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: 058504e ("fs/seq_file: fallback to vmalloc allocation") Suggested-by: Al Viro <[email protected]> Reported-by: Qualys Security Advisory <[email protected]> Signed-off-by: Eric Sandeen <[email protected]> Cc: [email protected] Signed-off-by: Linus Torvalds <[email protected]>
vieko · Jul 20, 2021 · 8cae8cd · 8cae8cd
1 parent 2734d6c
commit 8cae8cd
Showing 1 changed file with 3 additions and 0 deletions.
diff --git 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);
 }