aa_teardown_dfa_engine(void)
 {
+	aa_put_dfa(stacksplitdfa);
 	aa_put_dfa(nulldfa);
-	nulldfa = NULL;
 }
 
 /**
@@ -119,8 +136,8 @@ fail:
 }
 
 /**
- * verify_dfa - verify that transitions and states in the tables are in bounds.
- * @dfa: dfa to test  (NOT NULL)
+ * verify_table_headers - verify that the tables headers are as expected
+ * @tables - array of dfa tables to check (NOT NULL)
  * @flags: flags controlling what type of accept table are acceptable
  *
  * Assumes dfa has gone through the first pass verification done by unpacking
@@ -128,64 +145,98 @@ fail:
  *
  * Returns: %0 else error code on failure to verify
  */
-static int verify_dfa(struct aa_dfa *dfa, int flags)
+static int verify_table_headers(struct table_header **tables, int flags)
 {
-	size_t i, state_count, trans_count;
+	size_t state_count, trans_count;
 	int error = -EPROTO;
 
 	/* check that required tables exist */
-	if (!(dfa->tables[YYTD_ID_DEF] &&
-	      dfa->tables[YYTD_ID_BASE] &&
-	      dfa->tables[YYTD_ID_NXT] && dfa->tables[YYTD_ID_CHK]))
+	if (!(tables[YYTD_ID_DEF] && tables[YYTD_ID_BASE] &&
+	      tables[YYTD_ID_NXT] && tables[YYTD_ID_CHK]))
 		goto out;
 
 	/* accept.size == default.size == base.size */
-	state_count = dfa->tables[YYTD_ID_BASE]->td_lolen;
+	state_count = tables[YYTD_ID_BASE]->td_lolen;
 	if (ACCEPT1_FLAGS(flags)) {
-		if (!dfa->tables[YYTD_ID_ACCEPT])
+		if (!tables[YYTD_ID_ACCEPT])
 			goto out;
-		if (state_count != dfa->tables[YYTD_ID_ACCEPT]->td_lolen)
+		if (state_count != tables[YYTD_ID_ACCEPT]->td_lolen)
 			goto out;
 	}
 	if (ACCEPT2_FLAGS(flags)) {
-		if (!dfa->tables[YYTD_ID_ACCEPT2])
+		if (!tables[YYTD_ID_ACCEPT2])
 			goto out;
-		if (state_count != dfa->tables[YYTD_ID_ACCEPT2]->td_lolen)
+		if (state_count != tables[YYTD_ID_ACCEPT2]->td_lolen)
 			goto out;
 	}
-	if (state_count != dfa->tables[YYTD_ID_DEF]->td_lolen)
+	if (state_count != tables[YYTD_ID_DEF]->td_lolen)
 		goto out;
 
 	/* next.size == chk.size */
-	trans_count = dfa->tables[YYTD_ID_NXT]->td_lolen;
-	if (trans_count != dfa->tables[YYTD_ID_CHK]->td_lolen)
+	trans_count = tables[YYTD_ID_NXT]->td_lolen;
+	if (trans_count != tables[YYTD_ID_CHK]->td_lolen)
 		goto out;
 
 	/* if equivalence classes then its table size must be 256 */
-	if (dfa->tables[YYTD_ID_EC] &&
-	    dfa->tables[YYTD_ID_EC]->td_lolen != 256)
+	if (tables[YYTD_ID_EC] && tables[YYTD_ID_EC]->td_lolen != 256)
 		goto out;
 
-	if (flags & DFA_FLAG_VERIFY_STATES) {
-		for (i = 0; i < state_count; i++) {
-			if (DEFAULT_TABLE(dfa)[i] >= state_count)
-				goto out;
-			if (base_idx(BASE_TABLE(dfa)[i]) + 255 >= trans_count) {
-				printk(KERN_ERR "AppArmor DFA next/check upper "
-				       "bounds error\n");
-				goto out;
-			}
+	error = 0;
+out:
+	return error;
+}
+
+/**
+ * verify_dfa - verify that transitions and states in the tables are in bounds.
+ * @dfa: dfa to test  (NOT NULL)
+ *
+ * Assumes dfa has gone through the first pass verification done by unpacking
+ * NOTE: this does not valid accept table values
+ *
+ * Returns: %0 else error code on failure to verify
+ */
+static int verify_dfa(struct aa_dfa *dfa)
+{
+	size_t i, state_count, trans_count;
+	int error = -EPROTO;
+
+	state_count = dfa->tables[YYTD_ID_BASE]->td_lolen;
+	trans_count = dfa->tables[YYTD_ID_NXT]->td_lolen;
+	for (i = 0; i < state_count; i++) {
+		if (!(BASE_TABLE(dfa)[i] & MATCH_FLAG_DIFF_ENCODE) &&
+		    (DEFAULT_TABLE(dfa)[i] >= state_count))
+			goto out;
+		if (base_idx(BASE_TABLE(dfa)[i]) + 255 >= trans_count) {
+			pr_err("AppArmor DFA next/check upper bounds error\n");
+			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)
+	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;
+	}
+
+	/* Now that all the other tables are verified, verify diffencoding */
+	for (i = 0; i < state_count; i++) {
+		size_t j, k;
+
+		for (j = i;
+		     (BASE_TABLE(dfa)[j] & MATCH_FLAG_DIFF_ENCODE) &&
+		     !(BASE_TABLE(dfa)[j] & MARK_DIFF_ENCODE);
+		     j = k) {
+			k = DEFAULT_TABLE(dfa)[j];
+			if (j == k)
 				goto out;
+			if (k < j)
+				break;		/* already verified */
+			BASE_TABLE(dfa)[j] |= MARK_DIFF_ENCODE;
 		}
 	}
-
 	error = 0;
+
 out:
 	return error;
 }
@@ -257,6 +308,9 @@ struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags)
 		goto fail;
 
