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eafab235
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2021-03-24T11:38:36
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arm64e: Pull in pointer authentication code from Apple's arm64e libffi port (#565)
NOTES: This changes the ptrauth support from #548 to match what Apple is
shipping in its libffi-27 tag.
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
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d271dbe0
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2021-03-20T06:06:28
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Add some missing #if conditionals from Apple's code drop (#620)
* arm/aarch64: Add FFI_CLOSURES conditionals where appropriate
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
* aarch64: Don't emit the do_closure label when building without FFI_GO_CLOSURES
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
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9ba55921
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2021-03-05T10:07:30
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Static tramp v5 (#624)
* Static Trampolines
Closure Trampoline Security Issue
=================================
Currently, the trampoline code used in libffi is not statically defined in
a source file (except for MACH). The trampoline is either pre-defined
machine code in a data buffer. Or, it is generated at runtime. In order to
execute a trampoline, it needs to be placed in a page with executable
permissions.
Executable data pages are attack surfaces for attackers who may try to
inject their own code into the page and contrive to have it executed. The
security settings in a system may prevent various tricks used in user land
to write code into a page and to have it executed somehow. On such systems,
libffi trampolines would not be able to run.
Static Trampoline
=================
To solve this problem, the trampoline code needs to be defined statically
in a source file, compiled and placed in the text segment so it can be
mapped and executed naturally without any tricks. However, the trampoline
needs to be able to access the closure pointer at runtime.
PC-relative data referencing
============================
The solution implemented in this patch set uses PC-relative data references.
The trampoline is mapped in a code page. Adjacent to the code page, a data
page is mapped that contains the parameters of the trampoline:
- the closure pointer
- pointer to the ABI handler to jump to
The trampoline code uses an offset relative to its current PC to access its
data.
Some architectures support PC-relative data references in the ISA itself.
E.g., X64 supports RIP-relative references. For others, the PC has to
somehow be loaded into a general purpose register to do PC-relative data
referencing. To do this, we need to define a get_pc() kind of function and
call it to load the PC in a desired register.
There are two cases:
1. The call instruction pushes the return address on the stack.
In this case, get_pc() will extract the return address from the stack
and load it in the desired register and return.
2. The call instruction stores the return address in a designated register.
In this case, get_pc() will copy the return address to the desired
register and return.
Either way, the PC next to the call instruction is obtained.
Scratch register
================
In order to do its job, the trampoline code would need to use a scratch
register. Depending on the ABI, there may not be a register available for
scratch. This problem needs to be solved so that all ABIs will work.
The trampoline will save two values on the stack:
- the closure pointer
- the original value of the scratch register
This is what the stack will look like:
sp before trampoline ------> --------------------
| closure pointer |
--------------------
| scratch register |
sp after trampoline -------> --------------------
The ABI handler can do the following as needed by the ABI:
- the closure pointer can be loaded in a desired register
- the scratch register can be restored to its original value
- the stack pointer can be restored to its original value
(the value when the trampoline was invoked)
To do this, I have defined prolog code for each ABI handler. The legacy
trampoline jumps to the ABI handler directly. But the static trampoline
defined in this patch jumps tp the prolog code which performs the above
actions before jumping to the ABI handler.
Trampoline Table
================
In order to reduce the trampoline memory footprint, the trampoline code
would be defined as a code array in the text segment. This array would be
mapped into the address space of the caller. The mapping would, therefore,
contain a trampoline table.
Adjacent to the trampoline table mapping, there will be a data mapping that
contains a parameter table, one parameter block for each trampoline. The
parameter block will contain:
- a pointer to the closure
- a pointer to the ABI handler
The static trampoline code would finally look like this:
- Make space on the stack for the closure and the scratch register
by moving the stack pointer down
- Store the original value of the scratch register on the stack
- Using PC-relative reference, get the closure pointer
- Store the closure pointer on the stack
- Using PC-relative reference, get the ABI handler pointer
- Jump to the ABI handler
Mapping size
============
The size of the code mapping that contains the trampoline table needs to be
determined on a per architecture basis. If a particular architecture
supports multiple base page sizes, then the largest supported base page size
needs to be chosen. E.g., we choose 16K for ARM64.
Trampoline allocation and free
==============================
Static trampolines are allocated in ffi_closure_alloc() and freed in
ffi_closure_free().
Normally, applications use these functions. But there are some cases out
there where the user of libffi allocates and manages its own closure
memory. In such cases, static trampolines cannot be used. These will
fall back to using legacy trampolines. The user has to make sure that
the memory is executable.
ffi_closure structure
=====================
I did not want to make any changes to the size of the closure structure for
this feature to guarantee compatibility. But the opaque static trampoline
handle needs to be stored in the closure. I have defined it as follows:
- char tramp[FFI_TRAMPOLINE_SIZE];
+ union {
+ char tramp[FFI_TRAMPOLINE_SIZE];
+ void *ftramp;
+ };
If static trampolines are used, then tramp[] is not needed to store a
dynamic trampoline. That space can be reused to store the handle. Hence,
the union.
