From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-188.mta1.migadu.com [95.215.58.188]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CE2D83CEB83 for ; Thu, 27 Aug 2026 22:26:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.188 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787869591; cv=none; b=FyJHCuuGPTWR+MNzlnzv1lunBJUvosU9aKvMtjiA3/KKrNQG+PO/BLjLmCR9LeRc/OAq4JpfPKYIrz/Z5Yb+l5UcvEleEkMyQqxOqMQsoRxFCIxPswEajwGDzs/p3rs4WmuLRYYFfMVccfzCDSQyyizv/3DJC86BfBDX4s4PQpg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787869591; c=relaxed/simple; bh=VA5zxrFbY3PQTnPkLynSmZ3ClflLa+1PI3VDeQbSbE8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=lL6Wh/is4B6t3InY4dXp7UytJiAcLDfyHM/KB8COdLuFgUGgj1w7kz9hdxvNxepjFoc32JNuzOxZ0PU19t06iDDwfsrbMNka0Ac+tZDFyuKnwP/754li/bJF8emGKwgvV/8aP1k9Ss2gwaLogx1pTGb9f2HeWMYsp8TnzMxxYZ8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=dXj94TTs; arc=none smtp.client-ip=95.215.58.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="dXj94TTs" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=VA5zxrFbY3PQTnPkLynSmZ3ClflLa+1PI3VDeQbSbE8=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1787869579; v=1; x=1788474379; b=dXj94TTso6hS9NS7fUzJhJFz9IAuXM/mcfjoSuaE1b5LHM2OPoONfi2Ulh6cxJuxaMca3PL8 N66rj6RsX1IP8Tdpl5GgjagIs/vc0WaxV7dFMEeLy8H2STvr8ras0NS7+3uljYyHAp/0O6euI8F 4lgQ4p8QNkm9OZ6yaiE5T4SE= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 0e2bdeecd9b4d29a; Thu, 27 Aug 2026 22:26:09 +0000 X-Mizu-Trace-ID: 0e2bdeecd9b4d29a X-Migadu-Flow: FLOW_OUT Message-ID: Date: Thu, 27 Aug 2026 15:26:07 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] RDMA/rxe: validate access flags before swapping the MR's PD To: Norbert Szetei , linux-rdma@vger.kernel.org, "yanjun.zhu@linux.dev" Cc: Zhu Yanjun , Jason Gunthorpe , Leon Romanovsky , linux-kernel@vger.kernel.org References: <46E1D5C0-24BE-4D01-BDB3-634FE09B22C5@doyensec.com> From: Zhu Yanjun In-Reply-To: <46E1D5C0-24BE-4D01-BDB3-634FE09B22C5@doyensec.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 在 2026/8/27 10:18, Norbert Szetei 写道: > rxe_rereg_user_mr() reassigns mr->ibmr.pd first and only then > validates the IB_MR_REREG_ACCESS argument: > > if (flags & IB_MR_REREG_PD) { > rxe_put(old_pd); > rxe_get(pd); > mr->ibmr.pd = ibpd; > } > > if (flags & IB_MR_REREG_ACCESS) { > if (access & ~RXE_ACCESS_SUPPORTED_MR) > return ERR_PTR(-EOPNOTSUPP); > mr->access = access; > } > > Both flags pass the entry check because RXE_MR_REREG_SUPPORTED is > IB_MR_REREG_PD | IB_MR_REREG_ACCESS, so a caller can reach the access > check with mr->ibmr.pd already reassigned. > > mr->ibmr.pd is owned by the core, which adjusts pd->usecnt only on the > success path: ib_uverbs_rereg_mr() jumps to put_new_uobj on a driver error > without undoing the reassignment, so mr->pd == new_pd while the usecnts > still charge the MR to orig_pd. ib_dereg_mr_user() then decrements > new_pd, whose count can reach zero while a memory window still references > it; uverbs_free_pd() frees the PD on that count alone and rxe_mw_cleanup() > writes to freed memory: > > BUG: KASAN: slab-use-after-free in __rxe_put+0x31/0xa0 > Write of size 4 at addr ffff8881301dd690 by task rxe_poc/591 > __rxe_put+0x31/0xa0 > rxe_mw_cleanup+0x42/0x200 > __rxe_cleanup+0x115/0x370 > rxe_dealloc_mw+0x4c/0x80 > Allocated by task 591: > ib_uverbs_alloc_pd+0x258/0x540 > Freed by task 591: > ib_dealloc_pd_user+0x174/0x210 > uverbs_free_pd+0x8d/0xc0 > ib_uverbs_dealloc_pd+0x18e/0x1d0 > > Validate the access flags before mutating any state so the callback either > applies every requested change or none. > > Fixes: 544c7f62cf32 ("RDMA/rxe: Implement rereg_user_mr")> Cc: stable@vger.kernel.org > Signed-off-by: Norbert Szetei Thanks a lot. I am fine with this commit. Reviewed-by: Zhu Yanjun Zhu Yanjun > --- > drivers/infiniband/sw/rxe/rxe_verbs.c | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c b/drivers/infiniband/sw/rxe/rxe_verbs.c > index 96c7716057fe..3864284522eb 100644 > --- a/drivers/infiniband/sw/rxe/rxe_verbs.c > +++ b/drivers/infiniband/sw/rxe/rxe_verbs.c > @@ -1331,19 +1331,20 @@ static struct ib_mr *rxe_rereg_user_mr(struct ib_mr *ibmr, int flags, > if (err) > return ERR_PTR(err); > > + if ((flags & IB_MR_REREG_ACCESS) && > + (access & ~RXE_ACCESS_SUPPORTED_MR)) { > + rxe_err_mr(mr, "access = %#x not supported\n", access); > + return ERR_PTR(-EOPNOTSUPP); > + } > + > if (flags & IB_MR_REREG_PD) { > rxe_put(old_pd); > rxe_get(pd); > mr->ibmr.pd = ibpd; > } > > - if (flags & IB_MR_REREG_ACCESS) { > - if (access & ~RXE_ACCESS_SUPPORTED_MR) { > - rxe_err_mr(mr, "access = %#x not supported\n", access); > - return ERR_PTR(-EOPNOTSUPP); > - } > + if (flags & IB_MR_REREG_ACCESS) > mr->access = access; > - } > > return NULL; > }