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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-03-28 18:47:27 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-03-28 18:47:27 +0100 |
| commit | af0c11ca80dce01933738d9029625ab6af27f5de (patch) | |
| tree | 101877ae9543581b3ea300645f444b572a621360 /arch | |
| parent | Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmo... (diff) | |
| parent | ARC: signal handling robustify (diff) | |
| download | linux-af0c11ca80dce01933738d9029625ab6af27f5de.tar.xz linux-af0c11ca80dce01933738d9029625ab6af27f5de.zip | |
Merge tag 'arc-4.0-fixes-part-2' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
Pull ARC fixes from Vineet Gupta:
"We found some issues with signal handling taking down the system. I
know its late, but these are important and all marked for stable.
ARC signal handling related fixes uncovered during recent testing of
NPTL tools"
* tag 'arc-4.0-fixes-part-2' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
ARC: signal handling robustify
ARC: SA_SIGINFO ucontext regs off-by-one
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arc/kernel/signal.c | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/arch/arc/kernel/signal.c b/arch/arc/kernel/signal.c index 114234e83caa..edda76fae83f 100644 --- a/arch/arc/kernel/signal.c +++ b/arch/arc/kernel/signal.c @@ -67,7 +67,7 @@ stash_usr_regs(struct rt_sigframe __user *sf, struct pt_regs *regs, sigset_t *set) { int err; - err = __copy_to_user(&(sf->uc.uc_mcontext.regs), regs, + err = __copy_to_user(&(sf->uc.uc_mcontext.regs.scratch), regs, sizeof(sf->uc.uc_mcontext.regs.scratch)); err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(sigset_t)); @@ -83,7 +83,7 @@ static int restore_usr_regs(struct pt_regs *regs, struct rt_sigframe __user *sf) if (!err) set_current_blocked(&set); - err |= __copy_from_user(regs, &(sf->uc.uc_mcontext.regs), + err |= __copy_from_user(regs, &(sf->uc.uc_mcontext.regs.scratch), sizeof(sf->uc.uc_mcontext.regs.scratch)); return err; @@ -131,6 +131,15 @@ SYSCALL_DEFINE0(rt_sigreturn) /* Don't restart from sigreturn */ syscall_wont_restart(regs); + /* + * Ensure that sigreturn always returns to user mode (in case the + * regs saved on user stack got fudged between save and sigreturn) + * Otherwise it is easy to panic the kernel with a custom + * signal handler and/or restorer which clobberes the status32/ret + * to return to a bogus location in kernel mode. + */ + regs->status32 |= STATUS_U_MASK; + return regs->r0; badframe: @@ -229,8 +238,11 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) /* * handler returns using sigreturn stub provided already by userpsace + * If not, nuke the process right away */ - BUG_ON(!(ksig->ka.sa.sa_flags & SA_RESTORER)); + if(!(ksig->ka.sa.sa_flags & SA_RESTORER)) + return 1; + regs->blink = (unsigned long)ksig->ka.sa.sa_restorer; /* User Stack for signal handler will be above the frame just carved */ @@ -296,12 +308,12 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) { sigset_t *oldset = sigmask_to_save(); - int ret; + int failed; /* Set up the stack frame */ - ret = setup_rt_frame(ksig, oldset, regs); + failed = setup_rt_frame(ksig, oldset, regs); - signal_setup_done(ret, ksig, 0); + signal_setup_done(failed, ksig, 0); } void do_signal(struct pt_regs *regs) |