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From: "Christian Göttsche" <cgzones@googlemail.com>
To: selinux@vger.kernel.org
Subject: [PATCH 02/12] libsepol: use string literals as format strings
Date: Fri, 12 Nov 2021 16:41:51 +0100	[thread overview]
Message-ID: <20211112154201.78217-2-cgzones@googlemail.com> (raw)
In-Reply-To: <20211112154201.78217-1-cgzones@googlemail.com>

Use string literals as format strings so that compilers can validate the
count and types of the inherent arguments.

    kernel_to_cil.c: In function ‘class_constraint_rules_to_strs’:
    kernel_to_cil.c:301:17: error: format not a string literal, argument types not checked [-Werror=format-nonliteral]
      301 |                 rc = strs_create_and_add(strs, format_str, 3, classkey, perms+1, expr);
          |                 ^~
    kernel_to_cil.c: In function ‘class_validatetrans_rules_to_strs’:
    kernel_to_cil.c:341:17: error: format not a string literal, argument types not checked [-Werror=format-nonliteral]
      341 |                 rc = strs_create_and_add(strs, format_str, 2, classkey, expr);
          |                 ^~
    kernel_to_cil.c: In function ‘cats_ebitmap_to_str’:
    kernel_to_cil.c:1068:40: error: format not a string literal, argument types not checked [-Werror=format-nonliteral]
     1068 |                                        val_to_name[start], val_to_name[i]);
          |                                        ^~~~~~~~~~~

    kernel_to_conf.c: In function ‘class_constraint_rules_to_strs’:
    kernel_to_conf.c:301:42: error: format not a string literal, argument types not checked [-Werror=format-nonliteral]
      301 |                                          flavor, classkey, perms+1, expr);
          |                                          ^~~~~~
    kernel_to_conf.c: In function ‘cats_ebitmap_to_str’:
    kernel_to_conf.c:1059:40: error: format not a string literal, argument types not checked [-Werror=format-nonliteral]
     1059 |                                        val_to_name[start], sep, val_to_name[i]);
          |                                        ^~~~~~~~~~~
    kernel_to_conf.c:1062:25: error: format not a string literal, argument types not checked [-Werror=format-nonliteral]
     1062 |                         len = snprintf(p, remaining, fmt, val_to_name[start]);
          |                         ^~~

    module_to_cil.c: In function ‘cond_expr_to_cil’:
    module_to_cil.c:1340:25: error: format not a string literal, argument types not checked [-Werror=format-nonliteral]
     1340 |                         rlen = snprintf(new_val, len, fmt_str, op, val1, val2);
          |                         ^~~~
    module_to_cil.c: In function ‘constraint_expr_to_string’:
    module_to_cil.c:1881:25: error: format not a string literal, argument types not checked [-Werror=format-nonliteral]
     1881 |                         rlen = snprintf(new_val, len, fmt_str, op, val1, val2);
          |                         ^~~~

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
---
 libsepol/src/kernel_to_cil.c  | 29 +++++++++++++++++------------
 libsepol/src/kernel_to_conf.c | 23 +++++++++++++----------
 libsepol/src/module_to_cil.c  | 22 ++++++++--------------
 3 files changed, 38 insertions(+), 36 deletions(-)

diff --git a/libsepol/src/kernel_to_cil.c b/libsepol/src/kernel_to_cil.c
index 305567a5..b81cdb22 100644
--- a/libsepol/src/kernel_to_cil.c
+++ b/libsepol/src/kernel_to_cil.c
@@ -278,7 +278,7 @@ static int class_constraint_rules_to_strs(struct policydb *pdb, char *classkey,
 	char *expr = NULL;
 	int is_mls;
 	char *perms;
-	const char *format_str;
+	const char *key_word;
 	struct strs *strs;
 
 	for (curr = constraint_rules; curr != NULL; curr = curr->next) {
@@ -291,14 +291,14 @@ static int class_constraint_rules_to_strs(struct policydb *pdb, char *classkey,
 		perms = sepol_av_to_string(pdb, class->s.value, curr->permissions);
 
 		if (is_mls) {
-			format_str = "(mlsconstrain (%s (%s)) %s)";
+			key_word = "mlsconstrain";
 			strs = mls_list;
 		} else {
-			format_str = "(constrain (%s (%s)) %s)";
+			key_word = "constrain";
 			strs = non_mls_list;
 		}
 
-		rc = strs_create_and_add(strs, format_str, 3, classkey, perms+1, expr);
+		rc = strs_create_and_add(strs, "(%s (%s (%s)) %s)", 4, key_word, classkey, perms+1, expr);
 		free(expr);
 		if (rc != 0) {
 			goto exit;
@@ -319,7 +319,7 @@ static int class_validatetrans_rules_to_strs(struct policydb *pdb, char *classke
 	struct constraint_node *curr;
 	char *expr = NULL;
 	int is_mls;
-	const char *format_str;
+	const char *key_word;
 	struct strs *strs;
 	int rc = 0;
 
