Re: [PATCH] SUNRPC: fix a memleak in gss_import_v2_context

[Simon Horman <horms@kernel.org>]

On Sun, Dec 24, 2023 at 04:20:33PM +0800, Zhipeng Lu wrote:
> The ctx->mech_used.data allocated by kmemdup is not freed in neither
> gss_import_v2_context nor it only caller radeon_driver_open_kms.
> Thus, this patch reform the last call of gss_import_v2_context to the
> gss_krb5_import_ctx_v2, preventing the memleak while keepping the return
> formation.
> 
> Fixes: 47d848077629 ("gss_krb5: handle new context format from gssd")
> Signed-off-by: Zhipeng Lu <alexious@zju.edu.cn>
> ---
>  net/sunrpc/auth_gss/gss_krb5_mech.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/net/sunrpc/auth_gss/gss_krb5_mech.c b/net/sunrpc/auth_gss/gss_krb5_mech.c
> index e31cfdf7eadc..1e54bd63e3f0 100644
> --- a/net/sunrpc/auth_gss/gss_krb5_mech.c
> +++ b/net/sunrpc/auth_gss/gss_krb5_mech.c
> @@ -398,6 +398,7 @@ gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx,
>  	u64 seq_send64;
>  	int keylen;
>  	u32 time32;
> +	int ret;
>  
>  	p = simple_get_bytes(p, end, &ctx->flags, sizeof(ctx->flags));
>  	if (IS_ERR(p))
> @@ -450,8 +451,14 @@ gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx,
>  	}
>  	ctx->mech_used.len = gss_kerberos_mech.gm_oid.len;
>  
> -	return gss_krb5_import_ctx_v2(ctx, gfp_mask);
> +	ret = gss_krb5_import_ctx_v2(ctx, gfp_mask);
> +	if (ret) {
> +		p = ERR_PTR(ret);
> +		goto out_free;
> +	};

Hi Zhipeng Lu,

I think you need to handle the non-error case here:

	return 0;

>  
> +out_free:
> +	kfree(ctx->mech_used.data);
>  out_err:
>  	return PTR_ERR(p);
>  }
> -- 
> 2.34.1
>