From nobody Sun Apr 6 03:35:22 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=nongnu.org ARC-Seal: i=1; a=rsa-sha256; t=1736953726; cv=none; d=zohomail.com; s=zohoarc; b=TgI4f2vTVeusOd0SeOZYbsg/UrViHAQuDuPnHiFiVqlZitjgCVx710N3pWNQNsOEIfVU7nGqJPJlMYQLebJiLqlr1dHv2VfLKdyo7X+8ekSZpzSzokIzYfdjUtqny03TLB9ekIlx4w9S4nnLpMIP7hdm9y9FdycofI4/eUEMPRU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1736953726; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Reply-To:Reply-To:Sender:Subject:Subject:To:To:Message-Id; bh=Ey2mcddGlQdW94n6CUuISRqkDIVh6yZm/poQT3COiQE=; b=BuM+0YnNNQIHYZ83o+blhU7MGDxHkn6JgMLoP+xOxDSsBp/uYM+MUb86JtZPYNrQVm9N/wkyFGNUlZ0PZIGBIk4JIM2wqUYuwzXa2+2U+BtYE0710XF2bdIHzEGbEDqwQPx8r+hOLQCZ1sZ/N0mE3bwlo+lL7RN8BZieTaT3hRI= ARC-Authentication-Results: i=1; mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1736953726571826.2128642089547; Wed, 15 Jan 2025 07:08:46 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tY50O-0002zo-DJ; Wed, 15 Jan 2025 10:08:29 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tY4VR-0001hP-C2 for qemu-devel@nongnu.org; Wed, 15 Jan 2025 09:36:29 -0500 Received: from out-170.mta1.migadu.com ([95.215.58.170]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tY4VO-0006f3-0J for qemu-devel@nongnu.org; Wed, 15 Jan 2025 09:36:28 -0500 X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. To: qemu-devel@nongnu.org Cc: Arusekk , Laurent Vivier Subject: [PATCH] linux-user: Add syscall dispatch support Date: Wed, 15 Jan 2025 15:36:23 +0100 Message-ID: <20250115143623.8257-1-floss@arusekk.pl> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=95.215.58.170; envelope-from=floss@arusekk.pl; helo=out-170.mta1.migadu.com X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Wed, 15 Jan 2025 10:08:23 -0500 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-to: Arusekk From: Arusekk via Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1736953729460019000 Content-Type: text/plain; charset="utf-8" This commit adds support for the `prctl(PR_SET_SYSCALL_DISPATCH)` function in the Linux userspace emulator. It is implemented as a fully host-independent function, by forcing a SIGSYS early during syscall handling, if the PC is outside the allowed range. Tested on [uglendix][1], will probably also apply to recent versions of Wine that use syscall dispatch. [1]: https://sr.ht/~arusekk/uglendix Signed-off-by: Arusekk --- linux-user/main.c | 2 ++ linux-user/qemu.h | 5 +++ linux-user/syscall.c | 64 ++++++++++++++++++++++++++++++++++++++- linux-user/syscall_defs.h | 6 ++++ 4 files changed, 76 insertions(+), 1 deletion(-) diff --git a/linux-user/main.c b/linux-user/main.c index b97634a32d..7e9567efc9 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -230,6 +230,8 @@ void init_task_state(TaskState *ts) ts->start_boottime +=3D bt.tv_nsec * (uint64_t) ticks_per_sec / NANOSECONDS_PER_SECOND; } + + ts->sys_dispatch_len =3D (abi_ulong)~0ULL; } =20 CPUArchState *cpu_copy(CPUArchState *env) diff --git a/linux-user/qemu.h b/linux-user/qemu.h index 5f00750151..9b67e19542 100644 --- a/linux-user/qemu.h +++ b/linux-user/qemu.h @@ -161,6 +161,11 @@ struct TaskState { /* This thread's sigaltstack, if it has one */ struct target_sigaltstack sigaltstack_used; =20 + /* This thread's SYSCALL_USER_DISPATCH state, len=3D~0 means disabled = */ + abi_ulong sys_dispatch; + abi_ulong sys_dispatch_len; + abi_ulong sys_dispatch_selector; + /* Start time of task after system boot in clock ticks */ uint64_t start_boottime; }; diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 78c7c0b34e..f65ef9b8fc 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -6317,6 +6317,10 @@ abi_long do_arch_prctl(CPUX86State *env, int code, a= bi_ulong addr) #endif #ifndef PR_SET_SYSCALL_USER_DISPATCH # define PR_SET_SYSCALL_USER_DISPATCH 59 +# define PR_SYS_DISPATCH_OFF 0 +# define PR_SYS_DISPATCH_ON 1 +# define SYSCALL_DISPATCH_FILTER_ALLOW 0 +# define SYSCALL_DISPATCH_FILTER_BLOCK 1 #endif #ifndef PR_SME_SET_VL # define PR_SME_SET_VL 63 @@ -6446,6 +6450,37 @@ static abi_long do_prctl(CPUArchState *env, abi_long= option, abi_long arg2, case PR_SET_UNALIGN: return do_prctl_set_unalign(env, arg2); =20 + case PR_SET_SYSCALL_USER_DISPATCH: + { + TaskState *ts =3D get_task_state(env_cpu(env)); + switch (arg2) { + case PR_SYS_DISPATCH_OFF: + if (arg3 || arg4 || arg5) { + return -TARGET_EINVAL; + } + ts->sys_dispatch_len =3D (abi_ulong)~0ULL; + return 0; + case PR_SYS_DISPATCH_ON: + { + uint8_t sb; + + if (arg3 && arg3 + arg4 <=3D arg3) { + return -TARGET_EINVAL; + } + if (arg5 && get_user_u8(sb, arg5)) { + return -TARGET_EFAULT; + } + (void)sb; /* used later, only checked for access */ + ts->sys_dispatch =3D arg3; + ts->sys_dispatch_len =3D arg4; + ts->sys_dispatch_selector =3D arg5; + return 0; + } + default: + return -EINVAL; + } + } + case PR_CAP_AMBIENT: case PR_CAPBSET_READ: case PR_CAPBSET_DROP: @@ -6500,7 +6535,6 @@ static abi_long do_prctl(CPUArchState *env, abi_long = option, abi_long arg2, case PR_SET_MM: case PR_GET_SECCOMP: case PR_SET_SECCOMP: - case PR_SET_SYSCALL_USER_DISPATCH: case PR_GET_THP_DISABLE: case PR_SET_THP_DISABLE: case PR_GET_TSC: @@ -13852,12 +13886,34 @@ static abi_long do_syscall1(CPUArchState *cpu_env= , int num, abi_long arg1, return ret; } =20 +static bool sys_dispatch(abi_ulong pc, TaskState *ts) +{ + if (likely(ts->sys_dispatch_selector)) { + uint8_t sb; + if (get_user_u8(sb, ts->sys_dispatch_selector)) { + force_sig(SIGSEGV); + return true; + } + if (likely(sb =3D=3D SYSCALL_DISPATCH_FILTER_ALLOW)) { + return false; + } + if (unlikely(sb !=3D SYSCALL_DISPATCH_FILTER_BLOCK)) { + force_sig(SIGSYS); + return true; + } + } + force_sig_fault(TARGET_SIGSYS, TARGET_SYS_USER_DISPATCH, pc); + return true; +} + abi_long do_syscall(CPUArchState *cpu_env, int num, abi_long arg1, abi_long arg2, abi_long arg3, abi_long arg4, abi_long arg5, abi_long arg6, abi_long arg7, abi_long arg8) { CPUState *cpu =3D env_cpu(cpu_env); + TaskState *ts =3D get_task_state(cpu); + vaddr pc =3D cpu->cc->get_pc(cpu); abi_long ret; =20 #ifdef DEBUG_ERESTARTSYS @@ -13874,6 +13930,12 @@ abi_long do_syscall(CPUArchState *cpu_env, int num= , abi_long arg1, } #endif =20 + if (unlikely(pc - ts->sys_dispatch >=3D ts->sys_dispatch_len)) { + if (sys_dispatch(pc, ts)) { + return -QEMU_ESIGRETURN; + } + } + record_syscall_start(cpu, num, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8); =20 diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h index faad9147c9..be6f6fa676 100644 --- a/linux-user/syscall_defs.h +++ b/linux-user/syscall_defs.h @@ -693,6 +693,12 @@ typedef struct target_siginfo { #define TARGET_TRAP_HWBKPT (4) /* hardware breakpoint/watchpoint = */ #define TARGET_TRAP_UNK (5) /* undiagnosed trap */ =20 +/* + * SIGSYS si_codes + */ +#define TARGET_SYS_SECCOMP (1) /* seccomp triggered */ +#define TARGET_SYS_USER_DISPATCH (2) /* syscall user dispatch triggered */ + /* * SIGEMT si_codes */ --=20 2.47.1