mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
synced 2025-09-01 23:46:45 +00:00
942349413a
There was a typo that caused the extended FP state to be copied into the
wrong location on 32 bit. On 32 bit we only store the xstate internally
as that already contains everything. However, for compatibility, the
mcontext on 32 bit first contains the legacy FP state and then the
xstate.
The code copied the xstate on top of the legacy FP state instead of
using the correct offset. This offset was already calculated in the
xstate_* variables, so simply switch to those to fix the problem.
With this SECCOMP mode works on 32 bit, so lift the restriction.
Fixes: b1e1bd2e69 ("um: Add helper functions to get/set state for SECCOMP")
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20250604081705.934112-1-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
261 lines
7.3 KiB
C
261 lines
7.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#define __FRAME_OFFSETS
|
|
#include <linux/errno.h>
|
|
#include <linux/string.h>
|
|
#include <sys/ucontext.h>
|
|
#include <asm/ptrace.h>
|
|
#include <asm/sigcontext.h>
|
|
#include <sysdep/ptrace.h>
|
|
#include <sysdep/mcontext.h>
|
|
#include <arch.h>
|
|
|
|
void get_regs_from_mc(struct uml_pt_regs *regs, mcontext_t *mc)
|
|
{
|
|
#ifdef __i386__
|
|
#define COPY2(X,Y) regs->gp[X] = mc->gregs[REG_##Y]
|
|
#define COPY(X) regs->gp[X] = mc->gregs[REG_##X]
|
|
#define COPY_SEG(X) regs->gp[X] = mc->gregs[REG_##X] & 0xffff;
|
|
#define COPY_SEG_CPL3(X) regs->gp[X] = (mc->gregs[REG_##X] & 0xffff) | 3;
|
|
COPY_SEG(GS); COPY_SEG(FS); COPY_SEG(ES); COPY_SEG(DS);
|
|
COPY(EDI); COPY(ESI); COPY(EBP);
|
|
COPY2(UESP, ESP); /* sic */
|
|
COPY(EBX); COPY(EDX); COPY(ECX); COPY(EAX);
|
|
COPY(EIP); COPY_SEG_CPL3(CS); COPY(EFL); COPY_SEG_CPL3(SS);
|
|
#undef COPY2
|
|
#undef COPY
|
|
#undef COPY_SEG
|
|
#undef COPY_SEG_CPL3
|
|
#else
|
|
#define COPY2(X,Y) regs->gp[X/sizeof(unsigned long)] = mc->gregs[REG_##Y]
|
|
#define COPY(X) regs->gp[X/sizeof(unsigned long)] = mc->gregs[REG_##X]
|
|
COPY(R8); COPY(R9); COPY(R10); COPY(R11);
|
|
COPY(R12); COPY(R13); COPY(R14); COPY(R15);
|
|
COPY(RDI); COPY(RSI); COPY(RBP); COPY(RBX);
|
|
COPY(RDX); COPY(RAX); COPY(RCX); COPY(RSP);
|
|
COPY(RIP);
|
|
COPY2(EFLAGS, EFL);
|
|
COPY2(CS, CSGSFS);
|
|
regs->gp[SS / sizeof(unsigned long)] = mc->gregs[REG_CSGSFS] >> 48;
|
|
#undef COPY2
|
|
#undef COPY
|
|
#endif
|
|
}
|
|
|
|
void mc_set_rip(void *_mc, void *target)
|
|
{
|
|
mcontext_t *mc = _mc;
|
|
|
|
#ifdef __i386__
|
|
mc->gregs[REG_EIP] = (unsigned long)target;
|
|
#else
|
|
mc->gregs[REG_RIP] = (unsigned long)target;
|
|
#endif
|
|
}
|
|
|
|
/* Same thing, but the copy macros are turned around. */
|
|
void get_mc_from_regs(struct uml_pt_regs *regs, mcontext_t *mc, int single_stepping)
|
|
{
|
|
#ifdef __i386__
|
|
#define COPY2(X,Y) mc->gregs[REG_##Y] = regs->gp[X]
|
|
#define COPY(X) mc->gregs[REG_##X] = regs->gp[X]
|
|
#define COPY_SEG(X) mc->gregs[REG_##X] = regs->gp[X] & 0xffff;
|
|
#define COPY_SEG_CPL3(X) mc->gregs[REG_##X] = (regs->gp[X] & 0xffff) | 3;
|
|
COPY_SEG(GS); COPY_SEG(FS); COPY_SEG(ES); COPY_SEG(DS);
|
|
COPY(EDI); COPY(ESI); COPY(EBP);
|
|
COPY2(UESP, ESP); /* sic */
|
|
COPY(EBX); COPY(EDX); COPY(ECX); COPY(EAX);
|
|
COPY(EIP); COPY_SEG_CPL3(CS); COPY(EFL); COPY_SEG_CPL3(SS);
|
|
#else
|
|
#define COPY2(X,Y) mc->gregs[REG_##Y] = regs->gp[X/sizeof(unsigned long)]
