>From 27d444303e541c741d37ec9691c00f8b0e53d4d4 Mon Sep 17 00:00:00 2001 From: Tycho Andersen Date: Thu, 9 Mar 2017 17:47:46 -0800 Subject: [PATCH] gcc-plugins: add stackleak plugin to zero kernel stack This plugin adds an option to zero the kernel stack after a syscall return so that no information is leaked on the kernel stack. Ported from grsecurity/PaX. Minor changes to macro names to be more upstream-esque. Signed-off-by: Tycho Andersen --- arch/Kconfig | 15 ++ arch/x86/Kconfig | 1 + arch/x86/entry/common.c | 15 +- arch/x86/entry/entry_32.S | 68 +++++++ arch/x86/entry/entry_64.S | 69 +++++++ arch/x86/entry/entry_64_compat.S | 12 ++ arch/x86/include/asm/processor.h | 4 + arch/x86/kernel/asm-offsets.c | 9 + arch/x86/kernel/dumpstack_64.c | 33 ++++ fs/exec.c | 13 ++ scripts/Makefile.gcc-plugins | 3 + scripts/gcc-plugins/stackleak_plugin.c | 342 +++++++++++++++++++++++++++++++++ 12 files changed, 582 insertions(+), 2 deletions(-) create mode 100644 scripts/gcc-plugins/stackleak_plugin.c diff --git a/arch/Kconfig b/arch/Kconfig index cd211a1..48af925 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -436,6 +436,21 @@ config GCC_PLUGIN_STRUCTLEAK_VERBOSE initialized. Since not all existing initializers are detected by the plugin, this can produce false positive warnings. +config ARCH_HAS_STACKLEAK + def_bool n + +config GCC_PLUGIN_STACKLEAK + bool "Zero the kernel stack after syscalls" + depends on GCC_PLUGINS + depends on ARCH_HAS_STACKLEAK + help + This plugin zero-initializes the kernel stack after every system call. This + can prevent some classes of information exposures. + + This plugin was ported from grsecurity/PaX. More information at: + * https://grsecurity.net/ + * https://pax.grsecurity.net/ + config HAVE_CC_STACKPROTECTOR bool help diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index cc98d5a..5988a5f 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -56,6 +56,7 @@ config X86 select ARCH_HAS_PMEM_API if X86_64 select ARCH_HAS_SET_MEMORY select ARCH_HAS_SG_CHAIN + select ARCH_HAS_STACKLEAK select ARCH_HAS_STRICT_KERNEL_RWX select ARCH_HAS_STRICT_MODULE_RWX select ARCH_HAS_UBSAN_SANITIZE_ALL diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index 370c42c..39cb5fd 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -43,6 +43,12 @@ __visible inline void enter_from_user_mode(void) static inline void enter_from_user_mode(void) {} #endif +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +asmlinkage void erase_kstack(void); +#else +static void erase_kstack(void) {} +#endif + static void do_audit_syscall_entry(struct pt_regs *regs, u32 arch) { #ifdef CONFIG_X86_64 @@ -79,8 +85,10 @@ static long syscall_trace_enter(struct pt_regs *regs) emulated = true; if ((emulated || (work & _TIF_SYSCALL_TRACE)) && - tracehook_report_syscall_entry(regs)) + tracehook_report_syscall_entry(regs)) { + erase_kstack(); return -1L; + } if (emulated) return -1L; @@ -115,8 +123,10 @@ static long syscall_trace_enter(struct pt_regs *regs) } ret = __secure_computing(&sd); - if (ret == -1) + if (ret == -1) { + erase_kstack(); return ret; + } } #endif @@ -125,6 +135,7 @@ static long syscall_trace_enter(struct pt_regs *regs) do_audit_syscall_entry(regs, arch); + erase_kstack(); return ret ?: regs->orig_ax; } diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 57f7ec3..325db99 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -78,6 +78,66 @@ #endif .endm + +.macro erase_kstack +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + call erase_kstack +#endif +.endm + +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +/* + * ebp: thread_info + */ +ENTRY(erase_kstack) + pushl %edi + pushl %ecx + pushl %eax + pushl %ebp + + movl PER_CPU_VAR(current_task), %ebp + mov TASK_lowest_stack(%ebp), %edi + mov $-0xBEEF, %eax + std + +1: mov %edi, %ecx + and $THREAD_SIZE_asm - 1, %ecx + shr $2, %ecx + repne scasl + jecxz 2f + + cmp $2*16, %ecx + jc 2f + + mov $2*16, %ecx + repe scasl + jecxz 2f + jne 1b + +2: cld + or $2*4, %edi + mov %esp, %ecx + sub %edi, %ecx + + cmp $THREAD_SIZE_asm, %ecx + jb 3f + ud2 +3: + + shr $2, %ecx + rep stosl + + mov TASK_thread_sp0(%ebp), %edi + sub $128, %edi + mov %edi, TASK_lowest_stack(%ebp) + + popl %ebp + popl %eax + popl %ecx + popl %edi +ENDPROC(erase_kstack) +#endif + /* * User gs save/restore * @@ -440,6 +500,10 @@ ENTRY(entry_SYSENTER_32) ALTERNATIVE "testl %eax, %eax; jz .Lsyscall_32_done", \ "jmp .Lsyscall_32_done", X86_FEATURE_XENPV +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + erase_kstack +#endif + /* Opportunistic SYSEXIT */ TRACE_IRQS_ON /* User mode traces as IRQs on. */ movl PT_EIP(%esp), %edx /* pt_regs->ip */ @@ -526,6 +590,10 @@ ENTRY(entry_INT80_32) call do_int80_syscall_32 .Lsyscall_32_done: +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + erase_kstack +#endif + restore_all: TRACE_IRQS_IRET .Lrestore_all_notrace: diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 044d18e..024615e 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -58,6 +58,62 @@ ENDPROC(native_usergs_sysret64) #endif .endm +.macro erase_kstack +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + call erase_kstack +#endif +.endm + +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +ENTRY(erase_kstack) + pushq %rdi + pushq %rcx + pushq %rax + pushq %r11 + + movq PER_CPU_VAR(current_task), %r11 + mov TASK_lowest_stack(%r11), %rdi + mov $-0xBEEF, %rax + std + +1: mov %edi, %ecx + and $THREAD_SIZE_asm - 1, %ecx + shr $3, %ecx + repne scasq + jecxz 2f + + cmp $2*8, %ecx + jc 2f + + mov $2*8, %ecx + repe scasq + jecxz 2f + jne 1b + +2: cld + or $2*8, %rdi + mov %esp, %ecx + sub %edi, %ecx + + cmp $THREAD_SIZE_asm, %rcx + jb 3f + ud2 +3: + + shr $3, %ecx + rep stosq + + mov TASK_thread_sp0(%r11), %rdi + sub $256, %rdi + mov %rdi, TASK_lowest_stack(%r11) + + popq %r11 + popq %rax + popq %rcx + popq %rdi +ENDPROC(erase_kstack) +#endif + /* * When dynamic function tracer is enabled it will add a breakpoint * to all locations that it is about to modify, sync CPUs, update @@ -218,6 +274,10 @@ entry_SYSCALL_64_fastpath: testl $_TIF_ALLWORK_MASK, TASK_TI_flags(%r11) jnz 1f +#ifdef CONFIG_GCC_PLUGIN_STACKLEACK + erase_kstack +#endif + LOCKDEP_SYS_EXIT TRACE_IRQS_ON /* user mode is traced as IRQs on */ movq RIP(%rsp), %rcx @@ -246,6 +306,10 @@ entry_SYSCALL64_slow_path: call do_syscall_64 /* returns with IRQs disabled */ return_from_SYSCALL_64: +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + erase_kstack +#endif + RESTORE_EXTRA_REGS TRACE_IRQS_IRETQ /* we're about to change IF */ @@ -419,6 +483,9 @@ ENTRY(ret_from_fork) 2: leaq FRAME_OFFSET(%rsp),%rdi /* pt_regs pointer */ call syscall_return_slowpath /* returns with IRQs disabled */ +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + erase_kstack +#endif TRACE_IRQS_ON /* user mode is traced as IRQS on */ SWAPGS FRAME_END @@ -532,6 +599,8 @@ ret_from_intr: GLOBAL(retint_user) mov %rsp,%rdi call prepare_exit_to_usermode +# PaX has this here but commented out. Why? +# pax_erase_kstack TRACE_IRQS_IRETQ SWAPGS jmp restore_regs_and_iret diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index e1721da..63af1d5 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -18,6 +18,12 @@ .section .entry.text, "ax" + .macro erase_kstack +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + call erase_kstack +#endif + .endm + /* * 32-bit SYSENTER entry. * @@ -229,6 +235,9 @@ ENTRY(entry_SYSCALL_compat) /* Opportunistic SYSRET */ sysret32_from_system_call: +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + