From 196efb29b5231aad38eec31f060d0849f557cca5 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Wed, 20 Mar 2013 15:08:40 +1100 Subject: [PATCH] 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 Acked-by: Stanislav Kinsbursky Signed-off-by: Andrew Morton --- ipc/msg.c | 23 ++++++++++------------- 1 file changed, 10 insertions(+), 13 deletions(-) diff --git a/ipc/msg.c b/ipc/msg.c index e8d3f15ada16..418c5a5a6b2b 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); } @@ -818,18 +816,17 @@ 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); } + mode = convert_mode(&msgtyp, msgflg); msq = msg_lock_check(ns, msqid); @@ -861,8 +858,8 @@ 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; } else break; -- 2.39.5