Working ASLR implementation.
ASLR for shared libraries is controlled by "-a" in ota_from_target_files.
Binary files are self-contained (supported by apriori/soslim).
Signed-off-by: Hristo Bojinov <hristo@google.com>
Change-Id: I500e325bf4a70a8d69a2ab9b2938e83dadb4e65d
diff --git a/tools/apriori/apriori.c b/tools/apriori/apriori.c
index d1807b3..b25ac2b 100644
--- a/tools/apriori/apriori.c
+++ b/tools/apriori/apriori.c
@@ -1,4 +1,5 @@
#include <stdio.h>
+#include <stdlib.h>
#include <common.h>
#include <debug.h>
#include <libelf.h>
@@ -54,6 +55,154 @@
static source_t *sources = NULL;
+/* Retouch data is a very concise representation of the resolved relocations.
+ This data is used to randomize the location of prelinked libraries at
+ update time, on the device.
+ */
+
+// We will store retouch entries into this buffer, then dump them at the
+// end of the .so file before setup_prelink_info().
+#define RETOUCH_MAX_SIZE 500000
+static char *retouch_buf;
+static unsigned int retouch_byte_cnt;
+// Compression state.
+static int32_t offs_prev;
+static uint32_t cont_prev;
+
+#define false 0
+#define true 1
+
+void retouch_init(void) {
+ offs_prev = 0;
+ cont_prev = 0;
+ retouch_byte_cnt = 0;
+ retouch_buf = malloc(RETOUCH_MAX_SIZE+12);
+ FAILIF(retouch_buf == NULL,
+ "Could not allocate %d bytes.\n", RETOUCH_MAX_SIZE+12);
+}
+
+//
+// We use three encoding schemes; this takes care of much of the redundancy
+// inherent in lists of relocations:
+//
+// * two bytes, leading 1, 2b for d_offset ("s"), 13b for d_contents ("c")
+//
+// 76543210 76543210
+// 1ssccccc cccccccc
+//
+// * three bytes, leading 01, 2b for delta offset, 20b for delta contents
+//
+// 76543210 76543210 76543210
+// 01sscccc cccccccc cccccccc
+//
+// * eigth bytes, leading 00, 30b for offset, 32b for contents
+//
+// 76543210 76543210 76543210 76543210
+// 00ssssss ssssssss ssssssss ssssssss + 4 bytes contents
+//
+// NOTE 1: All deltas are w.r.t. the previous line in the list.
+// NOTE 2: Two-bit ("ss") offsets mean: "00"=4, "01"=8, "10"=12, and "11"=16.
+// NOTE 3: Delta contents are signed. To map back to a int32 we refill with 1s.
+// NOTE 4: Special encoding for -1 offset. Extended back to 32b when decoded.
+//
+
+void retouch_encode(int32_t offset, uint32_t contents) {
+ int64_t d_offs = offset-offs_prev;
+ int64_t d_cont = (int64_t)contents-(int64_t)cont_prev;
+
+ uint8_t output[8];
+ uint32_t output_size;
+
+ if ((d_offs > 3) &&
+ (d_offs % 4) == 0 &&
+ (d_offs / 4) < 5 &&
+ (d_cont < 4000) &&
+ (d_cont > -4000)) {
+ // we can fit in 2 bytes
+ output[0] =
+ 0x80 |
+ (((d_offs/4)-1) << 5) |
+ (((uint64_t)d_cont & 0x1f00) >> 8);
+ output[1] =
+ ((uint64_t)d_cont & 0xff);
+ output_size = 2;
+ } else if ((d_offs > 3) &&
+ (d_offs % 4) == 0 &&
+ (d_offs / 4) < 5 &&
+ (d_cont < 510000) &&
+ (d_cont > -510000)) {
+ // fit in 3 bytes
+ output[0] =
+ 0x40 |
+ (((d_offs/4)-1) << 4) |
+ (((uint64_t)d_cont & 0xf0000) >> 16);
+ output[1] =
+ ((uint64_t)d_cont & 0xff00) >> 8;
+ output[2] =
+ ((uint64_t)d_cont & 0xff);
+ output_size = 3;
+ } else {
+ // fit in 8 bytes; we can't support files bigger than (1GB-1)
+ // with this encoding: no library is that big anyway..
