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From 7ccea283dd62a05a320c1921e3d8d71a87772637 Mon Sep 17 00:00:00 2001
From: Chrostoper Ertl <chertl@microsoft.com>
Date: Thu, 28 Nov 2019 17:13:45 +0000
Subject: [PATCH 6/6] fru, sdr: Fix id_string buffer overflows
Final part of the fixes for CVE-2020-5208, see
https://github.com/ipmitool/ipmitool/security/advisories/GHSA-g659-9qxw-p7cp
9 variants of stack buffer overflow when parsing `id_string` field of
SDR records returned from `CMD_GET_SDR` command.
SDR record structs have an `id_code` field, and an `id_string` `char`
array.
The length of `id_string` is calculated as `(id_code & 0x1f) + 1`,
which can be larger than expected 16 characters (if `id_code = 0xff`,
then length will be `(0xff & 0x1f) + 1 = 32`).
In numerous places, this can cause stack buffer overflow when copying
into fixed buffer of size `17` bytes from this calculated length.
---
lib/ipmi_fru.c | 2 +-
lib/ipmi_sdr.c | 40 ++++++++++++++++++++++++----------------
2 files changed, 25 insertions(+), 17 deletions(-)
Index: ipmitool-1.8.18/lib/ipmi_fru.c
===================================================================
--- ipmitool-1.8.18.orig/lib/ipmi_fru.c
+++ ipmitool-1.8.18/lib/ipmi_fru.c
@@ -3062,7 +3062,7 @@ ipmi_fru_print(struct ipmi_intf * intf,
return 0;
memset(desc, 0, sizeof(desc));
- memcpy(desc, fru->id_string, fru->id_code & 0x01f);
+ memcpy(desc, fru->id_string, __min(fru->id_code & 0x01f, sizeof(desc)));
desc[fru->id_code & 0x01f] = 0;
printf("FRU Device Description : %s (ID %d)\n", desc, fru->device_id);
Index: ipmitool-1.8.18/lib/ipmi_sdr.c
===================================================================
--- ipmitool-1.8.18.orig/lib/ipmi_sdr.c
+++ ipmitool-1.8.18/lib/ipmi_sdr.c
@@ -2084,7 +2084,7 @@ ipmi_sdr_print_sensor_eventonly(struct i
return -1;
memset(desc, 0, sizeof (desc));
- snprintf(desc, (sensor->id_code & 0x1f) + 1, "%s", sensor->id_string);
+ snprintf(desc, sizeof(desc), "%.*s", (sensor->id_code & 0x1f) + 1, sensor->id_string);
if (verbose) {
printf("Sensor ID : %s (0x%x)\n",
@@ -2135,7 +2135,7 @@ ipmi_sdr_print_sensor_mc_locator(struct
return -1;
memset(desc, 0, sizeof (desc));
- snprintf(desc, (mc->id_code & 0x1f) + 1, "%s", mc->id_string);
+ snprintf(desc, sizeof(desc), "%.*s", (mc->id_code & 0x1f) + 1, mc->id_string);
if (verbose == 0) {
if (csv_output)
@@ -2228,7 +2228,7 @@ ipmi_sdr_print_sensor_generic_locator(st
char desc[17];
memset(desc, 0, sizeof (desc));
- snprintf(desc, (dev->id_code & 0x1f) + 1, "%s", dev->id_string);
+ snprintf(desc, sizeof(desc), "%.*s", (dev->id_code & 0x1f) + 1, dev->id_string);
if (!verbose) {
if (csv_output)
@@ -2285,7 +2285,7 @@ ipmi_sdr_print_sensor_fru_locator(struct
char desc[17];
memset(desc, 0, sizeof (desc));
- snprintf(desc, (fru->id_code & 0x1f) + 1, "%s", fru->id_string);
+ snprintf(desc, sizeof(desc), "%.*s", (fru->id_code & 0x1f) + 1, fru->id_string);
if (!verbose) {
if (csv_output)
@@ -2489,35 +2489,43 @@ ipmi_sdr_print_name_from_rawentry(struct
int rc =0;
char desc[17];
+ const char *id_string;
+ uint8_t id_code;
memset(desc, ' ', sizeof (desc));
switch ( type) {
case SDR_RECORD_TYPE_FULL_SENSOR:
record.full = (struct sdr_record_full_sensor *) raw;
- snprintf(desc, (record.full->id_code & 0x1f) +1, "%s",
- (const char *)record.full->id_string);
+ id_code = record.full->id_code;
+ id_string = record.full->id_string;
break;
+
case SDR_RECORD_TYPE_COMPACT_SENSOR:
record.compact = (struct sdr_record_compact_sensor *) raw ;
- snprintf(desc, (record.compact->id_code & 0x1f) +1, "%s",
- (const char *)record.compact->id_string);
+ id_code = record.compact->id_code;
+ id_string = record.compact->id_string;
break;
+
case SDR_RECORD_TYPE_EVENTONLY_SENSOR:
record.eventonly = (struct sdr_record_eventonly_sensor *) raw ;
- snprintf(desc, (record.eventonly->id_code & 0x1f) +1, "%s",
- (const char *)record.eventonly->id_string);
- break;
+ id_code = record.eventonly->id_code;
+ id_string = record.eventonly->id_string;
+ break;
+
case SDR_RECORD_TYPE_MC_DEVICE_LOCATOR:
record.mcloc = (struct sdr_record_mc_locator *) raw ;
- snprintf(desc, (record.mcloc->id_code & 0x1f) +1, "%s",
- (const char *)record.mcloc->id_string);
+ id_code = record.mcloc->id_code;
+ id_string = record.mcloc->id_string;
break;
+
default:
rc = -1;
- break;
- }
+ }
+ if (!rc) {
+ snprintf(desc, sizeof(desc), "%.*s", (id_code & 0x1f) + 1, id_string);
+ }
- lprintf(LOG_INFO, "ID: 0x%04x , NAME: %-16s", id, desc);
+ lprintf(LOG_INFO, "ID: 0x%04x , NAME: %-16s", id, desc);
return rc;
}
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