Change in coreboot[master]: src/security/tpm: Deal with zero length tlcl writes

[Patrick Georgi (Code Review)]

Attention is currently required from: Christian Walter.
Patrick Georgi has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/54095 )

Change subject: src/security/tpm: Deal with zero length tlcl writes
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src/security/tpm: Deal with zero length tlcl writes

While memcpy(foo, bar, 0) should be a no-op, that's hard to prove for a
compiler and so gcc 11.1 complains about the use of an uninitialized
"bar" even though it's harmless in this case.

Change-Id: Idbffa508c2cd68790efbc0b4ab97ae1b4d85ad51
Signed-off-by: Patrick Georgi 
---
M src/security/tpm/tss/tcg-1.2/tss.c
1 file changed, 2 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/95/54095/1

diff --git a/src/security/tpm/tss/tcg-1.2/tss.c b/src/security/tpm/tss/tcg-1.2/tss.c
index 8b7778d..413b681 100644
--- a/src/security/tpm/tss/tcg-1.2/tss.c
+++ b/src/security/tpm/tss/tcg-1.2/tss.c
@@ -215,7 +215,8 @@

to_tpm_uint32(cmd.buffer + tpm_nv_write_cmd.index, index);
    to_tpm_uint32(cmd.buffer + tpm_nv_write_cmd.length, length);
-	memcpy(cmd.buffer + tpm_nv_write_cmd.data, data, length);
+	if (length > 0)
+		memcpy(cmd.buffer + tpm_nv_write_cmd.data, data, length);

return tlcl_send_receive(cmd.buffer, response, sizeof(response));
 }