m32r: hole in shifting pc back
It's a userland pointer; worse, an untrustable one since ptrace has just provided a chance to modify it. X-Roothole-Covering-Cabal: TINRCC Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Родитель
a05c4e1d66
Коммит
bb9c861ee1
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@ -251,6 +251,19 @@ give_sigsegv:
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return -EFAULT;
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}
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static int prev_insn(struct pt_regs *regs)
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{
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u16 inst;
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if (get_user(&inst, (u16 __user *)(regs->bpc - 2)))
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return -EFAULT;
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if ((inst & 0xfff0) == 0x10f0) /* trap ? */
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regs->bpc -= 2;
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else
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regs->bpc -= 4;
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regs->syscall_nr = -1;
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return 0;
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}
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/*
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* OK, we're invoking a handler
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*/
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@ -259,8 +272,6 @@ static int
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handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
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sigset_t *oldset, struct pt_regs *regs)
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{
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unsigned short inst;
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/* Are we from a system call? */
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if (regs->syscall_nr >= 0) {
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/* If so, check system call restarting.. */
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@ -278,12 +289,8 @@ handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
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/* fallthrough */
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case -ERESTARTNOINTR:
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regs->r0 = regs->orig_r0;
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inst = *(unsigned short *)(regs->bpc - 2);
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if ((inst & 0xfff0) == 0x10f0) /* trap ? */
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regs->bpc -= 2;
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else
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regs->bpc -= 4;
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regs->syscall_nr = -1;
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if (prev_insn(regs) < 0)
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return -EFAULT;
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}
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}
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@ -310,7 +317,6 @@ static void do_signal(struct pt_regs *regs)
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siginfo_t info;
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int signr;
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struct k_sigaction ka;
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unsigned short inst;
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sigset_t *oldset;
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/*
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@ -353,21 +359,11 @@ static void do_signal(struct pt_regs *regs)
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regs->r0 == -ERESTARTSYS ||
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regs->r0 == -ERESTARTNOINTR) {
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regs->r0 = regs->orig_r0;
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inst = *(unsigned short *)(regs->bpc - 2);
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if ((inst & 0xfff0) == 0x10f0) /* trap ? */
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regs->bpc -= 2;
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else
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regs->bpc -= 4;
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regs->syscall_nr = -1;
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prev_insn(regs);
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} else if (regs->r0 == -ERESTART_RESTARTBLOCK){
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regs->r0 = regs->orig_r0;
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regs->r7 = __NR_restart_syscall;
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inst = *(unsigned short *)(regs->bpc - 2);
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if ((inst & 0xfff0) == 0x10f0) /* trap ? */
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regs->bpc -= 2;
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else
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regs->bpc -= 4;
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regs->syscall_nr = -1;
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prev_insn(regs);
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}
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}
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if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
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