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libubootenv: generate key modifier from fuses 

Until now the key modifier was being read from 'hwid_n' device tree
entries, but now those entries reflect the environment HWID, which
could be temporarily overriding the fuse HWID.

Ensure the key modifier is generated from the new 'hwid_fuse_n'
device tree entries created by U-Boot with the contents of the
fuse HWID, just as U-Boot does to encrypt/decrypt the environment.

https://onedigi.atlassian.net/browse/DEL-9123

Signed-off-by: Gonzalo Ruiz <Gonzalo.Ruiz@digi.com>
This commit is contained in:
Gonzalo Ruiz 2026-03-17 13:57:08 +01:00
parent 191f891f6c
commit 5d54f13c2d
1 changed files with 40 additions and 5 deletions
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45
meta-digi-arm/recipes-bsp/libubootenv/libubootenv/0003-Implement-support-for-environment-encryption-by-CAAM.patch
View File

@ -49,15 +49,35 @@ Generalize the code to make room for Optee-based encryption.
Optee) implementation.
Signed-off-by: Javier Viguera <javier.viguera@digi.com>
# This is the commit message #4:
crypt: read HWID from 'digi,hwid_fuse_n' dt properties
Now that U-Boot supports overriding the HWID, it inserts the local,
variable HWID into the 'digi,hwid_n' properties and the fused,
stable HWID into the 'digi,hwid_fuse_n' properties.
Read the HWID to compute the key modifier from 'digi,hwid_fuse_n'
as a preferred method. If those properties do not exist, fall back
to the previous method, 'digi,hwid_n'.
An outdated U-Boot that does not create the 'digi,hwid_fuse_n'
properties does not support HWID overriding either, so we can trust
'digi,hwid_n' to have the contents from the fuses.
https://onedigi.atlassian.net/browse/DEL-9123
Signed-off-by: Gonzalo Ruiz <Gonzalo.Ruiz@digi.com>
---
src/CMakeLists.txt | 4 +
src/caam_keyblob.h | 42 +++++++
src/crypt.c | 179 +++++++++++++++++++++++++++++
src/crypt.c | 194 ++++++++++++++++++++++++++++++++
src/crypt.h | 10 ++
src/md5.c | 275 +++++++++++++++++++++++++++++++++++++++++++++
src/md5.h | 24 ++++
src/uboot_env.c | 18 +++
7 files changed, 552 insertions(+)
7 files changed, 567 insertions(+)
create mode 100644 src/caam_keyblob.h
create mode 100644 src/crypt.c
create mode 100644 src/crypt.h
@ -129,10 +149,10 @@ index 0000000..e313e87
+#endif /* CAAM_KEYBLOB_H */
diff --git a/src/crypt.c b/src/crypt.c
new file mode 100644
index 0000000..213cffd
index 0000000..565d13d
--- /dev/null
+++ b/src/crypt.c
@@ -0,0 +1,179 @@
@@ -0,0 +1,194 @@
+/*
+ * Copyright 2024 Digi International Inc
+ *
@ -192,10 +212,25 @@ index 0000000..213cffd
+ int len;
+ int fd;
+ uint32_t ocotp_hwid[MAX_HWID_WORDS];
+ char dt_prop[32];
+ char dt_prop[40];
+ char buf[sizeof(uint32_t)];
+
+ for (i = 0; i < MAX_HWID_WORDS; i++) {
+ sprintf(dt_prop, "/proc/device-tree/digi,hwid_fuse_%d", i);
+ if (access(dt_prop, F_OK) != -1) {
+ fd = open(dt_prop, O_RDONLY);
+ if (fd < 0)
+ return fd;
+ len = read(fd, buf, sizeof(uint32_t));
+ if (len < 0) {
+ close(fd);
+ return -1;
+ }
+ ocotp_hwid[i] = ntohl(*(uint32_t *) buf);
+ close(fd);
+ continue;
+ }
+
+ sprintf(dt_prop, "/proc/device-tree/digi,hwid_%d", i);
+ if (access(dt_prop, F_OK) != -1) {
+ fd = open(dt_prop, O_RDONLY);