From 20cd514d0f3d288d968217028ca67b70e707d896 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 20 Sep 2010 15:13:04 +0100 Subject: frv: restart_block.fn needs to be reset on sigreturn Reset restart_block.fn on executing a sigreturn such that any currently pending system call restarts will be forced to return -EINTR. Signed-off-by: Al Viro Signed-off-by: David Howells Signed-off-by: Linus Torvalds --- arch/frv/kernel/signal.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/frv') diff --git a/arch/frv/kernel/signal.c b/arch/frv/kernel/signal.c index 0974c0e..7fc2961 100644 --- a/arch/frv/kernel/signal.c +++ b/arch/frv/kernel/signal.c @@ -121,6 +121,9 @@ static int restore_sigcontext(struct sigcontext __user *sc, int *_gr8) struct user_context *user = current->thread.user; unsigned long tbr, psr; + /* Always make any pending restarted system calls return -EINTR */ + current_thread_info()->restart_block.fn = do_no_restart_syscall; + tbr = user->i.tbr; psr = user->i.psr; if (copy_from_user(user, &sc->sc_context, sizeof(sc->sc_context))) -- cgit v1.1 From 5f4ad04a1e805d14de080ff9d5384b4d20518a9a Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 20 Sep 2010 15:13:09 +0100 Subject: frv: fix address verification holes in setup_frame/setup_rt_frame a) sa_handler might be maliciously set to point to kernel memory; blindly dereferencing it in FDPIC case is a Bad Idea(tm). b) I'm not sure you need that set_fs(USER_DS) there at all, but if you do, you'd better do it *before* checking the frame you've decided to use with access_ok(), lest sigaltstack() becomes a convenient roothole. Signed-off-by: Al Viro Signed-off-by: David Howells Signed-off-by: Linus Torvalds --- arch/frv/kernel/signal.c | 38 ++++++++++++++++++++++---------------- 1 file changed, 22 insertions(+), 16 deletions(-) (limited to 'arch/frv') diff --git a/arch/frv/kernel/signal.c b/arch/frv/kernel/signal.c index 7fc2961..5fb2d06 100644 --- a/arch/frv/kernel/signal.c +++ b/arch/frv/kernel/signal.c @@ -253,6 +253,8 @@ static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set) struct sigframe __user *frame; int rsig; + set_fs(USER_DS); + frame = get_sigframe(ka, sizeof(*frame)); if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) @@ -296,22 +298,23 @@ static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set) (unsigned long) (frame->retcode + 2)); } - /* set up registers for signal handler */ - __frame->sp = (unsigned long) frame; - __frame->lr = (unsigned long) &frame->retcode; - __frame->gr8 = sig; - + /* Set up registers for the signal handler */ if (current->personality & FDPIC_FUNCPTRS) { struct fdpic_func_descriptor __user *funcptr = (struct fdpic_func_descriptor __user *) ka->sa.sa_handler; - __get_user(__frame->pc, &funcptr->text); - __get_user(__frame->gr15, &funcptr->GOT); + struct fdpic_func_descriptor desc; + if (copy_from_user(&desc, funcptr, sizeof(desc))) + goto give_sigsegv; + __frame->pc = desc.text; + __frame->gr15 = desc.GOT; } else { __frame->pc = (unsigned long) ka->sa.sa_handler; __frame->gr15 = 0; } - set_fs(USER_DS); + __frame->sp = (unsigned long) frame; + __frame->lr = (unsigned long) &frame->retcode; + __frame->gr8 = sig; /* the tracer may want to single-step inside the handler */ if (test_thread_flag(TIF_SINGLESTEP)) @@ -341,6 +344,8 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, struct rt_sigframe __user *frame; int rsig; + set_fs(USER_DS); + frame = get_sigframe(ka, sizeof(*frame)); if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) @@ -395,22 +400,23 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, } /* Set up registers for signal handler */ - __frame->sp = (unsigned long) frame; - __frame->lr = (unsigned long) &frame->retcode; - __frame->gr8 = sig; - __frame->gr9 = (unsigned long) &frame->info; - if (current->personality & FDPIC_FUNCPTRS) { struct fdpic_func_descriptor __user *funcptr = (struct fdpic_func_descriptor __user *) ka->sa.sa_handler; - __get_user(__frame->pc, &funcptr->text); - __get_user(__frame->gr15, &funcptr->GOT); + struct fdpic_func_descriptor desc; + if (copy_from_user(&desc, funcptr, sizeof(desc))) + goto give_sigsegv; + __frame->pc = desc.text; + __frame->gr15 = desc.GOT; } else { __frame->pc = (unsigned long) ka->sa.sa_handler; __frame->gr15 = 0; } - set_fs(USER_DS); + __frame->sp = (unsigned long) frame; + __frame->lr = (unsigned long) &frame->retcode; + __frame->gr8 = sig; + __frame->gr9 = (unsigned long) &frame->info; /* the tracer may want to single-step inside the handler */ if (test_thread_flag(TIF_SINGLESTEP)) -- cgit v1.1 From ad0acab4557a91a60251b3ffe3478fad572d6f61 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 20 Sep 2010 15:13:14 +0100 Subject: frv: avoid infinite loop of SIGSEGV delivery Use force_sigsegv() rather than force_sig(SIGSEGV, ...) as the former resets the SEGV handler pointer which will kill the process, rather than leaving it open to an infinite loop if the SEGV handler itself caused a SEGV signal. Signed-off-by: Al Viro Signed-off-by: David Howells Signed-off-by: Linus Torvalds --- arch/frv/kernel/signal.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/frv') diff --git a/arch/frv/kernel/signal.c b/arch/frv/kernel/signal.c index 5fb2d06..48203c6 100644 --- a/arch/frv/kernel/signal.c +++ b/arch/frv/kernel/signal.c @@ -329,7 +329,7 @@ static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set) return 0; give_sigsegv: - force_sig(SIGSEGV, current); + force_sigsegv(sig, current); return -EFAULT; } /* end setup_frame() */ @@ -431,7 +431,7 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, return 0; give_sigsegv: - force_sig(SIGSEGV, current); + force_sigsegv(sig, current); return -EFAULT; } /* end setup_rt_frame() */ -- cgit v1.1 From 44c7afffa429a7cdcd1755019ab76566ff41e66d Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 20 Sep 2010 15:13:19 +0100 Subject: frv: handling of restart into restart_syscall is fscked do_signal() should place the syscall number in gr7, not gr8 when handling ERESTART_WOULDBLOCK. Signed-off-by: Al Viro Signed-off-by: David Howells Signed-off-by: Linus Torvalds --- arch/frv/kernel/signal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/frv') diff --git a/arch/frv/kernel/signal.c b/arch/frv/kernel/signal.c index 48203c6..bd13b57 100644 --- a/arch/frv/kernel/signal.c +++ b/arch/frv/kernel/signal.c @@ -547,7 +547,7 @@ no_signal: break; case -ERESTART_RESTARTBLOCK: - __frame->gr8 = __NR_restart_syscall; + __frame->gr7 = __NR_restart_syscall; __frame->pc -= 4; break; } -- cgit v1.1 From ed1cde68365c1251b920900c51e73675ff38dc66 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 20 Sep 2010 15:13:25 +0100 Subject: frv: double syscall restarts, syscall restart in sigreturn() We need to make sure that only the first do_signal() to be handled on the way out syscall will bother with syscall restarts; additionally, the check on the "signal has user handler" path had been wrong - compare with restart prevention in sigreturn()... Signed-off-by: Al Viro Signed-off-by: David Howells Signed-off-by: Linus Torvalds --- arch/frv/kernel/signal.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'arch/frv') diff --git a/arch/frv/kernel/signal.c b/arch/frv/kernel/signal.c index bd13b57..bab0129 100644 --- a/arch/frv/kernel/signal.c +++ b/arch/frv/kernel/signal.c @@ -446,7 +446,7 @@ static int handle_signal(unsigned long sig, siginfo_t *info, int ret; /* Are we from a system call? */ - if (in_syscall(__frame)) { + if (__frame->syscallno != -1) { /* If so, check system call restarting.. */ switch (__frame->gr8) { case -ERESTART_RESTARTBLOCK: @@ -465,6 +465,7 @@ static int handle_signal(unsigned long sig, siginfo_t *info, __frame->gr8 = __frame->orig_gr8; __frame->pc -= 4; } + __frame->syscallno = -1; } /* Set up the stack frame */ @@ -551,6 +552,7 @@ no_signal: __frame->pc -= 4; break; } + __frame->syscallno = -1; } /* if there's no signal to deliver, we just put the saved sigmask -- cgit v1.1