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Support backup/restore of FBE policies

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Change-Id: Iba8ef20f57b0fb57bb9406c53148a806441d0b59
This commit is contained in:
Ethan Yonker
2016-12-13 14:25:04 -06:00
parent bd7492de28
commit 79f88bdf8d
14 changed files with 585 additions and 45 deletions
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libtar/Android.mk
+22 -12
View File
@@ -5,16 +5,21 @@ include $(CLEAR_VARS)
LOCAL_MODULE := libtar
LOCAL_MODULE_TAGS := eng optional
LOCAL_CFLAGS :=
LOCAL_SRC_FILES = append.c block.c decode.c encode.c extract.c handle.c output.c util.c wrapper.c basename.c strmode.c libtar_hash.c libtar_list.c dirname.c
LOCAL_SRC_FILES := append.c block.c decode.c encode.c extract.c handle.c output.c util.c wrapper.c basename.c strmode.c libtar_hash.c libtar_list.c dirname.c
LOCAL_C_INCLUDES += $(LOCAL_PATH) \
external/zlib
external/zlib
LOCAL_SHARED_LIBRARIES += libz libc
ifeq ($(TWHAVE_SELINUX), true)
LOCAL_C_INCLUDES += external/libselinux/include
LOCAL_SHARED_LIBRARIES += libselinux
LOCAL_CFLAGS += -DHAVE_SELINUX
LOCAL_C_INCLUDES += external/libselinux/include
LOCAL_SHARED_LIBRARIES += libselinux
LOCAL_CFLAGS += -DHAVE_SELINUX
endif
ifeq ($(TW_INCLUDE_CRYPTO_FBE), true)
LOCAL_SHARED_LIBRARIES += libe4crypt
LOCAL_CFLAGS += -DHAVE_EXT4_CRYPT
LOCAL_C_INCLUDES += bootable/recovery/crypto/ext4crypt
endif
include $(BUILD_SHARED_LIBRARY)
@@ -24,16 +29,21 @@ include $(CLEAR_VARS)
LOCAL_MODULE := libtar_static
LOCAL_MODULE_TAGS := eng optional
LOCAL_CFLAGS =
LOCAL_SRC_FILES = append.c block.c decode.c encode.c extract.c handle.c output.c util.c wrapper.c basename.c strmode.c libtar_hash.c libtar_list.c dirname.c
LOCAL_SRC_FILES := append.c block.c decode.c encode.c extract.c handle.c output.c util.c wrapper.c basename.c strmode.c libtar_hash.c libtar_list.c dirname.c
LOCAL_C_INCLUDES += $(LOCAL_PATH) \
external/zlib
external/zlib
LOCAL_STATIC_LIBRARIES += libz libc
ifeq ($(TWHAVE_SELINUX), true)
LOCAL_C_INCLUDES += external/libselinux/include
LOCAL_STATIC_LIBRARIES += libselinux
LOCAL_CFLAGS += -DHAVE_SELINUX
LOCAL_C_INCLUDES += external/libselinux/include
LOCAL_STATIC_LIBRARIES += libselinux
LOCAL_CFLAGS += -DHAVE_SELINUX
endif
ifeq ($(TW_INCLUDE_CRYPTO_FBE), true)
LOCAL_SHARED_LIBRARIES += libe4crypt
LOCAL_CFLAGS += -DHAVE_EXT4_CRYPT
LOCAL_C_INCLUDES += bootable/recovery/crypto/ext4crypt
endif
include $(BUILD_STATIC_LIBRARY)
libtar/append.c
+32
View File
@@ -20,6 +20,7 @@
#include <time.h>
#include <sys/param.h>
#include <sys/types.h>
#include <stdbool.h>
#ifdef STDC_HEADERS
# include <stdlib.h>
@@ -34,6 +35,10 @@
# include "selinux/selinux.h"
#endif
#ifdef HAVE_EXT4_CRYPT
# include "ext4crypt_tar.h"
#endif
struct tar_dev
{
dev_t td_dev;
@@ -122,6 +127,33 @@ tar_append_file(TAR *t, const char *realname, const char *savename)
}
#endif
#ifdef HAVE_EXT4_CRYPT
if (TH_ISDIR(t) && t->options & TAR_STORE_EXT4_POL)
{
if (t->th_buf.e4crypt_policy != NULL)
{
free(t->th_buf.e4crypt_policy);
t->th_buf.e4crypt_policy = NULL;
}
char e4crypt_policy[EXT4_KEY_DESCRIPTOR_SIZE];
if (e4crypt_policy_get(realname, e4crypt_policy, EXT4_KEY_DESCRIPTOR_SIZE, 0))
{
char tar_policy[EXT4_KEY_DESCRIPTOR_SIZE];
memset(tar_policy, 0, sizeof(tar_policy));
char policy_hex[EXT4_KEY_DESCRIPTOR_HEX];
policy_to_hex(e4crypt_policy, policy_hex);
if (lookup_ref_key(e4crypt_policy, &tar_policy)) {
printf("found policy '%s' - '%s' - '%s'\n", realname, tar_policy, policy_hex);
