From e5e34797a899fed0f38c777d2a7c1e826d521794 Mon Sep 17 00:00:00 2001 From: topjohnwu Date: Fri, 15 Sep 2017 02:52:27 +0800 Subject: [PATCH] Patch fstab from dtb --- jni/Android.mk | 8 +++-- jni/magiskboot/boot_utils.c | 2 +- jni/magiskboot/dtb.c | 66 +++++++++++++++++++++++++++++++++++++ jni/magiskboot/magiskboot.h | 1 + jni/magiskboot/main.c | 5 +++ scripts/boot_patch.sh | 6 ++-- 6 files changed, 83 insertions(+), 5 deletions(-) create mode 100644 jni/magiskboot/dtb.c diff --git a/jni/Android.mk b/jni/Android.mk index 5206eeb74..c03e20d52 100644 --- a/jni/Android.mk +++ b/jni/Android.mk @@ -4,12 +4,14 @@ LOCAL_PATH := $(call my-dir) JNI_ROOT := jni SELINUX_PATH := jni/external/selinux COMPRESS_LIB := jni/external/ndk-compression +DTC_PATH := jni/external/dtc LIBSELINUX := $(SELINUX_PATH)/libselinux/include LIBSEPOL := $(SELINUX_PATH)/libsepol/include $(SELINUX_PATH)/libsepol/cil/include LIBZ := $(COMPRESS_LIB)/zlib LIBLZMA := $(COMPRESS_LIB)/xz/src/liblzma/api LIBLZ4 := $(COMPRESS_LIB)/lz4/lib LIBBZ2 := $(COMPRESS_LIB)/bzip2 +LIBFDT := $(DTC_PATH)/libfdt ######################## # Binaries @@ -64,13 +66,14 @@ include $(BUILD_EXECUTABLE) # magiskboot include $(CLEAR_VARS) LOCAL_MODULE := magiskboot -LOCAL_STATIC_LIBRARIES := libz liblzma liblz4 libbz2 +LOCAL_STATIC_LIBRARIES := libz liblzma liblz4 libbz2 libfdt LOCAL_C_INCLUDES := \ jni/include \ $(LIBZ) \ $(LIBLZMA) \ $(LIBLZ4) \ - $(LIBBZ2) + $(LIBBZ2) \ + $(LIBFDT) LOCAL_SRC_FILES := \ magiskboot/main.c \ @@ -81,6 +84,7 @@ LOCAL_SRC_FILES := \ magiskboot/cpio.c \ magiskboot/sha1.c \ magiskboot/types.c \ + magiskboot/dtb.c \ utils/xwrap.c \ utils/vector.c LOCAL_CFLAGS := -DZLIB_CONST diff --git a/jni/magiskboot/boot_utils.c b/jni/magiskboot/boot_utils.c index b003e9275..c73f6ac2b 100644 --- a/jni/magiskboot/boot_utils.c +++ b/jni/magiskboot/boot_utils.c @@ -86,7 +86,7 @@ int check_verity_pattern(const char *s) { if (strncmp(s + pos, "verify", 6) != 0) return -1; pos += 6; if (s[pos] == '=') { - while (s[pos] != ' ' && s[pos] != '\n' && s[pos] != ',') ++pos; + while (s[pos] != '\0' && s[pos] != ' ' && s[pos] != '\n' && s[pos] != ',') ++pos; } return pos; } diff --git a/jni/magiskboot/dtb.c b/jni/magiskboot/dtb.c new file mode 100644 index 000000000..a5904fb65 --- /dev/null +++ b/jni/magiskboot/dtb.c @@ -0,0 +1,66 @@ +#include +#include +#include + +#include "magiskboot.h" +#include "utils.h" + +/* Left here for debugging */ + +// static void print_subnode(const void *fdt, int parent, int depth) { +// int node; +// fdt_for_each_subnode(node, fdt, parent) { +// for (int i = 0; i < depth; ++i) printf(" "); +// printf("%d: %s\n", node, fdt_get_name(fdt, node, NULL)); +// print_subnode(fdt, node, depth + 1); +// } +// } + +static int find_fstab(const void *fdt, int parent) { + int node, fstab; + fdt_for_each_subnode(node, fdt, parent) { + if (strcmp(fdt_get_name(fdt, node, NULL), "fstab") == 0) + return node; + fstab = find_fstab(fdt, node); + if (fstab != -1) + return fstab; + } + return -1; +} + +void dtb_patch(const char *file) { + size_t size ; + void *dtb, *fdt; + fprintf(stderr, "Loading dtbs from [%s]\n\n", file); + mmap_rw(file, &dtb, &size); + // Loop through all the dtbs + int dtb_num = 0, patched = 0; + for (int i = 0; i < size; ++i) { + if (memcmp(dtb + i, DTB_MAGIC, 4) == 0) { + fdt = dtb + i; + int fstab = find_fstab(fdt, 0); + if (fstab > 0) { + fprintf(stderr, "Found fstab in dtb.