On Fri, 2007-12-21 at 14:36 -0800, Joe Perches wrote:
> On Fri, 2007-12-21 at 14:05 -0800, Michael Chan wrote:
> > diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
> > index 6b2e454..f760d41 100644
> > --- a/net/ethernet/eth.c
> > +++ b/net/ethernet/eth.c
> > @@ -359,10 +359,33 @@ struct net_device *alloc_etherdev_mq(int sizeof_priv,
> > unsigned int queue_count)
> > }
> > EXPORT_SYMBOL(alloc_etherdev_mq);
> >
> > +static ssize_t _format_mac_addr(char *buf, const unsigned char *addr, int
> > len)
> > +{
> > + int i;
> > + char *cp = buf;
> > +
> > + for (i = 0; i < len; i++) {
> > + cp += sprintf(cp, "%02x", addr[i]);
> > + if (i == len - 1)
> > + break;
> > + *cp++ = ':';
> > + }
> > + return cp - buf;
> > +}
> > +
> > +ssize_t format_mac_addr(char *buf, const unsigned char *addr, int len)
> > +{
> > + ssize_t l;
> > +
> > + l = _format_mac_addr(buf, addr, len);
> > + strcpy(buf + l, "\n");
> > + return l + 1;
> > +}
> > +EXPORT_SYMBOL(format_mac_addr);
> > +
> > char *print_mac(char *buf, const u8 *addr)
> > {
> > - sprintf(buf, MAC_FMT,
> > - addr[0], addr[1], addr[2], addr[3], addr[4], addr[5]);
> > + _format_mac_addr(buf, addr, ETH_ALEN);
> > return buf;
> > }
> > EXPORT_SYMBOL(print_mac);
>
> I think const unsigned char *addr should be const u8 *addr
The dev_addr is declared as unsigned char* in struct net_device. To be
consistent, can we change print_mac() and MAC_BUF to use unsigned char*?
They are really the same.
> ssize_t? shouldn't it be size_t?
I'm just keeping the prototype unchanged as originally defined in net-
sysfs.c
> Indexing buf by int len is unchecked.
> That could lead to unintended buffer overruns.
> Maybe add a buflen argument and use snprintf?
Again, I kept the semantics the same as the original, but will be happy
to add a buflen for better checking.
>
> I had a patch that added some type-safety to print_mac
> and prevented this unintended buffer overrun.
>
> It seems it wasn't applied.
>
> ---------------------------------------
>
> Subject: Re: [PATCH net-2.6.24] introduce MAC_FMT/MAC_ARG
> Date: Mon, 24 Sep 2007 10:28:36 -0700
>
> Here is a patch that adds some type safety to print_mac
> by using a struct print_mac_buf * instead of char *.
>
> It also reduces the defconfig vmlinux size by 8 bytes.
>
> Signed-off-by: Joe Perches <[EMAIL PROTECTED]>
>
> --
>
> include/linux/if_ether.h | 12 ++++++++++--
> net/ethernet/eth.c | 6 +++---
> 2 files changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/if_ether.h b/include/linux/if_ether.h
> index 57abca1..620d6b1 100644
> --- a/include/linux/if_ether.h
> +++ b/include/linux/if_ether.h
> @@ -126,7 +126,15 @@ extern struct ctl_table ether_table[];
> * Display a 6 byte device address (MAC) in a readable format.
> */
> #define MAC_FMT "%02x:%02x:%02x:%02x:%02x:%02x"
> -extern char *print_mac(char *buf, const u8 *addr);
> -#define DECLARE_MAC_BUF(var) char var[18] __maybe_unused
> +
> +struct print_mac_buf {
> + char formatted_mac_addr[18];
> +};
> +
> +#define DECLARE_MAC_BUF(var) \
> + struct print_mac_buf __maybe_unused _##var; \
> + struct print_mac_buf __maybe_unused *var = &_##var
> +
> +extern char *print_mac(struct print_mac_buf *buf, const u8 *addr);
>
> #endif /* _LINUX_IF_ETHER_H */
> diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
> index 2aaf6fa..ad82613 100644
> --- a/net/ethernet/eth.c
> +++ b/net/ethernet/eth.c
> @@ -338,10 +338,10 @@ struct net_device *alloc_etherdev_mq(int
> sizeof_priv, unsigned int queue_count)
> }
> EXPORT_SYMBOL(alloc_etherdev_mq);
>
> -char *print_mac(char *buf, const u8 *addr)
> +char *print_mac(struct print_mac_buf *buf, const u8 *addr)
> {
> - sprintf(buf, MAC_FMT,
> + sprintf(buf->formatted_mac_addr, MAC_FMT,
> addr[0], addr[1], addr[2], addr[3], addr[4], addr[5]);
> - return buf;
> + return buf->formatted_mac_addr;
> }
> EXPORT_SYMBOL(print_mac);
>
>
>
>
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