| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <1ce09739-14a4-42a2-b5c9-66fdc72ae999@arm.com>
Date: Tue, 20 Aug 2024 13:41:58 +0200
From: Kevin Brodsky <kevin.brodsky@....com>
To: Jinjie Ruan <ruanjinjie@...wei.com>
Cc: catalin.marinas@....com, will@...nel.org, oleg@...hat.com,
tglx@...utronix.de, peterz@...radead.org, luto@...nel.org, kees@...nel.org,
wad@...omium.org, rostedt@...dmis.org, arnd@...db.de, ardb@...nel.org,
broonie@...nel.org, mark.rutland@....com, rick.p.edgecombe@...el.com,
leobras@...hat.com, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v3 1/3] entry: Add some arch funcs to support arm64 to use
generic entry
On 29/06/2024 10:55, Jinjie Ruan wrote:
> Add some arch functions to support arm64 to use generic entry, which do not
> affect existing architectures that use generic entry:
>
> - arch_prepare/post_report_syscall_entry/exit().
>
> - arch_enter_from_kernel_mode(), arch_exit_to_kernel_mode_prepare().
>
> - arch_irqentry_exit_need_resched() to support architecture-related
> need_resched() check logic.
>
> Also make syscall_exit_work() not static and move report_single_step() to
> thread_info.h, which can be used by arm64 later.
>
> x86 and Riscv compilation test ok after this patch.
>
> Signed-off-by: Jinjie Ruan <ruanjinjie@...wei.com>
> Suggested-by: Thomas Gleixner <tglx@...utronix.de>
> ---
> v3:
> - Make the arch funcs not use __weak as Thomas suggested.
> - Make arch_forget_syscall() folded in arch_post_report_syscall_entry().
> - __always_inline -> inline.
> - Move report_single_step() to thread_info.h for arm64
> - Add Suggested-by.
> - Update the commit message.
>
> v2:
> - Fix a bug that not call arch_post_report_syscall_entry() in
> syscall_trace_enter() if ptrace_report_syscall_entry() return not zero.
> - Update the commit message.
> ---
> include/linux/entry-common.h | 90 ++++++++++++++++++++++++++++++++++++
> include/linux/thread_info.h | 13 ++++++
> kernel/entry/common.c | 37 +++++++--------
> 3 files changed, 122 insertions(+), 18 deletions(-)
>
> diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
> index b0fb775a600d..2aea23ca9d66 100644
> --- a/include/linux/entry-common.h
> +++ b/include/linux/entry-common.h
> @@ -290,6 +290,94 @@ static __always_inline void arch_exit_to_user_mode(void);
> static __always_inline void arch_exit_to_user_mode(void) { }
> #endif
>
> +/**
> + * arch_enter_from_kernel_mode - Architecture specific check work.
Maybe those comments could be expanded to be closer to the existing
ones, like arch_enter_from_user_mode()? It would help if they were more
specific as to where they are called (especially the *report_syscall*
ones) and how they are expected to be used.
> + */
> +static inline void arch_enter_from_kernel_mode(struct pt_regs *regs);
> +
> +#ifndef arch_enter_from_kernel_mode
> +static inline void arch_enter_from_kernel_mode(struct pt_regs *regs) { }
> +#endif
> +
> +/**
> + * arch_exit_to_kernel_mode_prepare - Architecture specific final work before
> + * exit to kernel mode.
> + */
> +static inline void arch_exit_to_kernel_mode_prepare(struct pt_regs *regs);
Any reason to suffix this function with "prepare"? Just
arch_exit_to_kernel_mode() seems appropriate (symmetric with
arch_enter_from_kernel_mode()).
> +
> +#ifndef arch_exit_to_kernel_mode_prepare
> +static inline void arch_exit_to_kernel_mode_prepare(struct pt_regs *regs) { }
> +#endif
> +
> +/**
> + * arch_prepare_report_syscall_entry - Architecture specific work before
> + * report_syscall_entry().
> + */
> +static inline unsigned long arch_prepare_report_syscall_entry(struct pt_regs *regs);
The most common naming patterns for such arch helper pairs seems to be
pre/post, so maybe arch_pre_report_syscall_entry()?
> +
> +#ifndef arch_prepare_report_syscall_entry
> +static inline unsigned long arch_prepare_report_syscall_entry(struct pt_regs *regs)
> +{
> + return 0;
> +}
> +#endif
> +
> +/**
> + * arch_post_report_syscall_entry - Architecture specific work after
> + * report_syscall_entry().
