From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Yznaga Subject: [RFC PATCH 5/5] mm: introduce MADV_DOEXEC Date: Mon, 27 Jul 2020 10:11:27 -0700 Message-ID: <1595869887-23307-6-git-send-email-anthony.yznaga@oracle.com> References: <1595869887-23307-1-git-send-email-anthony.yznaga@oracle.com> Return-path: In-Reply-To: <1595869887-23307-1-git-send-email-anthony.yznaga@oracle.com> Sender: linux-fsdevel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org Cc: mhocko@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, arnd@arndb.de, ebiederm@xmission.com, keescook@chromium.org, gerg@linux-m68k.org, ktkhai@virtuozzo.com, christian.brauner@ubuntu.com, peterz@infradead.org, esyr@redhat.com, jgg@ziepe.ca, christian@kellner.me, areber@redhat.com, cyphar@cyphar.com, steven.sistare@oracle.com List-Id: linux-arch.vger.kernel.org madvise MADV_DOEXEC preserves a memory range across exec. Initially only supported for non-executable, non-stack, anonymous memory. MADV_DONTEXEC reverts the effect of a previous MADV_DOXEXEC call and undoes the preservation of the range. After a successful exec call, the behavior of all ranges reverts to MADV_DONTEXEC. Signed-off-by: Steve Sistare Signed-off-by: Anthony Yznaga --- include/uapi/asm-generic/mman-common.h | 3 +++ mm/madvise.c | 25 +++++++++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h index f94f65d429be..7c5f616b28f7 100644 --- a/include/uapi/asm-generic/mman-common.h +++ b/include/uapi/asm-generic/mman-common.h @@ -72,6 +72,9 @@ #define MADV_COLD 20 /* deactivate these pages */ #define MADV_PAGEOUT 21 /* reclaim these pages */ +#define MADV_DOEXEC 22 /* do inherit across exec */ +#define MADV_DONTEXEC 23 /* don't inherit across exec */ + /* compatibility flags */ #define MAP_FILE 0 diff --git a/mm/madvise.c b/mm/madvise.c index dd1d43cf026d..b447fa748649 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -103,6 +103,26 @@ static long madvise_behavior(struct vm_area_struct *vma, case MADV_KEEPONFORK: new_flags &= ~VM_WIPEONFORK; break; + case MADV_DOEXEC: + /* + * MADV_DOEXEC is only supported on private, non-executable, + * non-stack anonymous memory and if the VM_EXEC_KEEP flag + * is available. + */ + if (!VM_EXEC_KEEP || vma->vm_file || vma->vm_flags & (VM_EXEC|VM_SHARED|VM_STACK)) { + error = -EINVAL; + goto out; + } + new_flags |= (new_flags & ~VM_MAYEXEC) | VM_EXEC_KEEP; + break; + case MADV_DONTEXEC: + if (!VM_EXEC_KEEP) { + error = -EINVAL; + goto out; + } + if (new_flags & VM_EXEC_KEEP) + new_flags |= (new_flags & ~VM_EXEC_KEEP) | VM_MAYEXEC; + break; case MADV_DONTDUMP: new_flags |= VM_DONTDUMP; break; @@ -983,6 +1003,8 @@ static int madvise_inject_error(int behavior, case MADV_SOFT_OFFLINE: case MADV_HWPOISON: #endif + case MADV_DOEXEC: + case MADV_DONTEXEC: return true; default: @@ -1037,6 +1059,9 @@ static int madvise_inject_error(int behavior, * MADV_DONTDUMP - the application wants to prevent pages in the given range * from being included in its core dump. * MADV_DODUMP - cancel MADV_DONTDUMP: no longer exclude from core dump. + * MADV_DOEXEC - On exec, preserve and duplicate this area in the new process + * if the new process allows it. + * MADV_DONTEXEC - Undo the effect of MADV_DOEXEC. * * return values: * zero - success -- 1.8.3.