From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1792) id 4EB753857005; Tue, 16 May 2023 14:09:26 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 4EB753857005 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1684246166; bh=zXozYNUQExXeEqPoWwHyHq1aVyPzqGoIaNRxj8nnMhs=; h=From:To:Subject:Date:From; b=uHIM8ybVGXipZ9M4gmdLI9n2rhdrnhS4sdM3MUXh1aOD+oZe8ScpTOU3+zhyYpyTb ItbCT0Hx/W4Q7L33u262V2YZ4iATrrSZZUm9apOzmV/8G+zu6kQ2pXF282MAgw/D8g 3Cj+t3n6CBcUZuuFNMzPDENSDt46wfgVO6F4WZjQ= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Samuel Thibault To: glibc-cvs@sourceware.org Subject: [glibc] hurd: Fix sc_i386_thread_state layout X-Act-Checkin: glibc X-Git-Author: Sergey Bugaev X-Git-Refname: refs/heads/master X-Git-Oldrev: ce96593c882b393461084048533120e9c1e9d328 X-Git-Newrev: e333759f7752593a69a8f9920a247ed3878fafef Message-Id: <20230516140926.4EB753857005@sourceware.org> Date: Tue, 16 May 2023 14:09:26 +0000 (GMT) List-Id: https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=e333759f7752593a69a8f9920a247ed3878fafef commit e333759f7752593a69a8f9920a247ed3878fafef Author: Sergey Bugaev Date: Mon May 15 11:33:22 2023 +0300 hurd: Fix sc_i386_thread_state layout The real i386_thread_state Mach structure has an alignment of 8 on x86_64. However, in struct sigcontext, the compiler was packing sc_gs (which is the first member of sc_i386_thread_state) into the same 8-byte slot as sc_error; this resulted in the rest of sc_i386_thread_state members having wrong offsets relative to each other, and the overall sc_i386_thread_state layout mismatching that of i386_thread_state. Fix this by explicitly adding the required padding members, and statically asserting that this results in the desired alignment. The same goes for sc_i386_float_state. Checked on x86_64-gnu. Signed-off-by: Sergey Bugaev Message-Id: <20230515083323.1358039-4-bugaevc@gmail.com> Diff: --- sysdeps/mach/hurd/x86/trampoline.c | 6 ++++++ sysdeps/mach/hurd/x86_64/bits/sigcontext.h | 8 ++++++++ 2 files changed, 14 insertions(+) diff --git a/sysdeps/mach/hurd/x86/trampoline.c b/sysdeps/mach/hurd/x86/trampoline.c index 1f92064ebf..6318c9528a 100644 --- a/sysdeps/mach/hurd/x86/trampoline.c +++ b/sysdeps/mach/hurd/x86/trampoline.c @@ -242,11 +242,17 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, const struct sigaction *action /* struct sigcontext is laid out so that starting at sc_gs mimics a struct i386_thread_state. */ + _Static_assert (offsetof (struct sigcontext, sc_i386_thread_state) + % __alignof__ (struct i386_thread_state) == 0, + "sc_i386_thread_state layout mismatch"); memcpy (&scp->sc_i386_thread_state, &state->basic, sizeof (state->basic)); /* struct sigcontext is laid out so that starting at sc_fpkind mimics a struct i386_float_state. */ + _Static_assert (offsetof (struct sigcontext, sc_i386_float_state) + % __alignof__ (struct i386_float_state) == 0, + "sc_i386_float_state layout mismatch"); ok = machine_get_state (ss->thread, state, i386_FLOAT_STATE, &state->fpu, &scp->sc_i386_float_state, sizeof (state->fpu)); diff --git a/sysdeps/mach/hurd/x86_64/bits/sigcontext.h b/sysdeps/mach/hurd/x86_64/bits/sigcontext.h index 3a3b34bc0a..6396054463 100644 --- a/sysdeps/mach/hurd/x86_64/bits/sigcontext.h +++ b/sysdeps/mach/hurd/x86_64/bits/sigcontext.h @@ -46,6 +46,11 @@ struct sigcontext /* Error code associated with this signal (interpreted as `error_t'). */ int sc_error; + /* Make sure the below members are properly aligned, and not packed + together with sc_error -- otherwise the layout won't match that of + i386_thread_state. */ + int sc_pad1; + /* All following members are machine-dependent. The rest of this structure is written to be laid out identically to: { @@ -86,6 +91,9 @@ struct sigcontext long sc_ursp; /* This stack pointer is used. */ int sc_ss; /* Stack segment register. */ + /* Make sure the below has the same layout as i386_float_state. */ + int sc_pad2; + /* Following mimics struct i386_float_state. Structures and symbolic values can be found in . */ #define sc_i386_float_state sc_fpkind