ipc/mqueue: strengthen checks on mqueue creation (113289cc) · Commits · 戴 / test

We already check the mq attr struct if it's passed in, but now that the admin can set system wide defaults separate from maximums, it's actually possible to set the defaults to something that would overflow. So, if there is no attr struct passed in to the open call, check the default values. While we are at it, simplify mq_attr_ok() by making it return 0 or an error condition, so that way if we add more tests to it later, we have the option of what error should be returned instead of the calling location having to pick a possibly inaccurate error code. [akpm@linux-foundation.org: s/ENOMEM/EOVERFLOW/] Signed-off-by:

Doug Ledford <dledford@redhat.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Manfred Spraul <manfred@colorfullife.com> Acked-by:

KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

ipc/mqueue.c

+18 −9

Original line number	Diff line number	Diff line
		@@ -680,26 +680,26 @@ static int mq_attr_ok(struct ipc_namespace ipc_ns, struct mq_attr attr)
		unsigned long total_size;

		if (attr->mq_maxmsg <= 0 \|\| attr->mq_msgsize <= 0)
		return 0;
		return -EINVAL;
		if (capable(CAP_SYS_RESOURCE)) {
		if (attr->mq_maxmsg > HARD_MSGMAX \|\|
		attr->mq_msgsize > HARD_MSGSIZEMAX)
		return 0;
		return -EINVAL;
		} else {
		if (attr->mq_maxmsg > ipc_ns->mq_msg_max \|\|
		attr->mq_msgsize > ipc_ns->mq_msgsize_max)
		return 0;
		return -EINVAL;
		}
		/* check for overflow */
		if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
		return 0;
		return -EOVERFLOW;
		mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +
		min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *
		sizeof(struct posix_msg_tree_node);
		total_size = attr->mq_maxmsg * attr->mq_msgsize;
		if (total_size + mq_treesize < total_size)
		return -EOVERFLOW;
		return 0;
		return 1;
		}

		/*
		@@ -714,12 +714,21 @@ static struct file do_create(struct ipc_namespace ipc_ns, struct dentry *dir,
		int ret;

		if (attr) {
		if (!mq_attr_ok(ipc_ns, attr)) {
		ret = -EINVAL;
		ret = mq_attr_ok(ipc_ns, attr);
		if (ret)
		goto out;
		}
		/* store for use during create */
		dentry->d_fsdata = attr;
		} else {
		struct mq_attr def_attr;

		def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
		ipc_ns->mq_msg_default);
		def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
		ipc_ns->mq_msgsize_default);
		ret = mq_attr_ok(ipc_ns, &def_attr);
		if (ret)
		goto out;
		}

		mode &= ~current_umask();

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