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-rw-r--r--arch/m68k/kernel/signal.c173
1 files changed, 61 insertions, 112 deletions
diff --git a/arch/m68k/kernel/signal.c b/arch/m68k/kernel/signal.c
index 16ea319d1ed..d5f4a82515f 100644
--- a/arch/m68k/kernel/signal.c
+++ b/arch/m68k/kernel/signal.c
@@ -286,36 +286,10 @@ out:
return err;
}
-static inline int
-restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, void __user *fp,
- int *pd0)
+static int mangle_kernel_stack(struct pt_regs *regs, int formatvec,
+ void __user *fp)
{
- int fsize, formatvec;
- struct sigcontext context;
- int err;
-
- /* Always make any pending restarted system calls return -EINTR */
- current_thread_info()->restart_block.fn = do_no_restart_syscall;
-
- /* get previous context */
- if (copy_from_user(&context, usc, sizeof(context)))
- goto badframe;
-
- /* restore passed registers */
- regs->d1 = context.sc_d1;
- regs->a0 = context.sc_a0;
- regs->a1 = context.sc_a1;
- regs->sr = (regs->sr & 0xff00) | (context.sc_sr & 0xff);
- regs->pc = context.sc_pc;
- regs->orig_d0 = -1; /* disable syscall checks */
- wrusp(context.sc_usp);
- formatvec = context.sc_formatvec;
- regs->format = formatvec >> 12;
- regs->vector = formatvec & 0xfff;
-
- err = restore_fpu_state(&context);
-
- fsize = frame_extra_sizes[regs->format];
+ int fsize = frame_extra_sizes[formatvec >> 12];
if (fsize < 0) {
/*
* user process trying to return with weird frame format
@@ -323,16 +297,22 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, void __u
#ifdef DEBUG
printk("user process returning with weird frame format\n");
#endif
- goto badframe;
+ return 1;
}
+ if (!fsize) {
+ regs->format = formatvec >> 12;
+ regs->vector = formatvec & 0xfff;
+ } else {
+ struct switch_stack *sw = (struct switch_stack *)regs - 1;
+ unsigned long buf[fsize / 2]; /* yes, twice as much */
- /* OK. Make room on the supervisor stack for the extra junk,
- * if necessary.
- */
+ /* that'll make sure that expansion won't crap over data */
+ if (copy_from_user(buf + fsize / 4, fp, fsize))
+ return 1;
- if (fsize) {
- struct switch_stack *sw = (struct switch_stack *)regs - 1;
- regs->d0 = context.sc_d0;
+ /* point of no return */
+ regs->format = formatvec >> 12;
+ regs->vector = formatvec & 0xfff;
#define frame_offset (sizeof(struct pt_regs)+sizeof(struct switch_stack))
__asm__ __volatile__
(" movel %0,%/a0\n\t"
@@ -344,30 +324,50 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, void __u
" lea %/sp@(%c3),%/a0\n\t" /* add offset of fmt */
" lsrl #2,%1\n\t"
" subql #1,%1\n\t"
- "2: movesl %4@+,%2\n\t"
- "3: movel %2,%/a0@+\n\t"
+ /* copy to the gap we'd made */
+ "2: movel %4@+,%/a0@+\n\t"
" dbra %1,2b\n\t"
" bral ret_from_signal\n"
- "4:\n"
- ".section __ex_table,\"a\"\n"
- " .align 4\n"
- " .long 2b,4b\n"
- " .long 3b,4b\n"
- ".previous"
: /* no outputs, it doesn't ever return */
: "a" (sw), "d" (fsize), "d" (frame_offset/4-1),
- "n" (frame_offset), "a" (fp)
+ "n" (frame_offset), "a" (buf + fsize/4)
: "a0");
#undef frame_offset
- /*
- * If we ever get here an exception occurred while
- * building the above stack-frame.
