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Administrator
Magisk
Commits
4e14dab6
Commit
4e14dab6
authored
Sep 06, 2022
by
topjohnwu
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Plain Diff
Specialize does not need to close logd_fd
parent
6e299018
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Showing
1 changed file
with
74 additions
and
78 deletions
+74
-78
hook.cpp
native/src/zygisk/hook.cpp
+74
-78
No files found.
native/src/zygisk/hook.cpp
View file @
4e14dab6
...
...
@@ -33,6 +33,7 @@ enum {
SERVER_FORK_AND_SPECIALIZE
,
DO_REVERT_UNMOUNT
,
CAN_UNLOAD_ZYGISK
,
SKIP_CLOSE_LOGD_FD
,
FLAG_MAX
};
...
...
@@ -41,6 +42,8 @@ enum {
void name##_pre(); \
void name##_post();
#define MAX_FD_SIZE 1024
struct
HookContext
{
JNIEnv
*
env
;
union
{
...
...
@@ -55,12 +58,12 @@ struct HookContext {
int
pid
;
bitset
<
FLAG_MAX
>
flags
;
uint32_t
info_flags
;
bitset
<
MAX_FD_SIZE
>
allowed_fds
;
HookContext
()
:
env
(
nullptr
),
args
{
nullptr
},
process
(
nullptr
),
pid
(
-
1
),
info_flags
(
0
)
{}
static
void
pre_specialize_start
(
DIR
*
dir
,
bitset
<
1024
>
&
allowed_fds
);
void
pre_specialize_end
(
DIR
*
dir
,
bitset
<
1024
>
&
allowed_fds
);
bool
setup_fd_ignore
(
bitset
<
1024
>
*
allowed_fds
=
nullptr
);
void
setup_fd_ignore
();
void
sanitize_fds
();
void
run_modules_pre
(
const
vector
<
int
>
&
fds
);
void
run_modules_post
();
...
...
@@ -149,7 +152,6 @@ DCL_HOOK_FUNC(int, jniRegisterNativeMethods,
}
// Skip actual fork and return cached result if applicable
// Also unload first stage zygisk if necessary
DCL_HOOK_FUNC
(
int
,
fork
)
{
return
(
g_ctx
&&
g_ctx
->
pid
>=
0
)
?
g_ctx
->
pid
:
old_fork
();
}
...
...
@@ -174,12 +176,18 @@ DCL_HOOK_FUNC(int, unshare, int flags) {
return
res
;
}
// A place to clean things up before zygote evaluates fd table
// Close logd_fd if necessary to prevent crashing
// For more info, check comments in zygisk_log_write
DCL_HOOK_FUNC
(
void
,
android_log_close
)
{
if
(
g_ctx
==
nullptr
||
!
g_ctx
->
flags
[
APP_SPECIALIZE
])
{
// Close fd to prevent crashing.
// For more info, check comments in zygisk_log_write.
if
(
g_ctx
==
nullptr
||
g_ctx
->
pid
>
0
)
{
// This happens either in the zygote daemon or during nativeForkApp, nativeForkUsap etc.
close
(
logd_fd
.
exchange
(
-
1
));
// Do NOT revert back to android logging
}
else
if
(
!
g_ctx
->
flags
[
SKIP_CLOSE_LOGD_FD
])
{
close
(
logd_fd
.
exchange
(
-
1
));
// Switch to plain old android logging because we cannot talk
// to magiskd to fetch our log pipe afterwards anyways.
android_logging
();
}
old_android_log_close
();
}
...
...
@@ -381,81 +389,98 @@ uint32_t ZygiskModule::getFlags() {
// -----------------------------------------------------------------
bool
HookContext
::
setup_fd_ignore
(
bitset
<
1024
>
*
allowed_fds
)
{
if
(
flags
[
APP_SPECIALIZE
])
{
void
HookContext
::
setup_fd_ignore
(
)
{
if
(
flags
[
APP_
FORK_AND_
SPECIALIZE
])
{
if
(
args
.
app
->
fds_to_ignore
==
nullptr
)
{
// The field fds_to_ignore don't exist if
// - Running before Android 8.0
// - Called by nativeSpecializeAppProcess
// In either case, FDs are not checked, so we can simply skip
return
true
;
// The field fds_to_ignore don't exist before Android 8.0, which FDs are not checked
flags
[
SKIP_CLOSE_LOGD_FD
]
=
true
;
return
;
}
bool
success
=
false
;
if
(
jintArray
fdsToIgnore
=
*
args
.