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp2130.oracle.com ([156.151.31.86]:59392 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729403AbgG0RH7 (ORCPT ); Mon, 27 Jul 2020 13:07:59 -0400 From: Anthony Yznaga Subject: [RFC PATCH 5/5] mm: introduce MADV_DOEXEC Date: Mon, 27 Jul 2020 10:11:27 -0700 Message-ID: <1595869887-23307-6-git-send-email-anthony.yznaga@oracle.com> In-Reply-To: <1595869887-23307-1-git-send-email-anthony.yznaga@oracle.com> References: <1595869887-23307-1-git-send-email-anthony.yznaga@oracle.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org Cc: mhocko@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, arnd@arndb.de, ebiederm@xmission.com, keescook@chromium.org, gerg@linux-m68k.org, ktkhai@virtuozzo.com, christian.brauner@ubuntu.com, peterz@infradead.org, esyr@redhat.com, jgg@ziepe.ca, christian@kellner.me, areber@redhat.com, cyphar@cyphar.com, steven.sistare@oracle.com Message-ID: <20200727171127.qhaNevvihR6HGk1WpCBzoDa84ebGd1zG4c-_oMDUN8E@z> madvise MADV_DOEXEC preserves a memory range across exec. Initially only supported for non-executable, non-stack, anonymous memory. MADV_DONTEXEC reverts the effect of a previous MADV_DOXEXEC call and undoes the preservation of the range. After a successful exec call, the behavior of all ranges reverts to MADV_DONTEXEC. Signed-off-by: Steve Sistare Signed-off-by: Anthony Yznaga --- include/uapi/asm-generic/mman-common.h | 3 +++ mm/madvise.c | 25 +++++++++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h index f94f65d429be..7c5f616b28f7 100644 --- a/include/uapi/asm-generic/mman-common.h +++ b/include/uapi/asm-generic/mman-common.h @@ -72,6 +72,9 @@ #define MADV_COLD 20 /* deactivate these pages */ #define MADV_PAGEOUT 21 /* reclaim these pages */ +#define MADV_DOEXEC 22 /* do inherit across exec */ +#define MADV_DONTEXEC 23 /* don't inherit across exec */ + /* compatibility flags */ #define MAP_FILE 0 diff --git a/mm/madvise.c b/mm/madvise.c index dd1d43cf026d..b447fa748649 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -103,6 +103,26 @@ static long madvise_behavior(struct vm_area_struct *vma, case MADV_KEEPONFORK: new_flags &= ~VM_WIPEONFORK; break; + case MADV_DOEXEC: + /* + * MADV_DOEXEC is only supported on private, non-executable, + * non-stack anonymous memory and if the VM_EXEC_KEEP flag + * is available. + */ + if (!VM_EXEC_KEEP || vma->vm_file || vma->vm_flags & (VM_EXEC|VM_SHARED|VM_STACK)) { + error = -EINVAL; + goto out; + } + new_flags |= (new_flags & ~VM_MAYEXEC) | VM_EXEC_KEEP; + break; + case MADV_DONTEXEC: + if (!VM_EXEC_KEEP) { + error = -EINVAL; + goto out; + } + if (new_flags & VM_EXEC_KEEP) + new_flags |= (new_flags & ~VM_EXEC_KEEP) | VM_MAYEXEC; + break; case MADV_DONTDUMP: new_flags |= VM_DONTDUMP; break; @@ -983,6 +1003,8 @@ static int madvise_inject_error(int behavior, case MADV_SOFT_OFFLINE: case MADV_HWPOISON: #endif + case MADV_DOEXEC: + case MADV_DONTEXEC: return true; default: @@ -1037,6 +1059,9 @@ static int madvise_inject_error(int behavior, * MADV_DONTDUMP - the application wants to prevent pages in the given range * from being included in its core dump. * MADV_DODUMP - cancel MADV_DONTDUMP: no longer exclude from core dump. + * MADV_DOEXEC - On exec, preserve and duplicate this area in the new process + * if the new process allows it. + * MADV_DONTEXEC - Undo the effect of MADV_DOEXEC. * * return values: * zero - success -- 1.8.3.1