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From 907070918d5e81a515315b395f334e52589fe0fb Mon Sep 17 00:00:00 2001
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From: Guy Harris <guy@alum.mit.edu>
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Date: Wed, 18 Dec 2019 15:06:53 -0800
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Subject: [PATCH] Check for invalid IPv4 addresses.
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This should fix GitHub issue #893.
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---
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 gencode.c    | 9 ++++++++-
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 nametoaddr.c | 9 ++++++++-
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 2 files changed, 16 insertions(+), 2 deletions(-)
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diff --git a/gencode.c b/gencode.c
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index bdc35e646..040a55315 100644
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--- a/gencode.c
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+++ b/gencode.c
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@@ -6947,11 +6947,15 @@ gen_mcode(compiler_state_t *cstate, const char *s1, const char *s2,
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 		return (NULL);
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 	nlen = __pcap_atoin(s1, &n);
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+	if (nlen < 0)
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+		bpf_error(cstate, "invalid IPv4 address '%s'", s1);
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 	/* Promote short ipaddr */
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 	n <<= 32 - nlen;
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 	if (s2 != NULL) {
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 		mlen = __pcap_atoin(s2, &m);
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+		if (mlen < 0)
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+			bpf_error(cstate, "invalid IPv4 address '%s'", s2);
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 		/* Promote short ipaddr */
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 		m <<= 32 - mlen;
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 		if ((n & ~m) != 0)
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@@ -7009,8 +7013,11 @@ gen_ncode(compiler_state_t *cstate, const char *s, bpf_u_int32 v, struct qual q)
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 		vlen = __pcap_atodn(s, &v);
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 		if (vlen == 0)
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 			bpf_error(cstate, "malformed decnet address '%s'", s);
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-	} else
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+	} else {
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 		vlen = __pcap_atoin(s, &v);
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+		if (vlen < 0)
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+			bpf_error(cstate, "invalid IPv4 address '%s'", s);
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+	}
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 	switch (q.addr) {
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diff --git a/nametoaddr.c b/nametoaddr.c
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index 53070a285..13bf4c683 100644
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--- a/nametoaddr.c
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+++ b/nametoaddr.c
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@@ -674,8 +674,15 @@ __pcap_atoin(const char *s, bpf_u_int32 *addr)
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 	len = 0;
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 	for (;;) {
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 		n = 0;
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-		while (*s && *s != '.')
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+		while (*s && *s != '.') {
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+			if (n > 25) {
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+				/* The result will be > 255 */
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+				return -1;
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+			}
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 			n = n * 10 + *s++ - '0';
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+		}
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+		if (n > 255)
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+			return -1;
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 		*addr <<= 8;
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 		*addr |= n & 0xff;
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 		len += 8;