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Subject[PATCH v3 5/6] arm64: add support for uaccess logging
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arm64 does not use CONFIG_GENERIC_ENTRY, so add the support for
uaccess logging directly to the architecture.

Link: https://linux-review.googlesource.com/id/I88de539fb9c4a9d27fa8cccbe201a6e4382faf89
Signed-off-by: Peter Collingbourne <pcc@google.com>
---
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/thread_info.h | 7 ++++++-
arch/arm64/kernel/ptrace.c | 7 +++++++
arch/arm64/kernel/signal.c | 5 +++++
arch/arm64/kernel/syscall.c | 1 +
5 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index c4207cf9bb17..6023946abe4a 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -161,6 +161,7 @@ config ARM64
select HAVE_ARCH_THREAD_STRUCT_WHITELIST
select HAVE_ARCH_TRACEHOOK
select HAVE_ARCH_TRANSPARENT_HUGEPAGE
+ select HAVE_ARCH_UACCESS_BUFFER
select HAVE_ARCH_VMAP_STACK
select HAVE_ARM_SMCCC
select HAVE_ASM_MODVERSIONS
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index e1317b7c4525..0461b36251ea 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -82,6 +82,8 @@ int arch_dup_task_struct(struct task_struct *dst,
#define TIF_SVE_VL_INHERIT 24 /* Inherit SVE vl_onexec across exec */
#define TIF_SSBD 25 /* Wants SSB mitigation */
#define TIF_TAGGED_ADDR 26 /* Allow tagged user addresses */
+#define TIF_UACCESS_BUFFER_ENTRY 27 /* thread has non-zero uaccess_desc_addr_addr */
+#define TIF_UACCESS_BUFFER_EXIT 28 /* thread has non-zero kcur */

#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
@@ -98,6 +100,8 @@ int arch_dup_task_struct(struct task_struct *dst,
#define _TIF_SVE (1 << TIF_SVE)
#define _TIF_MTE_ASYNC_FAULT (1 << TIF_MTE_ASYNC_FAULT)
#define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL)
+#define _TIF_UACCESS_BUFFER_ENTRY (1 << TIF_UACCESS_BUFFER_ENTRY)
+#define _TIF_UACCESS_BUFFER_EXIT (1 << TIF_UACCESS_BUFFER_EXIT)

#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
_TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \
@@ -106,7 +110,8 @@ int arch_dup_task_struct(struct task_struct *dst,

#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
_TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
- _TIF_SYSCALL_EMU)
+ _TIF_SYSCALL_EMU | _TIF_UACCESS_BUFFER_ENTRY | \
+ _TIF_UACCESS_BUFFER_EXIT)

#ifdef CONFIG_SHADOW_CALL_STACK
#define INIT_SCS \
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 88a9034fb9b5..283372eccaeb 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -29,6 +29,7 @@
#include <linux/regset.h>
#include <linux/tracehook.h>
#include <linux/elf.h>
+#include <linux/uaccess-buffer.h>

#include <asm/compat.h>
#include <asm/cpufeature.h>
@@ -1854,6 +1855,9 @@ int syscall_trace_enter(struct pt_regs *regs)
if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
trace_sys_enter(regs, regs->syscallno);

+ if (flags & _TIF_UACCESS_BUFFER_ENTRY)
+ uaccess_buffer_syscall_entry();
+
audit_syscall_entry(regs->syscallno, regs->orig_x0, regs->regs[1],
regs->regs[2], regs->regs[3]);

@@ -1866,6 +1870,9 @@ void syscall_trace_exit(struct pt_regs *regs)

audit_syscall_exit(regs);

+ if (flags & _TIF_UACCESS_BUFFER_EXIT)
+ uaccess_buffer_syscall_exit();
+
if (flags & _TIF_SYSCALL_TRACEPOINT)
trace_sys_exit(regs, syscall_get_return_value(current, regs));

diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index 8f6372b44b65..5bbd98e5c257 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -20,6 +20,7 @@
#include <linux/tracehook.h>
#include <linux/ratelimit.h>
#include <linux/syscalls.h>
+#include <linux/uaccess-buffer.h>

#include <asm/daifflags.h>
#include <asm/debug-monitors.h>
@@ -919,6 +920,8 @@ static void do_signal(struct pt_regs *regs)

void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags)
{
+ bool uaccess_buffer_pending = uaccess_buffer_pre_exit_loop();
+
do {
if (thread_flags & _TIF_NEED_RESCHED) {
/* Unmask Debug and SError for the next task */
@@ -950,6 +953,8 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags)
local_daif_mask();
thread_flags = READ_ONCE(current_thread_info()->flags);
} while (thread_flags & _TIF_WORK_MASK);
+
+ uaccess_buffer_post_exit_loop(uaccess_buffer_pending);
}

unsigned long __ro_after_init signal_minsigstksz;
diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c
index 50a0f1a38e84..d59022b594f2 100644
--- a/arch/arm64/kernel/syscall.c
+++ b/arch/arm64/kernel/syscall.c
@@ -7,6 +7,7 @@
#include <linux/ptrace.h>
#include <linux/randomize_kstack.h>
#include <linux/syscalls.h>
+#include <linux/uaccess-buffer.h>

#include <asm/daifflags.h>
#include <asm/debug-monitors.h>
--
2.34.1.173.g76aa8bc2d0-goog
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