linux-kernel - [PATCH AUTOSEL 5.12 007/116] fs: dlm: change allocation limits

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Date:   Wed,  5 May 2021 12:29:35 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Alexander Aring <aahringo@...hat.com>,
        David Teigland <teigland@...hat.com>,
        Sasha Levin <sashal@...nel.org>, cluster-devel@...hat.com
Subject: [PATCH AUTOSEL 5.12 007/116] fs: dlm: change allocation limits

From: Alexander Aring <aahringo@...hat.com>

[ Upstream commit c45674fbdda138814ca21138475219c96fa5aa1f ]

While running tcpkill I experienced invalid header length values while
receiving to check that a node doesn't try to send a invalid dlm message
we also check on applications minimum allocation limit. Also use
DEFAULT_BUFFER_SIZE as maximum allocation limit. The define
LOWCOMMS_MAX_TX_BUFFER_LEN is to calculate maximum buffer limits on
application layer, future midcomms layer will subtract their needs from
this define.

Signed-off-by: Alexander Aring <aahringo@...hat.com>
Signed-off-by: David Teigland <teigland@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/dlm/lowcomms.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index c438ce0ac115..39d6418f6e89 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -1374,9 +1374,11 @@ void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
 	struct writequeue_entry *e;
 	int offset = 0;
 
-	if (len > LOWCOMMS_MAX_TX_BUFFER_LEN) {
-		BUILD_BUG_ON(PAGE_SIZE < LOWCOMMS_MAX_TX_BUFFER_LEN);
+	if (len > DEFAULT_BUFFER_SIZE ||
+	    len < sizeof(struct dlm_header)) {
+		BUILD_BUG_ON(PAGE_SIZE < DEFAULT_BUFFER_SIZE);
 		log_print("failed to allocate a buffer of size %d", len);
+		WARN_ON(1);
 		return NULL;
 	}
 
-- 
2.30.2