From 9a169606b99a7212131ef5f4dfc6bdf7d6f17d59 Mon Sep 17 00:00:00 2001 From: Doug Ledford Date: Thu, 3 May 2012 15:44:52 +1000 Subject: [PATCH] ipc/mqueue: strengthen checks on mqueue creation 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. Signed-off-by: Doug Ledford Cc: Stephen Rothwell Cc: Manfred Spraul Signed-off-by: Andrew Morton --- ipc/mqueue.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) diff --git a/ipc/mqueue.c b/ipc/mqueue.c index 51fe33bae455..b0461f8459b7 100644 --- a/ipc/mqueue.c +++ b/ipc/mqueue.c @@ -675,26 +675,26 @@ 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 -ENOMEM; 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 0; - return 1; + return -ENOMEM; + return 0; } /* @@ -709,12 +709,21 @@ 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(); -- 2.39.5