From 605405557102c04e740fc3249675cc5154436d11 Mon Sep 17 00:00:00 2001 From: Lorenz <12514511+RincewindsHat@users.noreply.github.com> Date: Tue, 15 Mar 2022 22:00:55 +0100 Subject: check_icmp: buffer offerflow (#1733) * Fix different overflows * Less includes * Add testcases * Remove unused variable * Remove unused and commented includes --- plugins-root/check_icmp.c | 66 +++++++++++++++++++++++++-------------------- plugins-root/t/check_icmp.t | 7 ++++- 2 files changed, 43 insertions(+), 30 deletions(-) diff --git a/plugins-root/check_icmp.c b/plugins-root/check_icmp.c index f97b0ed7..61198237 100644 --- a/plugins-root/check_icmp.c +++ b/plugins-root/check_icmp.c @@ -50,19 +50,11 @@ const char *email = "devel@monitoring-plugins.org"; #if HAVE_SYS_SOCKIO_H #include #endif -#include + #include -#include -#include -#include -#include -#include -#include #include -#include +#include #include -#include -#include #include #include #include @@ -71,8 +63,6 @@ const char *email = "devel@monitoring-plugins.org"; #include #include #include -#include -#include /** sometimes undefined system macros (quite a few, actually) **/ @@ -207,7 +197,7 @@ static int add_target(char *); static int add_target_ip(char *, struct sockaddr_storage *); static int handle_random_icmp(unsigned char *, struct sockaddr_storage *); static void parse_address(struct sockaddr_storage *, char *, int); -static unsigned short icmp_checksum(unsigned short *, int); +static unsigned short icmp_checksum(uint16_t *, size_t); static void finish(int); static void crash(const char *, ...); @@ -465,7 +455,6 @@ main(int argc, char **argv) /* Parse protocol arguments first */ for(i = 1; i < argc; i++) { while((arg = getopt(argc, argv, opts_str)) != EOF) { - unsigned short size; switch(arg) { case '4': if (address_family != -1) @@ -488,10 +477,10 @@ main(int argc, char **argv) /* Reset argument scanning */ optind = 1; + unsigned short size; /* parse the arguments */ for(i = 1; i < argc; i++) { while((arg = getopt(argc, argv, opts_str)) != EOF) { - unsigned short size; switch(arg) { case 'v': debug++; @@ -720,7 +709,7 @@ main(int argc, char **argv) static void run_checks() { - u_int i, t, result; + u_int i, t; u_int final_wait, time_passed; /* this loop might actually violate the pkt_interval or target_interval @@ -738,9 +727,9 @@ run_checks() /* we're still in the game, so send next packet */ (void)send_icmp_ping(icmp_sock, table[t]); - result = wait_for_reply(icmp_sock, target_interval); + wait_for_reply(icmp_sock, target_interval); } - result = wait_for_reply(icmp_sock, pkt_interval * targets); + wait_for_reply(icmp_sock, pkt_interval * targets); } if(icmp_pkts_en_route && targets_alive) { @@ -760,7 +749,7 @@ run_checks() * haven't yet */ if(debug) printf("Waiting for %u micro-seconds (%0.3f msecs)\n", final_wait, (float)final_wait / 1000); - result = wait_for_reply(icmp_sock, final_wait); + wait_for_reply(icmp_sock, final_wait); } } @@ -779,7 +768,7 @@ static int wait_for_reply(int sock, u_int t) { int n, hlen; - static unsigned char buf[4096]; + static unsigned char buf[65536]; struct sockaddr_storage resp_addr; union ip_hdr *ip; union icmp_packet packet; @@ -916,9 +905,27 @@ wait_for_reply(int sock, u_int t) if(debug) { char address[INET6_ADDRSTRLEN]; parse_address(&resp_addr, address, sizeof(address)); - printf("%0.3f ms rtt from %s, outgoing ttl: %u, incoming ttl: %u, max: %0.3f, min: %0.3f\n", - (float)tdiff / 1000, address, - ttl, ip->ip.ip_ttl, (float)host->rtmax / 1000, (float)host->rtmin / 1000); + + switch(address_family) { + case AF_INET: { + printf("%0.3f ms rtt from %s, outgoing ttl: %u, incoming ttl: %u, max: %0.3f, min: %0.3f\n", + (float)tdiff / 1000, + address, + ttl, + ip->ip.ip_ttl, + (float)host->rtmax / 1000, + (float)host->rtmin / 1000); + break; + }; + case AF_INET6: { + printf("%0.3f ms rtt from %s, outgoing ttl: %u, max: %0.3f, min: %0.3f\n", + (float)tdiff / 1000, + address, + ttl, + (float)host->rtmax / 1000, + (float)host->rtmin / 1000); + }; + } } /* if we're in hostcheck mode, exit with limited printouts */ @@ -980,7 +987,7 @@ send_icmp_ping(int sock, struct rta_host *host) icp->icmp_cksum = 0; icp->icmp_id = htons(pid); icp->icmp_seq = htons(host->id++); - icp->icmp_cksum = icmp_checksum((unsigned short*)buf, icmp_pkt_size); + icp->icmp_cksum = icmp_checksum((uint16_t*)buf, (size_t)icmp_pkt_size); if (debug > 2) printf("Sending ICMP echo-request of len %lu, id %u, seq %u, cksum 0x%X to host %s\n", @@ -1517,18 +1524,19 @@ get_threshold(char *str, threshold *th) } unsigned short -icmp_checksum(unsigned short *p, int n) +icmp_checksum(uint16_t *p, size_t n) { unsigned short cksum; long sum = 0; - while(n > 2) { - sum += *p++; - n -= sizeof(unsigned short); + /* sizeof(uint16_t) == 2 */ + while(n >= 2) { + sum += *(p++); + n -= 2; } /* mop up the occasional odd byte */ - if(n == 1) sum += (unsigned char)*p; + if(n == 1) sum += *((uint8_t *)p -1); sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */ sum += (sum >> 16); /* add carry */ diff --git a/plugins-root/t/check_icmp.t b/plugins-root/t/check_icmp.t index 55edc31b..f6aa6813 100644 --- a/plugins-root/t/check_icmp.t +++ b/plugins-root/t/check_icmp.t @@ -12,7 +12,7 @@ my $allow_sudo = getTestParameter( "NP_ALLOW_SUDO", "no" ); if ($allow_sudo eq "yes" or $> == 0) { - plan tests => 18; + plan tests => 20; } else { plan skip_all => "Need sudo to test check_icmp"; } @@ -89,3 +89,8 @@ $res = NPTest->testCmd( is( $res->return_code, 0, "IPv4 source_ip accepted" ); like( $res->output, $successOutput, "Output OK" ); +$res = NPTest->testCmd( + "$sudo ./check_icmp -H $host_responsive -b 65507" + ); +is( $res->return_code, 0, "Try max paket size" ); +like( $res->output, $successOutput, "Output OK - Didn't overflow" ); -- cgit v1.2.3-74-g34f1