WIP cleanup

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

util/nvmutil/include/common.h

@@ -324,6 +324,12 @@ size_t conv_argv_part_num(const char *part_str);
  */
 
 void open_gbe_file(void);
+int fd_verify_regular(int fd,
+    const struct stat *expected,
+    struct stat *out);
+int fd_verify_identity(int fd,
+    const struct stat *expected,
+    struct stat *out);
 int is_owner(struct stat *st);
 int lock_file(int fd, int flags);
 int same_file(int fd, struct stat *st_old, int check_size);

util/nvmutil/lib/file.c

@@ -56,13 +56,8 @@ same_file(int fd, struct stat *st_old,
 	if (fstat(fd, &st) == -1)
 		goto err_same_file;
 
-	if (st.st_dev != st_old->st_dev ||
-	    st.st_ino != st_old->st_ino ||
-	    !S_ISREG(st.st_mode)) {
-
-		errno = ESTALE;
+	if (fd_verify_regular(fd, st_old, &st) < 0)
 		goto err_same_file;
-	}
 
 	if (check_size &&
 	    st.st_size != st_old->st_size)
@@ -90,6 +85,17 @@ err_same_file:
 	make it return, and handle the return value/errno
 
 	(this could return e.g. EINTR)
+
+  TODO: this function is not used by mkhtemp, nor will
+       it probably be, it's currently used by nvmutil,
+	for opening intel gbe nvm config files. i can
+      probably remove it though and unify witth some
+      of the verification code now used for mkhtemp
+
+TODO: and don't abort. return -1. and handle in the caller.
+
+minor obstacle: the mkhtemp code always requires absolute
+paths, whereas the gbe editor takes relative paths.
  */
 void
 xopen(int *fd_ptr, const char *path, int flags, struct stat *st)
@@ -259,15 +265,12 @@ new_tmpfile(int *fd, char **path)
 
 	size_t dirlen;
 	size_t destlen;
-	size_t baselen;
 	char *dest = NULL; /* final path */
 	int saved_errno = errno;
 	int dirfd = -1;
 	const char *fname = NULL;
 
 	struct stat st_dir_initial;
-	char *dir = NULL;
-	char *base = NULL;
 
 	if (path == NULL || fd == NULL) {
 		errno = EFAULT;
@@ -294,6 +297,10 @@ new_tmpfile(int *fd, char **path)
 
 	if (slen(tmpdir, maxlen, &dirlen) < 0)
 		goto err_new_tmpfile;
+	if (*tmpdir == '\0')
+		goto err_new_tmpfile;
+	if (*tmpdir != '/')
+		goto err_new_tmpfile;
 
 	/* using sizeof (not slen) adds an extra byte,
 	 * useful because we either want '.' or '/'
@@ -336,10 +343,6 @@ new_tmpfile(int *fd, char **path)
 		(void) close_on_eintr(dirfd);
 		dirfd = -1;
 	}
-	if (dir != NULL) {
-		free(dir);
-		dir = NULL;
-	}
 
 	errno = saved_errno;
 
@@ -371,11 +374,6 @@ err_new_tmpfile:
 		*fd = -1;
 	}
 
-	if (dir != NULL) {
-		free(dir);
-		dir = NULL;
-	}
-
 	errno = saved_errno;
 
 	return -1;
@@ -694,6 +692,7 @@ mkhtemp(int *fd,
 	size_t max_len = 4096;
 #endif
 	int r;
+	char *end;
 
 	if (fd == NULL ||
 	    template == NULL ||
@@ -736,14 +735,11 @@ mkhtemp(int *fd,
 	}
 
 	/* count trailing X */
-	{
-		char *end = template + len;
+	end = template + len;
+	while (end > template && *--end == 'X')
+		xc++;
 
-		while (end > template && *--end == 'X')
-			xc++;
-	}
-
-	if (xc < 6 || xc > len) {
+	if (xc < 12 || xc > len) {
 		errno = EINVAL;
 		return -1;
 	}
@@ -784,9 +780,11 @@ mkhtemp(int *fd,
 		    fd,
 		    st);
 
-		/* DoS mitigation; add jitter delay (0–1023 µs) */
-		if (r != 1 && retries >= MKHTEMP_SPIN_THRESHOLD)
-			usleep((useconds_t)rlong() & 0x3FF);
+		if (r != 1) {
+			if (retries >= MKHTEMP_SPIN_THRESHOLD)
+				usleep((useconds_t)rlong() & 0x3FF);
+			continue;
+		}
 
 		/* success: copy final name back */
 		memcpy(template + len - fname_len,
@@ -825,17 +823,18 @@ mkhtemp_try_create(int dirfd,
 	struct stat st_open;
 	int saved_errno = errno;
 	int close_errno;
+	int rval = -1;
 
 	if (mkhtemp_fill_random(p, xc) < 0)
-		return -1;
+		goto err;
 
 	if (fstat(dirfd, &st_dir_now) < 0)
-		return -1;
+		goto err;
 
 	if (st_dir_now.st_dev != st_dir_initial->st_dev ||
 	    st_dir_now.st_ino != st_dir_initial->st_ino) {
 		errno = ESTALE;
-		return -1;
+		goto err;
 	}
 
