From: Jason Gunthorpe <jgg@nvidia.com> mainline inclusion from mainline-v7.2-rc1 commit 50d5c02ab8e62325548bd3a6e6b758a9dcd6e7c3 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/17658 CVE: CVE-2026-74334 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Sashiko points out that, due to rereg_mr, the PD is actually variable and all the touches in nldev are racy. Use mr->device instead of mr->pd->device. Getting the PD restrack ID is more tricky. To avoid disturbing all the happy paths, add an rdma_restrack_sync() operation which is sort of like flush_workqueue() or synchronize_irq(): after it returns, all the old nldev touches to the mr are gone and everything sees the new PD. This makes it safe to reach into the PD pointer. Fixes: da5c85078215 ("RDMA/nldev: add driver-specific resource tracking") Link: https://patch.msgid.link/r/4-v1-29ebd2c229b5+fd5-ib_mr_pd_jgg@nvidia.com Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Conflicts: drivers/infiniband/core/restrack.c drivers/infiniband/core/uverbs_cmd.c include/rdma/ib_verbs.h [In restrack.c, rdma_restrack_count() in target tree lacks show_details parameter and RESTRACK_DD mark logic; only added xa_is_zero() check required by rdma_restrack_sync(). Removed RESTRACK_DD xa_get_mark() check in rdma_restrack_sync() as target tree does not have driver-specific resource tracking (RESTRACK_DD mark). In uverbs_cmd.c, kept downstream #include "uverbs_profile.h" alongside new #include "restrack.h".] Signed-off-by: Chen Jinghuang <chenjinghuang2@huawei.com> --- drivers/infiniband/core/nldev.c | 15 ++++---- drivers/infiniband/core/restrack.c | 52 +++++++++++++++++++++++++++- drivers/infiniband/core/restrack.h | 1 + drivers/infiniband/core/uverbs_cmd.c | 10 ++++-- include/rdma/ib_verbs.h | 5 +++ 5 files changed, 74 insertions(+), 9 deletions(-) diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c index 9d6627bde61a..6c4008a1e18f 100644 --- a/drivers/infiniband/core/nldev.c +++ b/drivers/infiniband/core/nldev.c @@ -644,7 +644,7 @@ static int fill_res_mr_entry(struct sk_buff *msg, bool has_cap_net_admin, struct rdma_restrack_entry *res, uint32_t port) { struct ib_mr *mr = container_of(res, struct ib_mr, res); - struct ib_device *dev = mr->pd->device; + struct ib_device *dev = mr->device; if (has_cap_net_admin) { if (nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_RKEY, mr->rkey)) @@ -660,9 +660,12 @@ static int fill_res_mr_entry(struct sk_buff *msg, bool has_cap_net_admin, if (nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_MRN, res->id)) return -EMSGSIZE; - if (!rdma_is_kernel_res(res) && - nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_PDN, mr->pd->res.id)) - return -EMSGSIZE; + if (!rdma_is_kernel_res(res)) { + struct ib_pd *pd = READ_ONCE(mr->pd); + + if (nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_PDN, pd->res.id)) + return -EMSGSIZE; + } if (fill_res_name_pid(msg, res)) return -EMSGSIZE; @@ -676,7 +679,7 @@ static int fill_res_mr_raw_entry(struct sk_buff *msg, bool has_cap_net_admin, struct rdma_restrack_entry *res, uint32_t port) { struct ib_mr *mr = container_of(res, struct ib_mr, res); - struct ib_device *dev = mr->pd->device; + struct ib_device *dev = mr->device; if (!dev->ops.fill_res_mr_entry_raw) return -EINVAL; @@ -966,7 +969,7 @@ static int fill_stat_mr_entry(struct sk_buff *msg, bool has_cap_net_admin, struct rdma_restrack_entry *res, uint32_t port) { struct ib_mr *mr = container_of(res, struct ib_mr, res); - struct ib_device *dev = mr->pd->device; + struct ib_device *dev = mr->device; if (nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_MRN, res->id)) goto err; diff --git a/drivers/infiniband/core/restrack.c b/drivers/infiniband/core/restrack.c index 438ed3588175..19a813e75486 100644 --- a/drivers/infiniband/core/restrack.c +++ b/drivers/infiniband/core/restrack.c @@ -68,8 +68,11 @@ int rdma_restrack_count(struct ib_device *dev, enum