From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794064589; b=dDYkl3IVSPwU6XlxRG9sNfLK994Vze7aLfxiAlZDDDvyIrVP9m/JEvfKRhrgfx3IQb+O mPrZ/z5YmqydEMh/MKD1/PLqkdoZZiwJ9gnFpgprYOjHt8X6W73Z+KX4GdXYQuV08TBiC 6nvZfUW2aEoyzRRm3kBgy8auyIeDdinGT3zi9g4iOUZ0nsUMP+tsEfUWEP0dUGSWBS2at pwLe058OVpZ29rJXIUEd9UwgpVg60no1NHo24kmj0iuCbJMnyPtMqt45aCP/GYC3HpEfh +C7ClcuSt1V5ebd642dKl1I687uIhUEDeMk2J4L/UOCEbq1NpRdnhQAcxMM6ZkqIfsw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794064589; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=wkz5nWVk2Vp1e3sOveQCTjT9ji5M+NH0emVjMiYY2W8=; b=wsk8Q6sH0J0GVpCsOWINalqgC5NgJ2I2OxgKNhlaNF4iSwSzgG8vvzN6HSYjetVDZh2o 1VCpE0fLmnKd2Je9ikL1JnXvF4oIbRoTgu3gt+6KJn2C/dYJxuyibSCvffQr19oXu/psx pDBxCyCQ+1ilGsxAsQIA7NZYvovFjK3373mZfUUE4zb+xwvWjlmetYps/cqZkRxeT1i+Z /ufvxbuFB5VKP+3r0oK/PHPxsH3tf7aEcxgP8D77mCpQOpgAwsX+IEkv/+Ava9IYhmGNy vT8FuxnedUtJ8fTWvWrBAVMrkxixQ4kqLO85dA3CVOKVA+XIVeHuX7hHfWIJwsnk88Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=s3EwsXh5; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 535DC606A332; Sat, 7 Nov 2026 15:16:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=s3EwsXh5 Received: by smtp.kernel.org (Postfix) with ESMTPSA id F26A51F0089F; Sat, 7 Nov 2026 15:16:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794064589; bh=wkz5nWVk2Vp1e3sOveQCTjT9ji5M+NH0emVjMiYY2W8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=s3EwsXh58YOf+8JLv2us1QRYJKivn8jzb4ij0n7Fph7osMjxRmJ8eerflcG5phzhP doq6p76R6BxIMQbu0a4qGeSP7TblP/Q9F/YjdBlV7PdtnLAYzbJSUawU3U7YlCyTLy S7fIHfi5vu8ESi0zmy1+uHxrqwgqwBkTuvz4b1Wc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yifei Gao , Ekansh Gupta , Srinivas Kandagatla , Sasha Levin Subject: [PATCH 7.3 0605/1257] misc: fastrpc: fix double-free in fastrpc_map_attach() error path Date: Sat, 7 Nov 2026 08:48:21 -0500 Message-ID: <20261107134956.023691657@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134939.434104957@linuxfoundation.org> References: <20261107134939.434104957@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yifei Gao [ Upstream commit 09fa66ec1b4896ab841da085ca58b6433f28f07f ] map->table is assigned right after dma_buf_map_attachment_unlocked() succeeds. The two failure checks that follow, the len > map->size test and, where subsystem VMIDs are configured, a failed qcom_scm_assign_mem(), jump to map_err with map->table already set. map_err manually calls dma_buf_detach() and dma_buf_put() and then falls through to fastrpc_map_put(). Since that change the error path tail is fastrpc_map_put() -> fastrpc_free_map(), and fastrpc_free_map() already unmaps, detaches and puts the dma-buf whenever map->table is set. The two operations therefore run twice: the second dma_buf_put() drops an extra reference on map->buf, and dma_buf_unmap_attachment_unlocked() dereferences the map->attach already freed by the manual dma_buf_detach(). kref_init() sets the refcount to 1 with no intervening get, so the final fastrpc_map_put() frees the map synchronously and the redundant cleanup is deterministic. The len > map->size branch is reachable by an unprivileged process via FASTRPC_IOCTL_MEM_MAP with an fd whose dma-buf is smaller than the requested length, before any DSP invocation. Route both map->table-is-set failure branches to get_err instead of map_err, so fastrpc_free_map() is the single owner of the unmap/detach/put sequence. map_err is retained for the dma_buf_map_attachment_unlocked() failure, which is reached with map->table still NULL and an attachment that fastrpc_free_map() will not clean up, so its dma_buf_detach()/dma_buf_put() must still run manually. Fixes: 334f1a1cbe03 ("misc: fastrpc: Use fastrpc_map_put in fastrpc_map_create on fail") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Yifei Gao Reviewed-by: Ekansh Gupta Signed-off-by: Srinivas Kandagatla Link: https://patch.msgid.link/20261002101220.1084101-2-srinivas.kandagatla@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/misc/fastrpc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index d4fac2caca867..b35751212095d 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -927,7 +927,7 @@ static int fastrpc_map_attach(struct fastrpc_user *fl, int fd, dev_dbg(sess->dev, "Bad size passed len 0x%llx map size 0x%llx\n", len, map->size); err = -EINVAL; - goto map_err; + goto get_err; } map->va = sg_virt(map->table->sgl); map->len = len; @@ -950,7 +950,7 @@ static int fastrpc_map_attach(struct fastrpc_user *fl, int fd, dev_err(sess->dev, "Failed to assign memory with dma_addr %pad size 0x%llx err %d\n", &map->dma_addr, map->len, err); - goto map_err; + goto get_err; } } spin_lock(&fl->lock); -- 2.53.0