t->th_buf.e4crypt_policy = strdup(tar_policy);
} else {
printf("failed to lookup tar policy for '%s' - '%s'\n", realname, policy_hex);
return -1;
}
} // else no policy found, but this is not an error as not all dirs will have a policy
}
#endif
/* check if it's a hardlink */
#ifdef DEBUG
puts("tar_append_file(): checking inode cache for hardlink...");
libtar/block.c
+113
View File
@@ -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 @@ th_read(TAR *t)
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 @@ th_read(TAR *t)
}
#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 @@ th_write(TAR *t)
}
#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
libtar/extract.c
+27 -1
View File
@@ -32,6 +32,10 @@
# include "selinux/selinux.h"
#endif
#ifdef HAVE_EXT4_CRYPT
# include "ext4crypt_tar.h"
#endif
const unsigned long long progress_size = (unsigned long long)(T_BLOCKSIZE);
static int
@@ -492,7 +496,7 @@ tar_extract_dir(TAR *t, const char *realname)
}
else
{
#ifdef DEBUG
#if 1 //def DEBUG
puts(" *** using existing directory");
#endif
return 1;
@@ -507,6 +511,28 @@ tar_extract_dir(TAR *t, const char *realname)
}
}
#ifdef HAVE_EXT4_CRYPT
if(t->th_buf.e4crypt_policy != NULL)
{
#ifdef DEBUG
printf("tar_extract_file(): restoring EXT4 crypt policy %s to dir %s\n", t->th_buf.e4crypt_policy, realname);
#endif
char binary_policy[EXT4_KEY_DESCRIPTOR_SIZE];
if (!lookup_ref_tar(t->th_buf.e4crypt_policy, &binary_policy)) {
printf("error looking up proper e4crypt policy for '%s' - %s\n", realname, t->th_buf.e4crypt_policy);
return -1;
}
char policy_hex[EXT4_KEY_DESCRIPTOR_HEX];
policy_to_hex(binary_policy, policy_hex);
printf("restoring policy %s > '%s' to '%s'\n", t->th_buf.e4crypt_policy, policy_hex, realname);
if (!e4crypt_policy_set(realname, binary_policy, EXT4_KEY_DESCRIPTOR_SIZE, 0))
{
printf("tar_extract_file(): failed to restore EXT4 crypt policy %s to dir '%s' '%s'!!!\n", t->th_buf.e4crypt_policy, realname, policy_hex);
//return -1; // This may not be an error in some cases, so log and ignore
}
}
#endif
return 0;
}
libtar/libtar.h
+11
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@@ -19,6 +19,11 @@
#include "libtar_listhash.h"
#ifdef HAVE_EXT4_CRYPT
#define EXT4_KEY_DESCRIPTOR_SIZE 8
#define EXT4_KEY_DESCRIPTOR_HEX 17
#endif
#ifdef __cplusplus
extern "C"
{
@@ -38,6 +43,7 @@ extern "C"
/* extended metadata for next file - used to store selinux_context */
#define TH_EXT_TYPE 'x'
#define TH_POL_TYPE 'p'
/* our version of the tar header structure */
struct tar_header
@@ -64,6 +70,9 @@ struct tar_header
#ifdef HAVE_SELINUX
char *selinux_context;
#endif
#ifdef HAVE_EXT4_CRYPT
char *e4crypt_policy;
#endif
};
@@ -108,6 +117,7 @@ TAR;
#define TAR_IGNORE_CRC 64 /* ignore CRC in file header */
#define TAR_STORE_SELINUX 128 /* store selinux context */
#define TAR_USE_NUMERIC_ID 256 /* favor numeric owner over names */
#define TAR_STORE_EXT4_POL 512 /* store ext4 crypto policy */
/* this is obsolete - it's here for backwards-compatibility only */
#define TAR_IGNORE_MAGIC 0
@@ -204,6 +214,7 @@ int th_write(TAR *t);
#define TH_ISLONGNAME(t) ((t)->th_buf.typeflag == GNU_LONGNAME_TYPE)
#define TH_ISLONGLINK(t) ((t)->th_buf.typeflag == GNU_LONGLINK_TYPE)
#define TH_ISEXTHEADER(t) ((t)->th_buf.typeflag == TH_EXT_TYPE)
#define TH_ISPOLHEADER(t) ((t)->th_buf.typeflag == TH_POL_TYPE)
/* decode tar header info */
#define th_get_crc(t) oct_to_int((t)->th_buf.chksum, sizeof((t)->th_buf.chksum))