* Reporting bug in mpi_ec_mul_point()
@ 2020-09-28 18:24 Gustavo A. R. Silva
2020-10-08 5:58 ` [PATCH] lib/mpi: Remove unused scalar_copied Herbert Xu
0 siblings, 1 reply; 2+ messages in thread
From: Gustavo A. R. Silva @ 2020-09-28 18:24 UTC (permalink / raw)
To: Tianjia Zhang, Xufeng Zhang, Herbert Xu; +Cc: linux-kernel, Gustavo A. R. Silva
Hi all,
I'm reporting the following bug detected by Coverity:
The _scalar_copied_ variable is set to 0 at
lib/mpi/ec.c:1255:
1255 int scalar_copied = 0;
and it is never updated before reaching the code below:
lib/mpi/ec.c:1317
1317 if (scalar_copied)
1318 mpi_free(scalar);
This code was introduced by commit d58bb7e55a8a ("lib/mpi: Introduce ec
implementation to MPI library")
Any ideas on what's the right solution for this?
Thanks
--
Gustavo
^ permalink raw reply [flat|nested] 2+ messages in thread
* [PATCH] lib/mpi: Remove unused scalar_copied
2020-09-28 18:24 Reporting bug in mpi_ec_mul_point() Gustavo A. R. Silva
@ 2020-10-08 5:58 ` Herbert Xu
0 siblings, 0 replies; 2+ messages in thread
From: Herbert Xu @ 2020-10-08 5:58 UTC (permalink / raw)
To: Gustavo A. R. Silva
Cc: Tianjia Zhang, Xufeng Zhang, linux-kernel, Linux Crypto Mailing List
On Mon, Sep 28, 2020 at 01:24:38PM -0500, Gustavo A. R. Silva wrote:
>
> I'm reporting the following bug detected by Coverity:
>
> The _scalar_copied_ variable is set to 0 at
>
> lib/mpi/ec.c:1255:
> 1255 int scalar_copied = 0;
>
> and it is never updated before reaching the code below:
>
> lib/mpi/ec.c:1317
> 1317 if (scalar_copied)
> 1318 mpi_free(scalar);
>
> This code was introduced by commit d58bb7e55a8a ("lib/mpi: Introduce ec
> implementation to MPI library")
>
> Any ideas on what's the right solution for this?
I think it should be removed.
---8<---
The scalar_copied variable is not as the scalar is never copied
in that block. This patch removes it.
Fixes: d58bb7e55a8a ("lib/mpi: Introduce ec implementation to...")
Reported-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/lib/mpi/ec.c b/lib/mpi/ec.c
index c21470122dfc..40f5908e57a4 100644
--- a/lib/mpi/ec.c
+++ b/lib/mpi/ec.c
@@ -1252,7 +1252,6 @@ void mpi_ec_mul_point(MPI_POINT result,
MPI_POINT q1, q2, prd, sum;
unsigned long sw;
mpi_size_t rsize;
- int scalar_copied = 0;
/* Compute scalar point multiplication with Montgomery Ladder.
* Note that we don't use Y-coordinate in the points at all.
@@ -1314,8 +1313,6 @@ void mpi_ec_mul_point(MPI_POINT result,
point_free(&p2);
point_free(&p1_);
point_free(&p2_);
- if (scalar_copied)
- mpi_free(scalar);
return;
}
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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