[PATCH] MIPS: Fix bounds check virt_addr_valid

From: Hauke Mehrtens <hauke@hauke-m.de>
To: paul.burton@mips.com
Cc: ralf@linux-mips.org, jhogan@kernel.org, f4bug@amsat.org,
	linux-mips@vger.kernel.org, ysu@wavecomp.com,
	jcristau@debian.org, Hauke Mehrtens <hauke@hauke-m.de>,
	stable@vger.kernel.org
Subject: [PATCH] MIPS: Fix bounds check virt_addr_valid
Date: Mon, 17 Jun 2019 00:30:39 +0200	[thread overview]
Message-ID: <20190616223039.28158-1-hauke@hauke-m.de> (raw)

The bounds check used the uninitialized variable vaddr, it should use
the given parameter kaddr instead. When using the uninitialized value
the compiler assumed it to be 0 and optimized this function to just
return 0 in all cases.

This should make the function check the range of the given address and
only do the page map check in case it is in the expected range of
virtual addresses.

Fixes: 074a1e1167af ("MIPS: Bounds check virt_addr_valid")
Cc: stable@vger.kernel.org # v4.12+
Cc: Paul Burton <paul.burton@mips.com>
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
---
 arch/mips/mm/mmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
index 50ee7213b432..d79f2b432318 100644
--- a/arch/mips/mm/mmap.c
+++ b/arch/mips/mm/mmap.c
@@ -203,7 +203,7 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
 
 bool __virt_addr_valid(const volatile void *kaddr)
 {
-	unsigned long vaddr = (unsigned long)vaddr;
+	unsigned long vaddr = (unsigned long)kaddr;
 
 	if ((vaddr < PAGE_OFFSET) || (vaddr >= MAP_BASE))
 		return false;
-- 
2.20.1

