[v4,5/7] lib, arm64: untag addrs passed to strncpy_from_user and strnlen_user
diff mbox

Message ID 8ccd13e2d13dea7143bd8b5be44b733c03aa3c02.1529507994.git.andreyknvl@google.com
State New
Headers show

Commit Message

Andrey Konovalov June 20, 2018, 3:24 p.m. UTC
strncpy_from_user and strnlen_user accept user addresses as arguments, and
do not go through the same path as copy_from_user and others, so here we
need to handle the case of tagged user addresses separately.

Untag user pointers passed to these functions.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 lib/strncpy_from_user.c | 2 ++
 lib/strnlen_user.c      | 2 ++
 2 files changed, 4 insertions(+)

Patch
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diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c
index b53e1b5d80f4..97467cd2bc59 100644
--- a/lib/strncpy_from_user.c
+++ b/lib/strncpy_from_user.c
@@ -106,6 +106,8 @@  long strncpy_from_user(char *dst, const char __user *src, long count)
 	if (unlikely(count <= 0))
 		return 0;
 
+	src = untagged_addr(src);
+
 	max_addr = user_addr_max();
 	src_addr = (unsigned long)src;
 	if (likely(src_addr < max_addr)) {
diff --git a/lib/strnlen_user.c b/lib/strnlen_user.c
index 60d0bbda8f5e..8b5f56466e00 100644
--- a/lib/strnlen_user.c
+++ b/lib/strnlen_user.c
@@ -108,6 +108,8 @@  long strnlen_user(const char __user *str, long count)
 	if (unlikely(count <= 0))
 		return 0;
 
+	str = untagged_addr(str);
+
 	max_addr = user_addr_max();
 	src_addr = (unsigned long)str;
 	if (likely(src_addr < max_addr)) {