From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Drewry Subject: [PATCH v15 11/13] ptrace,seccomp: Add PTRACE_SECCOMP support Date: Wed, 14 Mar 2012 22:12:03 -0500 Message-ID: <1331781125-15658-12-git-send-email-wad@chromium.org> References: <1331781125-15658-1-git-send-email-wad@chromium.org> Reply-To: kernel-hardening@lists.openwall.com Return-path: List-Post: List-Help: List-Unsubscribe: List-Subscribe: In-Reply-To: <1331781125-15658-1-git-send-email-wad@chromium.org> To: linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, kernel-hardening@lists.openwall.com, netdev@vger.kernel.org, x86@kernel.org, arnd@arndb.de, davem@davemloft.net, hpa@zytor.com, mingo@redhat.com, oleg@redhat.com, peterz@infradead.org, rdunlap@xenotime.net, mcgrathr@chromium.org, tglx@linutronix.de, luto@mit.edu, eparis@redhat.com, serge.hallyn@canonical.com, djm@mindrot.org, scarybeasts@gmail.com, indan@nul.nu, pmoore@redhat.com, akpm@linux-foundation.org, corbet@lwn.net, eric.dumazet@gmail.com, markus@chromium.org, coreyb@linux.vnet.ibm.com, keescook@chromium.org, Will Drewry List-Id: linux-arch.vger.kernel.org This change adds support for a new ptrace option, PTRACE_O_TRACESECCOMP, and a new return value for seccomp BPF programs, SECCOMP_RET_TRACE. When a tracer specifies the PTRACE_O_TRACESECCOMP ptrace option, the tracer will be notified, via PTRACE_EVENT_SECCOMP, for any syscall that results in a BPF program returning SECCOMP_RET_TRACE. The 16-bit SECCOMP_RET_DATA mask of the BPF program return value will be passed as the ptrace_message and may be retrieved using PTRACE_GETEVENTMSG. If the subordinate process is not using seccomp filter, then no system call notifications will occur even if the option is specified. If there is no tracer with PTRACE_O_TRACESECCOMP when SECCOMP_RET_TRACE is returned, the system call will not be executed and an -ENOSYS errno will be returned to userspace. This change adds a dependency on the system call slow path. Any future efforts to use the system call fast path for seccomp filter will need to address this restriction. v15: - add audit support for non-zero return codes - clean up style (indan@nul.nu) v14: - rebase/nochanges v13: - rebase on to 88ebdda6159ffc15699f204c33feb3e431bf9bdc (Brings back a change to ptrace.c and the masks.) v12: - rebase to linux-next - use ptrace_event and update arch/Kconfig to mention slow-path dependency - drop all tracehook changes and inclusion (oleg@redhat.com) v11: - invert the logic to just make it a PTRACE_SYSCALL accelerator (indan@nul.nu) v10: - moved to PTRACE_O_SECCOMP / PT_TRACE_SECCOMP v9: - n/a v8: - guarded PTRACE_SECCOMP use with an ifdef v7: - introduced Signed-off-by: Will Drewry --- arch/Kconfig | 11 ++++++----- include/linux/ptrace.h | 7 +++++-- include/linux/seccomp.h | 1 + kernel/ptrace.c | 3 +++ kernel/seccomp.c | 13 +++++++++++-- 5 files changed, 26 insertions(+), 9 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index d92a78e..3f8132c 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -202,15 +202,16 @@ config HAVE_CMPXCHG_DOUBLE config HAVE_ARCH_SECCOMP_FILTER bool help - This symbol should be selected by an architecure if it provides: - asm/syscall.h: + An arch should select this symbol if it provides all of these things: - syscall_get_arch() - syscall_get_arguments() - syscall_rollback() - syscall_set_return_value() - SIGSYS siginfo_t support must be implemented. - __secure_computing_int()/secure_computing()'s return value must be - checked, with -1 resulting in the syscall being skipped. + - SIGSYS siginfo_t support + - uses __secure_computing_int() or secure_computing() + - secure_computing is called from a ptrace_event()-safe context + - secure_computing return value is checked and a return value of -1 + results in the system call being skipped immediately. config SECCOMP_FILTER def_bool y diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index c2f1f6a..84b3418 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -62,8 +62,9 @@ #define PTRACE_O_TRACEEXEC 0x00000010 #define PTRACE_O_TRACEVFORKDONE 0x00000020 #define PTRACE_O_TRACEEXIT 0x00000040 +#define PTRACE_O_TRACESECCOMP 0x00000080 -#define PTRACE_O_MASK 0x0000007f +#define PTRACE_O_MASK 0x000000ff /* Wait extended result codes for the above trace options. */ #define PTRACE_EVENT_FORK 1 @@ -73,6 +74,7 @@ #define PTRACE_EVENT_VFORK_DONE 5 #define PTRACE_EVENT_EXIT 6 #define PTRACE_EVENT_STOP 7 +#define PTRACE_EVENT_SECCOMP 8 #include @@ -101,8 +103,9 @@ #define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC) #define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE) #define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT) +#define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP) -#define