• YueHaibing's avatar
    spi: bitbang: Fix NULL pointer dereference in spi_unregister_master · 5caaf29a
    YueHaibing authored
    If spi_register_master fails in spi_bitbang_start
    because device_add failure, We should return the
    error code other than 0, otherwise calling
    spi_bitbang_stop may trigger NULL pointer dereference
    like this:
    
    BUG: KASAN: null-ptr-deref in __list_del_entry_valid+0x45/0xd0
    Read of size 8 at addr 0000000000000000 by task syz-executor.0/3661
    
    CPU: 0 PID: 3661 Comm: syz-executor.0 Not tainted 5.1.0+ #28
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
    Call Trace:
     dump_stack+0xa9/0x10e
     ? __list_del_entry_valid+0x45/0xd0
     ? __list_del_entry_valid+0x45/0xd0
     __kasan_report+0x171/0x18d
     ? __list_del_entry_valid+0x45/0xd0
     kasan_report+0xe/0x20
     __list_del_entry_valid+0x45/0xd0
     spi_unregister_controller+0x99/0x1b0
     spi_lm70llp_attach+0x3ae/0x4b0 [spi_lm70llp]
     ? 0xffffffffc1128000
     ? klist_next+0x131/0x1e0
     ? driver_detach+0x40/0x40 [parport]
     port_check+0x3b/0x50 [parport]
     bus_for_each_dev+0x115/0x180
     ? subsys_dev_iter_exit+0x20/0x20
     __parport_register_driver+0x1f0/0x210 [parport]
     ? 0xffffffffc1150000
     do_one_initcall+0xb9/0x3b5
     ? perf_trace_initcall_level+0x270/0x270
     ? kasan_unpoison_shadow+0x30/0x40
     ? kasan_unpoison_shadow+0x30/0x40
     do_init_module+0xe0/0x330
     load_module+0x38eb/0x4270
     ? module_frob_arch_sections+0x20/0x20
     ? kernel_read_file+0x188/0x3f0
     ? find_held_lock+0x6d/0xd0
     ? fput_many+0x1a/0xe0
     ? __do_sys_finit_module+0x162/0x190
     __do_sys_finit_module+0x162/0x190
     ? __ia32_sys_init_module+0x40/0x40
     ? __mutex_unlock_slowpath+0xb4/0x3f0
     ? wait_for_completion+0x240/0x240
     ? vfs_write+0x160/0x2a0
     ? lockdep_hardirqs_off+0xb5/0x100
     ? mark_held_locks+0x1a/0x90
     ? do_syscall_64+0x14/0x2a0
     do_syscall_64+0x72/0x2a0
     entry_SYSCALL_64_after_hwframe+0x49/0xbe
    Reported-by: default avatarHulk Robot <hulkci@huawei.com>
    Fixes: 702a4879 ("spi: bitbang: Let spi_bitbang_start() take a reference to master")
    Signed-off-by: default avatarYueHaibing <yuehaibing@huawei.com>
    Reviewed-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
    Reviewed-by: default avatarAxel Lin <axel.lin@ingics.com>
    Reviewed-by: default avatarMukesh Ojha <mojha@codeaurora.org>
    Signed-off-by: default avatarMark Brown <broonie@kernel.org>
    5caaf29a
spi-bitbang.c 10.9 KB