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Merge "Properly handle wrap system property in zygote" am: c7e5064bcb am: 2d3104f0fa

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Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1978990

Change-Id: If6dd70b2443ef55fa54e78d4ae0bffa52343aff5
This commit is contained in:
Hans Boehm
2022-03-10 22:00:58 +00:00
committed by Automerger Merge Worker
parent 1d7298bcec 2d3104f0fa
commit 73d67abbdc
1 changed files with 20 additions and 4 deletions
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24
core/jni/com_android_internal_os_ZygoteCommandBuffer.cpp
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@@ -34,6 +34,7 @@
#include <sys/mman.h> #include <sys/mman.h>
#include <sys/types.h> #include <sys/types.h>
#include <sys/socket.h> #include <sys/socket.h>
#include <sys/system_properties.h>
#include <vector> #include <vector>
namespace android { namespace android {
@@ -43,10 +44,10 @@ using android::base::StringPrintf;
using android::zygote::ZygoteFailure; using android::zygote::ZygoteFailure;
// WARNING: Knows a little about the wire protocol used to communicate with Zygote. // WARNING: Knows a little about the wire protocol used to communicate with Zygote.
// TODO: Fix error handling.
// Commands and nice names have large arbitrary size limits to avoid dynamic memory allocation.
constexpr size_t MAX_COMMAND_BYTES = 32768; constexpr size_t MAX_COMMAND_BYTES = 32768;
constexpr size_t NICE_NAME_BYTES = 50; constexpr size_t NICE_NAME_BYTES = 128;
// A buffer optionally bundled with a file descriptor from which we can fill it. // A buffer optionally bundled with a file descriptor from which we can fill it.
// Does not own the file descriptor; destroying a NativeCommandBuffer does not // Does not own the file descriptor; destroying a NativeCommandBuffer does not
@@ -190,6 +191,9 @@ class NativeCommandBuffer {
size_t copy_len = std::min(name_len, NICE_NAME_BYTES - 1); size_t copy_len = std::min(name_len, NICE_NAME_BYTES - 1);
memcpy(mNiceName, arg_start + NN_LENGTH, copy_len); memcpy(mNiceName, arg_start + NN_LENGTH, copy_len);
mNiceName[copy_len] = '\0'; mNiceName[copy_len] = '\0';
if (haveWrapProperty()) {
return false;
}
continue; continue;
} }
if (arg_end - arg_start == IW_LENGTH if (arg_end - arg_start == IW_LENGTH
@@ -222,6 +226,8 @@ class NativeCommandBuffer {
} }
saw_setgid = true; saw_setgid = true;
} }
// ro.debuggable can be handled entirely in the child unless --invoke-with is also specified.
// Thus we do not need to check it here.
} }
return saw_runtime_args && saw_setuid && saw_setgid; return saw_runtime_args && saw_setuid && saw_setgid;
} }
@@ -249,6 +255,14 @@ class NativeCommandBuffer {
} }
private: private:
bool haveWrapProperty() {
static const char* WRAP = "wrap.";
static const size_t WRAP_LENGTH = strlen(WRAP);
char propNameBuf[WRAP_LENGTH + NICE_NAME_BYTES];
strcpy(propNameBuf, WRAP);
strlcpy(propNameBuf + WRAP_LENGTH, mNiceName, NICE_NAME_BYTES);
return __system_property_find(propNameBuf) != nullptr;
}
// Picky version of atoi(). No sign or unexpected characters allowed. Return -1 on failure. // Picky version of atoi(). No sign or unexpected characters allowed. Return -1 on failure.
static int digitsVal(char* start, char* end) { static int digitsVal(char* start, char* end) {
int result = 0; int result = 0;
@@ -269,7 +283,7 @@ class NativeCommandBuffer {
uint32_t mNext; // Index of first character past last line returned by readLine. uint32_t mNext; // Index of first character past last line returned by readLine.
int32_t mLinesLeft; // Lines in current command that haven't yet been read. int32_t mLinesLeft; // Lines in current command that haven't yet been read.
int mFd; // Open file descriptor from which we can read more. -1 if none. int mFd; // Open file descriptor from which we can read more. -1 if none.
char mNiceName[NICE_NAME_BYTES]; char mNiceName[NICE_NAME_BYTES]; // Always null terminated.
char mBuffer[MAX_COMMAND_BYTES]; char mBuffer[MAX_COMMAND_BYTES];
}; };
@@ -372,6 +386,7 @@ jboolean com_android_internal_os_ZygoteCommandBuffer_nativeForkRepeatedly(
jint minUid, jint minUid,
jstring managed_nice_name) { jstring managed_nice_name) {
ALOGI("Entering forkRepeatedly native zygote loop");
NativeCommandBuffer* n_buffer = reinterpret_cast<NativeCommandBuffer*>(j_buffer); NativeCommandBuffer* n_buffer = reinterpret_cast<NativeCommandBuffer*>(j_buffer);
int session_socket = n_buffer->getFd(); int session_socket = n_buffer->getFd();
std::vector<int> session_socket_fds {session_socket}; std::vector<int> session_socket_fds {session_socket};
@@ -400,7 +415,8 @@ jboolean com_android_internal_os_ZygoteCommandBuffer_nativeForkRepeatedly(
socklen_t cred_size = sizeof credentials; socklen_t cred_size = sizeof credentials;
if (getsockopt(n_buffer->getFd(), SOL_SOCKET, SO_PEERCRED, &credentials, &cred_size) == -1 if (getsockopt(n_buffer->getFd(), SOL_SOCKET, SO_PEERCRED, &credentials, &cred_size) == -1
|| cred_size != sizeof credentials) { || cred_size != sizeof credentials) {
fail_fn_1(CREATE_ERROR("ForkMany failed to get initial credentials, %s", strerror(errno))); fail_fn_1(CREATE_ERROR("ForkRepeatedly failed to get initial credentials, %s",
strerror(errno)));
} }
bool first_time = true; bool first_time = true;