diff options
| author | Will Deacon <will.deacon@arm.com> | 2012-07-30 14:42:43 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-07-30 17:25:21 -0700 |
| commit | 05ba3f1aa1b04e921068249dd52a80bc84c2aeb4 (patch) | |
| tree | 1176cbea1c1272e7f9567d8f2e71c56510f6efcf | |
| parent | b610c04c667f3c056243fd64041c7f152a512ee4 (diff) | |
ipc: compat: use signed size_t types for msgsnd and msgrcv
The msgsnd and msgrcv system calls use size_t to represent the size of the
message being transferred. POSIX states that values of msgsz greater than
SSIZE_MAX cause the result to be implementation-defined. On Linux, this
equates to returning -EINVAL if (long) msgsz < 0.
For compat tasks where !CONFIG_ARCH_WANT_OLD_COMPAT_IPC and compat_size_t
is smaller than size_t, negative size values passed from userspace will be
interpreted as positive values by do_msg{rcv,snd} and will fail to exit
early with -EINVAL.
This patch changes the compat prototypes for msg{rcv,snd} so that the
message size is represented as a compat_ssize_t, which we cast to the
native ssize_t type for the core IPC code.
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/compat.h | 4 | ||||
| -rw-r--r-- | ipc/compat.c | 8 |
2 files changed, 6 insertions, 6 deletions
diff --git a/include/linux/compat.h b/include/linux/compat.h index 9f68e90a14e..f2b8fe20cc8 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -266,9 +266,9 @@ long compat_sys_shmat(int first, int second, compat_uptr_t third, int version, #else long compat_sys_semctl(int semid, int semnum, int cmd, int arg); long compat_sys_msgsnd(int msqid, struct compat_msgbuf __user *msgp, - size_t msgsz, int msgflg); + compat_ssize_t msgsz, int msgflg); long compat_sys_msgrcv(int msqid, struct compat_msgbuf __user *msgp, - size_t msgsz, long msgtyp, int msgflg); + compat_ssize_t msgsz, long msgtyp, int msgflg); long compat_sys_shmat(int shmid, compat_uptr_t shmaddr, int shmflg); #endif long compat_sys_msgctl(int first, int second, void __user *uptr); diff --git a/ipc/compat.c b/ipc/compat.c index a41600f6ba5..20f92b2f293 100644 --- a/ipc/compat.c +++ b/ipc/compat.c @@ -373,21 +373,21 @@ long compat_sys_semctl(int semid, int semnum, int cmd, int arg) } long compat_sys_msgsnd(int msqid, struct compat_msgbuf __user *msgp, - size_t msgsz, int msgflg) + compat_ssize_t msgsz, int msgflg) { compat_long_t mtype; if (get_user(mtype, &msgp->mtype)) return -EFAULT; - return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg); + return do_msgsnd(msqid, mtype, msgp->mtext, (ssize_t)msgsz, msgflg); } long compat_sys_msgrcv(int msqid, struct compat_msgbuf __user *msgp, - size_t msgsz, long msgtyp, int msgflg) + compat_ssize_t msgsz, long msgtyp, int msgflg) { long err, mtype; - err = do_msgrcv(msqid, &mtype, msgp->mtext, msgsz, msgtyp, msgflg); + err = do_msgrcv(msqid, &mtype, msgp->mtext, (ssize_t)msgsz, msgtyp, msgflg); if (err < 0) goto out; |