Provide ksys_msgrcv() and compat_ksys_msgrcv() wrappers to avoid in-kernel calls to these syscalls. The ksys_ prefix denotes that these functions are meant as a drop-in replacement for the syscalls. In particular, they use the same calling convention as sys_msgrcv() and compat_sys_msgrcv(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@xxxxxxxxxxxxxxxxxxxxxxxxxx Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx> --- ipc/msg.c | 19 ++++++++++++++++--- ipc/syscall.c | 8 ++++---- ipc/util.h | 4 ++++ 3 files changed, 24 insertions(+), 7 deletions(-) diff --git a/ipc/msg.c b/ipc/msg.c index 5b026868df07..abc5826270a6 100644 --- a/ipc/msg.c +++ b/ipc/msg.c @@ -1150,10 +1150,16 @@ static long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, in return bufsz; } +long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz, + long msgtyp, int msgflg) +{ + return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill); +} + SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, long, msgtyp, int, msgflg) { - return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill); + return ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg); } #ifdef CONFIG_COMPAT @@ -1171,12 +1177,19 @@ static long compat_do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bu return msgsz; } -COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp, - compat_ssize_t, msgsz, compat_long_t, msgtyp, int, msgflg) +long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz, + compat_long_t msgtyp, int msgflg) { return do_msgrcv(msqid, compat_ptr(msgp), (ssize_t)msgsz, (long)msgtyp, msgflg, compat_do_msg_fill); } + +COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp, + compat_ssize_t, msgsz, compat_long_t, msgtyp, + int, msgflg) +{ + return compat_ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg); +} #endif int msg_init_ns(struct ipc_namespace *ns) diff --git a/ipc/syscall.c b/ipc/syscall.c index aa29b0802e26..0228c7afd882 100644 --- a/ipc/syscall.c +++ b/ipc/syscall.c @@ -59,11 +59,11 @@ SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second, (struct ipc_kludge __user *) ptr, sizeof(tmp))) return -EFAULT; - return sys_msgrcv(first, tmp.msgp, second, + return ksys_msgrcv(first, tmp.msgp, second, tmp.msgtyp, third); } default: - return sys_msgrcv(first, + return ksys_msgrcv(first, (struct msgbuf __user *) ptr, second, fifth, third); } @@ -156,10 +156,10 @@ COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second, return -EINVAL; if (copy_from_user(&ipck, uptr, sizeof(ipck))) return -EFAULT; - return compat_sys_msgrcv(first, ipck.msgp, second, + return compat_ksys_msgrcv(first, ipck.msgp, second, ipck.msgtyp, third); } - return compat_sys_msgrcv(first, ptr, second, fifth, third); + return compat_ksys_msgrcv(first, ptr, second, fifth, third); } case MSGGET: return ksys_msgget(first, second); diff --git a/ipc/util.h b/ipc/util.h index 47837b4af3f2..c16aceb1bdec 100644 --- a/ipc/util.h +++ b/ipc/util.h @@ -244,6 +244,8 @@ long ksys_semget(key_t key, int nsems, int semflg); long ksys_semctl(int semid, int semnum, int cmd, unsigned long arg); long ksys_msgget(key_t key, int msgflg); long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf); +long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz, + long msgtyp, int msgflg); long ksys_shmget(key_t key, size_t size, int shmflg); long ksys_shmdt(char __user *shmaddr); long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf); @@ -255,6 +257,8 @@ long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems, const struct compat_timespec __user *timeout); long compat_ksys_semctl(int semid, int semnum, int cmd, int arg); long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr); +long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz, + compat_long_t msgtyp, int msgflg); long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr); #endif /* CONFIG_COMPAT */ -- 2.16.3
