erofs: using domain_id in the safer way

Either the existing fscache usecase or the upcoming page
cache sharing case, the `domain_id` should be protected as
sensitive information, so we use the safer helpers to allocate,
free and display domain_id.

Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

diff --git a/Documentation/filesystems/erofs.rst b/Documentation/filesystems/erofs.rst
index 96101c3fe53a5fe9290933caa403b67392ed35c2..9f98d18c39f6ea4daf0f0cb7d6df0d822dd6eeaa 100644 (file)
--- a/Documentation/filesystems/erofs.rst
+++ b/Documentation/filesystems/erofs.rst
@@ -128,8 +128,9 @@ device=%s              Specify a path to an extra device to be used together.
 directio               (For file-backed mounts) Use direct I/O to access backing
                        files, and asynchronous I/O will be enabled if supported.
 fsid=%s                Specify a filesystem image ID for Fscache back-end.
-domain_id=%s           Specify a domain ID in fscache mode so that different images
-                       with the same blobs under a given domain ID can share storage.
+domain_id=%s           Specify a trusted domain ID for fscache mode so that
+                       different images with the same blobs, identified by blob IDs,
+                       can share storage within the same trusted domain.
 fsoffset=%llu          Specify block-aligned filesystem offset for the primary device.
 ===================    =========================================================
 

diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
index f4937b025038be8bfc3581c6f13ef9ef05c2add9..a2cc0f3fa9d04c03cbf263127695762117139536 100644 (file)
--- a/fs/erofs/fscache.c
+++ b/fs/erofs/fscache.c
@@ -379,7 +379,7 @@ static void erofs_fscache_domain_put(struct erofs_domain *domain)
                }
                fscache_relinquish_volume(domain->volume, NULL, false);
                mutex_unlock(&erofs_domain_list_lock);
-               kfree(domain->domain_id);
+               kfree_sensitive(domain->domain_id);
                kfree(domain);
                return;
        }
@@ -446,7 +446,7 @@ static int erofs_fscache_init_domain(struct super_block *sb)
        sbi->domain = domain;
        return 0;
 out:
-       kfree(domain->domain_id);
+       kfree_sensitive(domain->domain_id);
        kfree(domain);
        return err;
 }

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index c9ea70d600ad71c767c3a721b369fc4dc4475ed2..13876fa597ee85ad0d0c11c694aeda690dc361f9 100644 (file)
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -527,10 +527,8 @@ static int erofs_fc_parse_param(struct fs_context *fc,
                        return -ENOMEM;
                break;
        case Opt_domain_id:
-               kfree(sbi->domain_id);
-               sbi->domain_id = kstrdup(param->string, GFP_KERNEL);
-               if (!sbi->domain_id)
-                       return -ENOMEM;
+               kfree_sensitive(sbi->domain_id);
+               sbi->domain_id = no_free_ptr(param->string);
                break;
 #else
        case Opt_fsid:
@@ -626,7 +624,7 @@ static void erofs_set_sysfs_name(struct super_block *sb)
 {
        struct erofs_sb_info *sbi = EROFS_SB(sb);
 
-       if (sbi->domain_id)
+       if (sbi->domain_id && sbi->fsid)
                super_set_sysfs_name_generic(sb, "%s,%s", sbi->domain_id,
                                             sbi->fsid);
        else if (sbi->fsid)
@@ -861,7 +859,7 @@ static void erofs_sb_free(struct erofs_sb_info *sbi)
 {
        erofs_free_dev_context(sbi->devs);
        kfree(sbi->fsid);
-       kfree(sbi->domain_id);
+       kfree_sensitive(sbi->domain_id);
        if (sbi->dif0.file)
                fput(sbi->dif0.file);
        kfree(sbi->volume_name);