f2fs-tools: support to show fscrypt_context_v2 in print_xattr_entry

As the fscrypt context has two versions now, this patch adds the
support of fscrypt_context_v2 for print_xattr_entry.

Signed-off-by: Weichao Guo <guoweichao@oppo.com>
Signed-off-by: Sheng Yong <shengyong@oppo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

2 files changed, 85 insertions, 25 deletions

diff --git a/fsck/mount.c b/fsck/mount.c
index 397feb5..dbb516b 100644
--- a/fsck/mount.c
+++ b/fsck/mount.c
@@ -196,7 +196,9 @@ static void print_xattr_entry(const struct f2fs_xattr_entry *ent)
 {
 	const u8 *value = (const u8 *)&ent->e_name[ent->e_name_len];
 	const int size = le16_to_cpu(ent->e_value_size);
-	const struct fscrypt_context *ctx;
+	char *enc_name = F2FS_XATTR_NAME_ENCRYPTION_CONTEXT;
+	u32 enc_name_len = strlen(enc_name);
+	const union fscrypt_context *ctx;
 	int i;
 
 	MSG(0, "\nxattr: e_name_index:%d e_name:", ent->e_name_index);
@@ -213,22 +215,41 @@ static void print_xattr_entry(const struct f2fs_xattr_entry *ent)
 		return;
 #endif
 	case F2FS_XATTR_INDEX_ENCRYPTION:
-		ctx = (const struct fscrypt_context *)value;
-		if (size != sizeof(*ctx) ||
-		    ctx->format != FS_ENCRYPTION_CONTEXT_FORMAT_V1)
+		if (ent->e_name_len != enc_name_len ||
+			memcmp(ent->e_name, enc_name, enc_name_len))
 			break;
-		MSG(0, "format: %d\n", ctx->format);
-		MSG(0, "contents_encryption_mode: 0x%x\n", ctx->contents_encryption_mode);
-		MSG(0, "filenames_encryption_mode: 0x%x\n", ctx->filenames_encryption_mode);
-		MSG(0, "flags: 0x%x\n", ctx->flags);
-		MSG(0, "master_key_descriptor: ");
-		for (i = 0; i < FS_KEY_DESCRIPTOR_SIZE; i++)
-			MSG(0, "%02X", ctx->master_key_descriptor[i]);
-		MSG(0, "\nnonce: ");
-		for (i = 0; i < FS_KEY_DERIVATION_NONCE_SIZE; i++)
-			MSG(0, "%02X", ctx->nonce[i]);
-		MSG(0, "\n");
-		return;
+		ctx = (const union fscrypt_context *)value;
+		if (size == 0 || size != fscrypt_context_size(ctx))
+			break;
+		switch (ctx->version) {
+		case FSCRYPT_CONTEXT_V1:
+			MSG(0, "format: %d\n", ctx->version);
+			MSG(0, "contents_encryption_mode: 0x%x\n", ctx->v1.contents_encryption_mode);
+			MSG(0, "filenames_encryption_mode: 0x%x\n", ctx->v1.filenames_encryption_mode);
+			MSG(0, "flags: 0x%x\n", ctx->v1.flags);
+			MSG(0, "master_key_descriptor: ");
+			for (i = 0; i < FSCRYPT_KEY_DESCRIPTOR_SIZE; i++)
+				MSG(0, "%02X", ctx->v1.master_key_descriptor[i]);
+			MSG(0, "\nnonce: ");
+			for (i = 0; i < FSCRYPT_FILE_NONCE_SIZE; i++)
+				MSG(0, "%02X", ctx->v1.nonce[i]);
+			MSG(0, "\n");
+			return;
+		case FSCRYPT_CONTEXT_V2:
+			MSG(0, "format: %d\n", ctx->version);
+			MSG(0, "contents_encryption_mode: 0x%x\n", ctx->v2.contents_encryption_mode);
+			MSG(0, "filenames_encryption_mode: 0x%x\n", ctx->v2.filenames_encryption_mode);
+			MSG(0, "flags: 0x%x\n", ctx->v2.flags);
+			MSG(0, "master_key_identifier: ");
+			for (i = 0; i < FSCRYPT_KEY_IDENTIFIER_SIZE; i++)
+				MSG(0, "%02X", ctx->v2.master_key_identifier[i]);
+			MSG(0, "\nnonce: ");
+			for (i = 0; i < FSCRYPT_FILE_NONCE_SIZE; i++)
+				MSG(0, "%02X", ctx->v2.nonce[i]);
+			MSG(0, "\n");
+			return;
+		}
+		break;
 	}
 	for (i = 0; i < size; i++)
 		MSG(0, "%02X", value[i]);
diff --git a/fsck/xattr.h b/fsck/xattr.h
index 22ea35c..cddafa7 100644
--- a/fsck/xattr.h
+++ b/fsck/xattr.h
@@ -34,22 +34,61 @@ struct f2fs_xattr_entry {
 	char e_name[0];		/* attribute name */
 };
 
-#define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1
-#ifndef FS_KEY_DESCRIPTOR_SIZE
-#define FS_KEY_DESCRIPTOR_SIZE 8
+#define FSCRYPT_CONTEXT_V1 1
+#define FSCRYPT_CONTEXT_V2 2
+#ifndef FSCRYPT_KEY_DESCRIPTOR_SIZE
+#define FSCRYPT_KEY_DESCRIPTOR_SIZE 8
 #endif
-#define FS_KEY_DERIVATION_NONCE_SIZE 16
+#ifndef FSCRYPT_KEY_IDENTIFIER_SIZE
+#define FSCRYPT_KEY_IDENTIFIER_SIZE	16
+#endif
+#define FSCRYPT_FILE_NONCE_SIZE 16
+#define F2FS_XATTR_NAME_ENCRYPTION_CONTEXT    "c"
+
+struct fscrypt_context_v1 {
+	u8 version; /* FSCRYPT_CONTEXT_V1 */
+	u8 contents_encryption_mode;
+	u8 filenames_encryption_mode;
+	u8 flags;
+	u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
+	u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
+};
 
-struct fscrypt_context {
-	u8 format;
+struct fscrypt_context_v2 {
+	u8 version; /* FSCRYPT_CONTEXT_V2 */
 	u8 contents_encryption_mode;
 	u8 filenames_encryption_mode;
 	u8 flags;
-	u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
-	u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
+	u8 __reserved[4];
+	u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
+	u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
 };
 
-static_assert(sizeof(struct fscrypt_context) == 28, "");
+union fscrypt_context {
+	u8 version;
+	struct fscrypt_context_v1 v1;
+	struct fscrypt_context_v2 v2;
+};
+
+static_assert(sizeof(struct fscrypt_context_v1) == 28, "");
+static_assert(sizeof(struct fscrypt_context_v2) == 40, "");
+
+/*
+* Return the size expected for the given fscrypt_context based on its version
+* number, or 0 if the context version is unrecognized.
+*/
+static inline int fscrypt_context_size(const union fscrypt_context *ctx)
+{
+	switch (ctx->version) {
+	case FSCRYPT_CONTEXT_V1:
+		return sizeof(ctx->v1);
+	case FSCRYPT_CONTEXT_V2:
+		return sizeof(ctx->v2);
+	default:
+		MSG(0, "Unsupported fscrypt_context format!\n");
+	}
+	return 0;
+}
 
 #define F2FS_ACL_VERSION	0x0001