2023-12-14 03:08:46

by Tianjia Zhang

Subject: [PATCH] crypto: lib/mpi - Fix unexpected pointer access

When the mpi_ec_ctx structure is initialized, some fields are not
cleared, causing a crash when referencing the field when the
structure was released. Initially, this issue was ignored because
memory for mpi_ec_ctx is allocated with the __GFP_ZERO flag.
For example, this error will be triggered when calculating the
Za value for SM2 separately.

Fixes: d58bb7e55a8a ("lib/mpi: Introduce ec implementation to MPI library")
Cc: [email protected] # v6.5
Signed-off-by: Tianjia Zhang <[email protected]>
---
lib/crypto/mpi/ec.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/lib/crypto/mpi/ec.c b/lib/crypto/mpi/ec.c
index 40f5908e57a4..e16dca1e23d5 100644
--- a/lib/crypto/mpi/ec.c
+++ b/lib/crypto/mpi/ec.c
@@ -584,6 +584,9 @@ void mpi_ec_init(struct mpi_ec_ctx *ctx, enum gcry_mpi_ec_models model,
ctx->a = mpi_copy(a);
ctx->b = mpi_copy(b);

+ ctx->d = NULL;
+ ctx->t.two_inv_p = NULL;
+
ctx->t.p_barrett = use_barrett > 0 ? mpi_barrett_init(ctx->p, 0) : NULL;

mpi_ec_get_reset(ctx);
--
2.24.3 (Apple Git-128)

2023-12-22 04:37:11

by Herbert Xu

Subject: Re: [PATCH] crypto: lib/mpi - Fix unexpected pointer access

On Thu, Dec 14, 2023 at 11:08:34AM +0800, Tianjia Zhang wrote:
> When the mpi_ec_ctx structure is initialized, some fields are not
> cleared, causing a crash when referencing the field when the
> structure was released. Initially, this issue was ignored because
> memory for mpi_ec_ctx is allocated with the __GFP_ZERO flag.
> For example, this error will be triggered when calculating the
> Za value for SM2 separately.
>
> Fixes: d58bb7e55a8a ("lib/mpi: Introduce ec implementation to MPI library")
> Cc: [email protected] # v6.5
> Signed-off-by: Tianjia Zhang <[email protected]>
> ---
> lib/crypto/mpi/ec.c | 3 +++
> 1 file changed, 3 insertions(+)

Patch applied. Thanks.
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt