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- From 960dbb956d9f9cb05b719087faed53c88dc80956 Mon Sep 17 00:00:00 2001
- From: Chrostoper Ertl <chertl@microsoft.com>
- Date: Thu, 28 Nov 2019 16:33:59 +0000
- Subject: [PATCH 06/11] fru: Fix buffer overflow vulnerabilities
-
- Partial fix for CVE-2020-5208, see
- https://github.com/ipmitool/ipmitool/security/advisories/GHSA-g659-9qxw-p7cp
-
- The `read_fru_area_section` function only performs size validation of
- requested read size, and falsely assumes that the IPMI message will not
- respond with more than the requested amount of data; it uses the
- unvalidated response size to copy into `frubuf`. If the response is
- larger than the request, this can result in overflowing the buffer.
-
- The same issue affects the `read_fru_area` function.
- ---
- lib/ipmi_fru.c | 33 +++++++++++++++++++++++++++++++--
- 1 file changed, 31 insertions(+), 2 deletions(-)
-
- diff --git a/lib/ipmi_fru.c b/lib/ipmi_fru.c
- index cf00effc82a2..af99aa99444c 100644
- --- a/lib/ipmi_fru.c
- +++ b/lib/ipmi_fru.c
- @@ -615,7 +615,10 @@ int
- read_fru_area(struct ipmi_intf * intf, struct fru_info *fru, uint8_t id,
- uint32_t offset, uint32_t length, uint8_t *frubuf)
- {
- - uint32_t off = offset, tmp, finish;
- + uint32_t off = offset;
- + uint32_t tmp;
- + uint32_t finish;
- + uint32_t size_left_in_buffer;
- struct ipmi_rs * rsp;
- struct ipmi_rq req;
- uint8_t msg_data[4];
- @@ -628,10 +631,12 @@ read_fru_area(struct ipmi_intf * intf, struct fru_info *fru, uint8_t id,
-
- finish = offset + length;
- if (finish > fru->size) {
- + memset(frubuf + fru->size, 0, length - fru->size);
- finish = fru->size;
- lprintf(LOG_NOTICE, "Read FRU Area length %d too large, "
- "Adjusting to %d",
- offset + length, finish - offset);
- + length = finish - offset;
- }
-
- memset(&req, 0, sizeof(req));
- @@ -667,6 +672,7 @@ read_fru_area(struct ipmi_intf * intf, struct fru_info *fru, uint8_t id,
- }
- }
-
- + size_left_in_buffer = length;
- do {
- tmp = fru->access ? off >> 1 : off;
- msg_data[0] = id;
- @@ -707,9 +713,18 @@ read_fru_area(struct ipmi_intf * intf, struct fru_info *fru, uint8_t id,
- }
-
- tmp = fru->access ? rsp->data[0] << 1 : rsp->data[0];
- + if(rsp->data_len < 1
- + || tmp > rsp->data_len - 1
- + || tmp > size_left_in_buffer)
- + {
- + printf(" Not enough buffer size");
- + return -1;
- + }
- +
- memcpy(frubuf, rsp->data + 1, tmp);
- off += tmp;
- frubuf += tmp;
- + size_left_in_buffer -= tmp;
- /* sometimes the size returned in the Info command
- * is too large. return 0 so higher level function
- * still attempts to parse what was returned */
- @@ -742,7 +757,9 @@ read_fru_area_section(struct ipmi_intf * intf, struct fru_info *fru, uint8_t id,
- uint32_t offset, uint32_t length, uint8_t *frubuf)
- {
- static uint32_t fru_data_rqst_size = 20;
- - uint32_t off = offset, tmp, finish;
- + uint32_t off = offset;
- + uint32_t tmp, finish;
- + uint32_t size_left_in_buffer;
- struct ipmi_rs * rsp;
- struct ipmi_rq req;
- uint8_t msg_data[4];
- @@ -755,10 +772,12 @@ read_fru_area_section(struct ipmi_intf * intf, struct fru_info *fru, uint8_t id,
-
- finish = offset + length;
- if (finish > fru->size) {
- + memset(frubuf + fru->size, 0, length - fru->size);
- finish = fru->size;
- lprintf(LOG_NOTICE, "Read FRU Area length %d too large, "
- "Adjusting to %d",
- offset + length, finish - offset);
- + length = finish - offset;
- }
-
- memset(&req, 0, sizeof(req));
- @@ -773,6 +792,8 @@ read_fru_area_section(struct ipmi_intf * intf, struct fru_info *fru, uint8_t id,
- if (fru->access && fru_data_rqst_size > 16)
- #endif
- fru_data_rqst_size = 16;
- +
- + size_left_in_buffer = length;
- do {
- tmp = fru->access ? off >> 1 : off;
- msg_data[0] = id;
- @@ -804,8 +825,16 @@ read_fru_area_section(struct ipmi_intf * intf, struct fru_info *fru, uint8_t id,
- }
-
- tmp = fru->access ? rsp->data[0] << 1 : rsp->data[0];
- + if(rsp->data_len < 1
- + || tmp > rsp->data_len - 1
- + || tmp > size_left_in_buffer)
- + {
- + printf(" Not enough buffer size");
- + return -1;
- + }
- memcpy((frubuf + off)-offset, rsp->data + 1, tmp);
- off += tmp;
- + size_left_in_buffer -= tmp;
-
- /* sometimes the size returned in the Info command
- * is too large. return 0 so higher level function
- --
- 2.27.0
-
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