From 31931c93dfe05a76385a443ed28244a50e915a46 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Tue, 24 Apr 2018 20:59:47 -0500 Subject: [PATCH] signal: Extend siginfo_layout with SIL_FAULT_{MCEERR|BNDERR|PKUERR} Update the siginfo_layout function and enum siginfo_layout to represent all of the possible field layouts of struct siginfo. This allows the uses of siginfo_layout in um and arm64 where they are testing for SIL_FAULT to be more accurate as this rules out the other cases. Further this allows the switch statements on siginfo_layout to be simpler if perhaps a little more wordy. Making it easier to understand what is actually going on. As SIL_FAULT_BNDERR and SIL_FAULT_PKUERR are never expected to appear in signalfd just treat them as SIL_FAULT. To include them would take 20 extra bytes an pretty much fill up what is left of signalfd_siginfo. Signed-off-by: "Eric W. Biederman" --- fs/signalfd.c | 24 ++++++++----- include/linux/signal.h | 3 ++ kernel/signal.c | 81 +++++++++++++++++++++++++++++------------- 3 files changed, 75 insertions(+), 33 deletions(-) diff --git a/fs/signalfd.c b/fs/signalfd.c index f652249f59f9..cbb42f77a2bd 100644 --- a/fs/signalfd.c +++ b/fs/signalfd.c @@ -112,19 +112,27 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo, new.ssi_band = kinfo->si_band; new.ssi_fd = kinfo->si_fd; break; + case SIL_FAULT_BNDERR: + case SIL_FAULT_PKUERR: + /* + * Fall through to the SIL_FAULT case. Both SIL_FAULT_BNDERR + * and SIL_FAULT_PKUERR are only generated by faults that + * deliver them synchronously to userspace. In case someone + * injects one of these signals and signalfd catches it treat + * it as SIL_FAULT. + */ case SIL_FAULT: new.ssi_addr = (long) kinfo->si_addr; #ifdef __ARCH_SI_TRAPNO new.ssi_trapno = kinfo->si_trapno; #endif - /* - * Other callers might not initialize the si_lsb field, - * so check explicitly for the right codes here. - */ - if (kinfo->si_signo == SIGBUS && - ((kinfo->si_code == BUS_MCEERR_AR) || - (kinfo->si_code == BUS_MCEERR_AO))) - new.ssi_addr_lsb = (short) kinfo->si_addr_lsb; + break; + case SIL_FAULT_MCEERR: + new.ssi_addr = (long) kinfo->si_addr; +#ifdef __ARCH_SI_TRAPNO + new.ssi_trapno = kinfo->si_trapno; +#endif + new.ssi_addr_lsb = (short) kinfo->si_addr_lsb; break; case SIL_CHLD: new.ssi_pid = kinfo->si_pid; diff --git a/include/linux/signal.h b/include/linux/signal.h index a9bc7e1b077e..3c5200137b24 100644 --- a/include/linux/signal.h +++ b/include/linux/signal.h @@ -28,6 +28,9 @@ enum siginfo_layout { SIL_TIMER, SIL_POLL, SIL_FAULT, + SIL_FAULT_MCEERR, + SIL_FAULT_BNDERR, + SIL_FAULT_PKUERR, SIL_CHLD, SIL_RT, SIL_SYS, diff --git a/kernel/signal.c b/kernel/signal.c index 376b42f26e6d..8a85da8aaa7c 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2820,8 +2820,19 @@ enum siginfo_layout siginfo_layout(int sig, int si_code) [SIGPOLL] = { NSIGPOLL, SIL_POLL }, [SIGSYS] = { NSIGSYS, SIL_SYS }, }; - if ((sig < ARRAY_SIZE(filter)) && (si_code <= filter[sig].limit)) + if ((sig < ARRAY_SIZE(filter)) && (si_code <= filter[sig].limit)) { layout = filter[sig].layout; + /* Handle the exceptions */ + if ((sig == SIGBUS) && + (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO)) + layout = SIL_FAULT_MCEERR; + else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR)) + layout = SIL_FAULT_BNDERR; +#ifdef SEGV_PKUERR + else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR)) + layout = SIL_FAULT_PKUERR; +#endif + } else if (si_code <= NSIGPOLL) layout = SIL_POLL; } else { @@ -2878,19 +2889,28 @@ int __copy_siginfo_to_user32(struct compat_siginfo __user *to, #ifdef __ARCH_SI_TRAPNO new.si_trapno = from->si_trapno; #endif - if ((from->si_signo == SIGBUS) && - ((from->si_code == BUS_MCEERR_AR) || - (from->si_code == BUS_MCEERR_AO))) - new.si_addr_lsb = from->si_addr_lsb; - - if ((from->si_signo == SIGSEGV) && - (from->si_code == SEGV_BNDERR)) { - new.si_lower = ptr_to_compat(from->si_lower); - new.si_upper = ptr_to_compat(from->si_upper); - } - if ((from->si_signo == SIGSEGV) && - (from->si_code == SEGV_PKUERR)) - new.si_pkey = from->si_pkey; + break; + case SIL_FAULT_MCEERR: + new.si_addr = ptr_to_compat(from->si_addr); +#ifdef __ARCH_SI_TRAPNO + new.si_trapno = from->si_trapno; +#endif + new.si_addr_lsb = from->si_addr_lsb; + break; + case SIL_FAULT_BNDERR: + new.si_addr = ptr_to_compat(from->si_addr); +#ifdef __ARCH_SI_TRAPNO + new.si_trapno = from->si_trapno; +#endif + new.si_lower = ptr_to_compat(from->si_lower); + new.si_upper = ptr_to_compat(from->si_upper); + break; + case SIL_FAULT_PKUERR: + new.si_addr = ptr_to_compat(from->si_addr); +#ifdef __ARCH_SI_TRAPNO + new.si_trapno = from->si_trapno; +#endif + new.si_pkey = from->si_pkey; break; case SIL_CHLD: new.si_pid = from->si_pid; @@ -2956,17 +2976,28 @@ int copy_siginfo_from_user32(struct siginfo *to, #ifdef __ARCH_SI_TRAPNO to->si_trapno = from.si_trapno; #endif - if ((from.si_signo == SIGBUS) && - ((from.si_code == BUS_MCEERR_AR) || - (from.si_code == BUS_MCEERR_AO))) - to->si_addr_lsb = from.si_addr_lsb; - - if ((from.si_signo == SIGSEGV) && (from.si_code == SEGV_BNDERR)) { - to->si_lower = compat_ptr(from.si_lower); - to->si_upper = compat_ptr(from.si_upper); - } - if ((from.si_signo == SIGSEGV) && (from.si_code == SEGV_PKUERR)) - to->si_pkey = from.si_pkey; + break; + case SIL_FAULT_MCEERR: + to->si_addr = compat_ptr(from.si_addr); +#ifdef __ARCH_SI_TRAPNO + to->si_trapno = from.si_trapno; +#endif + to->si_addr_lsb = from.si_addr_lsb; + break; + case SIL_FAULT_BNDERR: + to->si_addr = compat_ptr(from.si_addr); +#ifdef __ARCH_SI_TRAPNO + to->si_trapno = from.si_trapno; +#endif + to->si_lower = compat_ptr(from.si_lower); + to->si_upper = compat_ptr(from.si_upper); + break; + case SIL_FAULT_PKUERR: + to->si_addr = compat_ptr(from.si_addr); +#ifdef __ARCH_SI_TRAPNO + to->si_trapno = from.si_trapno; +#endif + to->si_pkey = from.si_pkey; break; case SIL_CHLD: to->si_pid = from.si_pid;