- From 98b47424cf548f58c4d295fa8235210406ea85ca Mon Sep 17 00:00:00 2001
- From: Chrostoper Ertl <chertl@microsoft.com>
- Date: Thu, 28 Nov 2019 17:13:45 +0000
- Subject: [PATCH 11/11] 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(-)
-
- --- a/lib/ipmi_fru.c
- +++ b/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);
-
- --- a/lib/ipmi_sdr.c
- +++ b/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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