CVE-2023-53578

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume()<br /> <br /> Syzbot reported a bug as following:<br /> <br /> =====================================================<br /> BUG: KMSAN: uninit-value in qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230<br /> qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230<br /> qrtr_endpoint_post+0xf85/0x11b0 net/qrtr/af_qrtr.c:519<br /> qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108<br /> call_write_iter include/linux/fs.h:2189 [inline]<br /> aio_write+0x63a/0x950 fs/aio.c:1600<br /> io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019<br /> __do_sys_io_submit fs/aio.c:2078 [inline]<br /> __se_sys_io_submit+0x293/0x770 fs/aio.c:2048<br /> __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048<br /> do_syscall_x64 arch/x86/entry/common.c:50 [inline]<br /> do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80<br /> entry_SYSCALL_64_after_hwframe+0x63/0xcd<br /> <br /> Uninit was created at:<br /> slab_post_alloc_hook mm/slab.h:766 [inline]<br /> slab_alloc_node mm/slub.c:3452 [inline]<br /> __kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491<br /> __do_kmalloc_node mm/slab_common.c:967 [inline]<br /> __kmalloc_node_track_caller+0x114/0x3b0 mm/slab_common.c:988<br /> kmalloc_reserve net/core/skbuff.c:492 [inline]<br /> __alloc_skb+0x3af/0x8f0 net/core/skbuff.c:565<br /> __netdev_alloc_skb+0x120/0x7d0 net/core/skbuff.c:630<br /> qrtr_endpoint_post+0xbd/0x11b0 net/qrtr/af_qrtr.c:446<br /> qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108<br /> call_write_iter include/linux/fs.h:2189 [inline]<br /> aio_write+0x63a/0x950 fs/aio.c:1600<br /> io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019<br /> __do_sys_io_submit fs/aio.c:2078 [inline]<br /> __se_sys_io_submit+0x293/0x770 fs/aio.c:2048<br /> __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048<br /> do_syscall_x64 arch/x86/entry/common.c:50 [inline]<br /> do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80<br /> entry_SYSCALL_64_after_hwframe+0x63/0xcd<br /> <br /> It is because that skb-&gt;len requires at least sizeof(struct qrtr_ctrl_pkt)<br /> in qrtr_tx_resume(). And skb-&gt;len equals to size in qrtr_endpoint_post().<br /> But size is less than sizeof(struct qrtr_ctrl_pkt) when qrtr_cb-&gt;type<br /> equals to QRTR_TYPE_RESUME_TX in qrtr_endpoint_post() under the syzbot<br /> scenario. This triggers the uninit variable access bug.<br /> <br /> Add size check when qrtr_cb-&gt;type equals to QRTR_TYPE_RESUME_TX in<br /> qrtr_endpoint_post() to fix the bug.