[lkml]   [2005]   [Mar]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: Bogus buffer length check in linux-2.6.11 read()
linux-os wrote:
> The attached file shows that the kernel thinks it's doing
> something helpful by checking the length of the input
> buffer for a read(). It will return "Bad Address" until
> the length is 1632 bytes. Apparently the kernel thinks
> 1632 is a good length!

Likely because only 1632 bytes of memory is accessible after the start
of the buf buffer, and trying to read in more than that results in
copy_to_user failing to write some data.

> Did anybody consider the overhead necessary to do this
> and the fact that the kernel has no way of knowing if
> the pointer to the buffer is valid until it actually
> does the write. What was wrong with copy_to_user()?
> Why is there the additional bogus check?

What additional check?

Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from
Home Page:

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 14:11    [W:0.041 / U:10.316 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site