CVE-2023-53344

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> can: bcm: bcm_tx_setup(): fix KMSAN uninit-value in vfs_write<br /> <br /> Syzkaller reported the following issue:<br /> <br /> =====================================================<br /> BUG: KMSAN: uninit-value in aio_rw_done fs/aio.c:1520 [inline]<br /> BUG: KMSAN: uninit-value in aio_write+0x899/0x950 fs/aio.c:1600<br /> aio_rw_done fs/aio.c:1520 [inline]<br /> aio_write+0x899/0x950 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+0x11d/0x3b0 mm/slab_common.c:981<br /> kmalloc_array include/linux/slab.h:636 [inline]<br /> bcm_tx_setup+0x80e/0x29d0 net/can/bcm.c:930<br /> bcm_sendmsg+0x3a2/0xce0 net/can/bcm.c:1351<br /> sock_sendmsg_nosec net/socket.c:714 [inline]<br /> sock_sendmsg net/socket.c:734 [inline]<br /> sock_write_iter+0x495/0x5e0 net/socket.c:1108<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 /> CPU: 1 PID: 5034 Comm: syz-executor350 Not tainted 6.2.0-rc6-syzkaller-80422-geda666ff2276 #0<br /> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023<br /> =====================================================<br /> <br /> We can follow the call chain and find that &amp;#39;bcm_tx_setup&amp;#39; function<br /> calls &amp;#39;memcpy_from_msg&amp;#39; to copy some content to the newly allocated<br /> frame of &amp;#39;op-&gt;frames&amp;#39;. After that the &amp;#39;len&amp;#39; field of copied structure<br /> being compared with some constant value (64 or 8). However, if<br /> &amp;#39;memcpy_from_msg&amp;#39; returns an error, we will compare some uninitialized<br /> memory. This triggers &amp;#39;uninit-value&amp;#39; issue.<br /> <br /> This patch will add &amp;#39;memcpy_from_msg&amp;#39; possible errors processing to<br /> avoid uninit-value issue.<br /> <br /> Tested via syzkaller