From 70cfb8f7762b9e40341583009e49c2b728eea254 Mon Sep 17 00:00:00 2001
From: Eric Sandeen <sandeen@redhat.com>
Date: Tue, 6 Jul 2021 19:56:03 +0200
Subject: [PATCH] [PATCH] seq_file: Disallow extremely large seq buffer
 allocations

There is no reasonable need for a buffer larger than this,
and it avoids int overflow pitfalls.

Fixes: 058504edd026 ("fs/seq_file: fallback to vmalloc allocation")
Reported-by: Qualys Security Advisory <qsa@qualys.com>
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>

Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name seq_file-Disallow-extremely-large-seq-buffer-allocat.patch
---
 fs/seq_file.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/seq_file.c b/fs/seq_file.c
index 03a369ccd28..472714716be 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -32,6 +32,9 @@ static void seq_set_overflow(struct seq_file *m)
 
 static void *seq_buf_alloc(unsigned long size)
 {
+	if (unlikely(size > MAX_RW_COUNT))
+		return NULL;
+
 	return kvmalloc(size, GFP_KERNEL_ACCOUNT);
 }
 
-- 
2.30.2