+ FAILIF(offset < -1 || offset > 0x3ffffffe, "Offset out of range.\n");
+ output[0] = (offset & 0x3f000000) >> 24;
+ output[1] = (offset & 0xff0000) >> 16;
+ output[2] = (offset & 0xff00) >> 8;
+ output[3] = (offset & 0xff);
+ output[4] = (contents & 0xff000000) >> 24;
+ output[5] = (contents & 0xff0000) >> 16;
+ output[6] = (contents & 0xff00) >> 8;
+ output[7] = (contents & 0xff);
+ output_size = 8;
+ }
+
+ // If this happens, the retouch buffer size can be bumped up.
+ // Currently, the largest case is libwebcore, at about 250K.
+ FAILIF((retouch_byte_cnt+output_size) > RETOUCH_MAX_SIZE,
+ "About to overflow retouch buffer.\n");
+
+ memcpy(retouch_buf+retouch_byte_cnt, output, output_size);
+ retouch_byte_cnt += output_size;
+
+ offs_prev = offset;
+ cont_prev = contents;
+}
+
+void retouch_dump(const char *fname, int elf_little,
+ unsigned int retouch_byte_cnt, char *retouch_buf) {
+ int fd = open(fname, O_WRONLY);
+ FAILIF(fd < 0,
+ "open(%s, O_WRONLY): %s (%d)\n" ,
+ fname, strerror(errno), errno);
+ off_t sz = lseek(fd, 0, SEEK_END);
+ FAILIF(sz == (off_t)-1,
+ "lseek(%d, 0, SEEK_END): %s (%d)!\n",
+ fd, strerror(errno), errno);
+
+ // The retouch blob ends with "RETOUCH XXXX", where XXXX is the 4-byte
+ // size of the retouch blob, in target endianness.
+ strncpy(retouch_buf+retouch_byte_cnt, "RETOUCH ", 8);
+ if (elf_little ^ is_host_little()) {
+ *(unsigned int *)(retouch_buf+retouch_byte_cnt+8) =
+ switch_endianness(retouch_byte_cnt);
+ } else {
+ *(unsigned int *)(retouch_buf+retouch_byte_cnt+8) =
+ retouch_byte_cnt;
+ }
+
+ int num_written = write(fd, retouch_buf, retouch_byte_cnt+12);
+ FAILIF(num_written < 0,
+ "write(%d, &info, sizeof(info)): %s (%d)\n",
+ fd, strerror(errno), errno);
+ FAILIF((retouch_byte_cnt+12) != num_written,
+ "Could not write %d bytes as expected (wrote %d bytes instead)!\n",
+ retouch_byte_cnt, num_written);
+ FAILIF(close(fd) < 0, "close(%d): %s (%d)!\n", fd, strerror(errno), errno);
+}
+
+/* End of retouch code.
+ */
+
#if defined(DEBUG) && 0
static void print_shdr(source_t *source, Elf_Scn *scn)
@@ -325,6 +474,9 @@
basename(source->name));
}
+ /* Save some of the info; needed for retouching (ASLR). */
+ retouch_init();
+
source->newelf_fd = open(source->output,
O_RDWR | O_CREAT,
0666);
@@ -615,15 +767,15 @@
strerror(errno),
errno);
- FAILIF(fstat(source->elf_fd, &source->elf_file_info) < 0,
- "fstat(%s(fd %d)): %s (%d)\n",
- source->name,
- source->elf_fd,
- strerror(errno),
- errno);
- INFO("File [%s]'s size is %lld bytes!\n",
- source->name,
- source->elf_file_info.st_size);
+ FAILIF(fstat(source->elf_fd, &source->elf_file_info) < 0,
+ "fstat(%s(fd %d)): %s (%d)\n",
+ source->name,
+ source->elf_fd,
+ strerror(errno),
+ errno);
+ INFO("File [%s]'s size is %lld bytes!\n",
+ source->name,
+ source->elf_file_info.st_size);
INFO("Calling elf_begin(%s)...\n", full_path);
@@ -775,6 +927,11 @@
function setup_prelink_info() below. */
INFO("%s: setting up prelink tag at end of file.\n",
source->output ? source->output : source->name);
+ retouch_encode(-1, source->base);
+ retouch_dump(source->output ? source->output : source->name,
+ source->elf_hdr.e_ident[EI_DATA] == ELFDATA2LSB,
+ retouch_byte_cnt,
+ retouch_buf);
setup_prelink_info(source->output ? source->output : source->name,