@@ -331,14 +331,14 @@ static int class_validatetrans_rules_to_strs(struct policydb *pdb, char *classke
 		}
 
 		if (is_mls) {
-			format_str = "(mlsvalidatetrans %s %s)";
+			key_word = "mlsvalidatetrans";
 			strs = mls_list;
 		} else {
-			format_str = "(validatetrans %s %s)";
+			key_word = "validatetrans";
 			strs = non_mls_list;
 		}
 
-		rc = strs_create_and_add(strs, format_str, 2, classkey, expr);
+		rc = strs_create_and_add(strs, "(%s %s %s)", 3, key_word, classkey, expr);
 		free(expr);
 		if (rc != 0) {
 			goto exit;
@@ -1035,7 +1035,6 @@ static char *cats_ebitmap_to_str(struct ebitmap *cats, char **val_to_name)
 	struct ebitmap_node *node;
 	uint32_t i, start, range;
 	char *catsbuf = NULL, *p;
-	const char *fmt;
 	int len, remaining;
 
 	remaining = (int)cats_ebitmap_len(cats, val_to_name);
@@ -1063,9 +1062,15 @@ static char *cats_ebitmap_to_str(struct ebitmap *cats, char **val_to_name)
 			continue;
 
 		if (range > 1) {
-			fmt = (range == 2) ? "%s %s " : "(range %s %s) ";
-			len = snprintf(p, remaining, fmt,
-				       val_to_name[start], val_to_name[i]);
+			if (range == 2) {
+				len = snprintf(p, remaining, "%s %s ",
+					       val_to_name[start],
+					       val_to_name[i]);
+			} else {
+				len = snprintf(p, remaining, "(range %s %s) ",
+					       val_to_name[start],
+					       val_to_name[i]);
+			}
 		} else {
 			len = snprintf(p, remaining, "%s ", val_to_name[start]);
 		}
diff --git a/libsepol/src/kernel_to_conf.c b/libsepol/src/kernel_to_conf.c
index eb72e4ac..460209c8 100644
--- a/libsepol/src/kernel_to_conf.c
+++ b/libsepol/src/kernel_to_conf.c
@@ -271,7 +271,7 @@ static int class_constraint_rules_to_strs(struct policydb *pdb, char *classkey,
 {
 	struct constraint_node *curr;
 	struct strs *strs;
-	const char *format_str, *flavor;
+	const char *flavor, *perm_prefix, *perm_suffix;
 	char *perms, *expr;
 	int is_mls;
 	int rc = 0;
@@ -285,9 +285,11 @@ static int class_constraint_rules_to_strs(struct policydb *pdb, char *classkey,
 
 		perms = sepol_av_to_string(pdb, class->s.value, curr->permissions);
 		if (strchr(perms, ' ')) {
-			format_str = "%s %s { %s } %s;";
+			perm_prefix = "{ ";
+			perm_suffix = " }";
 		} else {
-			format_str = "%s %s %s %s";
+			perm_prefix = "";
+			perm_suffix = "";
 		}
 		if (is_mls) {
 			flavor = "mlsconstrain";
@@ -297,8 +299,10 @@ static int class_constraint_rules_to_strs(struct policydb *pdb, char *classkey,
 			strs = non_mls_list;
 		}
 
-		rc = strs_create_and_add(strs, format_str, 4,
-					 flavor, classkey, perms+1, expr);
+		rc = strs_create_and_add(strs, "%s %s %s%s%s %s;", 6,
+					 flavor, classkey,
+					 perm_prefix, perms+1, perm_suffix,
+					 expr);
 		free(expr);
 		if (rc != 0) {
 			goto exit;
@@ -1026,7 +1030,6 @@ static char *cats_ebitmap_to_str(struct ebitmap *cats, char **val_to_name)
 	struct ebitmap_node *node;
 	uint32_t i, start, range, first;
 	char *catsbuf = NULL, *p;
-	const char *fmt;
 	char sep;
 	int len, remaining;
 
@@ -1054,12 +1057,12 @@ static char *cats_ebitmap_to_str(struct ebitmap *cats, char **val_to_name)
 
 		if (range > 1) {
 			sep = (range == 2) ? ',' : '.';
-			fmt = first ? "%s%c%s" : ",%s%c%s";
-			len = snprintf(p, remaining, fmt,
+			len = snprintf(p, remaining, "%s%s%c%s",
+				       first ? "" : ",",
 				       val_to_name[start], sep, val_to_name[i]);
 		} else {
-			fmt = first ? "%s" : ",%s";
-			len = snprintf(p, remaining, fmt, val_to_name[start]);
+			len = snprintf(p, remaining, "%s%s", first ? "" : ",",
+				       val_to_name[start]);
 
