From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 29 Sep 2017 12:19:22 +0000 (+0200)
Subject: dissect: automatically mark partitions read-only that have a read-only file system
X-Git-Tag: v235~37^2~2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=896f937f58f42284dbebcd0a7f5ddc87fd5517b7;p=thirdparty%2Fsystemd.git

dissect: automatically mark partitions read-only that have a read-only file system

Specifically, squashfs and iso9660 are always read-only, hence make sure
we never even think about mounting them writable.
---

diff --git a/src/basic/mount-util.c b/src/basic/mount-util.c
index cff44116c88..843d266a2f5 100644
--- a/src/basic/mount-util.c
+++ b/src/basic/mount-util.c
@@ -578,6 +578,19 @@ bool fstype_is_api_vfs(const char *fstype) {
         return nulstr_contains(table, fstype);
 }
 
+bool fstype_is_ro(const char *fstype) {
+
+        /* All Linux file systems that are necessarily read-only */
+
+        static const char table[] =
+                "DM_verity_hash\0"
+                "iso9660\0"
+                "squashfs\0"
+                ;
+
+        return nulstr_contains(table, fstype);
+}
+
 int repeat_unmount(const char *path, int flags) {
         bool done = false;
 
diff --git a/src/basic/mount-util.h b/src/basic/mount-util.h
index 70af11c2ff0..3ec0e7d1f83 100644
--- a/src/basic/mount-util.h
+++ b/src/basic/mount-util.h
@@ -45,6 +45,7 @@ DEFINE_TRIVIAL_CLEANUP_FUNC(FILE*, endmntent);
 
 bool fstype_is_network(const char *fstype);
 bool fstype_is_api_vfs(const char *fstype);
+bool fstype_is_ro(const char *fsype);
 
 union file_handle_union {
         struct file_handle handle;
diff --git a/src/shared/dissect-image.c b/src/shared/dissect-image.c
index f11b5225582..b02b2897d3e 100644
--- a/src/shared/dissect-image.c
+++ b/src/shared/dissect-image.c
@@ -591,6 +591,9 @@ int dissect_image(int fd, const void *root_hash, size_t root_hash_size, DissectI
 
                 if (streq_ptr(p->fstype, "crypto_LUKS"))
                         m->encrypted = true;
+
+                if (p->fstype && fstype_is_ro(p->fstype))
+                        p->rw = false;
         }
 
         *ret = m;