#include <linux/pagemap.h>
#include <linux/audit.h>
#include <linux/syscalls.h>
+#include <linux/fcntl.h>
#include <asm/uaccess.h>
#include <asm/ioctls.h>
+/*
+ * The max size that a non-root user is allowed to grow the pipe. Can
+ * be set by root in /proc/sys/fs/pipe-max-pages
+ */
+unsigned int pipe_max_pages = PIPE_DEF_BUFFERS * 16;
+
/*
* We use a start+len construction, which provides full use of the
* allocated memory.
return kmap(buf->page);
}
+EXPORT_SYMBOL(generic_pipe_buf_map);
/**
* generic_pipe_buf_unmap - unmap a previously mapped pipe buffer
} else
kunmap(buf->page);
}
+EXPORT_SYMBOL(generic_pipe_buf_unmap);
/**
* generic_pipe_buf_steal - attempt to take ownership of a &pipe_buffer
return 1;
}
+EXPORT_SYMBOL(generic_pipe_buf_steal);
/**
* generic_pipe_buf_get - get a reference to a &struct pipe_buffer
{
page_cache_get(buf->page);
}
+EXPORT_SYMBOL(generic_pipe_buf_get);
/**
* generic_pipe_buf_confirm - verify contents of the pipe buffer
{
return 0;
}
+EXPORT_SYMBOL(generic_pipe_buf_confirm);
/**
* generic_pipe_buf_release - put a reference to a &struct pipe_buffer
{
page_cache_release(buf->page);
}
+EXPORT_SYMBOL(generic_pipe_buf_release);
static const struct pipe_buf_operations anon_pipe_buf_ops = {
.can_merge = 1,
switch (cmd) {
case F_SETPIPE_SZ:
+ if (!capable(CAP_SYS_ADMIN) && arg > pipe_max_pages) {
+ ret = -EINVAL;
+ goto out;
+ }
+ /*
+ * The pipe needs to be at least 2 pages large to
+ * guarantee POSIX behaviour.
+ */
+ if (arg < 2) {
+ ret = -EINVAL;
+ goto out;
+ }
ret = pipe_set_size(pipe, arg);
break;
case F_GETPIPE_SZ:
break;
}
+out:
mutex_unlock(&pipe->inode->i_mutex);
return ret;
}