The following commit has been merged into the core/entry branch of tip: Commit-ID: 23d67a54857a768acdb0804cdd6037c324a50ecd Gitweb: https://git.kernel.org/tip/23d67a54857a768acdb0804cdd6037c324a50ecd Author: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx> AuthorDate: Mon, 16 Nov 2020 12:42:00 -05:00 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitterDate: Mon, 16 Nov 2020 21:53:15 +01:00 seccomp: Migrate to use SYSCALL_WORK flag On architectures using the generic syscall entry code the architecture independent syscall work is moved to flags in thread_info::syscall_work. This removes architecture dependencies and frees up TIF bits. Define SYSCALL_WORK_SECCOMP, use it in the generic entry code and convert the code which uses the TIF specific helper functions to use the new *_syscall_work() helpers which either resolve to the new mode for users of the generic entry code or to the TIF based functions for the other architectures. Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxx> Link: https://lore.kernel.org/r/20201116174206.2639648-5-krisman@xxxxxxxxxxxxx --- include/asm-generic/syscall.h | 2 +- include/linux/entry-common.h | 8 ++------ include/linux/seccomp.h | 2 +- include/linux/thread_info.h | 6 ++++++ kernel/entry/common.c | 2 +- kernel/fork.c | 2 +- kernel/seccomp.c | 6 +++--- 7 files changed, 15 insertions(+), 13 deletions(-) diff --git a/include/asm-generic/syscall.h b/include/asm-generic/syscall.h index f3135e7..524d8e6 100644 --- a/include/asm-generic/syscall.h +++ b/include/asm-generic/syscall.h @@ -135,7 +135,7 @@ void syscall_set_arguments(struct task_struct *task, struct pt_regs *regs, * Returns the AUDIT_ARCH_* based on the system call convention in use. * * It's only valid to call this when @task is stopped on entry to a system - * call, due to %TIF_SYSCALL_TRACE, %TIF_SYSCALL_AUDIT, or %TIF_SECCOMP. + * call, due to %TIF_SYSCALL_TRACE, %TIF_SYSCALL_AUDIT, or %SYSCALL_WORK_SECCOMP. * * Architectures which permit CONFIG_HAVE_ARCH_SECCOMP_FILTER must * provide an implementation of this. diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index 3fe8f86..fa3cdb1 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -21,10 +21,6 @@ # define _TIF_SYSCALL_TRACEPOINT (0) #endif -#ifndef _TIF_SECCOMP -# define _TIF_SECCOMP (0) -#endif - #ifndef _TIF_SYSCALL_AUDIT # define _TIF_SYSCALL_AUDIT (0) #endif @@ -49,7 +45,7 @@ #endif #define SYSCALL_ENTER_WORK \ - (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \ + (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \ _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_EMU | \ ARCH_SYSCALL_ENTER_WORK) @@ -64,7 +60,7 @@ (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \ _TIF_SYSCALL_TRACEPOINT | ARCH_SYSCALL_EXIT_WORK) -#define SYSCALL_WORK_ENTER (0) +#define SYSCALL_WORK_ENTER (SYSCALL_WORK_SECCOMP) #define SYSCALL_WORK_EXIT (0) /* diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h index 02aef28..47763f3 100644 --- a/include/linux/seccomp.h +++ b/include/linux/seccomp.h @@ -42,7 +42,7 @@ struct seccomp { extern int __secure_computing(const struct seccomp_data *sd); static inline int secure_computing(void) { - if (unlikely(test_thread_flag(TIF_SECCOMP))) + if (unlikely(test_syscall_work(SECCOMP))) return __secure_computing(NULL); return 0; } diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h index 0e9fb15..a308ba4 100644 --- a/include/linux/thread_info.h +++ b/include/linux/thread_info.h @@ -35,6 +35,12 @@ enum { GOOD_STACK, }; +enum syscall_work_bit { + SYSCALL_WORK_BIT_SECCOMP, +}; + +#define SYSCALL_WORK_SECCOMP BIT(SYSCALL_WORK_BIT_SECCOMP) + #include <asm/thread_info.h> #ifdef __KERNEL__ diff --git a/kernel/entry/common.c b/kernel/entry/common.c index e7a11e3..5747a6e 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -54,7 +54,7 @@ static long syscall_trace_enter(struct pt_regs *regs, long syscall, } /* Do seccomp after ptrace, to catch any tracer changes. */ - if (ti_work & _TIF_SECCOMP) { + if (work & SYSCALL_WORK_SECCOMP) { ret = __secure_computing(NULL); if (ret == -1L) return ret; diff --git a/kernel/fork.c b/kernel/fork.c index 32083db..bc5b109 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1625,7 +1625,7 @@ static void copy_seccomp(struct task_struct *p) * to manually enable the seccomp thread flag here. */ if (p->seccomp.mode != SECCOMP_MODE_DISABLED) - set_tsk_thread_flag(p, TIF_SECCOMP); + set_task_syscall_work(p, SECCOMP); #endif } diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 8ad7a29..f67e92d 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -356,14 +356,14 @@ static inline void seccomp_assign_mode(struct task_struct *task, task->seccomp.mode = seccomp_mode; /* - * Make sure TIF_SECCOMP cannot be set before the mode (and + * Make sure SYSCALL_WORK_SECCOMP cannot be set before the mode (and * filter) is set. */ smp_mb__before_atomic(); /* Assume default seccomp processes want spec flaw mitigation. */ if ((flags & SECCOMP_FILTER_FLAG_SPEC_ALLOW) == 0) arch_seccomp_spec_mitigate(task); - set_tsk_thread_flag(task, TIF_SECCOMP); + set_task_syscall_work(task, SECCOMP); } #ifdef CONFIG_SECCOMP_FILTER @@ -929,7 +929,7 @@ static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd, /* * Make sure that any changes to mode from another thread have - * been seen after TIF_SECCOMP was seen. + * been seen after SYSCALL_WORK_SECCOMP was seen. */ rmb();
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