[v2,5/8] btrfs-progs: interpret encrypted file extents.

Commit Message

Sweet Tea Dorminy Aug. 8, 2023, 5:22 p.m. UTC

Encrypted file extents now have the 'encryption' field set to a
encryption type plus a context length, and have an extent context
appended to the item.  This necessitates adjusting the struct to have a
variable-length fscrypt_context member at the end, and printing contexts
if one is provided.

Signed-off-by: Sweet Tea Dorminy <[e-mail]>
---
 check/main.c               |  5 ++++-
 kernel-shared/print-tree.c | 27 +++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

Patch

diff --git a/check/main.c b/check/main.c
index d66e10e8f..00f73c43e 100644
--- a/check/main.c
+++ b/check/main.c
@@ -37,6 +37,7 @@ 
 #include "kernel-shared/ctree.h"
 #include "kernel-shared/volumes.h"
 #include "kernel-shared/disk-io.h"
+#include "kernel-shared/fscrypt.h"
 #include "kernel-shared/print-tree.h"
 #include "kernel-shared/transaction.h"
 #include "kernel-shared/free-space-cache.h"
@@ -6345,6 +6346,7 @@  static int run_next_block(struct btrfs_root *root,
 		for (i = 0; i < nritems; i++) {
 			struct btrfs_file_extent_item *fi;
 			unsigned long inline_offset;
+			u8 ctxsize;
 
 			inline_offset = offsetof(struct btrfs_file_extent_item,
 						 disk_bytenr);
@@ -6480,8 +6482,9 @@  static int run_next_block(struct btrfs_root *root,
 				continue;
 
 			/* Prealloc/regular extent must have fixed item size */
+			ctxsize = btrfs_file_extent_encryption_ctxsize(buf, fi);
 			if (btrfs_item_size(buf, i) !=
-			    sizeof(struct btrfs_file_extent_item)) {
+			    sizeof(struct btrfs_file_extent_item) + ctxsize) {
 				ret = -EUCLEAN;
 				error(
 			"invalid file extent item size, have %u expect %zu",
diff --git a/kernel-shared/print-tree.c b/kernel-shared/print-tree.c
index 0f7f7b72f..9f332f811 100644
--- a/kernel-shared/print-tree.c
+++ b/kernel-shared/print-tree.c
@@ -23,6 +23,7 @@ 
 #include "kerncompat.h"
 #include "kernel-shared/ctree.h"
 #include "kernel-shared/disk-io.h"
+#include "kernel-shared/fscrypt.h"
 #include "kernel-shared/print-tree.h"
 #include "kernel-shared/volumes.h"
 #include "kernel-shared/compression.h"
@@ -356,6 +357,27 @@  static void compress_type_to_str(u8 compress_type, char *ret)
 	}
 }
 
+static void generate_encryption_string(struct extent_buffer *leaf,
+				       struct btrfs_file_extent_item *fi,
+				       char *ret)
+{
+	u8 policy = btrfs_file_extent_encryption(leaf, fi);
+	u32 ctxsize = btrfs_file_extent_encryption_ctxsize(leaf, fi);
+	unsigned long offset = (unsigned long) fi;
+	const struct btrfs_file_extent_item *fi2 = (struct btrfs_file_extent_item *)(leaf->data + offset);
+	const __u8 *ctx = fi2->encryption_context;
+
+	ret += sprintf(ret, "(%hhu, %u", policy, ctxsize);
+
+	if (ctxsize) {
+		int i;
+		ret += sprintf(ret, ": context ");
+		for (i = 0; i < ctxsize; i++)
+			ret += sprintf(ret, "%02hhx", ctx[i]);
+	}
+	sprintf(ret, ")");
+}
+
 static const char* file_extent_type_to_str(u8 type)
 {
 	switch (type) {
@@ -372,9 +394,11 @@  static void print_file_extent_item(struct extent_buffer *eb,
 {
 	unsigned char extent_type = btrfs_file_extent_type(eb, fi);
 	char compress_str[16];
+	char encrypt_str[16];
 
 	compress_type_to_str(btrfs_file_extent_compression(eb, fi),
 			     compress_str);
+	generate_encryption_string(eb, fi, encrypt_str);
 
 	printf("\t\tgeneration %llu type %hhu (%s)\n",
 			btrfs_file_extent_generation(eb, fi),
@@ -407,6 +431,9 @@  static void print_file_extent_item(struct extent_buffer *eb,
 	printf("\t\textent compression %hhu (%s)\n",
 			btrfs_file_extent_compression(eb, fi),
 			compress_str);
+	printf("\t\textent encryption %hhu (%s)\n",
+			btrfs_file_extent_encryption(eb, fi),
+			encrypt_str);
 }
 
 /* Caller should ensure sizeof(*ret) >= 16("DATA|TREE_BLOCK") */