Architecture Support
====================
Support has been added for x64, i386, aarch64 and arm. Support for other
architectures can be added very easily in the future.
OS Support
==========
Support has been added for Linux. Support for other OSes can be added very
easily.
Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
* x86: Support for Static Trampolines
- Define the arch-specific initialization function ffi_tramp_arch ()
that returns trampoline size information to common code.
- Define the trampoline code mapping and data mapping sizes.
- Define the trampoline code table statically. Define two tables,
actually, one with CET and one without.
- Introduce a tiny prolog for each ABI handling function. The ABI
handlers addressed are:
- ffi_closure_unix64
- ffi_closure_unix64_sse
- ffi_closure_win64
The prolog functions are called:
- ffi_closure_unix64_alt
- ffi_closure_unix64_sse_alt
- ffi_closure_win64_alt
The legacy trampoline jumps to the ABI handler. The static
trampoline jumps to the prolog function. The prolog function uses
the information provided by the static trampoline, sets things up
for the ABI handler and then jumps to the ABI handler.
- Call ffi_tramp_set_parms () in ffi_prep_closure_loc () to
initialize static trampoline parameters.
Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
* i386: Support for Static Trampolines
- Define the arch-specific initialization function ffi_tramp_arch ()
that returns trampoline size information to common code.
- Define the trampoline code table statically. Define two tables,
actually, one with CET and one without.
- Define the trampoline code table statically.
- Introduce a tiny prolog for each ABI handling function. The ABI
handlers addressed are:
- ffi_closure_i386
- ffi_closure_STDCALL
- ffi_closure_REGISTER
The prolog functions are called:
- ffi_closure_i386_alt
- ffi_closure_STDCALL_alt
- ffi_closure_REGISTER_alt
The legacy trampoline jumps to the ABI handler. The static
trampoline jumps to the prolog function. The prolog function uses
the information provided by the static trampoline, sets things up
for the ABI handler and then jumps to the ABI handler.
- Call ffi_tramp_set_parms () in ffi_prep_closure_loc () to
initialize static trampoline parameters.
Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
* arm64: Support for Static Trampolines
- Define the arch-specific initialization function ffi_tramp_arch ()
that returns trampoline size information to common code.
- Define the trampoline code mapping and data mapping sizes.
- Define the trampoline code table statically.
- Introduce a tiny prolog for each ABI handling function. The ABI
handlers addressed are:
- ffi_closure_SYSV
- ffi_closure_SYSV_V
The prolog functions are called:
- ffi_closure_SYSV_alt
- ffi_closure_SYSV_V_alt
The legacy trampoline jumps to the ABI handler. The static
trampoline jumps to the prolog function. The prolog function uses
the information provided by the static trampoline, sets things up
for the ABI handler and then jumps to the ABI handler.
- Call ffi_tramp_set_parms () in ffi_prep_closure_loc () to
initialize static trampoline parameters.
Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
* arm: Support for Static Trampolines
- Define the arch-specific initialization function ffi_tramp_arch ()
that returns trampoline size information to common code.
- Define the trampoline code mapping and data mapping sizes.
- Define the trampoline code table statically.
- Introduce a tiny prolog for each ABI handling function. The ABI
handlers addressed are:
- ffi_closure_SYSV
- ffi_closure_VFP
The prolog functions are called:
- ffi_closure_SYSV_alt
- ffi_closure_VFP_alt
The legacy trampoline jumps to the ABI handler. The static
trampoline jumps to the prolog function. The prolog function uses
the information provided by the static trampoline, sets things up
for the ABI handler and then jumps to the ABI handler.
- Call ffi_tramp_set_parms () in ffi_prep_closure_loc () to
initialize static trampoline parameters.
Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
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8e58f88d
|
2020-06-30T22:59:28
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aarch64: Fix typo
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|
4c7bde32
|
2020-03-10T02:05:42
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|
Port to iOS/arm64e (#548)
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a7d6396f
|
2019-03-29T14:19:20
|
|
fix check for Linux/aarch64
fixes #473
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05a17964
|
2019-02-19T04:11:28
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|
Cleanup symbol exports on darwin and add architecture preprocessor checks to assist in building fat binaries (eg: i386+x86_64 on macOS or arm+aarch64 on iOS) (#450)
* x86: Ensure _efi64 suffixed symbols are not exported
* x86: Ensure we do not export ffi_prep_cif_machdep
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
* x86: Ensure we don't export ffi_call_win64, ffi_closure_win64, or ffi_go_closure_win64
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
* closures: Silence a semantic warning
libffi/src/closures.c:175:23: This function declaration is not a prototype
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
* aarch64: Ensure we don't export ffi_prep_cif_machdep
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
* arm: Ensure we don't export ffi_prep_cif_machdep
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
* aarch64, arm, x86: Add architecture preprocessor checks to support easier fat builds (eg: iOS)
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
* x86: Silence some static analysis warnings
libffi/src/x86/ffi64.c:286:21: The left operand of '!=' is a garbage value due to array index out of bounds
libffi/src/x86/ffi64.c:297:22: The left operand of '!=' is a garbage value due to array index out of bounds
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
* aarch: Use FFI_HIDDEN rather than .hidden
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
* ffi.h: Don't advertise ffi_java_rvalue_to_raw, ffi_prep_java_raw_closure, and ffi_prep_java_raw_closure_loc when FFI_NATIVE_RAW_API is 0
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
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b5ee3957
|
2018-05-05T07:41:53
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|
Revert "Remove some symbol exports and cleanup newline warnings (#433)"
This reverts commit a5a0f3cf36dfb4d64316414a872288c3170e6c1d.