PT_TRACE_MASK 0x000003f4 +#define PT_TRACE_MASK 0x00000ff4 /* single stepping state bits (used on ARM and PA-RISC) */ #define PT_SINGLESTEP_BIT 31 diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h index a5078fb..306733e 100644 --- a/include/linux/seccomp.h +++ b/include/linux/seccomp.h @@ -21,6 +21,7 @@ #define SECCOMP_RET_KILL 0x00000000U /* kill the task immediately */ #define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */ #define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */ +#define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */ #define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */ /* Masks for the return value sections. */ diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 00ab2ca..8cf6da1 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -551,6 +551,9 @@ static int ptrace_setoptions(struct task_struct *child, unsigned long data) if (data & PTRACE_O_TRACEEXIT) child->ptrace |= PT_TRACE_EXIT; + if (data & PTRACE_O_TRACESECCOMP) + child->ptrace |= PT_TRACE_SECCOMP; + return (data & ~PTRACE_O_MASK) ? -EINVAL : 0; } diff --git a/kernel/seccomp.c b/kernel/seccomp.c index fb3b993..725e83e 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -17,13 +17,13 @@ #include #include #include +#include #include #include #include #include #include -#include #include /* #define SECCOMP_DEBUG 1 */ @@ -398,7 +398,7 @@ int __secure_computing_int(int this_syscall) case SECCOMP_MODE_FILTER: ret = seccomp_run_filters(this_syscall); data = ret & SECCOMP_RET_DATA; - switch (code & SECCOMP_RET_ACTION) { + switch (ret & SECCOMP_RET_ACTION) { case SECCOMP_RET_ERRNO: /* Set the low-order 16-bits as a errno. */ syscall_set_return_value(current, task_pt_regs(current), @@ -410,6 +410,15 @@ int __secure_computing_int(int this_syscall) /* Let the filter pass back 16 bits of data. */ seccomp_send_sigsys(this_syscall, data); goto skip; + case SECCOMP_RET_TRACE: + /* Skip these calls if there is no tracer. */ + if (!ptrace_event_enabled(current, PTRACE_EVENT_SECCOMP)) + goto skip; + /* Allow the BPF to provide the event message */ + ptrace_event(PTRACE_EVENT_SECCOMP, data); + if (fatal_signal_pending(current)) + break; + return 0; case SECCOMP_RET_ALLOW: return 0; case SECCOMP_RET_KILL: -- 1.7.5.4 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yx0-f174.google.com ([209.85.213.174]:37718 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759938Ab2CODNn (ORCPT ); Wed, 14 Mar 2012 23:13:43 -0400 Received: by mail-yx0-f174.google.com with SMTP id l12so2585785yen.19 for ; Wed, 14 Mar 2012 20:13:43 -0700 (PDT) From: Will Drewry Subject: [PATCH v15 11/13] ptrace,seccomp: Add PTRACE_SECCOMP support Date: Wed, 14 Mar 2012 22:12:03 -0500 Message-ID: <1331781125-15658-12-git-send-email-wad@chromium.org> In-Reply-To: <1331781125-15658-1-git-send-email-wad@chromium.org> References: <1331781125-15658-1-git-send-email-wad@chromium.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, kernel-hardening@lists.openwall.com, netdev@vger.kernel.org, x86@kernel.org, arnd@arndb.de, davem@davemloft.net, hpa@zytor.com, mingo@redhat.com, oleg@redhat.com, peterz@infradead.org, rdunlap@xenotime.net, mcgrathr@chromium.org, tglx@linutronix.de, luto@mit.edu, eparis@redhat.com, serge.hallyn@canonical.com, djm@mindrot.org, scarybeasts@gmail.com, indan@nul.nu, pmoore@redhat.com, akpm@linux-foundation.org, corbet@lwn.net, eric.dumazet@gmail.com, markus@chromium.org, coreyb@linux.vnet.ibm.com, keescook@chromium.org, Will Drewry Message-ID: <20120315031203.d0r_woO7wF_jtG1XuSOQwKzetRss2PtjpBCxHqJFFJs@z> This change adds support for a new ptrace option, PTRACE_O_TRACESECCOMP, and a new return value for seccomp BPF programs, SECCOMP_RET_TRACE. When a tracer specifies the PTRACE_O_TRACESECCOMP ptrace option, the tracer will be notified, via PTRACE_EVENT_SECCOMP, for any syscall that results in a BPF program returning SECCOMP_RET_TRACE. The 16-bit SECCOMP_RET_DATA mask of the BPF program return value will be passed as the ptrace_message and may be retrieved using PTRACE_GETEVENTMSG. If the subordinate process is not using seccomp filter, then no system call notifications will occur even if the option is specified. If there is no tracer with PTRACE_O_TRACESECCOMP when SECCOMP_RET_TRACE is returned, the system call will not be executed and an -ENOSYS errno will be returned to userspace. This change adds a dependency on the system call slow path. Any future efforts to use the system call fast path for seccomp filter will need to address this restriction. v15: - add audit support for non-zero return codes - clean up style (indan@nul.nu) v14: - rebase/nochanges v13: - rebase on to 88ebdda6159ffc15699f204c33feb3e431bf9bdc (Brings back a change