source->elf_hdr.e_ident[EI_DATA] == ELFDATA2LSB,
source->base);
@@ -785,6 +942,7 @@
#endif/*SUPPORT_ANDROID_PRELINK_TAGS*/
do_destroy_source(source);
+ if (retouch_buf != NULL) { free(retouch_buf); retouch_buf = NULL; }
if (source->shstrtab_data != NULL)
FREEIF(source->shstrtab_data->d_buf); /* adjust_elf */
@@ -1226,8 +1384,11 @@
rel->r_offset,
found_sym->st_value,
sym_source->base);
- if (!dry_run)
+ if (!dry_run) {
+ PRINT("WARNING: Relocation type not supported "
+ "for retouching!");
*dest = found_sym->st_value + sym_source->base;
+ }
}
num_relocations++;
break;
@@ -1240,8 +1401,15 @@
sname,
symname ?: "(symbol has no name)",
rel->r_offset, *dest, source->base);
- if (!dry_run)
+ if (!dry_run) {
*dest += source->base;
+
+ /* Output an entry for the ASLR touch-up process. */
+ retouch_encode(rel->r_offset
+ -shdr_mem.sh_addr
+ +shdr_mem.sh_offset,
+ *dest);
+ }
num_relocations++;
break;
case R_ARM_COPY:
@@ -1352,15 +1520,21 @@
ASSERT(data->d_buf != NULL);
ASSERT(data->d_size >= rel->r_offset -
shdr_mem.sh_addr);
- if (!dry_run)
- memcpy(dest, src, found_sym->st_size);
+ if (!dry_run) {
+ PRINT("WARNING: Relocation type not supported "
+ "for retouching!");
+ memcpy(dest, src, found_sym->st_size);
+ }
}
else {
ASSERT(src == NULL);
ASSERT(elf_ndxscn(src_scn) ==
elf_ndxscn(sym_source->bss.scn));
- if (!dry_run)
- memset(dest, 0, found_sym->st_size);
+ if (!dry_run) {
+ PRINT("WARNING: Relocation type not supported "
+ "for retouching!");
+ memset(dest, 0, found_sym->st_size);
+ }
}
}
}
diff --git a/tools/apriori/source.h b/tools/apriori/source.h
index a5d96bd..5381a29 100644
--- a/tools/apriori/source.h
+++ b/tools/apriori/source.h
@@ -62,7 +62,8 @@
Elf_Data *shstrtab_data;
int elf_fd;
int newelf_fd; /* fd of output file, -1 if output == NULL */
- struct stat elf_file_info;
+ int newelf_relo_fd; /* fd of relocaion output file */
+ struct stat elf_file_info;
GElf_Ehdr elf_hdr, oldelf_hdr;
size_t shstrndx;
int shnum; /* number of sections */
diff --git a/tools/releasetools/edify_generator.py b/tools/releasetools/edify_generator.py
index 390bd4b..328700f 100644
--- a/tools/releasetools/edify_generator.py
+++ b/tools/releasetools/edify_generator.py
@@ -235,6 +235,20 @@
",\0".join(['"' + i + '"' for i in sorted(links)]) + ");")
self.script.append(self._WordWrap(cmd))
+ def RetouchBinaries(self, file_list):
+ """Execute the retouch instructions in files listed."""
+ cmd = ('retouch_binaries(' +
+ ', '.join(['"' + i[0] + '", "' + i[1] + '"' for i in file_list]) +
+ ');')
+ self.script.append(self._WordWrap(cmd))
+
+ def UndoRetouchBinaries(self, file_list):
+ """Undo the retouching (retouch to zero offset)."""
+ cmd = ('undo_retouch_binaries(' +
+ ', '.join(['"' + i[0] + '", "' + i[1] + '"' for i in file_list]) +
+ ');')
+ self.script.append(self._WordWrap(cmd))
+
def AppendExtra(self, extra):
"""Append text verbatim to the output script."""
self.script.append(extra)
diff --git a/tools/releasetools/ota_from_target_files b/tools/releasetools/ota_from_target_files
index 8cd1941..d249214 100755
--- a/tools/releasetools/ota_from_target_files
+++ b/tools/releasetools/ota_from_target_files
@@ -44,6 +44,8 @@
-e (--extra_script) <file>
Insert the contents of file at the end of the update script.
