From 646160e2175f9e0ba33e4f2bda12d84555e9c30e Mon Sep 17 00:00:00 2001

From: Alexander Amelkin <alexander@amelkin.msk.ru>

Date: Thu, 29 Nov 2018 13:10:53 +0300

Subject: [PATCH] lanplus: Cleanup. Refix 6dec83ff, fix be2c0c4b

This is a cleanup commit.

Commit 6dec83ff removed assignment of `rsp` pointer

in SOL-processing block of ipmi_lan_poll_single(),

but left the check for the pointer validity in place.

Although that has effectively fixed the bug of potentially

accessing the null `rsp` pointer in the `else` block introduced

with be2c0c4b, the resulting if/else looked suspicious and left

and impression that a NULL pointer could still be accessed.

This commit removes the check for `rsp` from the `if`

as it is checked at the start of the function where `rsp`

is initialized (and that is the only place where it is ever changed).

Signed-off-by: Alexander Amelkin <alexander@amelkin.msk.ru>

(cherry picked from commit 64727f59c4a1412fdb73e092fb838ae66e2aad1a)

lanplus: Fix segfault for truncated dcmi response

On occasion a dcmi power reading will return error C6, and a

truncated response payload. As the decrypted payload is shorter

than the expected length, lanplus_decrypt_aes_cbc_128() adjusts

the payload_size downward by one byte. In ipmi_lan_poll_single()

the calculation to determine if the payload size has increased

erroniously sets extra_data_length to -1, with a subsequent

segv when calling a memmove to shift response data.

The fix is to check for a positive value in the extra_data_length.

Resolves ipmitool/ipmitool#72

(cherry picked from commit 9ec2232321a7bca7e1fb8f939d071f12c8dfa7fd)

---

 src/plugins/lanplus/lanplus.c | 4 ++--

 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/plugins/lanplus/lanplus.c b/src/plugins/lanplus/lanplus.c

index c442c0e..ef132f6 100644

--- a/src/plugins/lanplus/lanplus.c

+++ b/src/plugins/lanplus/lanplus.c

@@ -814,7 +814,7 @@ ipmi_lan_poll_single(struct ipmi_intf * intf)

 			 * rsp->data_len becomes the length of that data

 			 */

 			extra_data_length = payload_size - (offset - payload_start) - 1;

-			if (extra_data_length) {

+			if (extra_data_length > 0) {

 				rsp->data_len = extra_data_length;

 				memmove(rsp->data, rsp->data + offset, extra_data_length);

 			} else {

@@ -868,7 +868,7 @@ ipmi_lan_poll_single(struct ipmi_intf * intf)

 		}

 		read_sol_packet(rsp, &offset);

 		extra_data_length = payload_size - (offset - payload_start);

-		if (rsp && extra_data_length) {

+		if (extra_data_length > 0) {

 			rsp->data_len = extra_data_length;

 			memmove(rsp->data, rsp->data + offset, extra_data_length);

 		} else {

-- 

2.26.3