Be consistent in handling of IFLA_IFNAME attribute in all places: if there is no attribute report bug to stderr and use ll_idx_n2a() as last measure to get name in "if%u" format instead of "<nil>".
Use check_ifname() to validate network device name: this catches both unexpected return from kernel and ll_idx_n2a(). Signed-off-by: Serhey Popovych <serhe.popov...@gmail.com> --- bridge/link.c | 8 ++++---- include/utils.h | 1 + ip/ipaddress.c | 20 ++++++++------------ lib/utils.c | 19 +++++++++++++++++++ 4 files changed, 32 insertions(+), 16 deletions(-) diff --git a/bridge/link.c b/bridge/link.c index 870ebe0..a11cbb1 100644 --- a/bridge/link.c +++ b/bridge/link.c @@ -99,9 +99,10 @@ int print_linkinfo(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg) { FILE *fp = arg; - int len = n->nlmsg_len; struct ifinfomsg *ifi = NLMSG_DATA(n); struct rtattr *tb[IFLA_MAX+1]; + int len = n->nlmsg_len; + const char *name; len -= NLMSG_LENGTH(sizeof(*ifi)); if (len < 0) { @@ -117,10 +118,9 @@ int print_linkinfo(const struct sockaddr_nl *who, parse_rtattr_flags(tb, IFLA_MAX, IFLA_RTA(ifi), len, NLA_F_NESTED); - if (tb[IFLA_IFNAME] == NULL) { - fprintf(stderr, "BUG: nil ifname\n"); + name = get_ifname_rta(ifi->ifi_index, tb[IFLA_IFNAME]); + if (!name) return -1; - } if (n->nlmsg_type == RTM_DELLINK) fprintf(fp, "Deleted "); diff --git a/include/utils.h b/include/utils.h index f81928a..ced5b7b 100644 --- a/include/utils.h +++ b/include/utils.h @@ -173,6 +173,7 @@ void duparg(const char *, const char *) __attribute__((noreturn)); void duparg2(const char *, const char *) __attribute__((noreturn)); int check_ifname(const char *); int get_ifname(char *, const char *); +const char *get_ifname_rta(int ifindex, const struct rtattr *rta); int matches(const char *arg, const char *pattern); int inet_addr_match(const inet_prefix *a, const inet_prefix *b, int bits); int inet_addr_match_rta(const inet_prefix *m, const struct rtattr *rta); diff --git a/ip/ipaddress.c b/ip/ipaddress.c index 89e3cc4..458d47c 100644 --- a/ip/ipaddress.c +++ b/ip/ipaddress.c @@ -941,12 +941,10 @@ int print_linkinfo_brief(const struct sockaddr_nl *who, return -1; parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), len); - if (tb[IFLA_IFNAME] == NULL) { - fprintf(stderr, "BUG: device with ifindex %d has nil ifname\n", ifi->ifi_index); - name = ll_idx_n2a(ifi->ifi_index); - } else { - name = rta_getattr_str(tb[IFLA_IFNAME]); - } + + name = get_ifname_rta(ifi->ifi_index, tb[IFLA_IFNAME]); + if (!name) + return -1; if (filter.label && (!filter.family || filter.family == AF_PACKET) && @@ -1068,12 +1066,10 @@ int print_linkinfo(const struct sockaddr_nl *who, return -1; parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), len); - if (tb[IFLA_IFNAME] == NULL) { - fprintf(stderr, "BUG: device with ifindex %d has nil ifname\n", ifi->ifi_index); - name = ll_idx_n2a(ifi->ifi_index); - } else { - name = rta_getattr_str(tb[IFLA_IFNAME]); - } + + name = get_ifname_rta(ifi->ifi_index, tb[IFLA_IFNAME]); + if (!name) + return -1; if (filter.label && (!filter.family || filter.family == AF_PACKET) && diff --git a/lib/utils.c b/lib/utils.c index 8e15625..22fe637 100644 --- a/lib/utils.c +++ b/lib/utils.c @@ -871,6 +871,25 @@ int get_ifname(char *buf, const char *name) return ret; } +const char *get_ifname_rta(int ifindex, const struct rtattr *rta) +{ + const char *name; + + if (rta) { + name = rta_getattr_str(rta); + } else { + fprintf(stderr, + "BUG: device with ifindex %d has nil ifname\n", + ifindex); + name = ll_idx_n2a(ifindex); + } + + if (check_ifname(name)) + return NULL; + + return name; +} + int matches(const char *cmd, const char *pattern) { int len = strlen(cmd); -- 1.7.10.4