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binder: remove unneeded size check code 

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: Jiazi.Li <jiazi.li@transsion.com>
Acked-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20221115120351.2769-1-jiazi.li@transsion.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiazi.Li 2022-11-15 20:03:51 +08:00 committed by Greg Kroah-Hartman
parent 5dc4c995db
commit 7feb35bc16
1 changed files with 2 additions and 13 deletions
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15
drivers/android/binder.c
View File

@ -5006,20 +5006,14 @@ static __poll_t binder_poll(struct file *filp,
return 0;
}
static int binder_ioctl_write_read(struct file *filp,
unsigned int cmd, unsigned long arg,
static int binder_ioctl_write_read(struct file *filp, unsigned long arg,
struct binder_thread *thread)
{
int ret = 0;
struct binder_proc *proc = filp->private_data;
unsigned int size = _IOC_SIZE(cmd);
void __user *ubuf = (void __user *)arg;
struct binder_write_read bwr;
if (size != sizeof(struct binder_write_read)) {
ret = -EINVAL;
goto out;
}
if (copy_from_user(&bwr, ubuf, sizeof(bwr))) {
ret = -EFAULT;
goto out;
@ -5296,7 +5290,6 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
int ret;
struct binder_proc *proc = filp->private_data;
struct binder_thread *thread;
unsigned int size = _IOC_SIZE(cmd);
void __user *ubuf = (void __user *)arg;
/*pr_info("binder_ioctl: %d:%d %x %lx\n",
@ -5318,7 +5311,7 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
switch (cmd) {
case BINDER_WRITE_READ:
ret = binder_ioctl_write_read(filp, cmd, arg, thread);
ret = binder_ioctl_write_read(filp, arg, thread);
if (ret)
goto err;
break;
@ -5361,10 +5354,6 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
case BINDER_VERSION: {
struct binder_version __user *ver = ubuf;
if (size != sizeof(struct binder_version)) {
ret = -EINVAL;
goto err;
}
if (put_user(BINDER_CURRENT_PROTOCOL_VERSION,
&ver->protocol_version)) {
ret = -EINVAL;