erase_kstack +#endif TRACE_IRQS_ON /* User mode traces as IRQs on. */ movq RBX(%rsp), %rbx /* pt_regs->rbx */ movq RBP(%rsp), %rbp /* pt_regs->rbp */ @@ -337,6 +346,9 @@ ENTRY(entry_INT80_compat) .Lsyscall_32_done: /* Go back to user mode. */ +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + erase_kstack +#endif TRACE_IRQS_ON SWAPGS jmp restore_regs_and_iret diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index f385eca..e47c9bd 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -469,6 +469,10 @@ struct thread_struct { mm_segment_t addr_limit; +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + unsigned long lowest_stack; +#endif + unsigned int sig_on_uaccess_err:1; unsigned int uaccess_err:1; /* uaccess failed */ diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c index de827d6..4ed7451 100644 --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -37,6 +37,10 @@ void common(void) { BLANK(); OFFSET(TASK_TI_flags, task_struct, thread_info.flags); OFFSET(TASK_addr_limit, task_struct, thread.addr_limit); +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + OFFSET(TASK_lowest_stack, task_struct, thread.lowest_stack); + OFFSET(TASK_thread_sp0, task_struct, thread.sp0); +#endif BLANK(); OFFSET(crypto_tfm_ctx_offset, crypto_tfm, __crt_ctx); @@ -73,6 +77,11 @@ void common(void) { OFFSET(PV_MMU_read_cr2, pv_mmu_ops, read_cr2); #endif +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + BLANK(); + DEFINE(THREAD_SIZE_asm, THREAD_SIZE); +#endif + #ifdef CONFIG_XEN BLANK(); OFFSET(XEN_vcpu_info_mask, vcpu_info, evtchn_upcall_mask); diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index a8b117e..dc29be8 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -188,3 +188,36 @@ int is_valid_bugaddr(unsigned long ip) return ud2 == 0x0b0f; } + +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +void __used check_alloca(unsigned long size) +{ + struct stack_info stack_info = {0}; + unsigned long visit_mask = 0; + unsigned long sp = (unsigned long)&sp; + unsigned long stack_left; + + BUG_ON(get_stack_info(&sp, current, &stack_info, &visit_mask)); + + switch (stack_info.type) { + case STACK_TYPE_TASK: + stack_left = sp & (THREAD_SIZE - 1); + break; + + case STACK_TYPE_IRQ: + stack_left = sp & (IRQ_STACK_SIZE - 1); + break; + + case STACK_TYPE_EXCEPTION ... STACK_TYPE_EXCEPTION_LAST: + stack_left = sp & (EXCEPTION_STKSZ - 1); + break; + + case STACK_TYPE_SOFTIRQ: + default: + BUG(); + } + + BUG_ON(stack_left < 256 || size >= stack_left - 256); +} +EXPORT_SYMBOL(check_alloca); +#endif diff --git a/fs/exec.c b/fs/exec.c index 65145a3..a116bd20 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1927,3 +1927,16 @@ COMPAT_SYSCALL_DEFINE5(execveat, int, fd, argv, envp, flags); } #endif + +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +void __used track_stack(void) +{ + unsigned long sp = (unsigned long)&sp; + if (sp < current->thread.lowest_stack && + sp >= (unsigned long)task_stack_page(current) + 2 * sizeof(unsigned long)) + current->thread.lowest_stack = sp; + if (unlikely((sp & ~(THREAD_SIZE - 1)) < (THREAD_SIZE/16))) + BUG(); +} +EXPORT_SYMBOL(track_stack); +#endif diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins index 8233553..c998092 100644 --- a/scripts/Makefile.gcc-plugins +++ b/scripts/Makefile.gcc-plugins @@ -29,6 +29,9 @@ ifdef CONFIG_GCC_PLUGINS gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_VERBOSE) += -fplugin-arg-structleak_plugin-verbose gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK) += -DSTRUCTLEAK_PLUGIN + gcc-plugin-$(CONFIG_PAX_MEMORY_STACKLEAK) += stackleak_plugin.so$ + gcc-plugin-cflags-$(CONFIG_PAX_MEMORY_STACKLEAK) += -DSTACKLEAK_PLUGIN -fplugin-arg-stackleak_plugin-track-lowest-sp=100$ + GCC_PLUGINS_CFLAGS := $(strip $(addprefix -fplugin=$(objtree)/scripts/gcc-plugins/, $(gcc-plugin-y)) $(gcc-plugin-cflags-y)) export PLUGINCC GCC_PLUGINS_CFLAGS GCC_PLUGIN GCC_PLUGIN_SUBDIR diff --git a/scripts/gcc-plugins/stackleak_plugin.c b/scripts/gcc-plugins/stackleak_plugin.c new file mode 100644 index 0000000..5694585 --- /dev/null +++ b/scripts/gcc-plugins/stackleak_plugin.c @@ -0,0 +1,342 @@ +/* + * Copyright 2011-2017 by the PaX Team + * Licensed under the GPL v2 + * + * Note: the choice of the license means that the compilation process is + * NOT 'eligible' as defined by gcc's library exception to the GPL v3, + * but for the kernel it doesn't matter since it doesn't link against + * any of the gcc libraries + * + * gcc plugin to help implement various PaX features + * + * - track lowest stack pointer + * + * TODO: + * - initialize all local variables + * + * BUGS: + * - none known + */ + +#include "gcc-common.h" + +__visible int plugin_is_GPL_compatible; + +static int track_frame_size = -1; +static const char track_function[] = "track_stack"; +static const char check_function[] = "check_alloca"; +static GTY(()) tree track_function_decl; +static GTY(()) tree check_function_decl; +static bool init_locals; + +static struct plugin_info stackleak_plugin_info = { + .version = "201602181345", + .help = "track-lowest-sp=nn\ttrack sp in functions whose frame size is at least nn bytes\n" +// "initialize-locals\t\tforcibly initialize all stack frames\n" +}; + +static void stackleak_check_alloca(gimple_stmt_iterator *gsi) +{ + gimple stmt; + gcall *check_alloca; + tree alloca_size; + cgraph_node_ptr node; + int frequency; + basic_block bb; + + // insert call to void pax_check_alloca(unsigned long size) + alloca_size = gimple_call_arg(gsi_stmt(*gsi), 0); + stmt = gimple_build_call(check_function_decl, 1, alloca_size); + check_alloca = as_a_gcall(stmt); + gsi_insert_before(gsi, check_alloca, GSI_SAME_STMT); + + // update the cgraph + bb = gimple_bb(check_alloca); + node = cgraph_get_create_node(check_function_decl); + gcc_assert(node); + frequency = compute_call_stmt_bb_frequency(current_function_decl, bb); + cgraph_create_edge(cgraph_get_node(current_function_decl), node, check_alloca, bb->count, frequency, bb->loop_depth); +} + +static void stackleak_add_instrumentation(gimple_stmt_iterator *gsi, bool after) +{ + gimple stmt; + gcall *track_stack; + cgraph_node_ptr node; + int frequency; + basic_block bb; + + // insert call to void pax_track_stack(void) + stmt = gimple_build_call(track_function_decl, 0); + track_stack = as_a_gcall(stmt); + if (after) + gsi_insert_after(gsi, track_stack, GSI_CONTINUE_LINKING); + else + gsi_insert_before(gsi, track_stack, GSI_SAME_STMT); + + // update the cgraph + bb = gimple_bb(track_stack); + node = cgraph_get_create_node(track_function_decl); + gcc_assert(node); + frequency = compute_call_stmt_bb_frequency(current_function_decl, bb); + cgraph_create_edge(cgraph_get_node(current_function_decl), node, track_stack, bb->count, frequency, bb->loop_depth); +} + +static bool is_alloca(gimple stmt) +{ + if (gimple_call_builtin_p(stmt, BUILT_IN_ALLOCA)) + return true; + +#if BUILDING_GCC_VERSION >= 4007 + if (gimple_call_builtin_p(stmt, BUILT_IN_ALLOCA_WITH_ALIGN)) + return true; +#endif + + return false; +} + +static unsigned int stackleak_tree_instrument_execute(void) +{ + basic_block bb, entry_bb; + bool prologue_instrumented = false, is_leaf = true; + + entry_bb = ENTRY_BLOCK_PTR_FOR_FN(cfun)->next_bb; + + // 1. loop through BBs and GIMPLE statements + FOR_EACH_BB_FN(bb, cfun) { + gimple_stmt_iterator gsi; + + for (gsi = gsi_start_bb(bb); !gsi_end_p(gsi); gsi_next(&gsi)) { + gimple stmt; + + stmt = gsi_stmt(gsi); + + if (is_gimple_call(stmt)) + is_leaf = false; + + // gimple match: align 8 built-in BUILT_IN_NORMAL:BUILT_IN_ALLOCA