|
|
#define COPY(X) mc->gregs[REG_##X] = regs->gp[X/sizeof(unsigned long)]
|
|
COPY(R8); COPY(R9); COPY(R10); COPY(R11);
|
|
COPY(R12); COPY(R13); COPY(R14); COPY(R15);
|
|
COPY(RDI); COPY(RSI); COPY(RBP); COPY(RBX);
|
|
COPY(RDX); COPY(RAX); COPY(RCX); COPY(RSP);
|
|
COPY(RIP);
|
|
COPY2(EFLAGS, EFL);
|
|
mc->gregs[REG_CSGSFS] = mc->gregs[REG_CSGSFS] & 0xffffffffffffl;
|
|
mc->gregs[REG_CSGSFS] |= (regs->gp[SS / sizeof(unsigned long)] & 0xffff) << 48;
|
|
#endif
|
|
|
|
if (single_stepping)
|
|
mc->gregs[REG_EFL] |= X86_EFLAGS_TF;
|
|
else
|
|
mc->gregs[REG_EFL] &= ~X86_EFLAGS_TF;
|
|
}
|
|
|
|
#ifdef CONFIG_X86_32
|
|
struct _xstate_64 {
|
|
struct _fpstate_64 fpstate;
|
|
struct _header xstate_hdr;
|
|
struct _ymmh_state ymmh;
|
|
/* New processor state extensions go here: */
|
|
};
|
|
|
|
/* Not quite the right structures as these contain more information */
|
|
int um_i387_from_fxsr(struct _fpstate_32 *i387,
|
|
const struct _fpstate_64 *fxsave);
|
|
int um_fxsr_from_i387(struct _fpstate_64 *fxsave,
|
|
const struct _fpstate_32 *from);
|
|
#else
|
|
#define _xstate_64 _xstate
|
|
#endif
|
|
|
|
static struct _fpstate *get_fpstate(struct stub_data *data,
|
|
mcontext_t *mcontext,
|
|
int *fp_size)
|
|
{
|
|
struct _fpstate *res;
|
|
|
|
/* Assume floating point registers are on the same page */
|
|
res = (void *)(((unsigned long)mcontext->fpregs &
|
|
(UM_KERN_PAGE_SIZE - 1)) +
|
|
(unsigned long)&data->sigstack[0]);
|
|
|
|
if ((void *)res + sizeof(struct _fpstate) >
|
|
(void *)data->sigstack + sizeof(data->sigstack))
|
|
return NULL;
|
|
|
|
if (res->sw_reserved.magic1 != FP_XSTATE_MAGIC1) {
|
|
*fp_size = sizeof(struct _fpstate);
|
|
} else {
|
|
char *magic2_addr;
|
|
|
|
magic2_addr = (void *)res;
|
|
magic2_addr += res->sw_reserved.extended_size;
|
|
magic2_addr -= FP_XSTATE_MAGIC2_SIZE;
|
|
|
|
/* We still need to be within our stack */
|
|
if ((void *)magic2_addr >
|
|
(void *)data->sigstack + sizeof(data->sigstack))
|
|
return NULL;
|
|
|
|
/* If we do not read MAGIC2, then we did something wrong */
|
|
if (*(__u32 *)magic2_addr != FP_XSTATE_MAGIC2)
|
|
return NULL;
|
|
|
|
/* Remove MAGIC2 from the size, we do not save/restore it */
|
|
*fp_size = res->sw_reserved.extended_size -
|
|
FP_XSTATE_MAGIC2_SIZE;
|
|
}
|
|
|
|
return res;
|
|
}
|
|
|
|
int get_stub_state(struct uml_pt_regs *regs, struct stub_data *data,
|
|
unsigned long *fp_size_out)
|
|
{
|
|
mcontext_t *mcontext;
|
|
struct _fpstate *fpstate_stub;
|
|
struct _xstate_64 *xstate_stub;
|
|
int fp_size, xstate_size;
|
|
|
|
/* mctx_offset is verified by wait_stub_done_seccomp */
|
|
mcontext = (void *)&data->sigstack[data->mctx_offset];
|
|
|
|
get_regs_from_mc(regs, mcontext);
|
|
|
|
fpstate_stub = get_fpstate(data, mcontext, &fp_size);
|
|
if (!fpstate_stub)
|
|
return -EINVAL;
|
|
|
|
#ifdef CONFIG_X86_32
|
|
xstate_stub = (void *)&fpstate_stub->_fxsr_env;
|
|
xstate_size = fp_size - offsetof(struct _fpstate_32, _fxsr_env);
|
|
#else
|
|
xstate_stub = (void *)fpstate_stub;
|
|
xstate_size = fp_size;
|
|
#endif
|
|
|
|
if (fp_size_out)
|
|
*fp_size_out = xstate_size;
|
|
|
|
if (xstate_size > host_fp_size)
|
|
return -ENOSPC;
|
|
|
|
memcpy(®s->fp, xstate_stub, xstate_size);
|
|
|
|
/* We do not need to read the x86_64 FS_BASE/GS_BASE registers as
|
|
* we do not permit userspace to set them directly.
