From: Kartik Rajput <kkartik@nvidia.com>
To: <thierry.reding@gmail.com>, <jonathanh@nvidia.com>,
<kkartik@nvidia.com>, <kees@kernel.org>,
<linux-tegra@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH] soc/tegra: fuse: Do not use fuse data as entropy source
Date: Tue, 24 Mar 2026 17:12:03 +0530 [thread overview]
Message-ID: <20260324114204.551879-1-kkartik@nvidia.com> (raw)
Fuse values are static and device-unique but not secret. Using them as an
entropy source weakens the overall randomness pool because the data is
constant and externally observable over the device’s lifetime.
Stop feeding fuse data into the kernel’s randomness subsystem.
Signed-off-by: Kartik Rajput <kkartik@nvidia.com>
---
drivers/soc/tegra/fuse/fuse-tegra30.c | 24 ------------------------
1 file changed, 24 deletions(-)
diff --git a/drivers/soc/tegra/fuse/fuse-tegra30.c b/drivers/soc/tegra/fuse/fuse-tegra30.c
index 524fa1b0cd3d..2fad8b13a3b9 100644
--- a/drivers/soc/tegra/fuse/fuse-tegra30.c
+++ b/drivers/soc/tegra/fuse/fuse-tegra30.c
@@ -64,28 +64,6 @@ static u32 tegra30_fuse_read(struct tegra_fuse *fuse, unsigned int offset)
return value;
}
-static void __init tegra30_fuse_add_randomness(void)
-{
- u32 randomness[12];
-
- randomness[0] = tegra_sku_info.sku_id;
- randomness[1] = tegra_read_straps();
- randomness[2] = tegra_read_chipid();
- randomness[3] = tegra_sku_info.cpu_process_id << 16;
- randomness[3] |= tegra_sku_info.soc_process_id;
- randomness[4] = tegra_sku_info.cpu_speedo_id << 16;
- randomness[4] |= tegra_sku_info.soc_speedo_id;
- randomness[5] = tegra_fuse_read_early(FUSE_VENDOR_CODE);
- randomness[6] = tegra_fuse_read_early(FUSE_FAB_CODE);
- randomness[7] = tegra_fuse_read_early(FUSE_LOT_CODE_0);
- randomness[8] = tegra_fuse_read_early(FUSE_LOT_CODE_1);
- randomness[9] = tegra_fuse_read_early(FUSE_WAFER_ID);
- randomness[10] = tegra_fuse_read_early(FUSE_X_COORDINATE);
- randomness[11] = tegra_fuse_read_early(FUSE_Y_COORDINATE);
-
- add_device_randomness(randomness, sizeof(randomness));
-}
-
static void __init tegra30_fuse_init(struct tegra_fuse *fuse)
{
fuse->read_early = tegra30_fuse_read_early;
@@ -95,8 +73,6 @@ static void __init tegra30_fuse_init(struct tegra_fuse *fuse)
if (fuse->soc->speedo_init)
fuse->soc->speedo_init(&tegra_sku_info);
-
- tegra30_fuse_add_randomness();
}
#endif
--
2.43.0
reply other threads:[~2026-03-24 11:42 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260324114204.551879-1-kkartik@nvidia.com \
--to=kkartik@nvidia.com \
--cc=jonathanh@nvidia.com \
--cc=kees@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tegra@vger.kernel.org \
--cc=thierry.reding@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox