Issue 357: New Linux file_id code doesn't persist across strip. r=agl,nealsid at http://breakpad.appspot.com/49008

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@461 4c0a9323-5329-0410-9bdc-e9ce6186880e
This commit is contained in:
ted.mielczarek 2009-12-23 17:09:27 +00:00
parent 1adb184d42
commit 0a5fc5d663
9 changed files with 283 additions and 36 deletions

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@ -39,6 +39,7 @@ TEST_CC_SRC=handler/exception_handler_unittest.cc \
minidump_writer/line_reader_unittest.cc \
minidump_writer/linux_dumper_unittest.cc \
minidump_writer/minidump_writer_unittest.cc \
../../common/linux/file_id.cc \
$(GOOGLETEST_CC_SRC)
TEST_CC_OBJ=$(patsubst %.cc, $(OBJ_DIR)/%.o,$(TEST_CC_SRC))

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@ -42,15 +42,20 @@
#include <string.h>
#include <unistd.h>
#include <elf.h>
#include <errno.h>
#include <fcntl.h>
#include <link.h>
#include <sys/types.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <algorithm>
#include "client/linux/minidump_writer/directory_reader.h"
#include "client/linux/minidump_writer/line_reader.h"
#include "common/linux/file_id.h"
#include "common/linux/linux_libc_support.h"
#include "common/linux/linux_syscall_support.h"
@ -156,6 +161,30 @@ LinuxDumper::BuildProcPath(char* path, pid_t pid, const char* node) const {
memcpy(path + total_length, "\0", 1);
}
bool
LinuxDumper::ElfFileIdentifierForMapping(unsigned int mapping_id,
uint8_t identifier[sizeof(MDGUID)])
{
assert(mapping_id < mappings_.size());
const MappingInfo* mapping = mappings_[mapping_id];
int fd = sys_open(mapping->name, O_RDONLY, 0);
if (fd < 0)
return false;
struct kernel_stat st;
if (sys_fstat(fd, &st) != 0) {
sys_close(fd);
return false;
}
void* base = sys_mmap2(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
sys_close(fd);
if (base == MAP_FAILED)
return false;
bool success = FileID::ElfFileIdentifierFromMappedFile(base, identifier);
sys_munmap(base, st.st_size);
return success;
}
void*
LinuxDumper::FindBeginningOfLinuxGateSharedLibrary(const pid_t pid) const {
char auxv_path[80];

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@ -37,6 +37,7 @@
#include <sys/user.h>
#include "common/linux/memory.h"
#include "google_breakpad/common/minidump_format.h"
namespace google_breakpad {
@ -122,6 +123,10 @@ class LinuxDumper {
// without any slashes.
void BuildProcPath(char* path, pid_t pid, const char* node) const;
// Generate a File ID from the .text section of a mapped entry
bool ElfFileIdentifierForMapping(unsigned int mapping_id,
uint8_t identifier[sizeof(MDGUID)]);
// Utility method to find the location of where the kernel has
// mapped linux-gate.so in memory(shows up in /proc/pid/maps as
// [vdso], but we can't guarantee that it's the only virtual dynamic

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@ -27,13 +27,25 @@
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include <limits.h>
#include <unistd.h>
#include "client/linux/minidump_writer/linux_dumper.h"
#include "common/linux/file_id.h"
#include "breakpad_googletest_includes.h"
using namespace google_breakpad;
// This provides a wrapper around system calls which may be
// interrupted by a signal and return EINTR. See man 7 signal.
#define HANDLE_EINTR(x) ({ \
typeof(x) __eintr_result__; \
do { \
__eintr_result__ = x; \
} while (__eintr_result__ == -1 && errno == EINTR); \
__eintr_result__;\
})
namespace {
typedef testing::Test LinuxDumperTest;
}
@ -116,3 +128,56 @@ TEST(LinuxDumperTest, MappingsIncludeLinuxGate) {
EXPECT_EQ(0, memcmp(linux_gate_loc, ELFMAG, SELFMAG));
}
}
TEST(LinuxDumperTest, FileIDsMatch) {
// Calculate the File ID of our binary using both
// FileID::ElfFileIdentifier and LinuxDumper::ElfFileIdentifierForMapping
// and ensure that we get the same result from both.
char exe_name[PATH_MAX];
ssize_t len = readlink("/proc/self/exe", exe_name, PATH_MAX - 1);
ASSERT_NE(len, -1);
exe_name[len] = '\0';
int fds[2];
ASSERT_NE(-1, pipe(fds));
// fork a child so we can ptrace it
const pid_t child = fork();
if (child == 0) {
close(fds[1]);
// now wait forever for the parent
char b;
HANDLE_EINTR(read(fds[0], &b, sizeof(b)));
close(fds[0]);
syscall(__NR_exit);
}
close(fds[0]);
LinuxDumper dumper(child);
ASSERT_TRUE(dumper.Init());
const wasteful_vector<MappingInfo*> mappings = dumper.mappings();
bool found_exe = false;
unsigned i;
for (i = 0; i < mappings.size(); ++i) {
const MappingInfo* mapping = mappings[i];
if (!strcmp(mapping->name, exe_name)) {
found_exe = true;
break;
}
}
ASSERT_TRUE(found_exe);
uint8_t identifier1[sizeof(MDGUID)];
uint8_t identifier2[sizeof(MDGUID)];
EXPECT_TRUE(dumper.ElfFileIdentifierForMapping(i, identifier1));
FileID fileid(exe_name);
EXPECT_TRUE(fileid.ElfFileIdentifier(identifier2));
char identifier_string1[37];
char identifier_string2[37];
FileID::ConvertIdentifierToString(identifier1, identifier_string1,
37);
FileID::ConvertIdentifierToString(identifier2, identifier_string2,
37);
EXPECT_STREQ(identifier_string1, identifier_string2);
close(fds[1]);
}

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@ -547,26 +547,11 @@ class MinidumpWriter {
const uint32_t cv_signature = MD_CVINFOPDB70_SIGNATURE;
memcpy(cv_ptr, &cv_signature, sizeof(cv_signature));
cv_ptr += sizeof(cv_signature);
{
// We XOR the first page of the file to get a signature for it.
uint8_t xor_buf[sizeof(MDGUID)];
size_t done = 0;
uint8_t* signature = cv_ptr;
cv_ptr += sizeof(xor_buf);
my_memset(signature, 0, sizeof(xor_buf));
while (done < 4096) {
dumper_.CopyFromProcess(xor_buf, crashing_tid_,
(void *) (mod.base_of_image + done),
sizeof(xor_buf));
for (unsigned i = 0; i < sizeof(xor_buf); ++i)
signature[i] ^= xor_buf[i];
done += sizeof(xor_buf);
}
my_memset(cv_ptr, 0, sizeof(uint32_t)); // Set age to 0 on Linux.
cv_ptr += sizeof(uint32_t);
}
uint8_t* signature = cv_ptr;
cv_ptr += sizeof(MDGUID);
dumper_.ElfFileIdentifierForMapping(i, signature);
my_memset(cv_ptr, 0, sizeof(uint32_t)); // Set age to 0 on Linux.
cv_ptr += sizeof(uint32_t);
// Write pdb_file_name
memcpy(cv_ptr, filename_ptr, filename_len + 1);

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@ -33,6 +33,8 @@
//
#include "common/linux/file_id.h"
#include "common/linux/linux_libc_support.h"
#include "common/linux/linux_syscall_support.h"
#include <arpa/inet.h>
#include <elf.h>
@ -42,6 +44,7 @@
#include <sys/mman.h>
#include <unistd.h>
#include <algorithm>
#include <cassert>
#include <cstdio>
@ -51,33 +54,94 @@ FileID::FileID(const char* path) {
strncpy(path_, path, sizeof(path_));
}
// These two functions are also used inside the crashed process, so be safe
// and use the syscall/libc wrappers instead of direct syscalls or libc.
static bool FindElfTextSection(const void *elf_mapped_base,
const void **text_start,
int *text_size) {
assert(elf_mapped_base);
assert(text_start);
assert(text_size);
const char* elf_base =
static_cast<const char*>(elf_mapped_base);
const ElfW(Ehdr)* elf_header =
reinterpret_cast<const ElfW(Ehdr)*>(elf_base);
if (my_strncmp(elf_base, ELFMAG, SELFMAG) != 0)
return false;
#if __ELF_NATIVE_CLASS == 32
#define ELFCLASS ELFCLASS32
#else
#define ELFCLASS ELFCLASS64
#endif
//TODO: support dumping 32-bit binaries from a 64-bit dump_syms?
if (elf_header->e_ident[EI_CLASS] != ELFCLASS)
return false;
*text_start = NULL;
*text_size = 0;
const ElfW(Shdr)* sections =
reinterpret_cast<const ElfW(Shdr)*>(elf_base + elf_header->e_shoff);
const char* text_section_name = ".text";
int name_len = my_strlen(text_section_name);
const ElfW(Shdr)* string_section = sections + elf_header->e_shstrndx;
const ElfW(Shdr)* text_section = NULL;
for (int i = 0; i < elf_header->e_shnum; ++i) {
if (sections[i].sh_type == SHT_PROGBITS) {
const char* section_name = (char*)(elf_base +
string_section->sh_offset +
sections[i].sh_name);
if (!my_strncmp(section_name, text_section_name, name_len)) {
text_section = &sections[i];
break;
}
}
}
if (text_section != NULL && text_section->sh_size > 0) {
*text_start = elf_base + text_section->sh_offset;
*text_size = text_section->sh_size;
}
return true;
}
// static
bool FileID::ElfFileIdentifierFromMappedFile(void* base,
uint8_t identifier[kMDGUIDSize])
{
const void* text_section = NULL;
int text_size = 0;
bool success = false;
if (FindElfTextSection(base, &text_section, &text_size) && (text_size > 0)) {
my_memset(identifier, 0, kMDGUIDSize);
const uint8_t* ptr = reinterpret_cast<const uint8_t*>(text_section);
const uint8_t* ptr_end = ptr + std::min(text_size, 4096);
while (ptr < ptr_end) {
for (unsigned i = 0; i < kMDGUIDSize; i++)
identifier[i] ^= ptr[i];
ptr += kMDGUIDSize;
}
success = true;
}
return success;
}
bool FileID::ElfFileIdentifier(uint8_t identifier[kMDGUIDSize]) {
const ssize_t mapped_len = 4096; // Page size (matches WriteMappings())
int fd = open(path_, O_RDONLY);
if (fd < 0)
return false;
struct stat st;
if (fstat(fd, &st) != 0 || st.st_size <= mapped_len) {
if (fstat(fd, &st) != 0) {
close(fd);
return false;
}
void* base = mmap(NULL, mapped_len,
void* base = mmap(NULL, st.st_size,
PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
close(fd);
if (base == MAP_FAILED)
return false;
memset(identifier, 0, kMDGUIDSize);
uint8_t* ptr = reinterpret_cast<uint8_t*>(base);
uint8_t* ptr_end = ptr + mapped_len;
while (ptr < ptr_end) {
for (unsigned i = 0; i < kMDGUIDSize; i++)
identifier[i] ^= ptr[i];
ptr += kMDGUIDSize;
}
munmap(base, mapped_len);
return true;
bool success = ElfFileIdentifierFromMappedFile(base, identifier);
munmap(base, st.st_size);
return success;
}
// static