attributes + if (!is_alloca(stmt)) + continue; + + // 2. insert stack overflow check before each __builtin_alloca call + stackleak_check_alloca(&gsi); + + // 3. insert track call after each __builtin_alloca call + stackleak_add_instrumentation(&gsi, true); + if (bb == entry_bb) + prologue_instrumented = true; + } + } + + // special cases for some bad linux code: taking the address of static inline functions will materialize them + // but we mustn't instrument some of them as the resulting stack alignment required by the function call ABI + // will break other assumptions regarding the expected (but not otherwise enforced) register clobbering ABI. + // case in point: native_save_fl on amd64 when optimized for size clobbers rdx if it were instrumented here. + if (is_leaf && !TREE_PUBLIC(current_function_decl) && DECL_DECLARED_INLINE_P(current_function_decl)) + return 0; + if (is_leaf && !strncmp(IDENTIFIER_POINTER(DECL_NAME(current_function_decl)), "_paravirt_", 10)) + return 0; + + // 4. insert track call at the beginning + if (!prologue_instrumented) { + gimple_stmt_iterator gsi; + + gcc_assert(single_succ_p(ENTRY_BLOCK_PTR_FOR_FN(cfun))); + bb = single_succ(ENTRY_BLOCK_PTR_FOR_FN(cfun)); + if (!single_pred_p(bb)) { +// gcc_assert(bb_loop_depth(bb) || (bb->flags & BB_IRREDUCIBLE_LOOP)); + split_edge(single_succ_edge(ENTRY_BLOCK_PTR_FOR_FN(cfun))); + gcc_assert(single_succ_p(ENTRY_BLOCK_PTR_FOR_FN(cfun))); + bb = single_succ(ENTRY_BLOCK_PTR_FOR_FN(cfun)); + } + gsi = gsi_after_labels(bb); + stackleak_add_instrumentation(&gsi, false); + } + + return 0; +} + +static unsigned int stackleak_final_execute(void) +{ + rtx_insn *insn, *next; + + if (cfun->calls_alloca) + return 0; + + // keep calls only if function frame is big enough + if (get_frame_size() >= track_frame_size) + return 0; + + // 1. find pax_track_stack calls + for (insn = get_insns(); insn; insn = next) { + // rtl match: (call_insn 8 7 9 3 (call (mem (symbol_ref ("pax_track_stack") [flags 0x41] ) [0 S1 A8]) (4)) -1 (nil) (nil)) + rtx body; + + next = NEXT_INSN(insn); + if (!CALL_P(insn)) + continue; + body = PATTERN(insn); + if (GET_CODE(body) != CALL) + continue; + body = XEXP(body, 0); + if (GET_CODE(body) != MEM) + continue; + body = XEXP(body, 0); + if (GET_CODE(body) != SYMBOL_REF) + continue; +// if (strcmp(XSTR(body, 0), track_function)) + if (SYMBOL_REF_DECL(body) != track_function_decl) + continue; +// warning(0, "track_frame_size: %d %ld %d", cfun->calls_alloca, get_frame_size(), track_frame_size); + // 2. delete call + delete_insn_and_edges(insn); +#if BUILDING_GCC_VERSION >= 4007 + if (GET_CODE(next) == NOTE && NOTE_KIND(next) == NOTE_INSN_CALL_ARG_LOCATION) { + insn = next; + next = NEXT_INSN(insn); + delete_insn_and_edges(insn); + } +#endif + } + +// print_simple_rtl(stderr, get_insns()); +// print_rtl(stderr, get_insns()); +// warning(0, "track_frame_size: %d %ld %d", cfun->calls_alloca, get_frame_size(), track_frame_size); + + return 0; +} + +static bool stackleak_track_stack_gate(void) +{ + tree section; + + if (ix86_cmodel != CM_KERNEL) + return false; + + section = lookup_attribute("section", DECL_ATTRIBUTES(current_function_decl)); + if (section && TREE_VALUE(section)) { + section = TREE_VALUE(TREE_VALUE(section)); + + if (!strncmp(TREE_STRING_POINTER(section), ".init.text", 10)) + return false; + if (!strncmp(TREE_STRING_POINTER(section), ".devinit.text", 13)) + return false; + if (!strncmp(TREE_STRING_POINTER(section), ".cpuinit.text", 13)) + return false; + if (!strncmp(TREE_STRING_POINTER(section), ".meminit.text", 13)) + return false; + } + + return track_frame_size >= 0; +} + +static void stackleak_start_unit(void *gcc_data __unused, void *user_data __unused) +{ + tree fntype; + + // void