From 972939e28592ec61e2e8334786152be2c80de677 Mon Sep 17 00:00:00 2001 From: Mickaël Salaün Date: Mon, 1 Aug 2016 23:01:55 +0200 Subject: um/ptrace: Fix the syscall_trace_leave call Keep the same semantic as before the commit 26703c636c1f: deallocate audit context and fake a proper syscall exit. This fix a kernel panic triggered by the seccomp_bpf test: > [ RUN ] global.ERRNO_valid > BUG: failure at kernel/auditsc.c:1504/__audit_syscall_entry()! > Kernel panic - not syncing: BUG! Fixes: 26703c636c1f ("um/ptrace: run seccomp after ptrace") Signed-off-by: Mickaël Salaün Acked-by: Kees Cook Cc: Jeff Dike Cc: Richard Weinberger Cc: James Morris Cc: user-mode-linux-devel@lists.sourceforge.net Signed-off-by: James Morris Signed-off-by: Kees Cook --- arch/um/kernel/skas/syscall.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/um/kernel/skas/syscall.c b/arch/um/kernel/skas/syscall.c index ef4b8f949b51..0728fee94398 100644 --- a/arch/um/kernel/skas/syscall.c +++ b/arch/um/kernel/skas/syscall.c @@ -21,11 +21,11 @@ void handle_syscall(struct uml_pt_regs *r) PT_REGS_SET_SYSCALL_RETURN(regs, -ENOSYS); if (syscall_trace_enter(regs)) - return; + goto out; /* Do the seccomp check after ptrace; failures should be fast. */ if (secure_computing(NULL) == -1) - return; + goto out; /* Update the syscall number after orig_ax has potentially been updated * with ptrace. @@ -37,5 +37,6 @@ void handle_syscall(struct uml_pt_regs *r) PT_REGS_SET_SYSCALL_RETURN(regs, EXECUTE_SYSCALL(syscall, regs)); +out: syscall_trace_leave(regs); } -- cgit v1.2.3 From ce29856a5e1aabe52e18b2c60db1490769a6ab55 Mon Sep 17 00:00:00 2001 From: Mickaël Salaün Date: Mon, 1 Aug 2016 23:01:56 +0200 Subject: um/ptrace: Fix the syscall number update after a ptrace Update the syscall number after each PTRACE_SETREGS on ORIG_*AX. This is needed to get the potentially altered syscall number in the seccomp filters after RET_TRACE. This fix four seccomp_bpf tests: > [ RUN ] TRACE_syscall.skip_after_RET_TRACE > seccomp_bpf.c:1560:TRACE_syscall.skip_after_RET_TRACE:Expected -1 (18446744073709551615) == syscall(39) (26) > seccomp_bpf.c:1561:TRACE_syscall.skip_after_RET_TRACE:Expected 1 (1) == (*__errno_location ()) (22) > [ FAIL ] TRACE_syscall.skip_after_RET_TRACE > [ RUN ] TRACE_syscall.kill_after_RET_TRACE > TRACE_syscall.kill_after_RET_TRACE: Test exited normally instead of by signal (code: 1) > [ FAIL ] TRACE_syscall.kill_after_RET_TRACE > [ RUN ] TRACE_syscall.skip_after_ptrace > seccomp_bpf.c:1622:TRACE_syscall.skip_after_ptrace:Expected -1 (18446744073709551615) == syscall(39) (26) > seccomp_bpf.c:1623:TRACE_syscall.skip_after_ptrace:Expected 1 (1) == (*__errno_location ()) (22) > [ FAIL ] TRACE_syscall.skip_after_ptrace > [ RUN ] TRACE_syscall.kill_after_ptrace > TRACE_syscall.kill_after_ptrace: Test exited normally instead of by signal (code: 1) > [ FAIL ] TRACE_syscall.kill_after_ptrace Fixes: 26703c636c1f ("um/ptrace: run seccomp after ptrace") Signed-off-by: Mickaël Salaün Acked-by: Kees Cook Cc: Jeff Dike Cc: Richard Weinberger Cc: James