Support backup/restore of FBE policies
Change-Id: Iba8ef20f57b0fb57bb9406c53148a806441d0b59
diff --git a/libtar/block.c b/libtar/block.c
index 5d3c9d8..2fd61bb 100644
--- a/libtar/block.c
+++ b/libtar/block.c
@@ -25,6 +25,10 @@
#define SELINUX_TAG "RHT.security.selinux="
#define SELINUX_TAG_LEN 21
+// Used to identify e4crypt_policy in extended ('x')
+#define E4CRYPT_TAG "TWRP.security.e4crypt="
+#define E4CRYPT_TAG_LEN 22
+
/* read a header block */
/* FIXME: the return value of this function should match the return value
of tar_block_read(), which is a macro which references a prototype
@@ -119,6 +123,11 @@
if (t->th_buf.selinux_context != NULL)
free(t->th_buf.selinux_context);
#endif
+#ifdef HAVE_EXT4_CRYPT
+ if (t->th_buf.e4crypt_policy != NULL) {
+ free(t->th_buf.e4crypt_policy);
+ }
+#endif
memset(&(t->th_buf), 0, sizeof(struct tar_header));
@@ -283,6 +292,57 @@
}
#endif
+#ifdef HAVE_EXT4_CRYPT
+ if(TH_ISPOLHEADER(t))
+ {
+ sz = th_get_size(t);
+
+ if(sz >= T_BLOCKSIZE) // Not supported
+ {
+#ifdef DEBUG
+ printf(" th_read(): Policy header is too long!\n");
+#endif
+ }
+ else
+ {
+ char buf[T_BLOCKSIZE];
+ i = tar_block_read(t, buf);
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+
+ // To be sure
+ buf[T_BLOCKSIZE-1] = 0;
+
+ int len = strlen(buf);
+ char *start = strstr(buf, E4CRYPT_TAG);
+ if(start && start+E4CRYPT_TAG_LEN < buf+len)
+ {
+ start += E4CRYPT_TAG_LEN;
+ char *end = strchr(start, '\n');
+ if(end)
+ {
+ t->th_buf.e4crypt_policy = strndup(start, end-start);
+#ifdef DEBUG
+ printf(" th_read(): E4Crypt policy detected: %s\n", t->th_buf.e4crypt_policy);
+#endif
+ }
+ }
+ }
+
+ i = th_read_internal(t);
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+ }
+#endif
+
return 0;
}
@@ -457,6 +517,59 @@
}
#endif
+#ifdef HAVE_EXT4_CRYPT
+ if((t->options & TAR_STORE_EXT4_POL) && t->th_buf.e4crypt_policy != NULL)
+ {
+#ifdef DEBUG
+ printf("th_write(): using e4crypt_policy %s\n",
+ t->th_buf.e4crypt_policy);
+#endif
+ /* save old size and type */
+ type2 = t->th_buf.typeflag;
+ sz2 = th_get_size(t);
+
+ /* write out initial header block with fake size and type */
+ t->th_buf.typeflag = TH_POL_TYPE;
+
+ /* setup size - EXT header has format "*size of this whole tag as ascii numbers* *space* *content* *newline* */
+ // size newline
+ sz = E4CRYPT_TAG_LEN + EXT4_KEY_DESCRIPTOR_HEX + 3 + 1;
+
+ if(sz >= 100) // another ascci digit for size
+ ++sz;
+
+ if(sz >= T_BLOCKSIZE) // impossible
+ {
+ errno = EINVAL;
+ return -1;
+ }
+
+ th_set_size(t, sz);
+ th_finish(t);
+ i = tar_block_write(t, &(t->th_buf));
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+
+ memset(buf, 0, T_BLOCKSIZE);
+ snprintf(buf, T_BLOCKSIZE, "%d "E4CRYPT_TAG"%s\n", (int)sz, t->th_buf.e4crypt_policy);
+ i = tar_block_write(t, &buf);
+ if (i != T_BLOCKSIZE)
+ {
+ if (i != -1)
+ errno = EINVAL;
+ return -1;
+ }
+
+ /* reset type and size to original values */
+ t->th_buf.typeflag = type2;
+ th_set_size(t, sz2);
+ }
+#endif
+
th_finish(t);
#ifdef DEBUG