to ptrace.c and the masks.) v12: - rebase to linux-next - use ptrace_event and update arch/Kconfig to mention slow-path dependency - drop all tracehook changes and inclusion (oleg@redhat.com) v11: - invert the logic to just make it a PTRACE_SYSCALL accelerator (indan@nul.nu) v10: - moved to PTRACE_O_SECCOMP / PT_TRACE_SECCOMP v9: - n/a v8: - guarded PTRACE_SECCOMP use with an ifdef v7: - introduced Signed-off-by: Will Drewry --- arch/Kconfig | 11 ++++++----- include/linux/ptrace.h | 7 +++++-- include/linux/seccomp.h | 1 + kernel/ptrace.c | 3 +++ kernel/seccomp.c | 13 +++++++++++-- 5 files changed, 26 insertions(+), 9 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index d92a78e..3f8132c 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -202,15 +202,16 @@ config HAVE_CMPXCHG_DOUBLE config HAVE_ARCH_SECCOMP_FILTER bool help - This symbol should be selected by an architecure if it provides: - asm/syscall.h: + An arch should select this symbol if it provides all of these things: - syscall_get_arch() - syscall_get_arguments() - syscall_rollback() - syscall_set_return_value() - SIGSYS siginfo_t support must be implemented. - __secure_computing_int()/secure_computing()'s return value must be - checked, with -1 resulting in the syscall being skipped. + - SIGSYS siginfo_t support + - uses __secure_computing_int() or secure_computing() + - secure_computing is called from a ptrace_event()-safe context + - secure_computing return value is checked and a return value of -1 + results in the system call being skipped immediately. config SECCOMP_FILTER def_bool y diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index c2f1f6a..84b3418 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -62,8 +62,9 @@ #define PTRACE_O_TRACEEXEC 0x00000010 #define PTRACE_O_TRACEVFORKDONE 0x00000020 #define PTRACE_O_TRACEEXIT 0x00000040 +#define PTRACE_O_TRACESECCOMP 0x00000080 -#define PTRACE_O_MASK 0x0000007f +#define PTRACE_O_MASK 0x000000ff /* Wait extended result codes for the above trace options. */ #define PTRACE_EVENT_FORK 1 @@ -73,6 +74,7 @@ #define PTRACE_EVENT_VFORK_DONE 5 #define PTRACE_EVENT_EXIT 6 #define PTRACE_EVENT_STOP 7 +#define PTRACE_EVENT_SECCOMP 8 #include @@ -101,8 +103,9 @@ #define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC) #define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE) #define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT) +#define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP) -#define PT_TRACE_MASK 0x000003f4 +#define PT_TRACE_MASK 0x00000ff4 /* single stepping state bits (used on ARM and PA-RISC) */ #define PT_SINGLESTEP_BIT 31 diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h index a5078fb..306733e 100644 --- a/include/linux/seccomp.h +++ b/include/linux/seccomp.h @@ -21,6 +21,7 @@ #define SECCOMP_RET_KILL 0x00000000U /* kill the task immediately */ #define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */ #define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */ +#define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */ #define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */ /* Masks for the return value sections. */ diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 00ab2ca..8cf6da1 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -551,6 +551,9 @@ static int ptrace_setoptions(struct task_struct *child, unsigned long data) if (data & PTRACE_O_TRACEEXIT) child->ptrace |= PT_TRACE_EXIT; + if (data & PTRACE_O_TRACESECCOMP) + child->ptrace |= PT_TRACE_SECCOMP; + return (data & ~PTRACE_O_MASK) ? -EINVAL : 0; } diff --git a/kernel/seccomp.c b/kernel/seccomp.c index fb3b993..725e83e 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -17,13 +17,13 @@ #include #include #include +#include #include #include #include #include #include -#include #include /* #define SECCOMP_DEBUG 1 */ @@ -398,7 +398,7 @@ int __secure_computing_int(int this_syscall) case SECCOMP_MODE_FILTER: ret = seccomp_run_filters(this_syscall); data = ret & SECCOMP_RET_DATA; - switch (code & SECCOMP_RET_ACTION) { + switch (ret & SECCOMP_RET_ACTION) { case SECCOMP_RET_ERRNO: /* Set the low-order 16-bits as a errno. */ syscall_set_return_value(current, task_pt_regs(current), @@ -410,6 +410,15 @@ int __secure_computing_int(int this_syscall) /* Let the filter pass back 16 bits of data. */ seccomp_send_sigsys(this_syscall, data); goto skip; + case SECCOMP_RET_TRACE: + /* Skip these calls if there is no tracer. */ + if (!ptrace_event_enabled(current, PTRACE_EVENT_SECCOMP)) + goto skip; + /* Allow the BPF to provide the event message */ + ptrace_event(PTRACE_EVENT_SECCOMP, data); + if (fatal_signal_pending(current)) + break; + return 0; case SECCOMP_RET_ALLOW: return 0; case SECCOMP_RET_KILL: -- 1.7.5.4