 	dfa->flags = ntohs(*(__be16 *) (data + 12));
+	if (dfa->flags != 0 && dfa->flags != YYTH_FLAG_DIFF_ENCODE)
+		goto fail;
+
 	data += hsize;
 	size -= hsize;
 
@@ -299,11 +353,16 @@ struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags)
 		size -= table_size(table->td_lolen, table->td_flags);
 		table = NULL;
 	}
-
-	error = verify_dfa(dfa, flags);
+	error = verify_table_headers(dfa->tables, flags);
 	if (error)
 		goto fail;
 
+	if (flags & DFA_FLAG_VERIFY_STATES) {
+		error = verify_dfa(dfa);
+		if (error)
+			goto fail;
+	}
+
 	return dfa;
 
 fail:
@@ -312,6 +371,20 @@ fail:
 	return ERR_PTR(error);
 }
 
+#define match_char(state, def, base, next, check, C)	\
+do {							\
+	u32 b = (base)[(state)];			\
+	unsigned int pos = base_idx(b) + (C);		\
+	if ((check)[pos] != (state)) {			\
+		(state) = (def)[(state)];		\
+		if (b & MATCH_FLAG_DIFF_ENCODE)		\
+			continue;			\
+		break;					\
+	}						\
+	(state) = (next)[pos];				\
+	break;						\
+} while (1)
+
 /**
  * aa_dfa_match_len - traverse @dfa to find state @str stops at
  * @dfa: the dfa to match @str against  (NOT NULL)
@@ -335,6 +408,118 @@ unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start,
 	u32 *base = BASE_TABLE(dfa);
 	u16 *next = NEXT_TABLE(dfa);
 	u16 *check = CHECK_TABLE(dfa);
+	unsigned int state = start;
+
+	if (state == 0)
+		return 0;
+
+	/* current state is <state>, matching character *str */
+	if (dfa->tables[YYTD_ID_EC]) {
+		/* Equivalence class table defined */
+		u8 *equiv = EQUIV_TABLE(dfa);
+		for (; len; len--)
+			match_char(state, def, base, next, check,
+				   equiv[(u8) *str++]);
+	} else {
+		/* default is direct to next state */
+		for (; len; len--)
+			match_char(state, def, base, next, check, (u8) *str++);
+	}
+
+	return state;
+}
+
+/**
+ * aa_dfa_match - traverse @dfa to find state @str stops at
+ * @dfa: the dfa to match @str against  (NOT NULL)
+ * @start: the state of the dfa to start matching in
+ * @str: the null terminated string of bytes to match against the dfa (NOT NULL)
+ *
+ * aa_dfa_match will match @str against the dfa and return the state it
+ * finished matching in. The final state can be used to look up the accepting
+ * label, or as the start state of a continuing match.
+ *
+ * Returns: final state reached after input is consumed
+ */
+unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start,
+			  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 = start;
+
+	if (state == 0)
+		return 0;
+
+	/* current state is <state>, matching character *str */
+	if (dfa->tables[YYTD_ID_EC]) {
+		/* Equivalence class table defined */
+		u8 *equiv = EQUIV_TABLE(dfa);
+		/* default is direct to next state */
+		while (*str)
+			match_char(state, def, base, next, check,
+				   equiv[(u8) *str++]);
+	} else {
+		/* default is direct to next state */
+		while (*str)
+			match_char(state, def, base, next, check, (u8) *str++);
+	}
+
+	return state;
+}
+
+/**
+ * aa_dfa_next - step one character to the next state in the dfa
+ * @dfa: the dfa to tranverse (NOT NULL)
+ * @state: the state to start in
+ * @c: the input character to transition on
+ *
+ * aa_dfa_match will step through the dfa by one input character @c
+ *
+ * Returns: state reach after input @c
+ */
+unsigned int aa_dfa_next(struct aa_dfa *dfa, unsigned int state,
+			  const char c)
+{
+	u16 *def = DEFAULT_TABLE(dfa);
+	u32 *base = BASE_TABLE(dfa);
+	u16 *next = NEXT_TABLE(dfa);
+	u16 *check = CHECK_TABLE(dfa);
+
+	/* current state is <state>, matching character *str */
+	if (dfa->tables[YYTD_ID_EC]) {
+		/* Equivalence class table defined */
+		u8 *equiv = EQUIV_TABLE(dfa);
+		match_char(state, def, base, next, check, equiv[(u8) c]);
+	} else
+		match_char(state, def, base, next, check, (u8) c);
+
+	return state;
+}
+
+/**
+ * aa_dfa_match_until - traverse @dfa until accept state or end of input
+ * @dfa: the dfa to match @str against  (NOT NULL)
+ * @start: the state of the dfa to start matching in
+ * @str: the null terminated string of bytes to match against the dfa (NOT NULL)
+ * @retpos: first character in str after match OR end of string
+ *
+ * aa_dfa_match will match @str against the dfa and return the state it
+ * finished matching in. The final state can be used to look up the accepting
+ * label, or as the start state of a continuing match.
+ *
+ * Returns: final state reached after input is consumed
+ */
+unsigned int aa_dfa_match_until(struct aa_dfa *dfa, unsigned int start,
+				const char *str, const char **retpos)
+{
+	u16 *def = DEFAULT_TABLE(dfa);
+	u32 *base = BASE_TABLE(dfa);
+	u16 *next = NEXT_TABLE(dfa);
+	u16 *check = CHECK_TABLE(dfa);
+	u32 *accept = ACCEPT_TABLE(dfa);
 	unsigned int state = start, pos;
 