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a5a0f3cf
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2018-05-05T03:44:33
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Remove some symbol exports and cleanup newline warnings (#433)
* build: Ensure darwin generated sources end with a new line
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@macports.org>
* build: Use .private_extern where missing to prevent exporting symbols that are not API
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@macports.org>
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1fb788ac
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2017-10-10T11:37:00
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aarch64: fix index base register for AArch64
The base is passed in `x3`, not in `x2`. This fixes the indexing base
so that the right value is used.
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00406945
|
2016-07-12T16:08:42
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|
Update Xcodeproj
Include all currently relevent files.
Call autogen is build script.
Fix compiler settings.
Fix mach include.
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bc4fc07a
|
2015-12-21T00:37:06
|
|
Fixed #181 -- Corrected problems with ARMv7 build under iOS.
Based on a patch from @fealebenpae, with input from @SolaWing and @rth7680,
and testing from @superdump.
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95df3791
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2015-02-11T08:31:48
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aarch64: Handle ILP32 ABI
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53636634
|
2015-01-16T15:19:38
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aarch64: implement the trampoline table workaround for ffi closures on Apple systems
This is a direct copy/paste port of the ARM code, with changes because of Aarch64 pc-relative addressing restrictions.
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05e65b4e
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2015-01-16T15:18:04
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aarch64: rewrite range syntax into list to appease Clang
Clang's assembler in Xcode 6 appears to choke when the operand of st4 is a range, but is happy with a list.
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9ae3bc87
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2014-12-06T23:58:41
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|
Fix for https://github.com/atgreen/libffi/issues/141
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0e41c73b
|
2014-10-22T23:48:12
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|
aarch64: Move x8 out of call_context
Reduces stack size. It was only used by the closure, and there
are available argument registers.
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c6352b66
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2014-10-23T00:26:14
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aarch64: Add support for Go closures
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12cf89ee
|
2014-10-22T21:53:30
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aarch64: Move return value handling into ffi_closure_SYSV
As with the change to ffi_call_SYSV, this avoids copying data
into a temporary buffer.
|
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4fe1aea1
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2014-10-22T17:06:19
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aarch64: Move return value handling into ffi_call_SYSV
This lets us pass return data directly to the caller of ffi_call
in most cases, rather than storing it into temporary storage first.
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325471ea
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2014-10-22T13:58:59
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aarch64: Merge prep_args with ffi_call
Use the trick to allocate the stack frame for ffi_call_SYSV
within ffi_call itself.
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2e32f9bf
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2014-10-21T22:49:05
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aarch64: Use correct return registers
There are fewer return registers than argument registers.
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95a04af1
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2014-10-21T22:41:07
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aarch64: Reduce the size of register_context
We don't need to store 32 general and vector registers.
Only 8 of each are used for parameter passing.
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a539f7ff
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2014-04-06T20:53:02
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Fix alignment of AArch64 assembler functions
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49f7729c
|
2014-02-28T00:17:16
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aarch64 fix
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0a333d6c
|
2014-01-09T14:03:29
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Darwin/aarch64: Fix size_t assumptions
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07175780
|
2013-12-30T17:48:22
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Darwin/aarch64: Fix invalid reference in assembly
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5658b089
|
2013-12-30T16:33:47
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Darwin/aarch64: Use CNAME, restrict .size like ARM
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3dc3f32c
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2013-12-05T16:23:25
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Undo iOS ARM64 changes.
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0278284e
|
2013-11-30T03:03:37
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Darwin/aarch64: size_t assumptions
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b513dfe7
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2013-11-30T02:05:22
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Darwin/aarch64: Restrict .size to ELF like arm32.
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bc978099
|
2013-11-30T02:04:57
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Darwin/aarch64: Potentially(?) fix compile error
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d6bb9314
|
2013-11-30T02:04:22
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Darwin/aarch64: Use CNAME refs
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128cd1d2
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2013-10-08T06:45:51
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Fix spelling errors
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58e8b66f
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2012-10-30T07:07:19
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AArch64 port
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fa5d7479
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2012-10-30T07:07:19
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AArch64 port
|