Extend is_filename_sane reserved character/name check

 - Instead of an open coded version, check against a
   list of bad names. On windows, the comparison needs
   to be done case insensitive.
 - If compiling for Windows, include the magic DOS
   device names in that list.
 - Also classify filenames as 'insane' if they contain
   back slashes, on all platforms.
 - If compiling for Windows, check for reserved characters.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 43 insertions, 4 deletions

diff --git a/lib/common/filename_sane.c b/lib/common/filename_sane.c
index 6b497c3..d089ba4 100644
--- a/lib/common/filename_sane.c
+++ b/lib/common/filename_sane.c
@@ -6,19 +6,58 @@
  */
 #include "common.h"
 
+#include <string.h>
+
+#ifdef _MSC_VER
+#define strncasecmp _strnicmp
+#define strcasecmp _stricmp
+#endif
+
+static const char *bad_names[] = {
+	".",
+	"..",
+#ifdef _WIN32
+	"CON", "PRN", "AUX", "NUL",
+	"COM1", "COM2", "COM3", "COM4", "COM5", "COM6", "COM7", "COM8", "COM9",
+	"LPT1", "LPT2", "LPT3", "LPT4", "LPT5", "LPT6", "LPT7", "LPT8", "LPT9",
+#endif
+};
+
 bool is_filename_sane(const char *name)
 {
-	if (name[0] == '.') {
-		if (name[1] == '\0')
+	size_t i = 0;
+
+	for (i = 0; i < sizeof(bad_names) / sizeof(bad_names[0]); ++i) {
+#ifdef _WIN32
+		size_t len = strlen(bad_names[i]);
+
+		if (strncasecmp(name, bad_names[i], len) != 0)
+			continue;
+
+		if (name[len] == '\0')
 			return false;
 
-		if (name[1] == '.' && name[2] == '\0')
+		if (name[len] == '.' && strchr(name + len + 1, '.') == NULL)
 			return false;
+#else
+		if (strcmp(name, bad_names[i]) == 0)
+			return false;
+#endif
 	}
 
 	while (*name != '\0') {
-		if (*name == '/')
+		if (*name == '/' || *name == '\\')
+			return false;
+
+#ifdef _WIN32
+		if (*name == '<' || *name == '>' || *name == ':')
 			return false;
+		if (*name == '"' || *name == '|' || *name == '?')
+			return false;
+		if (*name == '*' || *name <= 31)
+			return false;
+#endif
+
 		++name;
 	}