[compiler-rt] 0cf3c43 - [HWASan] Improve symbol indexing (#135967)
via llvm-commits
llvm-commits at lists.llvm.org
Fri May 23 09:43:08 PDT 2025
Author: Stefan Bossbaly
Date: 2025-05-23T09:43:04-07:00
New Revision: 0cf3c437c18ed27d9663d87804a9a15ff6874af2
URL: https://github.com/llvm/llvm-project/commit/0cf3c437c18ed27d9663d87804a9a15ff6874af2
DIFF: https://github.com/llvm/llvm-project/commit/0cf3c437c18ed27d9663d87804a9a15ff6874af2.diff
LOG: [HWASan] Improve symbol indexing (#135967)
Previously we would add any ELF that contained a build id regardless
whether the ELF contained symbols or not. This works for Android since
soong will strip the symbols into a new directory. However other
build systems, like BUCK, will write the stripped file in the same
directory as the unstripped file. This would cause the hwasan_symbolize
script sometimes add then stripped ELF to its index and ignore the
symbolized ELF. The logic has now been changed to only add ELFs that
contain symbols to the index. If two symbolized ELFs are encountered
with the same build id, we now exit out with an error.
Fixes #135966
---------
Co-authored-by: Stefan Bossbaly <sboss at meta.com>
Added:
Modified:
compiler-rt/lib/hwasan/scripts/hwasan_symbolize
Removed:
################################################################################
diff --git a/compiler-rt/lib/hwasan/scripts/hwasan_symbolize b/compiler-rt/lib/hwasan/scripts/hwasan_symbolize
index efca6b82809b9..19d948d1f0aaa 100755
--- a/compiler-rt/lib/hwasan/scripts/hwasan_symbolize
+++ b/compiler-rt/lib/hwasan/scripts/hwasan_symbolize
@@ -16,6 +16,7 @@ from __future__ import unicode_literals
import argparse
import glob
+import hashlib
import html
import json
import mmap
@@ -37,8 +38,9 @@ if sys.version_info.major < 3:
Ehdr_size = 64
e_shnum_offset = 60
e_shoff_offset = 40
-
+e_shstrndx_offset = 62
Shdr_size = 64
+sh_name_offset = 0
sh_type_offset = 4
sh_offset_offset = 24
sh_size_offset = 32
@@ -62,13 +64,32 @@ def handle_Nhdr(mv, sh_size):
offset += Nhdr_size + align_up(n_namesz, 4) + align_up(n_descsz, 4)
return None
-def handle_Shdr(mv):
+def handle_shstrtab(mv, e_shoff):
+ e_shstrndx, = struct.unpack_from('<H', buffer=mv, offset=e_shstrndx_offset)
+
+ start_shstrndx = e_shoff + e_shstrndx * Shdr_size
+ shstrndx_sh = mv[start_shstrndx: start_shstrndx + Shdr_size]
+ _, shstrndx_sh_offset, shstrndx_sh_size = handle_Shdr(shstrndx_sh)
+ return mv[shstrndx_sh_offset:shstrndx_sh_offset + shstrndx_sh_size]
+
+def read_string(mv):
+ name = ""
+ for byte in mv:
+ char = chr(byte)
+ if char == '\x00':
+ break
+ name += char
+ return name
+
+def unpack_sh_type(mv):
sh_type, = struct.unpack_from('<I', buffer=mv, offset=sh_type_offset)
- if sh_type != SHT_NOTE:
- return None, None
+ return sh_type
+
+def handle_Shdr(mv):
+ name_offset, = struct.unpack_from('<I', buffer=mv, offset=sh_name_offset)
sh_offset, = struct.unpack_from('<Q', buffer=mv, offset=sh_offset_offset)
sh_size, = struct.unpack_from('<Q', buffer=mv, offset=sh_size_offset)
- return sh_offset, sh_size
+ return name_offset, sh_offset, sh_size
def handle_elf(mv):
# \x02 is ELFCLASS64, \x01 is ELFDATA2LSB. HWASan currently only works on
@@ -76,19 +97,37 @@ def handle_elf(mv):
# have to extend the parsing code.
if mv[:6] != b'\x7fELF\x02\x01':
return None
+ found_symbols = False
+ bid = None
e_shnum, = struct.unpack_from('<H', buffer=mv, offset=e_shnum_offset)
e_shoff, = struct.unpack_from('<Q', buffer=mv, offset=e_shoff_offset)
+
+ # Section where all the section header names are stored.
+ shstr = handle_shstrtab(mv, e_shoff)
+
for i in range(0, e_shnum):
start = e_shoff + i * Shdr_size
- sh_offset, sh_size = handle_Shdr(mv[start: start + Shdr_size])
- if sh_offset is None:
- continue
- note_hdr = mv[sh_offset: sh_offset + sh_size]
- result = handle_Nhdr(note_hdr, sh_size)
- if result is not None:
- return result
+ sh = mv[start: start + Shdr_size]
+ sh_name_offset, sh_offset, sh_size = handle_Shdr(sh)
+ sh_name = read_string(shstr[sh_name_offset:])
+ sh_type = unpack_sh_type(sh)
+
+ if sh_name == ".debug_info":
+ found_symbols = True
+ if sh_type == SHT_NOTE:
+ if sh_offset is None:
+ continue
+ note_hdr = mv[sh_offset: sh_offset + sh_size]
+ result = handle_Nhdr(note_hdr, sh_size)
+ if result is not None:
+ bid = result
+
+ if found_symbols:
+ return bid
+ else:
+ return None
-def get_buildid(filename):
+def read_elf(filename):
with open(filename, "r") as fd:
if os.fstat(fd.fileno()).st_size < Ehdr_size:
return None
@@ -200,7 +239,7 @@ class Symbolizer:
if os.path.exists(full_path):
return full_path
if name not in self.__warnings:
- print("Could not find symbols for", name, file=sys.stderr)
+ print("Could not find symbols for {} (Build ID: {})".format(name, buildid), file=sys.stderr)
self.__warnings.add(name)
return None
@@ -268,13 +307,30 @@ class Symbolizer:
for fn in fnames:
filename = os.path.join(dname, fn)
try:
- bid = get_buildid(filename)
+ bid = read_elf(filename)
except FileNotFoundError:
continue
except Exception as e:
print("Failed to parse {}: {}".format(filename, e), file=sys.stderr)
continue
- if bid is not None:
+ if bid is None:
+ continue
+
+ if bid in self.__index:
+ index_filename = self.__index[bid]
+
+ if os.path.samefile(index_filename, filename):
+ continue
+
+ with open(filename, "rb") as f:
+ file_hash = hashlib.file_digest(f, "sha256")
+
+ with open(index_filename, "rb") as f:
+ index_file_hash = hashlib.file_digest(f, "sha256")
+
+ if index_file_hash.digest() != file_hash.digest():
+ print("Build ID collision! Files share the same BuildId ({}) but their contents
diff er. Files {} and {} ".format(bid, filename, index_filename), file=sys.stderr)
+ else:
self.__index[bid] = filename
def symbolize_line(self, line):
More information about the llvm-commits
mailing list