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From f1cdbb33ec61c4a64a32e107d4d02f936051c708 Mon Sep 17 00:00:00 2001
From: "Alan T. DeKok" <aland@freeradius.org>
Date: Mon, 7 Feb 2022 22:26:05 -0500
Subject: [PATCH] it's probably wrong to be completely retarded. Let's fix
that.
CVE: CVE-2022-41860
Upstream-Status: Backport
[https://github.com/FreeRADIUS/freeradius-server/commit/f1cdbb33ec61c4a64a32e107d4d02f936051c708]
Signed-off-by: Yi Zhao <yi.zhao@windriver.com>
---
src/modules/rlm_eap/libeap/eapsimlib.c | 69 +++++++++++++++++++-------
1 file changed, 52 insertions(+), 17 deletions(-)
diff --git a/src/modules/rlm_eap/libeap/eapsimlib.c b/src/modules/rlm_eap/libeap/eapsimlib.c
index cf1e8a7dd9..e438a844ea 100644
--- a/src/modules/rlm_eap/libeap/eapsimlib.c
+++ b/src/modules/rlm_eap/libeap/eapsimlib.c
@@ -307,42 +307,77 @@ int unmap_eapsim_basictypes(RADIUS_PACKET *r,
newvp->vp_length = 1;
fr_pair_add(&(r->vps), newvp);
+ /*
+ * EAP-SIM has a 1 octet of subtype, and 2 octets
+ * reserved.
+ */
attr += 3;
attrlen -= 3;
- /* now, loop processing each attribute that we find */
- while(attrlen > 0) {
+ /*
+ * Loop over each attribute. The format is:
+ *
+ * 1 octet of type
+ * 1 octet of length (value 1..255)
+ * ((4 * length) - 2) octets of data.
+ */
+ while (attrlen > 0) {
uint8_t *p;
- if(attrlen < 2) {
+ if (attrlen < 2) {
fr_strerror_printf("EAP-Sim attribute %d too short: %d < 2", es_attribute_count, attrlen);
return 0;
}
+ if (!attr[1]) {
+ fr_strerror_printf("EAP-Sim attribute %d (no.%d) has no data", eapsim_attribute,
+ es_attribute_count);
+ return 0;
+ }
+
eapsim_attribute = attr[0];
eapsim_len = attr[1] * 4;
+ /*
+ * The length includes the 2-byte header.
+ */
if (eapsim_len > attrlen) {
fr_strerror_printf("EAP-Sim attribute %d (no.%d) has length longer than data (%d > %d)",
eapsim_attribute, es_attribute_count, eapsim_len, attrlen);
return 0;
}
- if(eapsim_len > MAX_STRING_LEN) {
- eapsim_len = MAX_STRING_LEN;
- }
- if (eapsim_len < 2) {
- fr_strerror_printf("EAP-Sim attribute %d (no.%d) has length too small", eapsim_attribute,
- es_attribute_count);
- return 0;
- }
+ newvp = fr_pair_afrom_num(r, eapsim_attribute + PW_EAP_SIM_BASE, 0);
+ if (!newvp) {
+ /*
+ * RFC 4186 Section 8.1 says 0..127 are
+ * "non-skippable". If one such
+ * attribute is found and we don't
+ * understand it, the server has to send:
+ *
+ * EAP-Request/SIM/Notification packet with an
+ * (AT_NOTIFICATION code, which implies general failure ("General
+ * failure after authentication" (0), or "General failure" (16384),
+ * depending on the phase of the exchange), which terminates the
+ * authentication exchange.
+ */
+ if (eapsim_attribute <= 127) {
+ fr_strerror_printf("Unknown mandatory attribute %d, failing",
+ eapsim_attribute);
+ return 0;
+ }
- newvp = fr_pair_afrom_num(r, eapsim_attribute+PW_EAP_SIM_BASE, 0);
- newvp->vp_length = eapsim_len-2;
- newvp->vp_octets = p = talloc_array(newvp, uint8_t, newvp->vp_length);
- memcpy(p, &attr[2], eapsim_len-2);
- fr_pair_add(&(r->vps), newvp);
- newvp = NULL;
+ } else {
+ /*
+ * It's known, ccount for header, and
+ * copy the value over.
+ */
+ newvp->vp_length = eapsim_len - 2;
+
+ newvp->vp_octets = p = talloc_array(newvp, uint8_t, newvp->vp_length);
+ memcpy(p, &attr[2], newvp->vp_length);
+ fr_pair_add(&(r->vps), newvp);
+ }
/* advance pointers, decrement length */
attr += eapsim_len;
--
2.25.1
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