Date: Fri, 24 Feb 2023 14:59:29 GMT From: Cy Schubert <cy@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 70960bb86a3b - main - ping: Fix unsigned integer underflow resuling in a ping -R segfault Message-ID: <202302241459.31OExTc7077467@gitrepo.freebsd.org>
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The branch main has been updated by cy: URL: https://cgit.FreeBSD.org/src/commit/?id=70960bb86a3ba5b6f5c4652e613e6313a7ed1ac1 commit 70960bb86a3ba5b6f5c4652e613e6313a7ed1ac1 Author: Cy Schubert <cy@FreeBSD.org> AuthorDate: 2023-02-23 05:43:17 +0000 Commit: Cy Schubert <cy@FreeBSD.org> CommitDate: 2023-02-24 14:50:53 +0000 ping: Fix unsigned integer underflow resuling in a ping -R segfault ping -R (F_RROUTE) will loop at ping.c:1381 until it segfaults or the unsigned int hlen happens to be less than the size of an IP header: slippy$ ping -R 192.168.0.101 PING 192.168.0.101 (192.168.0.101): 56 data bytes 64 bytes from 192.168.0.101: icmp_seq=0 ttl=63 time=1.081 ms RR: 192.168.0.1 192.168.0.101 192.168.0.101 10.1.1.254 10.1.1.91 unknown option bb unknown option 32 unknown option 6 ... unknown option 96 unknown option 2d Segmentation fault The reason for this is while looping through loose source routing (LSRR) and strict source routing (SSRR), hlen will become smaller than the IP header. It may even become negative. This should terminate the loop. However, when hlen is unsigned, an integer underflow occurs becoming a large number causing the loop to continue virtually forever until hlen is either by chance smaller than the lenghth of an IP header or it segfaults. Reviewed by: asomers Fixes: 46d7b45a267b MFC after: 3 days Differential Revision: https://reviews.freebsd.org/D38744 --- sbin/ping/ping.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/sbin/ping/ping.c b/sbin/ping/ping.c index 6956b9a68ad2..2fc876e50776 100644 --- a/sbin/ping/ping.c +++ b/sbin/ping/ping.c @@ -1150,7 +1150,7 @@ pr_pack(char *buf, ssize_t cc, struct sockaddr_in *from, struct timespec *tv) ssize_t icmp_data_raw_len; double triptime; int dupflag, i, j, recv_len; - uint8_t hlen; + int8_t hlen; uint16_t seq; static int old_rrlen; static char old_rr[MAX_IPOPTLEN]; @@ -1171,7 +1171,7 @@ pr_pack(char *buf, ssize_t cc, struct sockaddr_in *from, struct timespec *tv) hlen = (l & 0x0f) << 2; /* Reject IP packets with a short header */ - if (hlen < sizeof(struct ip)) { + if (hlen < (int8_t) sizeof(struct ip)) { if (options & F_VERBOSE) warn("IHL too short (%d bytes) from %s", hlen, inet_ntoa(from->sin_addr));
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