[PATCH 5.7 135/265] RDMA/core: Check that type_attrs is not NULL prior access

Sasha Levin
2020-06-29T22:03:27Z

From: Leon Romanovsky <leonro@mellanox.com>

[ Upstream commit 4121fb0db68ed4de574f9bdc630b75fcc99b4835 ]

In disassociate flow, the type_attrs is set to be NULL, which is in an
implicit way is checked in alloc_uobj() by "if (!attrs->context)".

Change the logic to rely on that check, to be consistent with other
alloc_uobj() places that will fix the following kernel splat.

BUG: kernel NULL pointer dereference, address: 0000000000000018
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
CPU: 3 PID: 2743 Comm: python3 Not tainted 5.7.0-rc6-for-upstream-perf-2020-05-23_19-04-38-5 #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
RIP: 0010:alloc_begin_fd_uobject+0x18/0xf0 [ib_uverbs]
Code: 89 43 48 eb 97 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 55 49 89 f5 41 54 55 48 89 fd 53 48 83 ec 08 48 8b 1f <48> 8b 43 18 48 8b 80 80 00 00 00 48 3d 20 10 33 a0 74 1c 48 3d 30
RSP: 0018:ffffc90001127b70 EFLAGS: 00010282
RAX: ffffffffa0339fe0 RBX: 0000000000000000 RCX: 8000000000000007
RDX: fffffffffffffffb RSI: ffffc90001127d28 RDI: ffff88843fe1f600
RBP: ffff88843fe1f600 R08: ffff888461eb06d8 R09: ffff888461eb06f8
R10: ffff888461eb0700 R11: 0000000000000000 R12: ffff88846a5f6450
R13: ffffc90001127d28 R14: ffff88845d7d6ea0 R15: ffffc90001127cb8
FS: 00007f469bff1540(0000) GS:ffff88846f980000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000018 CR3: 0000000450018003 CR4: 0000000000760ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
? xa_store+0x28/0x40
rdma_alloc_begin_uobject+0x4f/0x90 [ib_uverbs]
ib_uverbs_create_comp_channel+0x87/0xf0 [ib_uverbs]
ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0xb1/0xf0 [ib_uverbs]
ib_uverbs_cmd_verbs.isra.8+0x96d/0xae0 [ib_uverbs]
? get_page_from_freelist+0x3bb/0xf70
? _copy_to_user+0x22/0x30
? uverbs_disassociate_api+0xd0/0xd0 [ib_uverbs]
? __wake_up_common_lock+0x87/0xc0
ib_uverbs_ioctl+0xbc/0x130 [ib_uverbs]
ksys_ioctl+0x83/0xc0
? ksys_write+0x55/0xd0
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x48/0x130
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f469ac43267

Fixes: 849e149063bd ("RDMA/core: Do not allow alloc_commit to fail")
Link: https://lore.kernel.org/r/20200617061826.2625359-1-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/infiniband/core/rdma_core.c | 36 +++++++++++++++++------------
1 file changed, 21 insertions(+), 15 deletions(-)

diff --git a/drivers/infiniband/core/rdma_core.c b/drivers/infiniband/core/rdma_core.c
index e0a5e897e4b1d..75bcbc625616e 100644
--- a/drivers/infiniband/core/rdma_core.c
+++ b/drivers/infiniband/core/rdma_core.c
@@ -459,40 +459,46 @@ static struct ib_uobject *
alloc_begin_fd_uobject(const struct uverbs_api_object *obj,
struct uverbs_attr_bundle *attrs)
{
- const struct uverbs_obj_fd_type *fd_type =
- container_of(obj->type_attrs, struct uverbs_obj_fd_type, type);
+ const struct uverbs_obj_fd_type *fd_type;
int new_fd;
- struct ib_uobject *uobj;
+ struct ib_uobject *uobj, *ret;
struct file *filp;

+ uobj = alloc_uobj(attrs, obj);
+ if (IS_ERR(uobj))
+ return uobj;
+
+ fd_type =
+ container_of(obj->type_attrs, struct uverbs_obj_fd_type, type);
if (WARN_ON(fd_type->fops->release != &uverbs_uobject_fd_release &&
- fd_type->fops->release != &uverbs_async_event_release))
- return ERR_PTR(-EINVAL);
+ fd_type->fops->release != &uverbs_async_event_release)) {
+ ret = ERR_PTR(-EINVAL);
+ goto err_fd;
+ }

new_fd = get_unused_fd_flags(O_CLOEXEC);
- if (new_fd < 0)
- return ERR_PTR(new_fd);
-
- uobj = alloc_uobj(attrs, obj);
- if (IS_ERR(uobj))
+ if (new_fd < 0) {
+ ret = ERR_PTR(new_fd);
goto err_fd;
+ }

/* Note that uverbs_uobject_fd_release() is called during abort */
filp = anon_inode_getfile(fd_type->name, fd_type->fops, NULL,
fd_type->flags);
if (IS_ERR(filp)) {
- uverbs_uobject_put(uobj);
- uobj = ERR_CAST(filp);
- goto err_fd;
+ ret = ERR_CAST(filp);
+ goto err_getfile;
}
uobj->object = filp;

uobj->id = new_fd;
return uobj;

-err_fd:
+err_getfile:
put_unused_fd(new_fd);
- return uobj;
+err_fd:
+ uverbs_uobject_put(uobj);
+ return ret;
}

struct ib_uobject *rdma_alloc_begin_uobject(const struct uverbs_api_object *obj,
--
2.25.1