From: Ziyang Xuan william.xuanziyang@huawei.com
[ Upstream commit 6417070918de3bcdbe0646e7256dae58fd8083ba ]
Syzbot reported a bug as following:
===================================================== BUG: KMSAN: uninit-value in qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230 qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230 qrtr_endpoint_post+0xf85/0x11b0 net/qrtr/af_qrtr.c:519 qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108 call_write_iter include/linux/fs.h:2189 [inline] aio_write+0x63a/0x950 fs/aio.c:1600 io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019 __do_sys_io_submit fs/aio.c:2078 [inline] __se_sys_io_submit+0x293/0x770 fs/aio.c:2048 __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd
Uninit was created at: slab_post_alloc_hook mm/slab.h:766 [inline] slab_alloc_node mm/slub.c:3452 [inline] __kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491 __do_kmalloc_node mm/slab_common.c:967 [inline] __kmalloc_node_track_caller+0x114/0x3b0 mm/slab_common.c:988 kmalloc_reserve net/core/skbuff.c:492 [inline] __alloc_skb+0x3af/0x8f0 net/core/skbuff.c:565 __netdev_alloc_skb+0x120/0x7d0 net/core/skbuff.c:630 qrtr_endpoint_post+0xbd/0x11b0 net/qrtr/af_qrtr.c:446 qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108 call_write_iter include/linux/fs.h:2189 [inline] aio_write+0x63a/0x950 fs/aio.c:1600 io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019 __do_sys_io_submit fs/aio.c:2078 [inline] __se_sys_io_submit+0x293/0x770 fs/aio.c:2048 __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd
It is because that skb->len requires at least sizeof(struct qrtr_ctrl_pkt) in qrtr_tx_resume(). And skb->len equals to size in qrtr_endpoint_post(). But size is less than sizeof(struct qrtr_ctrl_pkt) when qrtr_cb->type equals to QRTR_TYPE_RESUME_TX in qrtr_endpoint_post() under the syzbot scenario. This triggers the uninit variable access bug.
Add size check when qrtr_cb->type equals to QRTR_TYPE_RESUME_TX in qrtr_endpoint_post() to fix the bug.
Fixes: 5fdeb0d372ab ("net: qrtr: Implement outgoing flow control") Reported-by: syzbot+4436c9630a45820fda76@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=c14607f0963d27d5a3d5f4c8639b500909e4354... Suggested-by: Manivannan Sadhasivam mani@kernel.org Signed-off-by: Ziyang Xuan william.xuanziyang@huawei.com Reviewed-by: Simon Horman simon.horman@corigine.com Link: https://lore.kernel.org/r/20230410012352.3997823-1-william.xuanziyang@huawei... Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/qrtr/af_qrtr.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/net/qrtr/af_qrtr.c b/net/qrtr/af_qrtr.c index 6e88ba812d2a2..e0a27a404404f 100644 --- a/net/qrtr/af_qrtr.c +++ b/net/qrtr/af_qrtr.c @@ -498,6 +498,11 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len) if (!size || len != ALIGN(size, 4) + hdrlen) goto err;
+ if ((cb->type == QRTR_TYPE_NEW_SERVER || + cb->type == QRTR_TYPE_RESUME_TX) && + size < sizeof(struct qrtr_ctrl_pkt)) + goto err; + if (cb->dst_port != QRTR_PORT_CTRL && cb->type != QRTR_TYPE_DATA && cb->type != QRTR_TYPE_RESUME_TX) goto err; @@ -510,9 +515,6 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len) /* Remote node endpoint can bridge other distant nodes */ const struct qrtr_ctrl_pkt *pkt;
- if (size < sizeof(*pkt)) - goto err; - pkt = data + hdrlen; qrtr_node_assign(node, le32_to_cpu(pkt->server.node)); }