%04d\n", dtb_num++); + int block; + fdt_for_each_subnode(block, fdt, fstab) { + fprintf(stderr, "Found block [%s] in fstab\n", fdt_get_name(fdt, block, NULL)); + int skip, value_size; + char *value = (char *) fdt_getprop(fdt, block, "fsmgr_flags", &value_size); + for (int i = 0; i < value_size; ++i) { + if ((skip = check_verity_pattern(value + i)) > 0) { + fprintf(stderr, "Remove pattern [%.*s] in [fsmgr_flags]\n", skip, value + i); + memcpy(value + i, value + i + skip, value_size - i - skip); + memset(value + value_size - skip, '\0', skip); + patched = 1; + } + } + } + } + } + } + fprintf(stderr, "\n"); + munmap(dtb, size); + exit(!patched); +} + + diff --git a/jni/magiskboot/magiskboot.h b/jni/magiskboot/magiskboot.h index 3c228f61b..74be6a73c 100644 --- a/jni/magiskboot/magiskboot.h +++ b/jni/magiskboot/magiskboot.h @@ -22,6 +22,7 @@ int parse_img(void *orig, size_t size, boot_img *boot); int cpio_commands(const char *command, int argc, char *argv[]); void comp_file(const char *method, const char *from, const char *to); void decomp_file(char *from, const char *to); +void dtb_patch(const char *file); // Compressions size_t gzip(int mode, int fd, const void *buf, size_t size); diff --git a/jni/magiskboot/main.c b/jni/magiskboot/main.c index 99683b8d0..cf810b82d 100644 --- a/jni/magiskboot/main.c +++ b/jni/magiskboot/main.c @@ -54,6 +54,9 @@ static void usage(char *arg0) { " -stocksha1\n" " Get stock boot SHA1 recorded within \n" "\n" + " --dtb-patch \n" + " Search for fstab in and remove verity checks\n" + "\n" " --compress[=method] [outfile]\n" " Compress with [method] (default: gzip), optionally to [outfile]\n" " Supported methods: " @@ -110,6 +113,8 @@ int main(int argc, char *argv[]) { repack(argv[2], argc > 3 ? argv[3] : NEW_BOOT); } else if (argc > 2 && strcmp(argv[1], "--decompress") == 0) { decomp_file(argv[2], argc > 3 ? argv[3] : NULL); + } else if (argc > 2 && strcmp(argv[1], "--dtb-patch") == 0) { + dtb_patch(argv[2]); } else if (argc > 2 && strncmp(argv[1], "--compress", 10) == 0) { char *method; method = strchr(argv[1], '='); diff --git a/scripts/boot_patch.sh b/scripts/boot_patch.sh index f2c78e9d1..22d520bc4 100644 --- a/scripts/boot_patch.sh +++ b/scripts/boot_patch.sh @@ -226,8 +226,6 @@ if $SKIP_INITRAMFS; then fi [ -f sepolicy ] || abort_wrap "! Cannot get sepolicy" - # TODO: Patch dm-verity - cpio_add 750 init ./magiskinit cpio_mkdir 000 overlay cpio_add 750 overlay/init.magisk.rc init.magisk.rc @@ -252,6 +250,10 @@ rm -f sepolicy # Create ramdisk backups ./magiskboot --cpio-backup ramdisk.cpio ramdisk.cpio.orig +if ! $KEEPVERITY && [ -f dtb ]; then + ./magiskboot --dtb-patch dtb && ui_print "- Patching fstab in dtb to remove dm-verity" +fi + rm -f ramdisk.cpio.orig ##########################################################################################