app
->
fds_to_ignore
)
{
int
*
arr
=
env
->
GetIntArrayElements
(
fdsToIgnore
,
nullptr
);
int
len
=
env
->
GetArrayLength
(
fdsToIgnore
);
if
(
allowed_fds
)
{
for
(
int
i
=
0
;
i
<
len
;
++
i
)
{
int
fd
=
arr
[
i
];
if
(
fd
>=
0
&&
fd
<
1024
)
{
(
*
allowed_fds
)[
fd
]
=
true
;
}
if
(
fd
>=
0
&&
fd
<
MAX_FD_SIZE
)
{
allowed_fds
[
fd
]
=
true
;
}
}
jintArray
newFdList
=
nullptr
;
if
(
logd_fd
>=
0
&&
(
newFdList
=
env
->
NewIntArray
(
len
+
1
)))
{
success
=
true
;
env
->
SetIntArrayRegion
(
newFdList
,
0
,
len
,
arr
);
int
fd
=
logd_fd
;
env
->
SetIntArrayRegion
(
newFdList
,
len
,
1
,
&
fd
);
*
args
.
app
->
fds_to_ignore
=
newFdList
;
success
=
true
;
}
env
->
ReleaseIntArrayElements
(
fdsToIgnore
,
arr
,
JNI_ABORT
);
}
else
{
jintArray
newFdList
=
nullptr
;
if
(
logd_fd
>=
0
&&
(
newFdList
=
env
->
NewIntArray
(
1
)))
{
success
=
true
;
int
fd
=
logd_fd
;
env
->
SetIntArrayRegion
(
newFdList
,
0
,
1
,
&
fd
);
*
args
.
app
->
fds_to_ignore
=
newFdList
;
success
=
true
;
}
}
return
success
;
flags
[
SKIP_CLOSE_LOGD_FD
]
=
success
;
}
return
false
;
}
void
HookContext
::
pre_specialize_start
(
DIR
*
dir
,
bitset
<
1024
>
&
allowed_fds
)
{
// Record all open fds
for
(
dirent
*
entry
;
(
entry
=
xreaddir
(
dir
));)
{
void
HookContext
::
sanitize_fds
()
{
setup_fd_ignore
();
// Close all forbidden fds to prevent crashing
auto
dir
=
xopen_dir
(
"/proc/self/fd"
);
rewinddir
(
dir
.
get
());
int
dfd
=
dirfd
(
dir
.
get
());
for
(
dirent
*
entry
;
(
entry
=
xreaddir
(
dir
.
get
()));)
{
int
fd
=
parse_int
(
entry
->
d_name
);
if
(
fd
<
0
||
fd
>=
1024
)
{
if
(
(
fd
<
0
||
fd
>=
MAX_FD_SIZE
||
!
allowed_fds
[
fd
])
&&
fd
!=
dfd
)
{
close
(
fd
);
continue
;
}
allowed_fds
[
fd
]
=
true
;
}
}
void
HookContext
::
pre_specialize_end
(
DIR
*
dir
,
bitset
<
1024
>
&
allowed_fds
)
{
bool
disable_zygisk_logging
=
!
setup_fd_ignore
(
&
allowed_fds
);
int
sigmask
(
int
how
,
int
signum
)
{
sigset_t
set
;
sigemptyset
(
&
set
);
sigaddset
(
&
set
,
signum
);
return
sigprocmask
(
how
,
&
set
,
nullptr
);
}
// Close all forbidden fds to prevent crashing
rewinddir
(
dir
);
for
(
dirent
*
entry
;
(
entry
=
xreaddir
(
dir
));)
{
void
HookContext
::
fork_pre
()
{
g_ctx
=
this
;
// Do our own fork before loading any 3rd party code
// First block SIGCHLD, unblock after original fork is done
sigmask
(
SIG_BLOCK
,
SIGCHLD
);
pid
=
old_fork
();
if
(
pid
==
0
)
{
// Record all open fds
auto
dir
=
xopen_dir
(
"/proc/self/fd"
);
for
(
dirent
*
entry
;
(
entry
=
xreaddir
(
dir
.
get
()));)
{
int
fd
=
parse_int
(
entry
->
d_name
);
if
(
fd
<
0
||
fd
>=
1024
||
!
