From: Michael Tremer <michael.tremer@ipfire.org>
Date: Wed, 6 Jan 2021 11:34:31 +0000 (+0000)
Subject: misc-progs: Add functions to sanitise input arguments
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=db984059b22a4680046df31579b44fa05c8264d5;p=people%2Fms%2Fipfire-2.x.git

misc-progs: Add functions to sanitise input arguments

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---

diff --git a/src/misc-progs/setuid.c b/src/misc-progs/setuid.c
index 6637d3e6fc..efd181ad8c 100644
--- a/src/misc-progs/setuid.c
+++ b/src/misc-progs/setuid.c
@@ -199,3 +199,42 @@ int initsetuid(void) {
 
 	return 1;
 }
+
+/* Checks if a string only contains alphanumerical characters, dash or underscore */
+int is_valid_argument_alnum(const char* arg) {
+	size_t l = strlen(arg);
+
+	for (unsigned int i = 0; i < l; i++) {
+		char c = arg[i];
+
+		// Dash or underscore
+		if (c == '-' || c == '_')
+			continue;
+
+		// Any alphanumerical character
+		if (isalnum(c))
+			continue;
+
+		// Invalid
+		return 0;
+	}
+
+	return 1;
+}
+
+int is_valid_argument_num(const char* arg) {
+	size_t l = strlen(arg);
+
+	for (unsigned int i = 0; i < l; i++) {
+		char c = arg[i];
+
+		// Any digit
+		if (isdigit(c))
+			continue;
+
+		// Invalid
+		return 0;
+	}
+
+	return 1;
+}
diff --git a/src/misc-progs/setuid.h b/src/misc-progs/setuid.h
index aa265a52f7..2936c43997 100644
--- a/src/misc-progs/setuid.h
+++ b/src/misc-progs/setuid.h
@@ -33,6 +33,9 @@ int safe_system(char* command);
 int unpriv_system(char* command, uid_t uid, gid_t gid);
 int initsetuid(void);
 
+int is_valid_argument_alnum(const char* arg);
+int is_valid_argument_num(const char* arg);
+
 /* Compatibility for the local copy of strlcat,
  * which has been removed. */
 #define strlcat(src, dst, size) strncat(src, dst, size)