rdma_restrack_type type) u32 cnt = 0; xa_lock(&rt->xa); - xas_for_each(&xas, e, U32_MAX) + xas_for_each(&xas, e, U32_MAX) { + if (xa_is_zero(e)) + continue; cnt++; + } xa_unlock(&rt->xa); return cnt; } @@ -266,6 +269,53 @@ int rdma_restrack_put(struct rdma_restrack_entry *res) } EXPORT_SYMBOL(rdma_restrack_put); +/** + * rdma_restrack_sync() - Fence concurrent netlink dumps on an entry + * @res: resource entry + * + * After this returns any concurrent netlink dump threads will see the current + * value of the object. This is useful if the object has to be changed and there + * is not locking to protect the nl side. Eg for mr->pd. This effectively + * destroys the object from a kref/xarray perspective and then immediately + * restores it. The kref is acting like a lock to barrier concurrent nl threads. + * Callers must ensure rdma_restrack_del() is not concurrently called. + */ +void rdma_restrack_sync(struct rdma_restrack_entry *res) +{ + struct rdma_restrack_entry *old; + struct rdma_restrack_root *rt; + struct task_struct *task; + struct ib_device *dev; + + if (!res->valid || res->no_track) + return; + + dev = res_to_dev(res); + if (WARN_ON(!dev)) + return; + + rt = &dev->res[res->type]; + if (WARN_ON(xa_get_mark(&rt->xa, res->id, RESTRACK_DD))) + return; + + old = xa_cmpxchg(&rt->xa, res->id, res, XA_ZERO_ENTRY, GFP_KERNEL); + if (WARN_ON(old != res)) + return; + + task = res->task; + if (task) + get_task_struct(task); + rdma_restrack_put(res); + wait_for_completion(&res->comp); + reinit_completion(&res->comp); + if (task) + res->task = task; + kref_init(&res->kref); + + xa_cmpxchg(&rt->xa, res->id, XA_ZERO_ENTRY, res, GFP_KERNEL); +} +EXPORT_SYMBOL(rdma_restrack_sync); + /** * rdma_restrack_del() - delete object from the reource tracking database * @res: resource entry diff --git a/drivers/infiniband/core/restrack.h b/drivers/infiniband/core/restrack.h index 6a04fc41f738..75b8d1005a98 100644 --- a/drivers/infiniband/core/restrack.h +++ b/drivers/infiniband/core/restrack.h @@ -27,6 +27,7 @@ int rdma_restrack_init(struct ib_device *dev); void rdma_restrack_clean(struct ib_device *dev); void rdma_restrack_add(struct rdma_restrack_entry *res); void rdma_restrack_del(struct rdma_restrack_entry *res); +void rdma_restrack_sync(struct rdma_restrack_entry *res); void rdma_restrack_new(struct rdma_restrack_entry *res, enum rdma_restrack_type type); void rdma_restrack_set_name(struct rdma_restrack_entry *res, diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c index 2e4265ba35b7..f442cca3c05c 100644 --- a/drivers/infiniband/core/uverbs_cmd.c +++ b/drivers/infiniband/core/uverbs_cmd.c @@ -46,6 +46,7 @@ #include "uverbs.h" #include "core_priv.h" +#include "restrack.h" /* * Copy a response to userspace. If the provided 'resp' is larger than the @@ -813,6 +814,10 @@ static int ib_uverbs_rereg_mr(struct uverbs_attr_bundle *attrs) ret = PTR_ERR(new_pd); goto put_uobjs; } + if (new_pd == orig_pd) { + uobj_put_obj_read(new_pd); + cmd.flags &= ~IB_MR_REREG_PD; + } } else { new_pd = mr->pd; } @@ -858,9 +863,10 @@ static int ib_uverbs_rereg_mr(struct uverbs_attr_bundle *attrs) mr = new_mr; } else { if (cmd.flags & IB_MR_REREG_PD) { - atomic_dec(&orig_pd->usecnt); - mr->pd = new_pd; atomic_inc(&new_pd->usecnt); + WRITE_ONCE(mr->pd, new_pd); + rdma_restrack_sync(&mr->res); + atomic_dec(&orig_pd->usecnt); } if (cmd.flags & IB_MR_REREG_TRANS) { mr->iova = cmd.hca_va; diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h index 3eea95e51928..05b101693cd5 100644 --- a/include/rdma/ib_verbs.h +++ b/include/rdma/ib_verbs.h @@ -1833,6 +1833,11 @@ struct ib_dm { struct ib_mr { struct ib_device *device; + /* + * Due to IB_MR_REREG_PD pd is not a fixed pointer and can change. For a + * user MR, this value should only be read from a system call that holds + * the uobject lock, or the driver should disable in-place REREG_PD. + */ struct ib_pd *pd; u32 lkey; u32 rkey; -- 2.34.1