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From 9513a2daae84660f2ddd7d60d39bb49cd678adbe Mon Sep 17 00:00:00 2001
From: Natanael Copa <ncopa@alpinelinux.org>
Date: Tue, 29 Mar 2016 18:59:22 +0200
Subject: [PATCH] ping: make ping work without root privileges
---
networking/ping.c | 103 +++++++++++++++++++++++++++++++++++++++-------
1 file changed, 87 insertions(+), 16 deletions(-)
diff --git a/networking/ping.c b/networking/ping.c
index 8f85d3ec2..dc3f50968 100644
--- a/networking/ping.c
+++ b/networking/ping.c
@@ -165,6 +165,7 @@ enum {
pingsock = 0,
};
+static int using_dgram;
static void
#if ENABLE_PING6
create_icmp_socket(len_and_sockaddr *lsa)
@@ -181,9 +182,23 @@ create_icmp_socket(void)
#endif
sock = socket(AF_INET, SOCK_RAW, 1); /* 1 == ICMP */
if (sock < 0) {
- if (errno == EPERM)
- bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
- bb_perror_msg_and_die(bb_msg_can_not_create_raw_socket);
+ if (errno != EPERM)
+ bb_perror_msg_and_die(bb_msg_can_not_create_raw_socket);
+#if defined(__linux__) || defined(__APPLE__)
+ /* We don't have root privileges. Try SOCK_DGRAM instead.
+ * Linux needs net.ipv4.ping_group_range for this to work.
+ * MacOSX allows ICMP_ECHO, ICMP_TSTAMP or ICMP_MASKREQ
+ */
+#if ENABLE_PING6
+ if (lsa->u.sa.sa_family == AF_INET6)
+ sock = socket(AF_INET6, SOCK_DGRAM, IPPROTO_ICMPV6);
+ else
+#endif
+ sock = socket(AF_INET, SOCK_DGRAM, 1); /* 1 == ICMP */
+ if (sock < 0)
+#endif
+ bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
+ using_dgram = 1;
}
xmove_fd(sock, pingsock);
@@ -236,10 +251,12 @@ static void ping4(len_and_sockaddr *lsa)
bb_perror_msg("recvfrom");
continue;
}
- if (c >= 76) { /* ip + icmp */
- struct iphdr *iphdr = (struct iphdr *) G.packet;
+ if (c >= 76 || using_dgram && (c == 64)) { /* ip + icmp */
+ if(!using_dgram) {
+ struct iphdr *iphdr = (struct iphdr *) G.packet;
- pkt = (struct icmp *) (G.packet + (iphdr->ihl << 2)); /* skip ip hdr */
+ pkt = (struct icmp *) (G.packet + (iphdr->ihl << 2)); /* skip ip hdr */
+ } else pkt = (struct icmp *) G.packet;
if (pkt->icmp_id != G.myid)
continue; /* not our ping */
if (pkt->icmp_type == ICMP_ECHOREPLY)
@@ -636,19 +653,21 @@ static void unpack_tail(int sz, uint32_t *tp,
}
static int unpack4(char *buf, int sz, struct sockaddr_in *from)
{
- struct icmp *icmppkt;
struct iphdr *iphdr;
+ struct icmp *icmppkt;
int hlen;
/* discard if too short */
if (sz < (datalen + ICMP_MINLEN))
return 0;
+ if(!using_dgram) {
+ /* check IP header */
+ iphdr = (struct iphdr *) buf;
+ hlen = iphdr->ihl << 2;
+ sz -= hlen;
+ icmppkt = (struct icmp *) (buf + hlen);
+ } else icmppkt = (struct icmp *) buf;
- /* check IP header */
- iphdr = (struct iphdr *) buf;
- hlen = iphdr->ihl << 2;
- sz -= hlen;
- icmppkt = (struct icmp *) (buf + hlen);
if (icmppkt->icmp_id != myid)
return 0; /* not our ping */
@@ -660,7 +679,7 @@ static int unpack4(char *buf, int sz, struct sockaddr_in *from)
tp = (uint32_t *) icmppkt->icmp_data;
unpack_tail(sz, tp,
inet_ntoa(*(struct in_addr *) &from->sin_addr.s_addr),
- recv_seq, iphdr->ttl);
+ recv_seq, using_dgram ? 42 : iphdr->ttl);
return 1;
}
if (icmppkt->icmp_type != ICMP_ECHO) {
@@ -710,11 +729,31 @@ static void ping4(len_and_sockaddr *lsa)
int sockopt;
pingaddr.sin = lsa->u.sin;
- if (source_lsa) {
+ if (source_lsa && !using_dgram) {
if (setsockopt(pingsock, IPPROTO_IP, IP_MULTICAST_IF,
&source_lsa->u.sa, source_lsa->len))
bb_error_msg_and_die("can't set multicast source interface");
xbind(pingsock, &source_lsa->u.sa, source_lsa->len);
+ } else if(using_dgram) {
+ struct sockaddr_in sa;
+ socklen_t sl;
+
+ sa.sin_family = AF_INET;
+ sa.sin_port = 0;
+ sa.sin_addr.s_addr = source_lsa ?