 	if (state == 0)
@@ -345,48 +530,60 @@ unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start,
 		/* Equivalence class table defined */
 		u8 *equiv = EQUIV_TABLE(dfa);
 		/* default is direct to next state */
-		for (; len; len--) {
+		while (*str) {
 			pos = base_idx(base[state]) + equiv[(u8) *str++];
 			if (check[pos] == state)
 				state = next[pos];
 			else
 				state = def[state];
+			if (accept[state])
+				break;
 		}
 	} else {
 		/* default is direct to next state */
-		for (; len; len--) {
+		while (*str) {
 			pos = base_idx(base[state]) + (u8) *str++;
 			if (check[pos] == state)
 				state = next[pos];
 			else
 				state = def[state];
+			if (accept[state])
+				break;
 		}
 	}
 
+	*retpos = str;
 	return state;
 }
 
 /**
- * aa_dfa_match - traverse @dfa to find state @str stops at
+ * aa_dfa_matchn_until - traverse @dfa until accept or @n bytes consumed
  * @dfa: the dfa to match @str against  (NOT NULL)
  * @start: the state of the dfa to start matching in
- * @str: the null terminated string of bytes to match against the dfa (NOT NULL)
+ * @str: the string of bytes to match against the dfa  (NOT NULL)
+ * @n: length of the string of bytes to match
+ * @retpos: first character in str after match OR str + n
  *
- * aa_dfa_match will match @str against the dfa and return the state it
+ * aa_dfa_match_len will match @str against the dfa and return the state it
  * finished matching in. The final state can be used to look up the accepting
  * label, or as the start state of a continuing match.
  *
+ * This function will happily match again the 0 byte and only finishes
+ * when @n input is consumed.
+ *
  * Returns: final state reached after input is consumed
  */
-unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start,
-			  const char *str)
+unsigned int aa_dfa_matchn_until(struct aa_dfa *dfa, unsigned int start,
+				 const char *str, int n, const char **retpos)
 {
 	u16 *def = DEFAULT_TABLE(dfa);
 	u32 *base = BASE_TABLE(dfa);
 	u16 *next = NEXT_TABLE(dfa);
 	u16 *check = CHECK_TABLE(dfa);
+	u32 *accept = ACCEPT_TABLE(dfa);
 	unsigned int state = start, pos;
 
+	*retpos = NULL;
 	if (state == 0)
 		return 0;
 
@@ -395,65 +592,149 @@ unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start,
 		/* Equivalence class table defined */
 		u8 *equiv = EQUIV_TABLE(dfa);
 		/* default is direct to next state */
-		while (*str) {
+		for (; n; n--) {
 			pos = base_idx(base[state]) + equiv[(u8) *str++];
 			if (check[pos] == state)
 				state = next[pos];
 			else
 				state = def[state];
+			if (accept[state])
+				break;
 		}
 	} else {
 		/* default is direct to next state */
-		while (*str) {
+		for (; n; n--) {
 			pos = base_idx(base[state]) + (u8) *str++;
 			if (check[pos] == state)
 				state = next[pos];
 			else
 				state = def[state];
+			if (accept[state])
+				break;
 		}
 	}
 