+ -a (--use_aslr)
+ Specify whether to build the package with ASLR enabled (off by default).
"""
import sys
@@ -75,6 +77,7 @@
OPTIONS.wipe_user_data = False
OPTIONS.omit_prereq = False
OPTIONS.extra_script = None
+OPTIONS.aslr_mode = False
OPTIONS.worker_threads = 3
def MostPopularKey(d, default):
@@ -91,6 +94,10 @@
symlink."""
return (info.external_attr >> 16) == 0120777
+def IsRegular(info):
+ """Return true if the zipfile.ZipInfo object passed in represents a
+ symlink."""
+ return (info.external_attr >> 28) == 010
class Item:
@@ -246,13 +253,15 @@
substitute=None):
"""Copies files underneath system/ in the input zip to the output
zip. Populates the Item class with their metadata, and returns a
- list of symlinks. output_zip may be None, in which case the copy is
- skipped (but the other side effects still happen). substitute is an
- optional dict of {output filename: contents} to be output instead of
- certain input files.
+ list of symlinks as well as a list of files that will be retouched.
+ output_zip may be None, in which case the copy is skipped (but the
+ other side effects still happen). substitute is an optional dict
+ of {output filename: contents} to be output instead of certain input
+ files.
"""
symlinks = []
+ retouch_files = []
for info in input_zip.infolist():
if info.filename.startswith("SYSTEM/"):
@@ -270,6 +279,9 @@
data = substitute[fn]
else:
data = input_zip.read(info.filename)
+ if info.filename.startswith("SYSTEM/lib/") and IsRegular(info):
+ retouch_files.append(("/system/" + basefilename,
+ sha.sha(data).hexdigest()))
output_zip.writestr(info2, data)
if fn.endswith("/"):
Item.Get(fn[:-1], dir=True)
@@ -277,7 +289,7 @@
Item.Get(fn, dir=False)
symlinks.sort()
- return symlinks
+ return (symlinks, retouch_files)
def SignOutput(temp_zip_name, output_zip_name):
@@ -375,8 +387,12 @@
script.UnpackPackageDir("recovery", "/system")
script.UnpackPackageDir("system", "/system")
- symlinks = CopySystemFiles(input_zip, output_zip)
+ (symlinks, retouch_files) = CopySystemFiles(input_zip, output_zip)
script.MakeSymlinks(symlinks)
+ if OPTIONS.aslr_mode:
+ script.RetouchBinaries(retouch_files)
+ else:
+ script.UndoRetouchBinaries(retouch_files)
boot_img = File("boot.img", common.BuildBootableImage(
os.path.join(OPTIONS.input_tmp, "BOOT")))
@@ -432,12 +448,17 @@
"""Load all the files from SYSTEM/... in a given target-files
ZipFile, and return a dict of {filename: File object}."""
out = {}
+ retouch_files = []
for info in z.infolist():
if info.filename.startswith("SYSTEM/") and not IsSymlink(info):
- fn = "system/" + info.filename[7:]
+ basefilename = info.filename[7:]
+ fn = "system/" + basefilename
data = z.read(info.filename)
out[fn] = File(fn, data)
- return out
+ if info.filename.startswith("SYSTEM/lib/") and IsRegular(info):
+ retouch_files.append(("/system/" + basefilename,
+ out[fn].sha1))
+ return (out, retouch_files)
DIFF_PROGRAM_BY_EXT = {
@@ -600,9 +621,9 @@
metadata=metadata)
print "Loading target..."
- target_data = LoadSystemFiles(target_zip)
+ (target_data, target_retouch_files) = LoadSystemFiles(target_zip)
print "Loading source..."
