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@xxxxxxxxxx>
> ---
> 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;
> + };
>
> +out_free:
> + kfree(ctx->mech_used.data);
If the caller's error flow does not invoke
gss_krb5_delete_sec_context(), then I would expect more than just
mech_used.data would be leaked. What if, instead, you changed
gss_krb5_import_sec_context() like this (untested):
471 ret = gss_import_v2_context(p, end, ctx, gfp_mask);
472 memzero_explicit(&ctx->Ksess, sizeof(ctx->Ksess));
473 if (ret) {
- kfree(ctx);
+ gss_krb5_delete_sec_context(ctx);
475 return ret;
476 }
Obviously you would need to add a forward declaration of
gss_krb5_import_sec_context() to make this compile. The question
is whether gss_krb5_delete_sec_context() will deal with a partially-
initialized @ctx.
How did you find this leak, and what kind of testing was done to
confirm the fix is safe?
> out_err:
> return PTR_ERR(p);
> }
> --
> 2.34.1
>
--
Chuck Lever
