From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 B2A722F6931; Mon, 13 Apr 2026 16:19:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776097192; cv=none; b=o7e+vo3ZBJN5r4a8TKcqgmYdx2/Z2iSJga2sj/b0+Ampvzp8DDL6nSolt5iAW57mIDkS6cAmt+aqGOdbu8takuMpmuvgUqqqni61koGqwhHRLoMsVyhXrXDUYpw+Nc6XxGisMGicEphX8d+pxUcoZ/qDgy8mpSNDfEa4u/iKqU0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776097192; c=relaxed/simple; bh=FUsXJZSNc57ubSqmmvGiXEu7vrGxkh08vC6uxD379KA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JvMXX2AjiTfG9HBjk+nYDIv+gVEK7NUqQFyKSzWKLy/v+PCwpIvjOux4UEDQqY2G5rF83BWemr71Eaam/p8qY2+K84QvdlQYHL0r7mI0MpiVtqyB9eGYrmhsS222N3H0vyAQuykwgmOFCR86qXEPgYbLsyxCom8ksncfsRjlEyM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=aiHnxxLJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="aiHnxxLJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49C88C2BCAF; Mon, 13 Apr 2026 16:19:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776097192; bh=FUsXJZSNc57ubSqmmvGiXEu7vrGxkh08vC6uxD379KA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aiHnxxLJS8cGn0AAbUMmrQQOjKUhXMgU2OGOH/1Tl+7SrSRXlBZxUG8HvygiglMvy j+TAFtrVEoQeYDFEhVU+PMDyj6q+4NE7QhjHRBeFqrWA8Qku4qHKQgRTmS/QOFWOPr ZVdAVfYoXCI5QJBO7Ud6o6bp6c/sYs/Gf/AqbaKM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Guenter Roeck , Jann Horn , Christian Brauner Subject: [PATCH 5.15 041/570] eventpoll: Fix integer overflow in ep_loop_check_proc() Date: Mon, 13 Apr 2026 17:52:52 +0200 Message-ID: <20260413155831.966916445@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260413155830.386096114@linuxfoundation.org> References: <20260413155830.386096114@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jann Horn commit fdcfce93073d990ed4b71752e31ad1c1d6e9d58b upstream. If a recursive call to ep_loop_check_proc() hits the `result = INT_MAX`, an integer overflow will occur in the calling ep_loop_check_proc() at `result = max(result, ep_loop_check_proc(ep_tovisit, depth + 1) + 1)`, breaking the recursion depth check. Fix it by using a different placeholder value that can't lead to an overflow. Reported-by: Guenter Roeck Fixes: f2e467a48287 ("eventpoll: Fix semi-unbounded recursion") Cc: stable@vger.kernel.org Signed-off-by: Jann Horn Link: https://patch.msgid.link/20260223-epoll-int-overflow-v1-1-452f35132224@google.com Signed-off-by: Christian Brauner Signed-off-by: Greg Kroah-Hartman --- fs/eventpoll.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -1952,7 +1952,8 @@ static int ep_poll(struct eventpoll *ep, * @ep: the &struct eventpoll to be currently checked. * @depth: Current depth of the path being checked. * - * Return: depth of the subtree, or INT_MAX if we found a loop or went too deep. + * Return: depth of the subtree, or a value bigger than EP_MAX_NESTS if we found + * a loop or went too deep. */ static int ep_loop_check_proc(struct eventpoll *ep, int depth) { @@ -1971,7 +1972,7 @@ static int ep_loop_check_proc(struct eve struct eventpoll *ep_tovisit; ep_tovisit = epi->ffd.file->private_data; if (ep_tovisit == inserting_into || depth > EP_MAX_NESTS) - result = INT_MAX; + result = EP_MAX_NESTS+1; else result = max(result, ep_loop_check_proc(ep_tovisit, depth + 1) + 1); if (result > EP_MAX_NESTS)