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@ -49,10 +49,16 @@ class FileID {
// Load the identifier for the elf file path specified in the constructor into
// |identifier|. Return false if the identifier could not be created for the
// file.
// The current implementation will XOR the first page of data to generate an
// identifier.
// The current implementation will XOR the first 4096 bytes of the
// .text section to generate an identifier.
bool ElfFileIdentifier(uint8_t identifier[kMDGUIDSize]);
// Load the identifier for the elf file mapped into memory at |base| into
// |identifier|. Return false if the identifier could not be created for the
// file.
static bool ElfFileIdentifierFromMappedFile(void* base,
uint8_t identifier[kMDGUIDSize]);
// Convert the |identifier| data to a NULL terminated string. The string will
// be formatted as a UUID (e.g., 22F065BB-FC9C-49F7-80FE-26A7CEBD7BCE).
// The |buffer| should be at least 37 bytes long to receive all of the data

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@ -0,0 +1,76 @@
// Copyright (c) 2009, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// Unit tests for FileID
#include <stdlib.h>
#include "common/linux/file_id.h"
#include "breakpad_googletest_includes.h"
using namespace google_breakpad;
namespace {
typedef testing::Test FileIDTest;
}
TEST(FileIDTest, FileIDStrip) {
// Calculate the File ID of our binary using
// FileID::ElfFileIdentifier, then make a copy of our binary,
// strip it, and ensure that we still get the same result.
char exe_name[PATH_MAX];
ssize_t len = readlink("/proc/self/exe", exe_name, PATH_MAX - 1);
ASSERT_NE(len, -1);
exe_name[len] = '\0';
// copy our binary to a temp file, and strip it
char templ[] = "/tmp/file-id-unittest-XXXXXX";
mktemp(templ);
char cmdline[4096];
sprintf(cmdline, "cp \"%s\" \"%s\"", exe_name, templ);
ASSERT_EQ(system(cmdline), 0);
sprintf(cmdline, "strip \"%s\"", templ);
ASSERT_EQ(system(cmdline), 0);
uint8_t identifier1[sizeof(MDGUID)];
uint8_t identifier2[sizeof(MDGUID)];
FileID fileid1(exe_name);
EXPECT_TRUE(fileid1.ElfFileIdentifier(identifier1));
FileID fileid2(templ);
EXPECT_TRUE(fileid2.ElfFileIdentifier(identifier2));
char identifier_string1[37];
char identifier_string2[37];
FileID::ConvertIdentifierToString(identifier1, identifier_string1,
37);
FileID::ConvertIdentifierToString(identifier2, identifier_string2,
37);
EXPECT_STREQ(identifier_string1, identifier_string2);
unlink(templ);
}

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@ -113,6 +113,22 @@ stabs_reader_unittest.o: override CPPFLAGS += $(GTEST_CPPFLAGS) \
clean::
rm -f stabs_reader_unittest
### Unit tests for google_breakpad::FileID.
check: check-file_id_unittest
check-file_id_unittest: file_id_unittest
file_id_unittest: \
gmock-all.o \
gtest-all.o \
gtest_main.o \
file_id.o \
$(empty)
CPP_EXECUTABLES += file_id_unittest
file_id_unittest.o: file_id_unittest.cc
file_id_unittest.o: override CPPFLAGS += $(GTEST_CPPFLAGS) \
$(GMOCK_CPPFLAGS)
clean::
rm -f file_id_unittest
### Generic compilation rules.