+	*retpos = str;
 	return state;
 }
 
-/**
- * aa_dfa_next - step one character to the next state in the dfa
- * @dfa: the dfa to tranverse (NOT NULL)
- * @state: the state to start in
- * @c: the input character to transition on
- *
- * aa_dfa_match will step through the dfa by one input character @c
- *
- * Returns: state reach after input @c
- */
-unsigned int aa_dfa_next(struct aa_dfa *dfa, unsigned int state,
-			  const char c)
+#define inc_wb_pos(wb)						\
+do {								\
+	wb->pos = (wb->pos + 1) & (wb->size - 1);		\
+	wb->len = (wb->len + 1) & (wb->size - 1);		\
+} while (0)
+
+/* For DFAs that don't support extended tagging of states */
+static bool is_loop(struct match_workbuf *wb, unsigned int state,
+		    unsigned int *adjust)
+{
+	unsigned int pos = wb->pos;
+	unsigned int i;
+
+	if (wb->history[pos] < state)
+		return false;
+
+	for (i = 0; i <= wb->len; i++) {
+		if (wb->history[pos] == state) {
+			*adjust = i;
+			return true;
+		}
+		if (pos == 0)
+			pos = wb->size;
+		pos--;
+	}
+
+	*adjust = i;
+	return true;
+}
+
+static unsigned int leftmatch_fb(struct aa_dfa *dfa, unsigned int start,
+				 const char *str, struct match_workbuf *wb,
+				 unsigned int *count)
 {
 	u16 *def = DEFAULT_TABLE(dfa);
 	u32 *base = BASE_TABLE(dfa);
 	u16 *next = NEXT_TABLE(dfa);
 	u16 *check = CHECK_TABLE(dfa);
-	unsigned int pos;
+	unsigned int state = start, pos;
+
+	AA_BUG(!dfa);
+	AA_BUG(!str);
+	AA_BUG(!wb);
+	AA_BUG(!count);
+
+	*count = 0;
+	if (state == 0)
+		return 0;
 
 	/* current state is <state>, matching character *str */
 	if (dfa->tables[YYTD_ID_EC]) {
 		/* Equivalence class table defined */
 		u8 *equiv = EQUIV_TABLE(dfa);
 		/* default is direct to next state */
+		while (*str) {
+			unsigned int adjust;
 
-		pos = base_idx(base[state]) + equiv[(u8) c];
-		if (check[pos] == state)
-			state = next[pos];
-		else
-			state = def[state];
+			wb->history[wb->pos] = state;
+			pos = base_idx(base[state]) + equiv[(u8) *str++];
+			if (check[pos] == state)
+				state = next[pos];
+			else
+				state = def[state];
+			if (is_loop(wb, state, &adjust)) {
+				state = aa_dfa_match(dfa, state, str);
+				*count -= adjust;
+				goto out;
+			}
+			inc_wb_pos(wb);
+			(*count)++;
+		}
 	} else {
 		/* default is direct to next state */
-		pos = base_idx(base[state]) + (u8) c;
-		if (check[pos] == state)
-			state = next[pos];
-		else
-			state = def[state];
+		while (*str) {
+			unsigned int adjust;
+
+			wb->history[wb->pos] = state;
+			pos = base_idx(base[state]) + (u8) *str++;
+			if (check[pos] == state)
+				state = next[pos];
+			else
+				state = def[state];
+			if (is_loop(wb, state, &adjust)) {
+				state = aa_dfa_match(dfa, state, str);
+				*count -= adjust;
+				goto out;
+			}
+			inc_wb_pos(wb);
+			(*count)++;
+		}
 	}
 
+out:
+	if (!state)
+		*count = 0;
 	return state;
 }
+
+/**
+ * aa_dfa_leftmatch - traverse @dfa to find state @str stops at
+ * @dfa: the dfa to match @str against  (NOT NULL)
+ * @start: the state of the dfa to start matching in
+ * @str: the null terminated string of bytes to match against the dfa (NOT NULL)
+ * @count: current count of longest left.
+ *
+ * aa_dfa_match will match @str against the dfa and return the state it
+ * finished matching in. The final state can be used to look up the accepting
+ * label, or as the start state of a continuing match.
+ *
+ * Returns: final state reached after input is consumed
+ */
+unsigned int aa_dfa_leftmatch(struct aa_dfa *dfa, unsigned int start,
+			      const char *str, unsigned int *count)
+{
+	DEFINE_MATCH_WB(wb);
+
+	/* TODO: match for extended state dfas */
+
+	return leftmatch_fb(dfa, start, str, &wb, count);
+}