+ source_lsa->u.sin.sin_addr.s_addr : 0;
+ sl = sizeof(sa);
+
+ if (bind(pingsock, (struct sockaddr *) &sa, sl) == -1) {
+ perror("bind");
+ exit(2);
+ }
+
+ if (getsockname(pingsock, (struct sockaddr *) &sa, &sl) == -1) {
+ perror("getsockname");
+ exit(2);
+ }
+ myid = sa.sin_port;
}
/* enable broadcast pings */
@@ -731,6 +770,15 @@ static void ping4(len_and_sockaddr *lsa)
setsockopt_int(pingsock, IPPROTO_IP, IP_MULTICAST_TTL, opt_ttl);
}
+ if(using_dgram) {
+ int hold = 65536;
+ if (setsockopt(pingsock, SOL_IP, IP_RECVTTL, (char *)&hold, sizeof(hold)))
+ perror("WARNING: setsockopt(IP_RECVTTL)");
+ if (setsockopt(pingsock, SOL_IP, IP_RETOPTS, (char *)&hold, sizeof(hold)))
+ perror("WARNING: setsockopt(IP_RETOPTS)");
+
+ }
+
signal(SIGINT, print_stats_and_exit);
/* start the ping's going ... */
@@ -768,10 +816,33 @@ static void ping6(len_and_sockaddr *lsa)
char control_buf[CMSG_SPACE(36)];
pingaddr.sin6 = lsa->u.sin6;
- if (source_lsa)
+ if (source_lsa && !using_dgram)
xbind(pingsock, &source_lsa->u.sa, source_lsa->len);
+ else if(using_dgram) {
+ struct sockaddr_in6 sa = {0};
+ socklen_t sl;
+
+ sa.sin6_family = AF_INET6;
+ sa.sin6_port = 0;
+ if(source_lsa) {
+ memcpy(&sa.sin6_addr, &source_lsa->u.sin6.sin6_addr, sizeof(struct in6_addr));
+ }
+ sl = sizeof(sa);
+
+ if (bind(pingsock, (struct sockaddr *) &sa, sl) == -1) {
+ perror("bind");
+ exit(2);
+ }
+
+ if (getsockname(pingsock, (struct sockaddr *) &sa, &sl) == -1) {
+ perror("getsockname");
+ exit(2);
+ }
+ myid = sa.sin6_port;
+ }
#ifdef ICMP6_FILTER
+ if(!using_dgram)
{
struct icmp6_filter filt;
if (!(option_mask32 & OPT_VERBOSE)) {
@@ -911,7 +982,7 @@ static int common_ping_main(int opt, char **argv)
G.deadline_us = 1 | ((d * 1000000) + monotonic_us());
}
- myid = (uint16_t) getpid();
+ if (!using_dgram) myid = (uint16_t) getpid();
hostname = argv[optind];
#if ENABLE_PING6
{
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