From: Arnd Bergmann <arnd@arndb.de> To: Russell King <linux@armlinux.org.uk>, Christoph Hellwig <hch@lst.de> Cc: Alexander Viro <viro@zeniv.linux.org.uk>, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, Arnd Bergmann <arnd@arndb.de> Subject: [PATCH v3 04/10] ARM: syscall: always store thread_info->syscall Date: Thu, 1 Oct 2020 16:12:27 +0200 [thread overview] Message-ID: <20201001141233.119343-5-arnd@arndb.de> (raw) In-Reply-To: <20201001141233.119343-1-arnd@arndb.de> The system call number is used in a a couple of places, in particular ptrace, seccomp and /proc/<pid>/syscall. The last one apparently never worked reliably on ARM for tasks that are not currently getting traced. Storing the syscall number in the normal entry path makes it work, as well as allowing us to see if the current system call is for OABI compat mode, which is the next thing I want to hook into. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- arch/arm/include/asm/syscall.h | 5 ++++- arch/arm/kernel/asm-offsets.c | 1 + arch/arm/kernel/entry-common.S | 8 ++++++-- arch/arm/kernel/ptrace.c | 9 +++++---- 4 files changed, 16 insertions(+), 7 deletions(-) diff --git a/arch/arm/include/asm/syscall.h b/arch/arm/include/asm/syscall.h index fd02761ba06c..89898497edd6 100644 --- a/arch/arm/include/asm/syscall.h +++ b/arch/arm/include/asm/syscall.h @@ -22,7 +22,10 @@ extern const unsigned long sys_call_table[]; static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs) { - return task_thread_info(task)->syscall; + if (IS_ENABLED(CONFIG_AEABI) && !IS_ENABLED(CONFIG_OABI_COMPAT)) + return task_thread_info(task)->syscall; + + return task_thread_info(task)->syscall & ~__NR_OABI_SYSCALL_BASE; } static inline void syscall_rollback(struct task_struct *task, diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c index a1570c8bab25..97af6735172b 100644 --- a/arch/arm/kernel/asm-offsets.c +++ b/arch/arm/kernel/asm-offsets.c @@ -46,6 +46,7 @@ int main(void) DEFINE(TI_CPU, offsetof(struct thread_info, cpu)); DEFINE(TI_CPU_DOMAIN, offsetof(struct thread_info, cpu_domain)); DEFINE(TI_CPU_SAVE, offsetof(struct thread_info, cpu_context)); + DEFINE(TI_SYSCALL, offsetof(struct thread_info, syscall)); DEFINE(TI_USED_CP, offsetof(struct thread_info, used_cp)); DEFINE(TI_TP_VALUE, offsetof(struct thread_info, tp_value)); DEFINE(TI_FPSTATE, offsetof(struct thread_info, fpstate)); diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 271cb8a1eba1..9a76467bbb47 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -223,6 +223,7 @@ ENTRY(vector_swi) /* saved_psr and saved_pc are now dead */ uaccess_disable tbl + get_thread_info tsk adr tbl, sys_call_table @ load syscall table pointer @@ -234,13 +235,17 @@ ENTRY(vector_swi) * get the old ABI syscall table address. */ bics r10, r10, #0xff000000 + strne r10, [tsk, #TI_SYSCALL] + streq scno, [tsk, #TI_SYSCALL] eorne scno, r10, #__NR_OABI_SYSCALL_BASE ldrne tbl, =sys_oabi_call_table #elif !defined(CONFIG_AEABI) bic scno, scno, #0xff000000 @ mask off SWI op-code + str scno, [tsk, #TI_SYSCALL] eor scno, scno, #__NR_SYSCALL_BASE @ check OS number +#else + str scno, [tsk, #TI_SYSCALL] #endif - get_thread_info tsk /* * Reload the registers that may have been corrupted on entry to * the syscall assembly (by tracing or context tracking.) @@ -285,7 +290,6 @@ ENDPROC(vector_swi) * context switches, and waiting for our parent to respond. */ __sys_trace: - mov r1, scno add r0, sp, #S_OFF bl syscall_trace_enter mov scno, r0 diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c index 2771e682220b..683edb8b627d 100644 --- a/arch/arm/kernel/ptrace.c +++ b/arch/arm/kernel/ptrace.c @@ -25,6 +25,7 @@ #include <linux/tracehook.h> #include <linux/unistd.h> +#include <asm/syscall.h> #include <asm/traps.h> #define CREATE_TRACE_POINTS @@ -885,9 +886,9 @@ static void tracehook_report_syscall(struct pt_regs *regs, regs->ARM_ip = ip; } -asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno) +asmlinkage int syscall_trace_enter(struct pt_regs *regs) { - current_thread_info()->syscall = scno; + int scno; if (test_thread_flag(TIF_SYSCALL_TRACE)) tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER); @@ -898,11 +899,11 @@ asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno) return -1; #else /* XXX: remove this once OABI gets fixed */ - secure_computing_strict(current_thread_info()->syscall); + secure_computing_strict(syscall_get_nr(current, regs)); #endif /* Tracer or seccomp may have changed syscall. */ - scno = current_thread_info()->syscall; + scno = syscall_get_nr(current, regs); if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) trace_sys_enter(regs, scno); -- 2.27.0
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de> To: Russell King <linux@armlinux.org.uk>, Christoph Hellwig <hch@lst.de> Cc: linux-arch@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Alexander Viro <viro@zeniv.linux.org.uk>, linux-arm-kernel@lists.infradead.org Subject: [PATCH v3 04/10] ARM: syscall: always store thread_info->syscall Date: Thu, 1 Oct 2020 16:12:27 +0200 [thread overview] Message-ID: <20201001141233.119343-5-arnd@arndb.de> (raw) In-Reply-To: <20201001141233.119343-1-arnd@arndb.de> The system call number is used in a a couple of places, in particular ptrace, seccomp and /proc/<pid>/syscall. The last one apparently never worked reliably on ARM for tasks that are not currently getting traced. Storing the syscall number in the normal entry path makes it work, as well as allowing us to see if the current system call is for OABI compat mode, which is the next thing I want to hook into. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- arch/arm/include/asm/syscall.h | 5 ++++- arch/arm/kernel/asm-offsets.c | 1 + arch/arm/kernel/entry-common.S | 8 ++++++-- arch/arm/kernel/ptrace.c | 9 +++++---- 4 files changed, 16 insertions(+), 7 deletions(-) diff --git a/arch/arm/include/asm/syscall.h b/arch/arm/include/asm/syscall.h index fd02761ba06c..89898497edd6 100644 --- a/arch/arm/include/asm/syscall.h +++ b/arch/arm/include/asm/syscall.h @@ -22,7 +22,10 @@ extern const unsigned long sys_call_table[]; static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs) { - return task_thread_info(task)->syscall; + if (IS_ENABLED(CONFIG_AEABI) && !IS_ENABLED(CONFIG_OABI_COMPAT)) + return task_thread_info(task)->syscall; + + return task_thread_info(task)->syscall & ~__NR_OABI_SYSCALL_BASE; } static inline void syscall_rollback(struct task_struct *task, diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c index a1570c8bab25..97af6735172b 100644 --- a/arch/arm/kernel/asm-offsets.c +++ b/arch/arm/kernel/asm-offsets.c @@ -46,6 +46,7 @@ int main(void) DEFINE(TI_CPU, offsetof(struct thread_info, cpu)); DEFINE(TI_CPU_DOMAIN, offsetof(struct thread_info, cpu_domain)); DEFINE(TI_CPU_SAVE, offsetof(struct thread_info, cpu_context)); + DEFINE(TI_SYSCALL, offsetof(struct thread_info, syscall)); DEFINE(TI_USED_CP, offsetof(struct thread_info, used_cp)); DEFINE(TI_TP_VALUE, offsetof(struct thread_info, tp_value)); DEFINE(TI_FPSTATE, offsetof(struct thread_info, fpstate)); diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 271cb8a1eba1..9a76467bbb47 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -223,6 +223,7 @@ ENTRY(vector_swi) /* saved_psr and saved_pc are now dead */ uaccess_disable tbl + get_thread_info tsk adr tbl, sys_call_table @ load syscall table pointer @@ -234,13 +235,17 @@ ENTRY(vector_swi) * get the old ABI syscall table address. */ bics r10, r10, #0xff000000 + strne r10, [tsk, #TI_SYSCALL] + streq scno, [tsk, #TI_SYSCALL] eorne scno, r10, #__NR_OABI_SYSCALL_BASE ldrne tbl, =sys_oabi_call_table #elif !defined(CONFIG_AEABI) bic scno, scno, #0xff000000 @ mask off SWI op-code + str scno, [tsk, #TI_SYSCALL] eor scno, scno, #__NR_SYSCALL_BASE @ check OS number +#else + str scno, [tsk, #TI_SYSCALL] #endif - get_thread_info tsk /* * Reload the registers that may have been corrupted on entry to * the syscall assembly (by tracing or context tracking.) @@ -285,7 +290,6 @@ ENDPROC(vector_swi) * context switches, and waiting for our parent to respond. */ __sys_trace: - mov r1, scno add r0, sp, #S_OFF bl syscall_trace_enter mov scno, r0 diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c index 2771e682220b..683edb8b627d 100644 --- a/arch/arm/kernel/ptrace.c +++ b/arch/arm/kernel/ptrace.c @@ -25,6 +25,7 @@ #include <linux/tracehook.h> #include <linux/unistd.h> +#include <asm/syscall.h> #include <asm/traps.h> #define CREATE_TRACE_POINTS @@ -885,9 +886,9 @@ static void tracehook_report_syscall(struct pt_regs *regs, regs->ARM_ip = ip; } -asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno) +asmlinkage int syscall_trace_enter(struct pt_regs *regs) { - current_thread_info()->syscall = scno; + int scno; if (test_thread_flag(TIF_SYSCALL_TRACE)) tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER); @@ -898,11 +899,11 @@ asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno) return -1; #else /* XXX: remove this once OABI gets fixed */ - secure_computing_strict(current_thread_info()->syscall); + secure_computing_strict(syscall_get_nr(current, regs)); #endif /* Tracer or seccomp may have changed syscall. */ - scno = current_thread_info()->syscall; + scno = syscall_get_nr(current, regs); if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) trace_sys_enter(regs, scno); -- 2.27.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-10-01 14:13 UTC|newest] Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-10-01 14:12 [PATCH v3 00/10] ARM: remove set_fs callers and implementation Arnd Bergmann 2020-10-01 14:12 ` Arnd Bergmann 2020-10-01 14:12 ` [PATCH v3 01/10] mm/maccess: fix unaligned copy_{from,to}_kernel_nofault Arnd Bergmann 2020-10-01 14:12 ` [PATCH v3 01/10] mm/maccess: fix unaligned copy_{from, to}_kernel_nofault Arnd Bergmann 2020-10-01 14:12 ` [PATCH v3 02/10] ARM: traps: use get_kernel_nofault instead of set_fs() Arnd Bergmann 2020-10-01 14:12 ` Arnd Bergmann 2020-10-01 14:12 ` [PATCH v3 03/10] ARM: oabi-compat: add epoll_pwait handler Arnd Bergmann 2020-10-01 14:12 ` Arnd Bergmann 2020-10-01 14:12 ` Arnd Bergmann [this message] 2020-10-01 14:12 ` [PATCH v3 04/10] ARM: syscall: always store thread_info->syscall Arnd Bergmann 2020-10-01 14:12 ` [PATCH v3 05/10] ARM: oabi-compat: rework epoll_wait/epoll_pwait emulation Arnd Bergmann 2020-10-01 14:12 ` Arnd Bergmann 2020-10-01 14:12 ` [PATCH v3 06/10] ARM: oabi-compat: rework sys_semtimedop emulation Arnd Bergmann 2020-10-01 14:12 ` Arnd Bergmann 2020-10-02 19:46 ` kernel test robot 2020-10-01 14:12 ` [PATCH v3 07/10] ARM: oabi-compat: rework fcntl64() emulation Arnd Bergmann 2020-10-01 14:12 ` Arnd Bergmann 2020-10-01 14:12 ` [PATCH v3 08/10] ARM: uaccess: add __{get,put}_kernel_nofault Arnd Bergmann 2020-10-01 14:12 ` Arnd Bergmann 2020-10-01 14:12 ` [PATCH v3 09/10] ARM: provide a TASK_SIZE_MAX definition Arnd Bergmann 2020-10-01 14:12 ` Arnd Bergmann 2020-10-01 14:12 ` [PATCH v3 10/10] ARM: uaccess: remove set_fs() implementation Arnd Bergmann 2020-10-01 14:12 ` Arnd Bergmann
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