From 212a36a17efe4d696d1e3c31ebd79a9fb0cbb14b Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Mon, 31 Jul 2017 17:15:31 -0500 Subject: signal: Unify and correct copy_siginfo_from_user32 The function copy_siginfo_from_user32 is used for two things, in ptrace since the dawn of siginfo for arbirarily modifying a signal that user space sees, and in sigqueueinfo to send a signal with arbirary siginfo data. Create a single copy of copy_siginfo_from_user32 that all architectures share, and teach it to handle all of the cases in the siginfo union. In the generic version of copy_siginfo_from_user32 ensure that all of the fields in siginfo are initialized so that the siginfo structure can be safely copied to userspace if necessary. When copying the embedded sigval union copy the si_int member. That ensures the 32bit values passes through the kernel unchanged. Signed-off-by: "Eric W. Biederman" --- arch/arm64/kernel/signal32.c | 10 ---------- 1 file changed, 10 deletions(-) (limited to 'arch/arm64/kernel/signal32.c') diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c index 22711ee8e36c..4377907dbb70 100644 --- a/arch/arm64/kernel/signal32.c +++ b/arch/arm64/kernel/signal32.c @@ -195,16 +195,6 @@ int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from) return err; } -int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from) -{ - if (copy_from_user(to, from, __ARCH_SI_PREAMBLE_SIZE) || - copy_from_user(to->_sifields._pad, - from->_sifields._pad, SI_PAD_SIZE)) - return -EFAULT; - - return 0; -} - /* * VFP save/restore code. * -- cgit From ea64d5acc8f033cd586182ae31531246cdeaea73 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Mon, 15 Jan 2018 18:03:33 -0600 Subject: signal: Unify and correct copy_siginfo_to_user32 Among the existing architecture specific versions of copy_siginfo_to_user32 there are several different implementation problems. Some architectures fail to handle all of the cases in in the siginfo union. Some architectures perform a blind copy of the siginfo union when the si_code is negative. A blind copy suggests the data is expected to be in 32bit siginfo format, which means that receiving such a signal via signalfd won't work, or that the data is in 64bit siginfo and the code is copying nonsense to userspace. Create a single instance of copy_siginfo_to_user32 that all of the architectures can share, and teach it to handle all of the cases in the siginfo union correctly, with the assumption that siginfo is stored internally to the kernel is 64bit siginfo format. A special case is made for x86 x32 format. This is needed as presence of both x32 and ia32 on x86_64 results in two different 32bit signal formats. By allowing this small special case there winds up being exactly one code base that needs to be maintained between all of the architectures. Vastly increasing the testing base and the chances of finding bugs. As the x86 copy of copy_siginfo_to_user32 the call of the x86 signal_compat_build_tests were moved into sigaction_compat_abi, so that they will keep running. Signed-off-by: "Eric W. Biederman" --- arch/arm64/kernel/signal32.c | 70 -------------------------------------------- 1 file changed, 70 deletions(-) (limited to 'arch/arm64/kernel/signal32.c') diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c index 4377907dbb70..cbc4edd1b1eb 100644 --- a/arch/arm64/kernel/signal32.c +++ b/arch/arm64/kernel/signal32.c @@ -125,76 +125,6 @@ static inline int get_sigset_t(sigset_t *set, return 0; } -int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from) -{ - int err; - - if (!access_ok(VERIFY_WRITE, to, sizeof(*to))) - return -EFAULT; - - /* If you change siginfo_t structure, please be sure - * this code is fixed accordingly. - * It should never copy any pad contained in the structure - * to avoid security leaks, but must copy the generic - * 3 ints plus the relevant union member. - * This routine must convert siginfo from 64bit to 32bit as well - * at the same time. - */ - err = __put_user(from->si_signo, &to->si_signo); - err |= __put_user(from->si_errno, &to->si_errno); - err |= __put_user(from->si_code, &to->si_code); - if (from->si_code < 0) - err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad, - SI_PAD_SIZE); - else switch (siginfo_layout(from->si_signo, from->si_code)) { - case SIL_KILL: - err |= __put_user(from->si_pid, &to->si_pid); - err |= __put_user(from->si_uid, &to->si_uid); - break; - case SIL_TIMER: - err |= __put_user(from->si_tid, &to->si_tid); - err |= __put_user(from->si_overrun, &to->si_overrun); - err |= __put_user(from->si_int, &to->si_int); - break; - case SIL_POLL: - err |= __put_user(from->si_band, &to->si_band); - err |= __put_user(from->si_fd, &to->si_fd); - break; - case SIL_FAULT: - err |= __put_user((compat_uptr_t)(unsigned long)from->si_addr, - &to->si_addr); -#ifdef BUS_MCEERR_AO - /* - * Other callers might not initialize the si_lsb field, - * so check explicitly for the right codes here. - */ - if (from->si_signo == SIGBUS && - (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)) - err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb); -#endif - break; - case SIL_CHLD: - err |= __put_user(from->si_pid, &to->si_pid); - err |= __put_user(from->si_uid, &to->si_uid); - err |= __put_user(from->si_status, &to->si_status); - err |= __put_user(from->si_utime, &to->si_utime); - err |= __put_user(from->si_stime, &to->si_stime); - break; - case SIL_RT: - err |= __put_user(from->si_pid, &to->si_pid); - err |= __put_user(from->si_uid, &to->si_uid); - err |= __put_user(from->si_int, &to->si_int); - break; - case SIL_SYS: - err |= __put_user((compat_uptr_t)(unsigned long) - from->si_call_addr, &to->si_call_addr); - err |= __put_user(from->si_syscall, &to->si_syscall); - err |= __put_user(from->si_arch, &to->si_arch); - break; - } - return err; -} - /* * VFP save/restore code. * -- cgit