Morris Cc: user-mode-linux-devel@lists.sourceforge.net Signed-off-by: James Morris Signed-off-by: Kees Cook --- arch/um/kernel/skas/syscall.c | 5 ----- arch/x86/um/ptrace_32.c | 3 +++ arch/x86/um/ptrace_64.c | 4 ++++ 3 files changed, 7 insertions(+), 5 deletions(-) diff --git a/arch/um/kernel/skas/syscall.c b/arch/um/kernel/skas/syscall.c index 0728fee94398..b783ac87d98a 100644 --- a/arch/um/kernel/skas/syscall.c +++ b/arch/um/kernel/skas/syscall.c @@ -27,12 +27,7 @@ void handle_syscall(struct uml_pt_regs *r) if (secure_computing(NULL) == -1) goto out; - /* Update the syscall number after orig_ax has potentially been updated - * with ptrace. - */ - UPT_SYSCALL_NR(r) = PT_SYSCALL_NR(r->gp); syscall = UPT_SYSCALL_NR(r); - if (syscall >= 0 && syscall <= __NR_syscall_max) PT_REGS_SET_SYSCALL_RETURN(regs, EXECUTE_SYSCALL(syscall, regs)); diff --git a/arch/x86/um/ptrace_32.c b/arch/x86/um/ptrace_32.c index ebd4dd6ef73b..a7ef7b131e25 100644 --- a/arch/x86/um/ptrace_32.c +++ b/arch/x86/um/ptrace_32.c @@ -84,7 +84,10 @@ int putreg(struct task_struct *child, int regno, unsigned long value) case EAX: case EIP: case UESP: + break; case ORIG_EAX: + /* Update the syscall number. */ + UPT_SYSCALL_NR(&child->thread.regs.regs) = value; break; case FS: if (value && (value & 3) != 3) diff --git a/arch/x86/um/ptrace_64.c b/arch/x86/um/ptrace_64.c index faab418876ce..0b5c184dd5b3 100644 --- a/arch/x86/um/ptrace_64.c +++ b/arch/x86/um/ptrace_64.c @@ -78,7 +78,11 @@ int putreg(struct task_struct *child, int regno, unsigned long value) case RSI: case RDI: case RBP: + break; + case ORIG_RAX: + /* Update the syscall number. */ + UPT_SYSCALL_NR(&child->thread.regs.regs) = value; break; case FS: -- cgit v1.2.3 From 4fadd04d504a82f7f1fdeaddc144a9c396d1285e Mon Sep 17 00:00:00 2001 From: Mickaël Salaün Date: Mon, 1 Aug 2016 23:01:57 +0200 Subject: seccomp: Remove 2-phase API documentation Fixes: 8112c4f140fa ("seccomp: remove 2-phase API") Signed-off-by: Mickaël Salaün Acked-by: Kees Cook Cc: Andy Lutomirski Cc: James Morris Signed-off-by: James Morris Signed-off-by: Kees Cook --- arch/Kconfig | 11 ----------- 1 file changed, 11 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index e9c9334507dd..fd6e9712af81 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -336,17 +336,6 @@ config HAVE_ARCH_SECCOMP_FILTER results in the system call being skipped immediately. - seccomp syscall wired up - For best performance, an arch should use seccomp_phase1 and - seccomp_phase2 directly. It should call seccomp_phase1 for all - syscalls if TIF_SECCOMP is set, but seccomp_phase1 does not - need to be called from a ptrace-safe context. It must then - call seccomp_phase2 if seccomp_phase1 returns anything other - than SECCOMP_PHASE1_OK or SECCOMP_PHASE1_SKIP. - - As an additional optimization, an arch may provide seccomp_data - directly to seccomp_phase1; this avoids multiple calls - to the syscall_xyz helpers for every syscall. - config SECCOMP_FILTER def_bool y depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET -- cgit v1.2.3