|
|
*/
|
|
|
|
#ifdef CONFIG_X86_32
|
|
/* Read the i387 legacy FP registers */
|
|
if (um_fxsr_from_i387((void *)®s->fp, fpstate_stub))
|
|
return -EINVAL;
|
|
#endif
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Copied because we cannot include regset.h here. */
|
|
struct task_struct;
|
|
struct user_regset;
|
|
struct membuf {
|
|
void *p;
|
|
size_t left;
|
|
};
|
|
|
|
int fpregs_legacy_get(struct task_struct *target,
|
|
const struct user_regset *regset,
|
|
struct membuf to);
|
|
|
|
int set_stub_state(struct uml_pt_regs *regs, struct stub_data *data,
|
|
int single_stepping)
|
|
{
|
|
mcontext_t *mcontext;
|
|
struct _fpstate *fpstate_stub;
|
|
struct _xstate_64 *xstate_stub;
|
|
int fp_size, xstate_size;
|
|
|
|
/* mctx_offset is verified by wait_stub_done_seccomp */
|
|
mcontext = (void *)&data->sigstack[data->mctx_offset];
|
|
|
|
if ((unsigned long)mcontext < (unsigned long)data->sigstack ||
|
|
(unsigned long)mcontext >
|
|
(unsigned long) data->sigstack +
|
|
sizeof(data->sigstack) - sizeof(*mcontext))
|
|
return -EINVAL;
|
|
|
|
get_mc_from_regs(regs, mcontext, single_stepping);
|
|
|
|
fpstate_stub = get_fpstate(data, mcontext, &fp_size);
|
|
if (!fpstate_stub)
|
|
return -EINVAL;
|
|
|
|
#ifdef CONFIG_X86_32
|
|
xstate_stub = (void *)&fpstate_stub->_fxsr_env;
|
|
xstate_size = fp_size - offsetof(struct _fpstate_32, _fxsr_env);
|
|
#else
|
|
xstate_stub = (void *)fpstate_stub;
|
|
xstate_size = fp_size;
|
|
#endif
|
|
|
|
memcpy(xstate_stub, ®s->fp, xstate_size);
|
|
|
|
#ifdef __i386__
|
|
/*
|
|
* On x86, the GDT entries are updated by arch_set_tls.
|
|
*/
|
|
|
|
/* Store the i387 legacy FP registers which the host will use */
|
|
if (um_i387_from_fxsr(fpstate_stub, (void *)®s->fp))
|
|
return -EINVAL;
|
|
#else
|
|
/*
|
|
* On x86_64, we need to sync the FS_BASE/GS_BASE registers using the
|
|
* arch specific data.
|
|
*/
|
|
if (data->arch_data.fs_base != regs->gp[FS_BASE / sizeof(unsigned long)]) {
|
|
data->arch_data.fs_base = regs->gp[FS_BASE / sizeof(unsigned long)];
|
|
data->arch_data.sync |= STUB_SYNC_FS_BASE;
|
|
}
|
|
if (data->arch_data.gs_base != regs->gp[GS_BASE / sizeof(unsigned long)]) {
|
|
data->arch_data.gs_base = regs->gp[GS_BASE / sizeof(unsigned long)];
|
|
data->arch_data.sync |= STUB_SYNC_GS_BASE;
|
|
}
|
|
#endif
|
|
|
|
return 0;
|
|
}
|