Thread (14 messages) 14 messages, 3 authors, 2021-11-02

Re: [PATCH 3/8] crypto: stm32/cryp - fix CTR counter carry

From: Ard Biesheuvel <ardb@kernel.org>
Date: 2021-10-31 12:29:13
Also in: linux-arm-kernel, lkml

On Fri, 29 Oct 2021 at 16:01, Nicolas Toromanoff
[off-list ref] wrote:
quoted hunk ↗ jump to hunk
Fix issue in CTR counter overflow, the carry-over is now properly
managed.
Fixes: bbb2832620ac ("crypto: stm32 - Fix sparse warnings")

Signed-off-by: Nicolas Toromanoff <redacted>
---
 drivers/crypto/stm32/stm32-cryp.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/drivers/crypto/stm32/stm32-cryp.c b/drivers/crypto/stm32/stm32-cryp.c
index 7b55ad6d2f1a..6eeeca0d70ce 100644
--- a/drivers/crypto/stm32/stm32-cryp.c
+++ b/drivers/crypto/stm32/stm32-cryp.c
@@ -163,7 +163,7 @@ struct stm32_cryp {
        struct scatter_walk     in_walk;
        struct scatter_walk     out_walk;

-       u32                     last_ctr[4];
+       __be32                  last_ctr[4];
        u32                     gcm_ctr;
 };
@@ -1219,25 +1219,26 @@ static void stm32_cryp_check_ctr_counter(struct stm32_cryp *cryp)

        if (unlikely(cryp->last_ctr[3] == 0xFFFFFFFF)) {
                cryp->last_ctr[3] = 0;
-               cryp->last_ctr[2]++;
+               cryp->last_ctr[2] = cpu_to_be32(be32_to_cpu(cryp->last_ctr[2]) + 1);
                if (!cryp->last_ctr[2]) {
-                       cryp->last_ctr[1]++;
+                       cryp->last_ctr[1] = cpu_to_be32(be32_to_cpu(cryp->last_ctr[1]) + 1);
                        if (!cryp->last_ctr[1])
-                               cryp->last_ctr[0]++;
+                               cryp->last_ctr[0] = cpu_to_be32(be32_to_cpu(cryp->last_ctr[0]) + 1);
                }
crypto_inc() ??
                cr = stm32_cryp_read(cryp, CRYP_CR);
                stm32_cryp_write(cryp, CRYP_CR, cr & ~CR_CRYPEN);

-               stm32_cryp_hw_write_iv(cryp, (__be32 *)cryp->last_ctr);
+               stm32_cryp_hw_write_iv(cryp, cryp->last_ctr);

                stm32_cryp_write(cryp, CRYP_CR, cr);
        }

-       cryp->last_ctr[0] = stm32_cryp_read(cryp, CRYP_IV0LR);
-       cryp->last_ctr[1] = stm32_cryp_read(cryp, CRYP_IV0RR);
-       cryp->last_ctr[2] = stm32_cryp_read(cryp, CRYP_IV1LR);
-       cryp->last_ctr[3] = stm32_cryp_read(cryp, CRYP_IV1RR);
+       /* The IV registers are BE  */
+       cryp->last_ctr[0] = cpu_to_be32(stm32_cryp_read(cryp, CRYP_IV0LR));
+       cryp->last_ctr[1] = cpu_to_be32(stm32_cryp_read(cryp, CRYP_IV0RR));
+       cryp->last_ctr[2] = cpu_to_be32(stm32_cryp_read(cryp, CRYP_IV1LR));
+       cryp->last_ctr[3] = cpu_to_be32(stm32_cryp_read(cryp, CRYP_IV1RR));
 }

 static bool stm32_cryp_irq_read_data(struct stm32_cryp *cryp)
--
2.17.1
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