- */
- goto badframe;
}
+ return 0;
+}
- *pd0 = context.sc_d0;
- return err;
+static inline int
+restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, void __user *fp)
+{
+ int formatvec;
+ struct sigcontext context;
+ int err;
+
+ /* Always make any pending restarted system calls return -EINTR */
+ current_thread_info()->restart_block.fn = do_no_restart_syscall;
+
+ /* get previous context */
+ if (copy_from_user(&context, usc, sizeof(context)))
+ goto badframe;
+
+ /* restore passed registers */
+ regs->d0 = context.sc_d0;
+ regs->d1 = context.sc_d1;
+ regs->a0 = context.sc_a0;
+ regs->a1 = context.sc_a1;
+ regs->sr = (regs->sr & 0xff00) | (context.sc_sr & 0xff);
+ regs->pc = context.sc_pc;
+ regs->orig_d0 = -1; /* disable syscall checks */
+ wrusp(context.sc_usp);
+ formatvec = context.sc_formatvec;
+
+ err = restore_fpu_state(&context);
+
+ if (err || mangle_kernel_stack(regs, formatvec, fp))
+ goto badframe;
+
+ return 0;
badframe:
return 1;
@@ -375,9 +375,9 @@ badframe:
static inline int
rt_restore_ucontext(struct pt_regs *regs, struct switch_stack *sw,
- struct ucontext __user *uc, int *pd0)
+ struct ucontext __user *uc)
{
- int fsize, temp;
+ int temp;
greg_t __user *gregs = uc->uc_mcontext.gregs;
unsigned long usp;
int err;
@@ -411,65 +411,16 @@ rt_restore_ucontext(struct pt_regs *regs, struct switch_stack *sw,
regs->sr = (regs->sr & 0xff00) | (temp & 0xff);
regs->orig_d0 = -1; /* disable syscall checks */
err |= __get_user(temp, &uc->uc_formatvec);
- regs->format = temp >> 12;
- regs->vector = temp & 0xfff;
err |= rt_restore_fpu_state(uc);
- if (do_sigaltstack(&uc->uc_stack, NULL, usp) == -EFAULT)
+ if (err || do_sigaltstack(&uc->uc_stack, NULL, usp) == -EFAULT)
goto badframe;
- fsize = frame_extra_sizes[regs->format];
- if (fsize < 0) {
- /*
- * user process trying to return with weird frame format
- */
-#ifdef DEBUG
- printk("user process returning with weird frame format\n");
-#endif
+ if (mangle_kernel_stack(regs, temp, &uc->uc_extra))
goto badframe;
- }
- /* OK. Make room on the supervisor stack for the extra junk,
- * if necessary.
- */
-
- if (fsize) {
-#define frame_offset (sizeof(struct pt_regs)+sizeof(struct switch_stack))
- __asm__ __volatile__
- (" movel %0,%/a0\n\t"
- " subl %1,%/a0\n\t" /* make room on stack */
- " movel %/a0,%/sp\n\t" /* set stack pointer */
- /* move switch_stack and pt_regs */
- "1: movel %0@+,%/a0@+\n\t"
- " dbra %2,1b\n\t"
- " lea %/sp@(%c3),%/a0\n\t" /* add offset of fmt */
- " lsrl #2,%1\n\t"
- " subql #1,%1\n\t"
- "2: movesl %4@+,%2\n\t"
- "3: movel %2,%/a0@+\n\t"
- " dbra %1,2b\n\t"
- " bral ret_from_signal\n"
- "4:\n"
- ".section __ex_table,\"a\"\n"
- " .align 4\n"
- " .long 2b,4b\n"
- " .long 3b,4b\n"
- ".previous"
- : /* no outputs, it doesn't ever return */
- : "a" (sw), "d" (fsize), "d" (frame_offset/4-1),
- "n" (frame_offset), "a" (&uc->uc_extra)
- : "a0");
-#undef frame_offset
- /*
- * If we ever get here an exception occurred while
- * building the above stack-frame.
- */
- goto badframe;
- }
-
- *pd0 = regs->d0;
- return err;
+ return 0;
badframe:
return 1;
@@ -482,7 +433,6 @@ asmlinkage int do_sigreturn(unsigned long __unused)
unsigned long usp = rdusp();
struct sigframe __user *frame = (struct sigframe __user *)(usp - 4);
sigset_t set;
- int d0;
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
@@ -496,9 +446,9 @@ asmlinkage int do_sigreturn(unsigned long __unused)
current->blocked = set;
recalc_sigpending();
- if (restore_sigcontext(regs, &frame->sc, frame + 1, &d0))
+ if (restore_sigcontext(regs, &frame->sc, frame + 1))
goto badframe;
- return d0;
+ return regs->d0;
badframe:
force_sig(SIGSEGV, current);
@@ -512,7 +462,6 @@ asmlinkage int do_rt_sigreturn(unsigned long __unused)
unsigned long usp = rdusp();
struct rt_sigframe __user *frame = (struct rt_sigframe __user *)(usp - 4);
sigset_t set;
- int d0;
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
@@ -523,9 +472,9 @@ asmlinkage int do_rt_sigreturn(unsigned long __unused)
current->blocked = set;
recalc_sigpending();
- if (rt_restore_ucontext(regs, sw, &frame->uc, &d0))
+ if (rt_restore_ucontext(regs, sw, &frame->uc))
goto badframe;
- return d0;
+ return regs->d0;
badframe:
force_sig(SIGSEGV, current);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-13 12:00:04 +0000