Re: [PATCH] kernel/sysctl.c: If "count" including the terminating byte '\0' the write system call should retrun success.

[Eric W. Biederman]

On August 24, 2015 1:56:13 AM PDT, Sean Fu <fxinrong@xxxxxxxxx> wrote:
>when the input argument "count" including the terminating byte "\0",
>The write system call return EINVAL on proc file.
>But it return success on regular file.

Nonsense.  It will write the '\0' to a regular file because it is just data.

Integers in proc are more than data.

So I see no justification for this change.


Eric

>E.g. Writting two bytes ("1\0") to
>"/proc/sys/net/ipv4/conf/eth0/rp_filter".
>write(fd, "1\0", 2) return EINVAL.
>
>Signed-off-by: Sean Fu <fxinrong@xxxxxxxxx>
>---
> kernel/sysctl.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/kernel/sysctl.c b/kernel/sysctl.c
>index 19b62b5..c2b0594 100644
>--- a/kernel/sysctl.c
>+++ b/kernel/sysctl.c
>@@ -2004,7 +2004,7 @@ static int do_proc_dointvec_conv(bool *negp,
>unsigned long *lvalp,
>        return 0;
> }
>
>-static const char proc_wspace_sep[] = { ' ', '\t', '\n' };
>+static const char proc_wspace_sep[] = { ' ', '\t', '\n', '\0' };
>
> static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
>                  int write, void __user *buffer,

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