WIP identity check unification

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

2 files changed, 36 insertions, 18 deletions

diff --git a/util/nvmutil/include/common.h b/util/nvmutil/include/common.h
index 6ae7af04..0fedeedd 100644
--- a/util/nvmutil/include/common.h
+++ b/util/nvmutil/include/common.h
@@ -330,6 +330,8 @@ int fd_verify_regular(int fd,
 int fd_verify_identity(int fd,
     const struct stat *expected,
     struct stat *out);
+int fd_verify_dir_identity(int fd,
+    const struct stat *expected);
 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);
diff --git a/util/nvmutil/lib/file.c b/util/nvmutil/lib/file.c
index a4ce7b89..f0cb5ad4 100644
--- a/util/nvmutil/lib/file.c
+++ b/util/nvmutil/lib/file.c
@@ -831,11 +831,8 @@ mkhtemp_try_create(int dirfd,
 	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;
+	if (fd_verify_dir_identity(dirfd, st_dir_initial) < 0)
 		goto err;
-	}
 
 	*fd = openat2p(dirfd, fname_copy,
 	    O_RDWR | O_CREAT | O_EXCL |
@@ -860,14 +857,8 @@ mkhtemp_try_create(int dirfd,
 	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;
+	if (fd_verify_dir_identity(dirfd, st_dir_initial) < 0)
 		goto err;
-	}
 
 	if (secure_file(fd, st, &st_open,
 	    O_APPEND, 1, 1, 0600) < 0)
@@ -1116,6 +1107,36 @@ fd_verify_identity(int fd,
 }
 
 int
+fd_verify_dir_identity(int fd,
+    const struct stat *expected)
+{
+	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 (!S_ISDIR(st_now.st_mode)) {
+		errno = ENOTDIR;
+		return -1;
+	}
+
+	errno = saved_errno;
+	return 0;
+}
+
+int
 is_owner(struct stat *st)
 {
 	if (st == NULL) {
@@ -1802,14 +1823,9 @@ fs_mkdir_p_at(int dirfd, const char *path, mode_t mode)
 			break;
 
 		/* check parent integrity */
-		if (fstat(dirfd, &st_parent_now) < 0)
-			goto err;
-
-		if (st_parent_now.st_dev != st_parent_initial.st_dev ||
-		    st_parent_now.st_ino != st_parent_initial.st_ino) {
-			errno = ESTALE;
+		if (fd_verify_identity(dirfd, &st_parent_initial,
+		    &st_parent_now) < 0)
 			goto err;
-		}
 
 		nextfd = openat2p(dirfd, name,
 		    O_RDONLY | O_DIRECTORY | O_CLOEXEC, 0);