| Message ID | 20200814084626.22953-1-s.hauer@pengutronix.de |
|---|---|
| State | Changes Requested |
| Delegated to: | stephen hemminger |
| Headers | show |
| Series | iproute2: ip maddress: Check multiaddr length | expand |
On Fri, 14 Aug 2020 10:46:26 +0200 Sascha Hauer <s.hauer@pengutronix.de> wrote: > ip maddress add|del takes a MAC address as argument, so insist on > getting a length of ETH_ALEN bytes. This makes sure the passed argument > is actually a MAC address and especially not an IPv4 address which > was previously accepted and silently taken as a MAC address. > > While at it, do not print *argv in the error path as this has been > modified by ll_addr_a2n() and doesn't contain the full string anymore, > which can lead to misleading error messages. > > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> > --- > ip/ipmaddr.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/ip/ipmaddr.c b/ip/ipmaddr.c > index 3400e055..9979ed58 100644 > --- a/ip/ipmaddr.c > +++ b/ip/ipmaddr.c > @@ -291,7 +291,7 @@ static int multiaddr_modify(int cmd, int argc, char **argv) > { > struct ifreq ifr = {}; > int family; > - int fd; > + int fd, len; > > if (cmd == RTM_NEWADDR) > cmd = SIOCADDMULTI; > @@ -313,9 +313,12 @@ static int multiaddr_modify(int cmd, int argc, char **argv) > usage(); > if (ifr.ifr_hwaddr.sa_data[0]) > duparg("address", *argv); > - if (ll_addr_a2n(ifr.ifr_hwaddr.sa_data, > - 14, *argv) < 0) { > - fprintf(stderr, "Error: \"%s\" is not a legal ll address.\n", *argv); > + len = ll_addr_a2n(ifr.ifr_hwaddr.sa_data, 14, *argv); While you are at it, get rid of the hard code 14 here and use sizeof(ifr.ifr_hwaddr.sa_data)?
On Fri, Aug 14, 2020 at 08:27:56AM -0700, Stephen Hemminger wrote: > On Fri, 14 Aug 2020 10:46:26 +0200 > Sascha Hauer <s.hauer@pengutronix.de> wrote: > > > ip maddress add|del takes a MAC address as argument, so insist on > > getting a length of ETH_ALEN bytes. This makes sure the passed argument > > is actually a MAC address and especially not an IPv4 address which > > was previously accepted and silently taken as a MAC address. > > > > While at it, do not print *argv in the error path as this has been > > modified by ll_addr_a2n() and doesn't contain the full string anymore, > > which can lead to misleading error messages. > > > > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> > > --- > > ip/ipmaddr.c | 11 +++++++---- > > 1 file changed, 7 insertions(+), 4 deletions(-) > > > > diff --git a/ip/ipmaddr.c b/ip/ipmaddr.c > > index 3400e055..9979ed58 100644 > > --- a/ip/ipmaddr.c > > +++ b/ip/ipmaddr.c > > @@ -291,7 +291,7 @@ static int multiaddr_modify(int cmd, int argc, char **argv) > > { > > struct ifreq ifr = {}; > > int family; > > - int fd; > > + int fd, len; > > > > if (cmd == RTM_NEWADDR) > > cmd = SIOCADDMULTI; > > @@ -313,9 +313,12 @@ static int multiaddr_modify(int cmd, int argc, char **argv) > > usage(); > > if (ifr.ifr_hwaddr.sa_data[0]) > > duparg("address", *argv); > > - if (ll_addr_a2n(ifr.ifr_hwaddr.sa_data, > > - 14, *argv) < 0) { > > - fprintf(stderr, "Error: \"%s\" is not a legal ll address.\n", *argv); > > + len = ll_addr_a2n(ifr.ifr_hwaddr.sa_data, 14, *argv); > > While you are at it, get rid of the hard code 14 here and use sizeof(ifr.ifr_hwaddr.sa_data)? Ok. I just sent out a v2. Sascha
diff --git a/ip/ipmaddr.c b/ip/ipmaddr.c index 3400e055..9979ed58 100644 --- a/ip/ipmaddr.c +++ b/ip/ipmaddr.c @@ -291,7 +291,7 @@ static int multiaddr_modify(int cmd, int argc, char **argv) { struct ifreq ifr = {}; int family; - int fd; + int fd, len; if (cmd == RTM_NEWADDR) cmd = SIOCADDMULTI; @@ -313,9 +313,12 @@ static int multiaddr_modify(int cmd, int argc, char **argv) usage(); if (ifr.ifr_hwaddr.sa_data[0]) duparg("address", *argv); - if (ll_addr_a2n(ifr.ifr_hwaddr.sa_data, - 14, *argv) < 0) { - fprintf(stderr, "Error: \"%s\" is not a legal ll address.\n", *argv); + len = ll_addr_a2n(ifr.ifr_hwaddr.sa_data, 14, *argv); + if (len < 0) + exit(1); + + if (len != ETH_ALEN) { + fprintf(stderr, "Error: Invalid address length %d - must be %d bytes\n", len, ETH_ALEN); exit(1); } }
ip maddress add|del takes a MAC address as argument, so insist on getting a length of ETH_ALEN bytes. This makes sure the passed argument is actually a MAC address and especially not an IPv4 address which was previously accepted and silently taken as a MAC address. While at it, do not print *argv in the error path as this has been modified by ll_addr_a2n() and doesn't contain the full string anymore, which can lead to misleading error messages. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> --- ip/ipmaddr.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)