mkhtemp: PROPER fd leak/overwrite fix

now this code should be stable. no leaks.

yes. hardened mkhtemp. oh yeah mate.

now all i need is a main() and a getopt
loop, and pledge, unveil, and blackjack,
and something dubious of a titilating
nature.

Signed-off-by: Leah Rowe <leah@libreboot.org>

2 files changed, 17 insertions, 43 deletions

diff --git a/util/nvmutil/lib/file.c b/util/nvmutil/lib/file.c
index c20165d1..786c51fb 100644
--- a/util/nvmutil/lib/file.c
+++ b/util/nvmutil/lib/file.c
@@ -1997,25 +1997,22 @@ int
 fs_resolve_at(int dirfd, const char *path, int flags)
 {
 	int nextfd = -1;
+	int curfd;
 	const char *p;
-	char name[256]; /* TODO: make configurable */
+	char name[256];
 	int saved_errno = errno;
-	int saved_close_errno;
 	int r;
 	int is_last;
 
-	if (dirfd < 0 ||
-	    path == NULL ||
-	    *path == '\0') {
-
+	if (dirfd < 0 || path == NULL || *path == '\0') {
 		errno = EINVAL;
 		return -1;
 	}
 
 	p = path;
+	curfd = dirfd; /* start here */
 
 	for (;;) {
-
 		r = fs_next_component(&p, name, sizeof(name));
 		if (r < 0)
 			goto err;
@@ -2024,55 +2021,32 @@ fs_resolve_at(int dirfd, const char *path, int flags)
 
 		is_last = (*p == '\0');
 
-		nextfd = fs_open_component(dirfd,
-		    name, flags, is_last);
+		nextfd = fs_open_component(curfd, name, flags, is_last);
 		if (nextfd < 0)
 			goto err;
 
-/*
-don't close fd.
-it's used next by a few functions.
-this results in a fd leak, but
-makes the code work:
-in practise, your program
-will free all descriptors
-on exit
-
-what we need to do is figure out a proper
-system of storing descriptors,
-and freeing them when it's safe;
-see how this function is called
-and whatt calls those and you see what i mean
-
-who owns what is currently not consistent.
-needs rework.
-
-this will be fixed at a later date.
-justt leaving thtis in here for future me.
-
-with this uncommented, i always just get
-"Bad file descriptor" error:
-
-		saved_close_errno = errno;
-		(void) close_on_eintr(dirfd);
-		errno = saved_close_errno;
-*/
+		/* close previous fd IF it is not the original input */
+		if (curfd != dirfd) {
+			(void) close_on_eintr(curfd);
+		}
 
-		dirfd = nextfd;
+		curfd = nextfd;
 		nextfd = -1;
 	}
 
 	errno = saved_errno;
-	return dirfd;
+	return curfd;
 
 err:
 	saved_errno = errno;
 
-	if (dirfd >= 0)
-		(void) close_on_eintr(dirfd);
 	if (nextfd >= 0)
 		(void) close_on_eintr(nextfd);
 
+	/* close curfd only if it's not the original */
+	if (curfd != dirfd && curfd >= 0)
+		(void) close_on_eintr(curfd);
+
 	errno = saved_errno;
 	return -1;
 }
diff --git a/util/nvmutil/nvmutil.c b/util/nvmutil/nvmutil.c
index b4715e5b..266654e8 100644
--- a/util/nvmutil/nvmutil.c
+++ b/util/nvmutil/nvmutil.c
@@ -38,11 +38,11 @@ main(int argc, char *argv[])
 	int rval;
 	char *test = NULL;
 	int fd = -1;
-	rval = new_tmpfile(&fd, &test);
+	rval = new_tmpdir(&fd, &test);
 	if (rval < 0)
 		err_no_cleanup(errno, "TESTERR: ");
 
-	printf("TEST: %s", test);
+	printf("TEST: %s\n", test);
 	exit(1);
 
 /* https://man.openbsd.org/pledge.2