AuroraMiddleware/glibc
1
0
Fork 0
mirror of https://sourceware.org/git/glibc.git synced 2025-01-11 11:50:06 +00:00
Code Issues Packages Projects Releases Wiki Activity

hurd: Fix sc_i386_thread_state layout

Browse Source 
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 <bugaevc@gmail.com>
Message-Id: <20230515083323.1358039-4-bugaevc@gmail.com>
This commit is contained in:
Sergey Bugaev 2023-05-15 11:33:22 +03:00 committed by Samuel Thibault
parent ce96593c88
commit e333759f77
2 changed files with 14 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
sysdeps/mach/hurd/x86/trampoline.c
View File

@ -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));

8
sysdeps/mach/hurd/x86_64/bits/sigcontext.h
View File

@ -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 <mach/i386/fp_reg.h>. */
#define sc_i386_float_state sc_fpkind