From: Ira Weiny <ira.weiny@intel.com>
Date: Sat, 4 Feb 2023 04:06:32 +0000 (-0800)
Subject: highmem: Enhance is_kmap_addr() to check kmap_local_page() mappings
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=f3837ab7adbc1799a3c5648d34e3e27eb70709a6;p=linux.git

highmem: Enhance is_kmap_addr() to check kmap_local_page() mappings

is_kmap_addr() is only looking at the kmap() address range which may
cause check_heap_object() to miss checking an overflow on a
kmap_local_page() page.

Add a check for the kmap_local_page() address range to is_kmap_addr().

Cc: Matthew Wilcox <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Andrew Morton <akpm@linux-foudation.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
---

diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h
index e098f38422af5..a3028e400a9c6 100644
--- a/include/linux/highmem-internal.h
+++ b/include/linux/highmem-internal.h
@@ -152,7 +152,10 @@ static inline void totalhigh_pages_add(long count)
 static inline bool is_kmap_addr(const void *x)
 {
 	unsigned long addr = (unsigned long)x;
-	return addr >= PKMAP_ADDR(0) && addr < PKMAP_ADDR(LAST_PKMAP);
+
+	return (addr >= PKMAP_ADDR(0) && addr < PKMAP_ADDR(LAST_PKMAP)) ||
+		(addr >= __fix_to_virt(FIX_KMAP_END) &&
+		 addr < __fix_to_virt(FIX_KMAP_BEGIN));
 }
 #else /* CONFIG_HIGHMEM */