> + */
> +static inline void arch_post_report_syscall_entry(struct pt_regs *regs,
> + unsigned long saved_reg,
> + long ret);
> +
> +#ifndef arch_post_report_syscall_entry
> +static inline void arch_post_report_syscall_entry(struct pt_regs *regs,
> + unsigned long saved_reg,
> + long ret)
> +{
> +}
> +#endif
> +
> +/**
> + * arch_prepare_report_syscall_exit - Architecture specific work before
> + * report_syscall_exit().
> + */
> +static inline unsigned long arch_prepare_report_syscall_exit(struct pt_regs *regs,
> + unsigned long work);
> +
> +#ifndef arch_prepare_report_syscall_exit
> +static inline unsigned long arch_prepare_report_syscall_exit(struct pt_regs *regs,
> + unsigned long work)
> +{
> + return 0;
> +}
> +#endif
> +
> +/**
> + * arch_post_report_syscall_exit - Architecture specific work after
> + * report_syscall_exit().
> + */
> +static inline void arch_post_report_syscall_exit(struct pt_regs *regs,
> + unsigned long saved_reg,
> + unsigned long work);
> +
> +#ifndef arch_post_report_syscall_exit
> +static inline void arch_post_report_syscall_exit(struct pt_regs *regs,
> + unsigned long saved_reg,
> + unsigned long work)
> +{
> +}
> +#endif
> +
> +/**
> + * arch_irqentry_exit_need_resched - Architecture specific need resched function
> + */
> +static inline bool arch_irqentry_exit_need_resched(void);
> +
> +#ifndef arch_irqentry_exit_need_resched
> +static inline bool arch_irqentry_exit_need_resched(void) { return true; }
> +#endif
Nit: the existing arch_* hooks seem to be declared close to the function
they are called from (e.g. arch_enter_from_user_mode() just before
enter_from_user_mode()), maybe we could do the same with those new
hooks, where possible.
> +
> /**
> * arch_do_signal_or_restart - Architecture specific signal delivery function
> * @regs: Pointer to currents pt_regs
> @@ -552,4 +640,6 @@ irqentry_state_t noinstr irqentry_nmi_enter(struct pt_regs *regs);
> */
> void noinstr irqentry_nmi_exit(struct pt_regs *regs, irqentry_state_t irq_state);
>
> +void syscall_exit_work(struct pt_regs *regs, unsigned long work);
> +
> #endif
> diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
> index 9ea0b28068f4..062de9666ef3 100644
> --- a/include/linux/thread_info.h
> +++ b/include/linux/thread_info.h
> @@ -55,6 +55,19 @@ enum syscall_work_bit {
> #define SYSCALL_WORK_SYSCALL_AUDIT BIT(SYSCALL_WORK_BIT_SYSCALL_AUDIT)
> #define SYSCALL_WORK_SYSCALL_USER_DISPATCH BIT(SYSCALL_WORK_BIT_SYSCALL_USER_DISPATCH)
> #define SYSCALL_WORK_SYSCALL_EXIT_TRAP BIT(SYSCALL_WORK_BIT_SYSCALL_EXIT_TRAP)
> +
> +/*
> + * If SYSCALL_EMU is set, then the only reason to report is when
> + * SINGLESTEP is set (i.e. PTRACE_SYSEMU_SINGLESTEP). This syscall
> + * instruction has been already reported in syscall_enter_from_user_mode().
> + */
> +static inline bool report_single_step(unsigned long work)
> +{
> + if (work & SYSCALL_WORK_SYSCALL_EMU)
> + return false;
> +
> + return work & SYSCALL_WORK_SYSCALL_EXIT_TRAP;
> +}
> #endif
>
> #include <asm/thread_info.h>
> diff --git a/kernel/entry/common.c b/kernel/entry/common.c
> index 90843cc38588..cd76391ffcb9 100644
> --- a/kernel/entry/common.c
> +++ b/kernel/entry/common.c
> @@ -28,6 +28,7 @@ static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
> long syscall_trace_enter(struct pt_regs *regs, long syscall,
> unsigned long work)
> {
> + unsigned long saved_reg;
Nit: could be declared inside the if block.
Kevin
> long ret = 0;
>
> /*
> @@ -42,8 +43,10 @@ long syscall_trace_enter(struct pt_regs *regs, long syscall,
>
> /* Handle ptrace */
> if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) {
> + saved_reg = arch_prepare_report_syscall_entry(regs);
> ret = ptrace_report_syscall_entry(regs);
> - if (ret || (work & SYSCALL_WORK_SYSCALL_EMU))
> + arch_post_report_syscall_entry(regs, saved_reg, ret);
> + if (ret || work & SYSCALL_WORK_SYSCALL_EMU)
> return -1L;
> }
>
> [...]
Powered by blists - more mailing lists