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| author | Peter Hurley <peter@hurleysoftware.com> | 2013-04-30 19:14:54 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-05-01 08:12:57 -0700 |
| commit | 8ac6ed5857c8d583e0dc2ab2165966ab143930ad (patch) | |
| tree | d5c7606ce371ff52213915267b8b34898232a7e3 /ipc | |
| parent | 852028af861ed6c7ab7e73053dd664eb28e55200 (diff) | |
| download | linux-8ac6ed5857c8d583e0dc2ab2165966ab143930ad.tar.gz linux-8ac6ed5857c8d583e0dc2ab2165966ab143930ad.tar.bz2 linux-8ac6ed5857c8d583e0dc2ab2165966ab143930ad.zip | |
ipc: implement MSG_COPY as a new receive mode
Teach the helper routines about MSG_COPY so that msgtyp is preserved as
the message number to copy.
The security functions affected by this change were audited and no
additional changes are necessary.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'ipc')
| -rw-r--r-- | ipc/msg.c | 22 |
1 files changed, 9 insertions, 13 deletions
diff --git a/ipc/msg.c b/ipc/msg.c index b46473074662..7c209b4f5e38 100644 --- a/ipc/msg.c +++ b/ipc/msg.c @@ -66,6 +66,7 @@ struct msg_sender { #define SEARCH_EQUAL 2 #define SEARCH_NOTEQUAL 3 #define SEARCH_LESSEQUAL 4 +#define SEARCH_NUMBER 5 #define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS]) @@ -583,6 +584,7 @@ static int testmsg(struct msg_msg *msg, long type, int mode) switch(mode) { case SEARCH_ANY: + case SEARCH_NUMBER: return 1; case SEARCH_LESSEQUAL: if (msg->m_type <=type) @@ -738,6 +740,8 @@ SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, static inline int convert_mode(long *msgtyp, int msgflg) { + if (msgflg & MSG_COPY) + return SEARCH_NUMBER; /* * find message of correct type. * msgtyp = 0 => get first. @@ -774,14 +778,10 @@ static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz) * This function creates new kernel message structure, large enough to store * bufsz message bytes. */ -static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz, - int msgflg, long *msgtyp, - unsigned long *copy_number) +static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) { struct msg_msg *copy; - *copy_number = *msgtyp; - *msgtyp = 0; /* * Create dummy message to copy real message to. */ @@ -797,9 +797,7 @@ static inline void free_copy(struct msg_msg *copy) free_msg(copy); } #else -static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz, - int msgflg, long *msgtyp, - unsigned long *copy_number) +static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) { return ERR_PTR(-ENOSYS); } @@ -818,15 +816,13 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int mode; struct ipc_namespace *ns; struct msg_msg *copy = NULL; - unsigned long copy_number = 0; ns = current->nsproxy->ipc_ns; if (msqid < 0 || (long) bufsz < 0) return -EINVAL; if (msgflg & MSG_COPY) { - copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax), - msgflg, &msgtyp, ©_number); + copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax)); if (IS_ERR(copy)) return PTR_ERR(copy); } @@ -861,8 +857,8 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, if (mode == SEARCH_LESSEQUAL && walk_msg->m_type != 1) { msgtyp = walk_msg->m_type - 1; - } else if (msgflg & MSG_COPY) { - if (copy_number == msg_counter) + } else if (mode == SEARCH_NUMBER) { + if (msgtyp == msg_counter) break; msg = ERR_PTR(-EAGAIN); } else |