From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B230F4A9D4B for ; Fri, 4 Sep 2026 14:29:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788532183; cv=none; b=bhuTCZRYhRqqPscF5FRnS/R/Qlpu/xMgjbjMwb/HxUbxnlqza8MOSclHsf+oUASQwv485T734kt7/d6b3mygMkc7a56NnogayNBUjJMVXZb4dQcgR1kOZGX3TGpmtKcOwjp+MlDxumEe4dQY/PzsaDrOW5wjJBpfaXnBO+Y3LcI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788532183; c=relaxed/simple; bh=JXH6+ThsPYnrXpFrMNIvtXwvciUNvcR52qq63GHuS2E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mvZuRVlJUppTgAhbxY1SOCbtcocG3Td5xXMSDffh3VUPjetpgr5JuiKToZ7JlB5b9x0caePKP3lF33DdP6lZLHp7QqgjiBVK/wKx5WteJqo00EU9T6Z0cy831W2cJS5FJ0MocqT1xREst7pUTrX3aU0gI6EoLvpD4Lv3eZm60kg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WMrkgboW; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WMrkgboW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B77871F00A3E; Fri, 4 Sep 2026 14:29:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788532182; bh=YD7QdqAjh3xTqu5dJ4IuD81T6B2V2IX/BtFI8Oo0fvw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=WMrkgboW7RQ1dHuYXa3TlIrC8IxNtUZ+Yr4NbGS6S3KiUMsdwhwVIfRFc7eTecR8N 1H9THnhb3WGLb4cCWwLqY6prYNH+/33P6D+qd/1vXGdgGW3qOLCBVtImfQl0gtbRiH cmrUvYEdSap+ihYK18oTnkHHRG5Ma+qJH0ZtwS+Xbf7U4ofDYobAMUyF2WtkosMrvm AKkCkO2Ej9YNPsCU6spOztUO8TDHCANL+ffQmdqpDyAHEqnJIrjZd2jBhxqjgMQs2Z /wwtCioV+CHCS1A4JtIO5R/Coy8Rc8KKYp79yO4MTlYQlxFxs7PXbImwYTizJv11BS u7GLPsrqierZw== From: Sasha Levin To: stable@vger.kernel.org Cc: Neill Kapron , Xingyu Jin , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 6.18.y 2/2] usb: gadget: f_fs: Fix Use-After-Free in AIO error path Date: Fri, 4 Sep 2026 10:29:39 -0400 Message-ID: <20260904142939.798242-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260904142939.798242-1-sashal@kernel.org> References: <2026090331-width-covenant-cd4e@gregkh> <20260904142939.798242-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Neill Kapron [ Upstream commit e78dcb1f7ec271449c54984dc90c62a5ba272de7 ] In ffs_epfile_write_iter() and ffs_epfile_read_iter(), when ffs_epfile_io() fails with an error other than -EIOCBQUEUED, the io_data structure (`p`) is freed. However, for AIO operations, the kiocb cancel function was already armed and kiocb->private was set to `p`. If a concurrent cancel operation (such as sys_io_cancel()) executes after ffs_epfile_io() fails but before the function frees `p`, a Use-After-Free can occur when the cancellation handler accesses the freed pointer. To securely fix this race condition, we must properly un-arm the cancellation. Invoking `kiocb->ki_complete()` does exactly this by acquiring `ctx->ctx_lock` and safely removing the kiocb from the active sequence. In doing so, it ensures that a parallel io_cancel can no longer discover the kiocb, effectively closing the race window. We then return -EIOCBQUEUED to notify the VFS layer that the kiocb has been consumed and it should avoid attempting to complete the request again or triggering subsequent completion handlers. Fixes: de2080d41b5d ("gadget/function/f_fs.c: close leaks") Cc: stable@vger.kernel.org Reported-by: Xingyu Jin Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Neill Kapron Link: https://patch.msgid.link/20260724235100.106011-1-nkapron@google.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/usb/gadget/function/f_fs.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index a00bf66bdf878..df66441bec46f 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1255,8 +1255,10 @@ static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from) if (res == -EIOCBQUEUED) return res; if (p->aio) { + kiocb->ki_complete(kiocb, res); mmdrop(p->mm); kfree(p); + return -EIOCBQUEUED; } else { *from = p->data; } @@ -1304,9 +1306,11 @@ static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to) return res; if (p->aio) { + kiocb->ki_complete(kiocb, res); mmdrop(p->mm); kfree(p->to_free); kfree(p); + return -EIOCBQUEUED; } else { *to = p->data; } -- 2.53.0