- source_data = LoadSystemFiles(source_zip)
+ (source_data, source_retouch_files) = LoadSystemFiles(source_zip)
verbatim_targets = []
patch_list = []
@@ -769,7 +790,7 @@
script.ShowProgress(0.1, 10)
- target_symlinks = CopySystemFiles(target_zip, None)
+ (target_symlinks, target_retouch_dummies) = CopySystemFiles(target_zip, None)
target_symlinks_d = dict([(i[1], i[0]) for i in target_symlinks])
temp_script = script.MakeTemporary()
@@ -778,7 +799,7 @@
# Note that this call will mess up the tree of Items, so make sure
# we're done with it.
- source_symlinks = CopySystemFiles(source_zip, None)
+ (source_symlinks, source_retouch_dummies) = CopySystemFiles(source_zip, None)
source_symlinks_d = dict([(i[1], i[0]) for i in source_symlinks])
# Delete all the symlinks in source that aren't in target. This
@@ -812,6 +833,10 @@
to_create.append((dest, link))
script.DeleteFiles([i[1] for i in to_create])
script.MakeSymlinks(to_create)
+ if OPTIONS.aslr_mode:
+ script.RetouchBinaries(target_retouch_files)
+ else:
+ script.UndoRetouchBinaries(target_retouch_files)
# Now that the symlinks are created, we can set all the
# permissions.
@@ -842,6 +867,8 @@
OPTIONS.omit_prereq = True
elif o in ("-e", "--extra_script"):
OPTIONS.extra_script = a
+ elif o in ("-a", "--use_aslr"):
+ OPTIONS.aslr_mode = True
elif o in ("--worker_threads"):
OPTIONS.worker_threads = int(a)
else:
@@ -849,14 +876,15 @@
return True
args = common.ParseOptions(argv, __doc__,
- extra_opts="b:k:i:d:wne:",
+ extra_opts="b:k:i:d:wne:a",
extra_long_opts=["board_config=",
"package_key=",
"incremental_from=",
"wipe_user_data",
"no_prereq",
"extra_script=",
- "worker_threads="],
+ "worker_threads=",
+ "use_aslr"],
extra_option_handler=option_handler)
if len(args) != 2:
diff --git a/tools/soslim/main.c b/tools/soslim/main.c
index dd8a60b..e23fbce 100644
--- a/tools/soslim/main.c
+++ b/tools/soslim/main.c
@@ -188,9 +188,13 @@
else INFO("Not building symbol filter, filter file is empty.\n");
}
#ifdef SUPPORT_ANDROID_PRELINK_TAGS
- int prelinked = 0;
+ int prelinked = 0, retouched = 0;
int elf_little; /* valid if prelinked != 0 */
long prelink_addr; /* valid if prelinked != 0 */
+#define RETOUCH_MAX_SIZE 500000
+ /* _cnt valid if retouched != 0 */
+ unsigned int retouch_byte_cnt = RETOUCH_MAX_SIZE;
+ char retouch_buf[RETOUCH_MAX_SIZE]; /* valid if retouched != 0 */
#endif
clone_elf(elf, newelf,
infile, outfile,
@@ -200,7 +204,10 @@
#ifdef SUPPORT_ANDROID_PRELINK_TAGS
, &prelinked,
&elf_little,
- &prelink_addr
+ &prelink_addr,
+ &retouched,
+ &retouch_byte_cnt,
+ retouch_buf
#endif
,
true, /* rebuild the section-header-strings table */
@@ -223,6 +230,13 @@
infile, strerror(errno), errno);
#ifdef SUPPORT_ANDROID_PRELINK_TAGS
+ if (retouched) {
+ INFO("File has retouch data, putting it back in place.\n");
+ retouch_dump(outfile != NULL ? outfile : infile,
+ elf_little,
+ retouch_byte_cnt,
+ retouch_buf);
+ }
if (prelinked) {
INFO("File is prelinked, putting prelink TAG back in place.\n");
setup_prelink_info(outfile != NULL ? outfile : infile,
diff --git a/tools/soslim/prelink_info.c b/tools/soslim/prelink_info.c
index 81d5de3..2600ac7 100644
--- a/tools/soslim/prelink_info.c
+++ b/tools/soslim/prelink_info.c
@@ -11,6 +11,7 @@
#include <debug.h>
#include <common.h>
