Re: [PATCH] kernel: kallsyms: parameters checking, for EXPORT_SYMBOL_GPL functions

Rusty Russell
2013-04-10T10:35:32Z

Chen Gang <gang.chen@asianux.com> writes:
> for EXPORT_SYMBOL_GPL functions, necessary to check their parameters.
>
> Signed-off-by: Chen Gang <gang.chen@asianux.com>

Why?

If someone misuses these functions, they crash and thus indicate that
the caller shouldn't do that.

Or is someone already doing this?

Confused,
Rusty.

> ---
> kernel/kallsyms.c | 12 ++++++++++++
> 1 files changed, 12 insertions(+), 0 deletions(-)
>
> diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
> index 2169fee..4ba57a9 100644
> --- a/kernel/kallsyms.c
> +++ b/kernel/kallsyms.c
> @@ -175,6 +175,9 @@ unsigned long kallsyms_lookup_name(const char *name)
> unsigned long i;
> unsigned int off;
>
> + if (!name || !name[0])
> + return 0;
> +
> for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
> off = kallsyms_expand_symbol(off, namebuf);
>
> @@ -194,6 +197,9 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
> unsigned int off;
> int ret;
>
> + if (!fn)
> + return -EINVAL;
> +
> for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
> off = kallsyms_expand_symbol(off, namebuf);
> ret = fn(data, namebuf, NULL, kallsyms_addresses[i]);
> @@ -382,6 +388,9 @@ static int __sprint_symbol(char *buffer, unsigned long address,
> */
> int sprint_symbol(char *buffer, unsigned long address)
> {
> + if (!buffer)
> + return 0;
> +
> return __sprint_symbol(buffer, address, 0, 1);
> }
> EXPORT_SYMBOL_GPL(sprint_symbol);
> @@ -399,6 +408,9 @@ EXPORT_SYMBOL_GPL(sprint_symbol);
> */
> int sprint_symbol_no_offset(char *buffer, unsigned long address)
> {
> + if (!buffer)
> + return 0;
> +
> return __sprint_symbol(buffer, address, 0, 0);
> }
> EXPORT_SYMBOL_GPL(sprint_symbol_no_offset);
> --
> 1.7.7.6