 		}
 		if (len < 0 || len >= remaining) {
diff --git a/libsepol/src/module_to_cil.c b/libsepol/src/module_to_cil.c
index 16e4004e..b231d7f8 100644
--- a/libsepol/src/module_to_cil.c
+++ b/libsepol/src/module_to_cil.c
@@ -1259,7 +1259,7 @@ static int cond_expr_to_cil(int indent, struct policydb *pdb, struct cond_expr *
 	char *val2 = NULL;
 	unsigned int num_params;
 	const char *op;
-	const char *fmt_str;
+	const char *sep;
 	const char *type;
 
 	rc = stack_init(&stack);
@@ -1308,11 +1308,11 @@ static int cond_expr_to_cil(int indent, struct policydb *pdb, struct cond_expr *
 					rc = -1;
 					goto exit;
 				}
-				fmt_str = "(%s %s)";
+				sep = "";
 			} else {
 				val2 = stack_pop(stack);
 				val1 = stack_pop(stack);
-				fmt_str = "(%s %s %s)";
+				sep = " ";
 			}
 
 			if (val1 == NULL || val2 == NULL) {
@@ -1334,10 +1334,7 @@ static int cond_expr_to_cil(int indent, struct policydb *pdb, struct cond_expr *
 				goto exit;
 			}
 
-			// although we always supply val2 and there isn't always a 2nd
-			// value, it should only be used when there are actually two values
-			// in the format strings
-			rlen = snprintf(new_val, len, fmt_str, op, val1, val2);
+			rlen = snprintf(new_val, len, "(%s %s%s%s)", op, val1, sep, val2);
 			if (rlen < 0 || rlen >= len) {
 				log_err("Failed to generate conditional expression");
 				rc = -1;
@@ -1711,7 +1708,7 @@ static int constraint_expr_to_string(struct policydb *pdb, struct constraint_exp
 	char *val2 = NULL;
 	uint32_t num_params;
 	const char *op;
-	const char *fmt_str;
+	const char *sep;
 	const char *attr1;
 	const char *attr2;
 	char *names = NULL;
@@ -1849,11 +1846,11 @@ static int constraint_expr_to_string(struct policydb *pdb, struct constraint_exp
 					rc = -1;
 					goto exit;
 				}
-				fmt_str = "(%s %s)";
+				sep = "";
 			} else {
 				val2 = stack_pop(stack);
 				val1 = stack_pop(stack);
-				fmt_str = "(%s %s %s)";
+				sep = " ";
 			}
 
 			if (val1 == NULL || val2 == NULL) {
@@ -1875,10 +1872,7 @@ static int constraint_expr_to_string(struct policydb *pdb, struct constraint_exp
 				goto exit;
 			}
 
-			// although we always supply val2 and there isn't always a 2nd
-			// value, it should only be used when there are actually two values
-			// in the format strings
-			rlen = snprintf(new_val, len, fmt_str, op, val1, val2);
+			rlen = snprintf(new_val, len, "(%s %s%s%s)", op, val1, sep, val2);
 			if (rlen < 0 || rlen >= len) {
 				log_err("Failed to generate constraint expression");
 				rc = -1;
-- 
2.33.1


  reply	other threads:[~2021-11-12 15:42 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-12 15:41 [PATCH 01/12] checkpolicy: use correct unsigned format specifiers Christian Göttsche
2021-11-12 15:41 ` Christian Göttsche [this message]
2021-11-12 15:41 ` [PATCH 03/12] policycoreutils: use string literal as format strings Christian Göttsche
2021-11-12 15:41 ` [PATCH 04/12] Enable extra global compiler warnings Christian Göttsche
2021-11-12 15:41 ` [PATCH 05/12] checkpolicy: ignore possible string truncation Christian Göttsche
2021-11-12 15:41 ` [PATCH 06/12] policycoreutils: mark local functions static Christian Göttsche
2021-11-12 15:41 ` [PATCH 07/12] sandbox: " Christian Göttsche
2021-11-12 15:41 ` [PATCH 08/12] python: " Christian Göttsche
2021-11-12 15:41 ` [PATCH 09/12] mcstrans: avoid missing prototypes Christian Göttsche
2021-11-12 15:41 ` [PATCH 10/12] libsemanage: mark local functions static Christian Göttsche
2021-11-12 15:42 ` [PATCH 11/12] libsemanage: include paired header for prototypes Christian Göttsche
2021-11-12 15:42 ` [PATCH 12/12] libsemanage: add extern prototype for legacy function Christian Göttsche
2021-11-15 21:48 ` [PATCH 01/12] checkpolicy: use correct unsigned format specifiers James Carter
2021-11-18 16:17   ` James Carter

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