utils-std

commit: 83a9997e35618e884044c769960a794986990cf3
parent 436a3dd3efeb509446a7ea27cb26cdbb5fd42382
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Thu, 11 Apr 2024 10:02:22 +0200

cmd/mkdir: Fix TOCTOU issues with -p

For once flawfinder was right…

Diffstat:
M
cmd/mkdir.c
83
+++++++++++++++++++++++++++++++++++++++++++++++++------------------------------

1 file changed, 52 insertions(+), 31 deletions(-)
diff --git a/cmd/mkdir.c b/cmd/mkdir.c
@@ -16,50 +16,62 @@
 #include <sys/stat.h> // mkdir
 #include <unistd.h>   // getopt
 
-bool parents = false, verbose = false;
+bool verbose = false;
 mode_t filemask;
 
 static int
-do_mkdir(char *path, mode_t mode)
+mkdir_simple(char *path, mode_t mode)
 {
-	for(int i = strlen(path) - 1; i >= 0; i--)
+	assert(errno == 0);
+	if(mkdir(path, mode) < 0)
 	{
-		if(path[i] != '/')
-			break;
-		else
-			path[i] = 0;
+		fprintf(stderr, "mkdir: Failed making directory '%s': %s\n", path, strerror(errno));
+		errno = 0;
+		return -1;
 	}
 
-	if(parents)
+	if(verbose) fprintf(stderr, "mkdir: Made directory: %s\n", path);
+
+	return 0;
+}
+
+static int
+mkdir_parents(char *path, mode_t mode)
+{
+	assert(errno == 0);
+
+	for(int i = strlen(path) - 1; i >= 0; i--)
 	{
-		assert(errno == 0);
-		/* flawfinder: ignore */
-		if(access(path, F_OK) == 0) return 0;
+		if(path[i] != '/') break;
 
-		errno = 0;
+		path[i] = 0;
+	}
 
-		char parent[PATH_MAX] = "";
-		strncpy(parent, path, PATH_MAX);
+	char parent[PATH_MAX] = "";
+	strncpy(parent, path, PATH_MAX);
 
-		for(int i = strlen(parent)-1; i >= 0; i--)
-		{
-			char c    = parent[i];
-			parent[i] = 0;
-			if(c == '/') break;
-		}
+	for(int i = strlen(parent) - 1; i >= 0; i--)
+	{
+		if(parent[i] == '/') break;
 
-		/* flawfinder: ignore */
-		if(parent[0] != 0 && access(parent, F_OK) != 0)
-		{
-			errno              = 0;
-			mode_t parent_mode = (S_IWUSR | S_IXUSR | ~filemask) & 0777;
-			if(do_mkdir(parent, parent_mode) < 0) return -1;
-		}
+		parent[i] = 0;
 	}
 
+	if(path[0] == 0) return 0;
+
+	mode_t parent_mode = (S_IWUSR | S_IXUSR | ~filemask) & 0777;
+
+	if(mkdir_parents(parent, parent_mode) < 0) return -1;
+
 	assert(errno == 0);
 	if(mkdir(path, mode) < 0)
 	{
+		if(errno == EEXIST)
+		{
+			errno = 0;
+			return 0;
+		}
+
 		fprintf(stderr, "mkdir: Failed making directory '%s': %s\n", path, strerror(errno));
 		errno = 0;
 		return -1;
@@ -79,20 +91,22 @@ usage()
 int
 main(int argc, char *argv[])
 {
+	// clang-format off
+	mode_t mode = (S_IRWXU | S_IRWXG | S_IRWXO | ~filemask) & 0777;
+	bool opt_p = false;
 	const char *errstr = NULL;
+	// clang-format on
 
 	filemask = umask(0);
 	umask(filemask);
 
-	mode_t mode = (S_IRWXU | S_IRWXG | S_IRWXO | ~filemask) & 0777;
-
 	int c = -1;
 	while((c = getopt(argc, argv, ":pvm:")) != -1)
 	{
 		switch(c)
 		{
 		case 'p':
-			parents = true;
+			opt_p = true;
 			break;
 		case 'v':
 			verbose = true;
@@ -132,7 +146,14 @@ main(int argc, char *argv[])
 
 	for(int i = 0; i < argc; i++)
 	{
-		if(do_mkdir(argv[i], mode) < 0) return 1;
+		int ret = 0;
+
+		if(opt_p)
+			ret = mkdir_parents(argv[i], mode);
+		else
+			ret = mkdir_simple(argv[i], mode);
+
+		if(ret < 0) return 1;
 	}
 
 	return 0;