+#define RETOUCH_SUFFIX_SIZE 12
typedef struct {
uint32_t mmap_addr;
char tag[4]; /* 'P', 'R', 'E', ' ' */
@@ -28,7 +29,7 @@
}
else {
/* Different endianness */
- *prelink_addr = switch_endianness(info->mmap_addr);
+ *prelink_addr = switch_endianness(info->mmap_addr);
}
}
}
@@ -67,10 +68,104 @@
set_prelink(prelink_addr, elf_little, &info);
prelinked = 1;
}
- FAILIF(close(fd) < 0, "close(%d): %s (%d)!\n", fd, strerror(errno), errno);
+ FAILIF(close(fd) < 0,
+ "close(%d): %s (%d)!\n", fd, strerror(errno), errno);
return prelinked;
}
+int check_retouched(const char *fname, int elf_little,
+ unsigned int *retouch_byte_cnt, char *retouch_buf) {
+ FAILIF(sizeof(prelink_info_t) != 8,
+ "Unexpected sizeof(prelink_info_t) == %d!\n",
+ sizeof(prelink_info_t));
+ int fd = open(fname, O_RDONLY);
+ FAILIF(fd < 0, "open(%s, O_RDONLY): %s (%d)!\n",
+ fname, strerror(errno), errno);
+ off_t end = lseek(fd, 0, SEEK_END);
+ int nr = sizeof(prelink_info_t);
+ off_t sz = lseek(fd, -nr-RETOUCH_SUFFIX_SIZE, SEEK_CUR);
+ ASSERT((long)(end - sz) == (long)(nr+RETOUCH_SUFFIX_SIZE));
+ FAILIF(sz == (off_t)-1,
+ "lseek(%d, 0, SEEK_END): %s (%d)!\n",
+ fd, strerror(errno), errno);
+
+ char retouch_meta[RETOUCH_SUFFIX_SIZE];
+ int num_read = read(fd, &retouch_meta, RETOUCH_SUFFIX_SIZE);
+ FAILIF(num_read < 0,
+ "read(%d, &info, sizeof(prelink_info_t)): %s (%d)!\n",
+ fd, strerror(errno), errno);
+ FAILIF(num_read != RETOUCH_SUFFIX_SIZE,
+ "read(%d, &info, sizeof(prelink_info_t)): did not read %d bytes as "
+ "expected (read %d)!\n",
+ fd, RETOUCH_SUFFIX_SIZE, num_read);
+
+ int retouched = 0;
+ if (!strncmp(retouch_meta, "RETOUCH ", 8)) {
+ unsigned int retouch_byte_cnt_meta;
+ if (!(elf_little ^ is_host_little()))
+ retouch_byte_cnt_meta = *(unsigned int *)(retouch_meta+8);
+ else
+ retouch_byte_cnt_meta =
+ switch_endianness(*(unsigned int *)(retouch_meta+8));
+ FAILIF(*retouch_byte_cnt < retouch_byte_cnt_meta,
+ "Retouch buffer too small at %d bytes (%d needed).",
+ *retouch_byte_cnt, retouch_byte_cnt_meta);
+ *retouch_byte_cnt = retouch_byte_cnt_meta;
+ off_t sz = lseek(fd,
+ -((long)*retouch_byte_cnt)-RETOUCH_SUFFIX_SIZE-nr,
+ SEEK_END);
+ ASSERT((long)(end - sz) ==
+ (long)(*retouch_byte_cnt+RETOUCH_SUFFIX_SIZE+nr));
+ FAILIF(sz == (off_t)-1,
+ "lseek(%d, 0, SEEK_END): %s (%d)!\n",
+ fd, strerror(errno), errno);
+ num_read = read(fd, retouch_buf, *retouch_byte_cnt);
+ FAILIF(num_read < 0,
+ "read(%d, &info, sizeof(prelink_info_t)): %s (%d)!\n",
+ fd, strerror(errno), errno);
+ FAILIF(num_read != *retouch_byte_cnt,
+ "read(%d, retouch_buf, %u): did not read %d bytes as "
+ "expected (read %d)!\n",
+ fd, *retouch_byte_cnt, *retouch_byte_cnt, num_read);
+
+ retouched = 1;
+ }
+ FAILIF(close(fd) < 0, "close(%d): %s (%d)!\n", fd, strerror(errno), errno);
+ return retouched;
+}
+
+void retouch_dump(const char *fname, int elf_little,
+ unsigned int retouch_byte_cnt, char *retouch_buf) {
+ int fd = open(fname, O_WRONLY);
+ FAILIF(fd < 0,
+ "open(%s, O_WRONLY): %s (%d)\n",
+ fname, strerror(errno), errno);
+ off_t sz = lseek(fd, 0, SEEK_END);
+ FAILIF(sz == (off_t)-1,
+ "lseek(%d, 0, SEEK_END): %s (%d)!\n",
+ fd, strerror(errno), errno);
+
+ // The retouch blob ends with "RETOUCH XXXX", where XXXX is the 4-byte
+ // size of the retouch blob, in target endianness.
