From e824c23316ae50beb7f7488f2055ac65e8b341f2 Mon Sep 17 00:00:00 2001
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From: Chrostoper Ertl <chertl@microsoft.com>
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Date: Thu, 28 Nov 2019 16:33:59 +0000
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Subject: [PATCH] fru: Fix buffer overflow vulnerabilities
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Partial fix for CVE-2020-5208, see
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https://github.com/ipmitool/ipmitool/security/advisories/GHSA-g659-9qxw-p7cp
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The `read_fru_area_section` function only performs size validation of
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requested read size, and falsely assumes that the IPMI message will not
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respond with more than the requested amount of data; it uses the
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unvalidated response size to copy into `frubuf`. If the response is
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larger than the request, this can result in overflowing the buffer.
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The same issue affects the `read_fru_area` function.
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Upstream-Status: Backport[https://github.com/ipmitool/ipmitool/commit/e824c23316ae50beb7f7488f2055ac65e8b341f2]
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CVE: CVE-2020-5208
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Signed-off-by: Wenlin Kang <wenlin.kang@windriver.com>
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---
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lib/ipmi_fru.c | 33 +++++++++++++++++++++++++++++++--
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1 file changed, 31 insertions(+), 2 deletions(-)
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diff --git a/lib/ipmi_fru.c b/lib/ipmi_fru.c
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index c2a139d..2e323ff 100644
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--- a/lib/ipmi_fru.c
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+++ b/lib/ipmi_fru.c
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@@ -663,7 +663,10 @@ int
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read_fru_area(struct ipmi_intf * intf, struct fru_info *fru, uint8_t id,
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uint32_t offset, uint32_t length, uint8_t *frubuf)
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{
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- uint32_t off = offset, tmp, finish;
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+ uint32_t off = offset;
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+ uint32_t tmp;
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+ uint32_t finish;
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+ uint32_t size_left_in_buffer;
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struct ipmi_rs * rsp;
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struct ipmi_rq req;
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uint8_t msg_data[4];
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@@ -676,10 +679,12 @@ read_fru_area(struct ipmi_intf * intf, struct fru_info *fru, uint8_t id,
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finish = offset + length;
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if (finish > fru->size) {
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+ memset(frubuf + fru->size, 0, length - fru->size);
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finish = fru->size;
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lprintf(LOG_NOTICE, "Read FRU Area length %d too large, "
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"Adjusting to %d",
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offset + length, finish - offset);
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+ length = finish - offset;
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}
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memset(&req, 0, sizeof(req));
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@@ -715,6 +720,7 @@ read_fru_area(struct ipmi_intf * intf, struct fru_info *fru, uint8_t id,
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}
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}
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+ size_left_in_buffer = length;
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do {
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tmp = fru->access ? off >> 1 : off;
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msg_data[0] = id;
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@@ -756,9 +762,18 @@ read_fru_area(struct ipmi_intf * intf, struct fru_info *fru, uint8_t id,
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}
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tmp = fru->access ? rsp->data[0] << 1 : rsp->data[0];
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+ if(rsp->data_len < 1
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+ || tmp > rsp->data_len - 1
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+ || tmp > size_left_in_buffer)
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+ {
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+ printf(" Not enough buffer size");
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+ return -1;
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+ }
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+
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memcpy(frubuf, rsp->data + 1, tmp);
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off += tmp;
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frubuf += tmp;
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+ size_left_in_buffer -= tmp;
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/* sometimes the size returned in the Info command
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* is too large. return 0 so higher level function
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* still attempts to parse what was returned */
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@@ -791,7 +806,9 @@ read_fru_area_section(struct ipmi_intf * intf, struct fru_info *fru, uint8_t id,
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uint32_t offset, uint32_t length, uint8_t *frubuf)
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{
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static uint32_t fru_data_rqst_size = 20;
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- uint32_t off = offset, tmp, finish;
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+ uint32_t off = offset;
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+ uint32_t tmp, finish;
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+ uint32_t size_left_in_buffer;
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struct ipmi_rs * rsp;
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struct ipmi_rq req;
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uint8_t msg_data[4];
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@@ -804,10 +821,12 @@ read_fru_area_section(struct ipmi_intf * intf, struct fru_info *fru, uint8_t id,
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finish = offset + length;
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if (finish > fru->size) {
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+ memset(frubuf + fru->size, 0, length - fru->size);
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finish = fru->size;
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lprintf(LOG_NOTICE, "Read FRU Area length %d too large, "
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"Adjusting to %d",
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offset + length, finish - offset);
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+ length = finish - offset;
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}
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memset(&req, 0, sizeof(req));
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@@ -822,6 +841,8 @@ read_fru_area_section(struct ipmi_intf * intf, struct fru_info *fru, uint8_t id,
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if (fru->access && fru_data_rqst_size > 16)
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#endif
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fru_data_rqst_size = 16;
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+
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+ size_left_in_buffer = length;
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do {
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tmp = fru->access ? off >> 1 : off;
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msg_data[0] = id;
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@@ -853,8 +874,16 @@ read_fru_area_section(struct ipmi_intf * intf, struct fru_info *fru, uint8_t id,
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}
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tmp = fru->access ? rsp->data[0] << 1 : rsp->data[0];
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+ if(rsp->data_len < 1
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+ || tmp > rsp->data_len - 1
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+ || tmp > size_left_in_buffer)
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+ {
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+ printf(" Not enough buffer size");
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+ return -1;
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+ }
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memcpy((frubuf + off)-offset, rsp->data + 1, tmp);
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off += tmp;
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+ size_left_in_buffer -= tmp;
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/* sometimes the size returned in the Info command
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* is too large. return 0 so higher level function
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--
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2.17.1
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