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authorZiyang Xuan <william.xuanziyang@huawei.com>2023-04-10 09:23:52 +0800
committerPaolo Abeni <pabeni@redhat.com>2023-04-13 09:35:30 +0200
commit6417070918de3bcdbe0646e7256dae58fd8083ba (patch)
treef498ec96216dd9aed85a0fa90dc5b3a156446590 /net/qrtr
parent59d3efd27c11c59b32291e5ebc307bed2edb65ee (diff)
net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume()
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=c14607f0963d27d5a3d5f4c8639b500909e43540 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.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net/qrtr')
-rw-r--r--net/qrtr/af_qrtr.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/net/qrtr/af_qrtr.c b/net/qrtr/af_qrtr.c
index 3a70255c8d02..76f0434d3d06 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));
}