 	*fd = openat2p(dirfd, fname_copy,
@@ -843,40 +842,53 @@ mkhtemp_try_create(int dirfd,
 	    O_NOFOLLOW | O_CLOEXEC | O_NOCTTY,
 	    0600);
 
-	if (*fd >= 0) {
+	if (*fd < 0) {
+		if (errno == EEXIST ||
+		    errno == EINTR ||
+		    errno == EAGAIN ||
+		    errno == EWOULDBLOCK ||
+		    errno == ETXTBSY) {
 
-		if (fstat(*fd, &st_open) < 0)
-			return -1;
-
-		if (fstat(dirfd, &st_dir_now) < 0)
-			return -1;
-
-		if (st_dir_now.st_dev != st_dir_initial->st_dev ||
-		    st_dir_now.st_ino != st_dir_initial->st_ino) {
-
-			close_errno = errno;
-			(void) close_on_eintr(*fd);
-			errno = close_errno;
-
-			errno = ESTALE;
-			return -1;
+			rval = 0;
+			goto out;
 		}
-
-		if (secure_file(fd, st, &st_open, O_APPEND, 1, 1, 0600) < 0)
-			return -1;
-
-		errno = saved_errno;
-		return 1; /* success */
+		goto err;
 	}
 
-	if (errno == EEXIST ||
-	    errno == EINTR ||
-	    errno == EAGAIN ||
-	    errno == EWOULDBLOCK ||
-	    errno == ETXTBSY)
-		return 0; /* retry */
+	/* fd is now live */
 
-	return -1; /* fatal */
+	if (fstat(*fd, &st_open) < 0)
+		goto err;
+
+	if (fstat(dirfd, &st_dir_now) < 0)
+		goto err;
+
+	if (st_dir_now.st_dev != st_dir_initial->st_dev ||
+	    st_dir_now.st_ino != st_dir_initial->st_ino) {
+		errno = ESTALE;
+		goto err;
+	}
+
+	if (secure_file(fd, st, &st_open,
+	    O_APPEND, 1, 1, 0600) < 0)
+		goto err;
+
+	errno = saved_errno;
+	rval = 1;
+	goto out;
+
+err:
+	close_errno = errno;
+
+	if (fd != NULL && *fd >= 0) {
+		(void) close_on_eintr(*fd);
+		*fd = -1;
+	}
+
+	errno = close_errno;
+	rval = -1;
+out:
+	return rval;
 }
 
 int
@@ -985,21 +997,17 @@ int secure_file(int *fd,
 		}
 	}
 
-	if (fstat(*fd, st) == -1)
+	if (fstat(*fd, &st_now) == -1)
 		goto err_secure_file;
 
-	/* verify inode/device stability */
 	if (expected != NULL) {
-
 		if (st_now.st_dev != expected->st_dev ||
-			st_now.st_ino != expected->st_ino) {
-
+		    st_now.st_ino != expected->st_ino) {
 			errno = ESTALE;
 			goto err_secure_file;
 		}
 	}
 
-	/* now copy to caller */
 	*st = st_now;
 
 	if (!S_ISREG(st->st_mode)) {
@@ -1007,6 +1015,9 @@ int secure_file(int *fd,
 		goto err_secure_file;
 	}
 
+	if (fd_verify_regular(*fd, expected, st) < 0)
+		goto err_secure_file;
+
 	if (check_seek) {
 
 		/* check if it's seekable */
@@ -1057,6 +1068,51 @@ err_secure_file:
 	return -1;
 }
 
+int
+fd_verify_regular(int fd,
+    const struct stat *expected,
+    struct stat *out)
+{
+	if (fd_verify_identity(fd, expected, out) < 0)
+		return -1;
+
+	if (!S_ISREG(out->st_mode)) {
+		errno = EBADF;
+		return -1;
+	}
+
+	return 0; /* regular file */
+}
+
+int
+fd_verify_identity(int fd,
+    const struct stat *expected,
+    struct stat *out)
+{
+	struct stat st_now;
+	int saved_errno = errno;
+
+	if (fd < 0 || expected == NULL) {
+		errno = EFAULT;
+		return -1;
+	}
+
+	if (fstat(fd, &st_now) < 0)
+		return -1;
+
+	if (st_now.st_dev != expected->st_dev ||
+	    st_now.st_ino != expected->st_ino) {
+		errno = ESTALE;
+		return -1;
+	}
+
+	if (out != NULL)
+		*out = st_now;
+
+	errno = saved_errno;
+	return 0;
+}
+
 int
 is_owner(struct stat *st)
 {
@@ -1812,7 +1868,7 @@ fs_open(const char *path, int flags)
 	}
 
 	fs = rootfs();
-	if (!fs)
+	if (fs == NULL)
 		return -1;
 
 	rel = path + 1;