kernel: Fix MIPS bounds check virt_addr_valid

This is pending to get into the upstream kernel.
This fixes a bug in the upstream kernel which was added to stable some
time ago.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

1 files changed, 33 insertions, 0 deletions

diff --git a/target/linux/generic/pending-4.14/303-MIPS-Fix-bounds-check-virt_addr_valid.patch b/target/linux/generic/pending-4.14/303-MIPS-Fix-bounds-check-virt_addr_valid.patch
new file mode 100644
index 0000000000..d4c3e66105
--- /dev/null
+++ b/target/linux/generic/pending-4.14/303-MIPS-Fix-bounds-check-virt_addr_valid.patch
@@ -0,0 +1,33 @@
+From 415e0feec4f927af0059f72a6831f6c5a104f0fc Mon Sep 17 00:00:00 2001
+From: Hauke Mehrtens <hauke@hauke-m.de>
+Date: Mon, 17 Jun 2019 00:13:08 +0200
+Subject: [PATCH] MIPS: Fix bounds check virt_addr_valid
+
+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(-)
+
+--- a/arch/mips/mm/mmap.c
++++ b/arch/mips/mm/mmap.c
+@@ -203,7 +203,7 @@ unsigned long arch_randomize_brk(struct
+ 
+ int __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 0;