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authorWill Deacon <will.deacon@arm.com>2012-07-31 01:42:43 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-31 04:25:21 +0400
commit05ba3f1aa1b04e921068249dd52a80bc84c2aeb4 (patch)
tree1176cbea1c1272e7f9567d8f2e71c56510f6efcf /include/linux/compat.h
parentb610c04c667f3c056243fd64041c7f152a512ee4 (diff)
downloadlinux-05ba3f1aa1b04e921068249dd52a80bc84c2aeb4.tar.xz
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>
Diffstat (limited to 'include/linux/compat.h')
-rw-r--r--include/linux/compat.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 9f68e90a14ec..f2b8fe20cc8e 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);