+ strncpy(retouch_buf+retouch_byte_cnt, "RETOUCH ", 8);
+ if (elf_little ^ is_host_little()) {
+ *(unsigned int *)(retouch_buf+retouch_byte_cnt+8) =
+ switch_endianness(retouch_byte_cnt);
+ } else {
+ *(unsigned int *)(retouch_buf+retouch_byte_cnt+8) =
+ retouch_byte_cnt;
+ }
+
+ int num_written = write(fd, retouch_buf, retouch_byte_cnt+12);
+ FAILIF(num_written < 0,
+ "write(%d, &info, sizeof(info)): %s (%d)\n",
+ fd, strerror(errno), errno);
+ FAILIF((retouch_byte_cnt+12) != num_written,
+ "Could not write %d bytes as expected (wrote %d bytes instead)!\n",
+ retouch_byte_cnt, num_written);
+ FAILIF(close(fd) < 0, "close(%d): %s (%d)!\n", fd, strerror(errno), errno);
+}
+
void setup_prelink_info(const char *fname, int elf_little, long base)
{
FAILIF(sizeof(prelink_info_t) != 8, "Unexpected sizeof(prelink_info_t) == %zd!\n", sizeof(prelink_info_t));
@@ -92,7 +187,7 @@
else {
/* Different endianness */
INFO("Host and ELF file [%s] have different endianness.\n", fname);
- info.mmap_addr = switch_endianness(base);
+ info.mmap_addr = switch_endianness(base);
}
strncpy(info.tag, "PRE ", 4);
diff --git a/tools/soslim/prelink_info.h b/tools/soslim/prelink_info.h
index e2787cb..efa84fd 100644
--- a/tools/soslim/prelink_info.h
+++ b/tools/soslim/prelink_info.h
@@ -3,6 +3,10 @@
#ifdef SUPPORT_ANDROID_PRELINK_TAGS
int check_prelinked(const char *fname, int elf_little, long *prelink_addr);
+int check_retouched(const char *fname, int elf_little,
+ unsigned int *retouch_byte_cnt, char *retouch_buf);
+void retouch_dump(const char *fname, int elf_little,
+ unsigned int retouch_byte_cnt, char *retouch_buf);
void setup_prelink_info(const char *fname, int elf_little, long base);
#endif
diff --git a/tools/soslim/soslim.c b/tools/soslim/soslim.c
index 125e29e..33b1ee7 100644
--- a/tools/soslim/soslim.c
+++ b/tools/soslim/soslim.c
@@ -27,7 +27,10 @@
#ifdef SUPPORT_ANDROID_PRELINK_TAGS
, int *prelinked,
int *elf_little,
- long *prelink_addr
+ long *prelink_addr,
+ int *retouched,
+ unsigned int *retouch_byte_cnt,
+ char *retouch_buf
#endif
, bool rebuild_shstrtab,
bool strip_debug,
@@ -70,6 +73,11 @@
ASSERT(elf_little);
*elf_little = (ehdr->e_ident[EI_DATA] == ELFDATA2LSB);
*prelinked = check_prelinked(elf_name, *elf_little, prelink_addr);
+ ASSERT(retouched);
+ ASSERT(retouch_byte_cnt);
+ ASSERT(retouch_buf);
+ *retouched = check_retouched(elf_name, *elf_little,
+ retouch_byte_cnt, retouch_buf);
#endif
INFO("\n\nCALCULATING MODIFICATIONS\n\n");
diff --git a/tools/soslim/soslim.h b/tools/soslim/soslim.h
index dfcb085..952c960 100644
--- a/tools/soslim/soslim.h
+++ b/tools/soslim/soslim.h
@@ -23,7 +23,10 @@
#ifdef SUPPORT_ANDROID_PRELINK_TAGS
, int *prelinked,
int *elf_little,
- long *prelink_addr
+ long *prelink_addr,
+ int *retouched,
+ unsigned int *retouch_byte_cnt,
+ char *retouch_buf
#endif
, bool rebuild_shstrtab,
bool strip_debug,