• Jason Gunthorpe's avatar
    RDMA/cma: Do not change route.addr.src_addr.ss_family · bc0bdc5a
    Jason Gunthorpe authored
    If the state is not idle then rdma_bind_addr() will immediately fail and
    no change to global state should happen.
    
    For instance if the state is already RDMA_CM_LISTEN then this will corrupt
    the src_addr and would cause the test in cma_cancel_operation():
    
    		if (cma_any_addr(cma_src_addr(id_priv)) && !id_priv->cma_dev)
    
    To view a mangled src_addr, eg with a IPv6 loopback address but an IPv4
    family, failing the test.
    
    This would manifest as this trace from syzkaller:
    
      BUG: KASAN: use-after-free in __list_add_valid+0x93/0xa0 lib/list_debug.c:26
      Read of size 8 at addr ffff8881546491e0 by task syz-executor.1/32204
    
      CPU: 1 PID: 32204 Comm: syz-executor.1 Not tainted 5.12.0-rc8-syzkaller #0
      Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
      Call Trace:
       __dump_stack lib/dump_stack.c:79 [inline]
       dump_stack+0x141/0x1d7 lib/dump_stack.c:120
       print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:232
       __kasan_report mm/kasan/report.c:399 [inline]
       kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416
       __list_add_valid+0x93/0xa0 lib/list_debug.c:26
       __list_add include/linux/list.h:67 [inline]
       list_add_tail include/linux/list.h:100 [inline]
       cma_listen_on_all drivers/infiniband/core/cma.c:2557 [inline]
       rdma_listen+0x787/0xe00 drivers/infiniband/core/cma.c:3751
       ucma_listen+0x16a/0x210 drivers/infiniband/core/ucma.c:1102
       ucma_write+0x259/0x350 drivers/infiniband/core/ucma.c:1732
       vfs_write+0x28e/0xa30 fs/read_write.c:603
       ksys_write+0x1ee/0x250 fs/read_write.c:658
       do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x44/0xae
    
    Which is indicating that an rdma_id_private was destroyed without doing
    cma_cancel_listens().
    
    Instead of trying to re-use the src_addr memory to indirectly create an
    any address build one explicitly on the stack and bind to that as any
    other normal flow would do.
    
    Link: https://lore.kernel.org/r/0-v1-9fbb33f5e201+2a-cma_listen_jgg@nvidia.com
    Cc: stable@vger.kernel.org
    Fixes: 732d41c5 ("RDMA/cma: Make the locking for automatic state transition more clear")
    Reported-by: syzbot+6bb0528b13611047209c@syzkaller.appspotmail.com
    Tested-by: default avatarHao Sun <sunhao.th@gmail.com>
    Reviewed-by: default avatarLeon Romanovsky <leonro@nvidia.com>
    Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
    bc0bdc5a
cma.c 134 KB