• Jiazi.Li's avatar
    binder: remove unneeded size check code · 7feb35bc
    Jiazi.Li authored
    In binder_ioctl function, the legitimacy check of cmd size has been
    done in switch-case code:
    switch (cmd) {
    	case BINDER_WRITE_READ;//BINDER_WRITE_READ contains size info
    
    So unneeded do size check in binder_ioctl and binder_ioctl_write_read
    again.
    
    In the following version of Google GKI:
    
    Linux version 5.10.110-android12-9-00011-g2c814f559132-ab8969555
    
    It seems that the compiler has made optimization and has not passed
    cmd parameters to binder_ioctl_write_read:
    <binder_ioctl+628>:  mov     w8, #0x6201                     // #25089
    <binder_ioctl+632>:  movk    w8, #0xc030, lsl #16
    <binder_ioctl+636>:  cmp     w20, w8
    <binder_ioctl+640>:  b.ne    0xffffffda8aa97880 <binder_ioctl+3168>
    <binder_ioctl+644>:  mov     x0, x23 //filp
    <binder_ioctl+648>:  mov     x1, x27 //arg
    <binder_ioctl+652>:  mov     x2, x22 //thread
    <binder_ioctl+656>:  bl      0xffffffda8aa9e6e4 <binder_ioctl_write_read>
    <binder_ioctl+660>:  mov     w26, w0
    Signed-off-by: default avatarJiazi.Li <jiazi.li@transsion.com>
    Acked-by: default avatarCarlos Llamas <cmllamas@google.com>
    Link: https://lore.kernel.org/r/20221115120351.2769-1-jiazi.li@transsion.comSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    7feb35bc
binder.c 185 KB