From f454322efbf6faee695f517c6b52c4dc03cacd3e Mon Sep 17 00:00:00 2001 From: "Dmitry V. Levin" Date: Tue, 22 Aug 2017 02:16:11 +0300 Subject: [PATCH] signal: replace sigset_to_compat() with put_compat_sigset() There are 4 callers of sigset_to_compat() in the entire kernel. One is in sparc compat rt_sigaction(2), the rest are in kernel/signal.c itself. All are followed by copy_to_user(), and all but the sparc one are under "if it's big-endian..." ifdefs. Let's transform sigset_to_compat() into put_compat_sigset() that also calls copy_to_user(). Suggested-by: Al Viro Signed-off-by: Dmitry V. Levin Signed-off-by: Al Viro --- arch/sparc/kernel/sys_sparc32.c | 6 +++--- include/linux/compat.h | 3 ++- kernel/compat.c | 20 ++++++++++++++------ kernel/signal.c | 27 ++++++--------------------- 4 files changed, 25 insertions(+), 31 deletions(-) diff --git a/arch/sparc/kernel/sys_sparc32.c b/arch/sparc/kernel/sys_sparc32.c index bca44f3e6b86..5e2bec9e41b2 100644 --- a/arch/sparc/kernel/sys_sparc32.c +++ b/arch/sparc/kernel/sys_sparc32.c @@ -159,7 +159,6 @@ COMPAT_SYSCALL_DEFINE5(rt_sigaction, int, sig, { struct k_sigaction new_ka, old_ka; int ret; - compat_sigset_t set32; /* XXX: Don't preclude handling different sized sigset_t's. */ if (sigsetsize != sizeof(compat_sigset_t)) @@ -167,6 +166,7 @@ COMPAT_SYSCALL_DEFINE5(rt_sigaction, int, sig, if (act) { u32 u_handler, u_restorer; + compat_sigset_t set32; new_ka.ka_restorer = restorer; ret = get_user(u_handler, &act->sa_handler); @@ -183,9 +183,9 @@ COMPAT_SYSCALL_DEFINE5(rt_sigaction, int, sig, ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); if (!ret && oact) { - sigset_to_compat(&set32, &old_ka.sa.sa_mask); ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), &oact->sa_handler); - ret |= copy_to_user(&oact->sa_mask, &set32, sizeof(compat_sigset_t)); + ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask, + sizeof(oact->sa_mask)); ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags); ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer), &oact->sa_restorer); if (ret) diff --git a/include/linux/compat.h b/include/linux/compat.h index a5619de3437d..ab1baa79abe8 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -456,7 +456,8 @@ asmlinkage long compat_sys_settimeofday(struct compat_timeval __user *tv, asmlinkage long compat_sys_adjtimex(struct compat_timex __user *utp); extern void sigset_from_compat(sigset_t *set, const compat_sigset_t *compat); -extern void sigset_to_compat(compat_sigset_t *compat, const sigset_t *set); +extern int put_compat_sigset(compat_sigset_t __user *compat, + const sigset_t *set, unsigned int size); asmlinkage long compat_sys_migrate_pages(compat_pid_t pid, compat_ulong_t maxnode, const compat_ulong_t __user *old_nodes, diff --git a/kernel/compat.c b/kernel/compat.c index 772e038d04d9..18dd902c9052 100644 --- a/kernel/compat.c +++ b/kernel/compat.c @@ -497,15 +497,23 @@ sigset_from_compat(sigset_t *set, const compat_sigset_t *compat) } EXPORT_SYMBOL_GPL(sigset_from_compat); -void -sigset_to_compat(compat_sigset_t *compat, const sigset_t *set) +int +put_compat_sigset(compat_sigset_t __user *compat, const sigset_t *set, + unsigned int size) { + /* size <= sizeof(compat_sigset_t) <= sizeof(sigset_t) */ +#ifdef __BIG_ENDIAN + compat_sigset_t v; switch (_NSIG_WORDS) { - case 4: compat->sig[7] = (set->sig[3] >> 32); compat->sig[6] = set->sig[3]; - case 3: compat->sig[5] = (set->sig[2] >> 32); compat->sig[4] = set->sig[2]; - case 2: compat->sig[3] = (set->sig[1] >> 32); compat->sig[2] = set->sig[1]; - case 1: compat->sig[1] = (set->sig[0] >> 32); compat->sig[0] = set->sig[0]; + case 4: v.sig[7] = (set->sig[3] >> 32); v.sig[6] = set->sig[3]; + case 3: v.sig[5] = (set->sig[2] >> 32); v.sig[4] = set->sig[2]; + case 2: v.sig[3] = (set->sig[1] >> 32); v.sig[2] = set->sig[1]; + case 1: v.sig[1] = (set->sig[0] >> 32); v.sig[0] = set->sig[0]; } + return copy_to_user(compat, &v, size) ? -EFAULT : 0; +#else + return copy_to_user(compat, set, size) ? -EFAULT : 0; +#endif } #ifdef CONFIG_NUMA diff --git a/kernel/signal.c b/kernel/signal.c index 800a18f77732..14ad6bb90dad 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2621,13 +2621,7 @@ COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset, if (error) return error; } - if (oset) { - compat_sigset_t old32; - sigset_to_compat(&old32, &old_set); - if (copy_to_user(oset, &old32, sizeof(compat_sigset_t))) - return -EFAULT; - } - return 0; + return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0; #else return sys_rt_sigprocmask(how, (sigset_t __user *)nset, (sigset_t __user *)oset, sigsetsize); @@ -2669,20 +2663,11 @@ SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize) COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset, compat_size_t, sigsetsize) { -#ifdef __BIG_ENDIAN sigset_t set; int err = do_sigpending(&set, sigsetsize); - if (!err) { - compat_sigset_t set32; - sigset_to_compat(&set32, &set); - /* we can get here only if sigsetsize <= sizeof(set) */ - if (copy_to_user(uset, &set32, sigsetsize)) - err = -EFAULT; - } + if (!err) + err = put_compat_sigset(uset, &set, sigsetsize); return err; -#else - return sys_rt_sigpending((sigset_t __user *)uset, sigsetsize); -#endif } #endif @@ -3451,7 +3436,6 @@ COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig, compat_size_t, sigsetsize) { struct k_sigaction new_ka, old_ka; - compat_sigset_t mask; #ifdef __ARCH_HAS_SA_RESTORER compat_uptr_t restorer; #endif @@ -3463,6 +3447,7 @@ COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig, if (act) { compat_uptr_t handler; + compat_sigset_t mask; ret = get_user(handler, &act->sa_handler); new_ka.sa.sa_handler = compat_ptr(handler); #ifdef __ARCH_HAS_SA_RESTORER @@ -3478,10 +3463,10 @@ COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig, ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); if (!ret && oact) { - sigset_to_compat(&mask, &old_ka.sa.sa_mask); ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), &oact->sa_handler); - ret |= copy_to_user(&oact->sa_mask, &mask, sizeof(mask)); + ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask, + sizeof(oact->sa_mask)); ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags); #ifdef __ARCH_HAS_SA_RESTORER ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),