allowed_fds
[
fd
]
)
{
if
(
fd
<
0
||
fd
>=
MAX_FD_SIZE
)
{
close
(
fd
);
continue
;
}
allowed_fds
[
fd
]
=
true
;
}
if
(
disable_zygisk_logging
)
{
close
(
logd_fd
.
exchange
(
-
1
));
android_logging
();
// The dirfd should not be allowed
allowed_fds
[
dirfd
(
dir
.
get
())]
=
false
;
}
}
void
HookContext
::
fork_post
()
{
// Unblock SIGCHLD in case the original method didn't
sigmask
(
SIG_UNBLOCK
,
SIGCHLD
);
g_ctx
=
nullptr
;
unload_zygisk
();
}
void
HookContext
::
run_modules_pre
(
const
vector
<
int
>
&
fds
)
{
// Because the data structure stored in the vector is self referencing, in order to prevent
// dangling pointers, the vector has to be pre-allocated to ensure reallocation does not occur
...
...
@@ -528,12 +553,10 @@ void HookContext::nativeSpecializeAppProcess_pre() {
ZLOGV
(
"pre forkAndSpecialize [%s]
\n
"
,
process
);
}
else
{
ZLOGV
(
"pre specialize [%s]
\n
"
,
process
);
// App specialize does not check FD
flags
[
SKIP_CLOSE_LOGD_FD
]
=
true
;
}
bitset
<
1024
>
allowed_fds
;
auto
dir
=
open_dir
(
"/proc/self/fd"
);
pre_specialize_start
(
dir
.
get
(),
allowed_fds
);
vector
<
int
>
module_fds
;
int
fd
=
remote_get_info
(
args
.
app
->
uid
,
process
,
&
info_flags
,
module_fds
);
if
((
info_flags
&
UNMOUNT_MASK
)
==
UNMOUNT_MASK
)
{
...
...
@@ -543,8 +566,6 @@ void HookContext::nativeSpecializeAppProcess_pre() {
run_modules_pre
(
module_fds
);
}
close
(
fd
);
pre_specialize_end
(
dir
.
get
(),
allowed_fds
);
}
void
HookContext
::
nativeSpecializeAppProcess_post
()
{
...
...
@@ -577,10 +598,6 @@ void HookContext::nativeForkSystemServer_pre() {
ZLOGV
(
"pre forkSystemServer
\n
"
);
bitset
<
1024
>
allowed_fds
;
auto
dir
=
open_dir
(
"/proc/self/fd"
);
pre_specialize_start
(
dir
.
get
(),
allowed_fds
);
vector
<
int
>
module_fds
;
int
fd
=
remote_get_info
(
1000
,
"system_server"
,
&
info_flags
,
module_fds
);
if
(
fd
>=
0
)
{
...
...
@@ -602,7 +619,7 @@ void HookContext::nativeForkSystemServer_pre() {
close
(
fd
);
}
pre_specialize_end
(
dir
.
get
(),
allowed_fds
);
sanitize_fds
(
);
}
void
HookContext
::
nativeForkSystemServer_post
()
{
...
...
@@ -618,8 +635,9 @@ void HookContext::nativeForkAndSpecialize_pre() {
flags
[
APP_FORK_AND_SPECIALIZE
]
=
true
;
if
(
pid
==
0
)
{
nativeSpecializeAppProcess_pre
();
}
else
if
(
!
setup_fd_ignore
())
{
close
(
logd_fd
.
exchange
(
-
1
));
sanitize_fds
();
}
else
{
setup_fd_ignore
();
}
}
...
...
@@ -630,28 +648,6 @@ void HookContext::nativeForkAndSpecialize_post() {
fork_post
();
}
int
sigmask
(
int
how
,
int
signum
)
{
sigset_t
set
;
sigemptyset
(
&
set
);
sigaddset
(
&
set
,
signum
);
return
sigprocmask
(
how
,
&
set
,
nullptr
);
}
// Do our own fork before loading any 3rd party code
// First block SIGCHLD, unblock after original fork is done
void
HookContext
::
fork_pre
()
{
g_ctx
=
this
;
sigmask
(
SIG_BLOCK
,
SIGCHLD
);
pid
=
old_fork
();
}
// Unblock SIGCHLD in case the original method didn't
void
HookContext
::
fork_post
()
{
sigmask
(
SIG_UNBLOCK
,
SIGCHLD
);
g_ctx
=
nullptr
;
unload_zygisk
();
}
}
// namespace
static
bool
hook_refresh
()
{
...
...
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