Re: [ETH]: Combine format_addr() with print_mac().
From: Joe Perches <joe@perches.com>
Date: 2007-12-21 22:37:22
Subsystem:
networking drivers, networking [general], the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
On Fri, 2007-12-21 at 14:05 -0800, Michael Chan wrote:
quoted hunk ↗ jump to hunk
[ETH]: Combine format_addr() with print_mac(). print_mac() used by most net drivers and format_addr() used by net-sysfs.c are very similar and they can be integrated. format_addr() is also identically redefined in the qla4xxx iscsi driver.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 ssize_t? shouldn't it be size_t? Indexing buf by int len is unchecked. That could lead to unintended buffer overruns. Maybe add a buflen argument and use snprintf? 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 <joe@perches.com> -- 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(intsizeof_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);