pax_track_stack(void) + fntype = build_function_type_list(void_type_node, NULL_TREE); + track_function_decl = build_fn_decl(track_function, fntype); + DECL_ASSEMBLER_NAME(track_function_decl); // for LTO + TREE_PUBLIC(track_function_decl) = 1; + TREE_USED(track_function_decl) = 1; + DECL_EXTERNAL(track_function_decl) = 1; + DECL_ARTIFICIAL(track_function_decl) = 1; + DECL_PRESERVE_P(track_function_decl) = 1; + + // void pax_check_alloca(unsigned long) + fntype = build_function_type_list(void_type_node, long_unsigned_type_node, NULL_TREE); + check_function_decl = build_fn_decl(check_function, fntype); + DECL_ASSEMBLER_NAME(check_function_decl); // for LTO + TREE_PUBLIC(check_function_decl) = 1; + TREE_USED(check_function_decl) = 1; + DECL_EXTERNAL(check_function_decl) = 1; + DECL_ARTIFICIAL(check_function_decl) = 1; + DECL_PRESERVE_P(check_function_decl) = 1; +} + +static bool stackleak_tree_instrument_gate(void) +{ + return stackleak_track_stack_gate(); +} + +#define PASS_NAME stackleak_tree_instrument +#define PROPERTIES_REQUIRED PROP_gimple_leh | PROP_cfg +#define TODO_FLAGS_START TODO_verify_ssa | TODO_verify_flow | TODO_verify_stmts +#define TODO_FLAGS_FINISH TODO_verify_ssa | TODO_verify_stmts | TODO_dump_func | TODO_update_ssa | TODO_rebuild_cgraph_edges +#include "gcc-generate-gimple-pass.h" + +static bool stackleak_final_gate(void) +{ + return stackleak_track_stack_gate(); +} + +#define PASS_NAME stackleak_final +#define TODO_FLAGS_FINISH TODO_dump_func +#include "gcc-generate-rtl-pass.h" + +__visible int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version) +{ + const char * const plugin_name = plugin_info->base_name; + const int argc = plugin_info->argc; + const struct plugin_argument * const argv = plugin_info->argv; + int i; + + static const struct ggc_root_tab gt_ggc_r_gt_stackleak[] = { + { + .base = &track_function_decl, + .nelt = 1, + .stride = sizeof(track_function_decl), + .cb = >_ggc_mx_tree_node, + .pchw = >_pch_nx_tree_node + }, + { + .base = &check_function_decl, + .nelt = 1, + .stride = sizeof(check_function_decl), + .cb = >_ggc_mx_tree_node, + .pchw = >_pch_nx_tree_node + }, + LAST_GGC_ROOT_TAB + }; + +// PASS_INFO(stackleak_tree_instrument, "tree_profile", 1, PASS_POS_INSERT_BEFORE); + PASS_INFO(stackleak_tree_instrument, "optimized", 1, PASS_POS_INSERT_BEFORE); + PASS_INFO(stackleak_final, "final", 1, PASS_POS_INSERT_BEFORE); + + if (!plugin_default_version_check(version, &gcc_version)) { + error_gcc_version(version); + return 1; + } + + register_callback(plugin_name, PLUGIN_INFO, NULL, &stackleak_plugin_info); + + for (i = 0; i < argc; ++i) { + if (!strcmp(argv[i].key, "track-lowest-sp")) { + if (!argv[i].value) { + error(G_("no value supplied for option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key); + continue; + } + track_frame_size = atoi(argv[i].value); + if (argv[i].value[0] < '0' || argv[i].value[0] > '9' || track_frame_size < 0) + error(G_("invalid option argument '-fplugin-arg-%s-%s=%s'"), plugin_name, argv[i].key, argv[i].value); + continue; + } + if (!strcmp(argv[i].key, "initialize-locals")) { + if (argv[i].value) { + error(G_("invalid option argument '-fplugin-arg-%s-%s=%s'"), plugin_name, argv[i].key, argv[i].value); + continue; + } + init_locals = true; + continue; + } + error(G_("unknown option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key); + } + + register_callback(plugin_name, PLUGIN_START_UNIT, &stackleak_start_unit, NULL); + register_callback(plugin_name, PLUGIN_REGISTER_GGC_ROOTS, NULL, (void *)>_ggc_r_gt_stackleak); + register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &stackleak_tree_instrument_pass_info); + register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &stackleak_final_pass_info); + + return 0; +} -- 2.9.3