uaccess: Selectively open read or write user access
When opening user access to only perform reads, only open read access.
When opening user access to only perform writes, only open write
access.
Signed-off-by: Christophe Leroy <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/2e73bc57125c2c6ab12a587586a4eed3a47105fc.1585898438.git.christophe.leroy@c-s.fr
diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c
index 706020b..b90ec55 100644
--- a/lib/strncpy_from_user.c
+++ b/lib/strncpy_from_user.c
@@ -116,9 +116,9 @@ long strncpy_from_user(char *dst, const char __user *src, long count)
kasan_check_write(dst, count);
check_object_size(dst, count, false);
- if (user_access_begin(src, max)) {
+ if (user_read_access_begin(src, max)) {
retval = do_strncpy_from_user(dst, src, count, max);
- user_access_end();
+ user_read_access_end();
return retval;
}
}
diff --git a/lib/strnlen_user.c b/lib/strnlen_user.c
index 41670d4..1616710 100644
--- a/lib/strnlen_user.c
+++ b/lib/strnlen_user.c
@@ -109,9 +109,9 @@ long strnlen_user(const char __user *str, long count)
if (max > count)
max = count;
- if (user_access_begin(str, max)) {
+ if (user_read_access_begin(str, max)) {
retval = do_strnlen_user(str, count, max);
- user_access_end();
+ user_read_access_end();
return retval;
}
}
diff --git a/lib/usercopy.c b/lib/usercopy.c
index cbb4d9e..ca2a697 100644
--- a/lib/usercopy.c
+++ b/lib/usercopy.c
@@ -58,7 +58,7 @@ int check_zeroed_user(const void __user *from, size_t size)
from -= align;
size += align;
- if (!user_access_begin(from, size))
+ if (!user_read_access_begin(from, size))
return -EFAULT;
unsafe_get_user(val, (unsigned long __user *) from, err_fault);
@@ -79,10 +79,10 @@ int check_zeroed_user(const void __user *from, size_t size)
val &= aligned_byte_mask(size);
done:
- user_access_end();
+ user_read_access_end();
return (val == 0);
err_fault:
- user_access_end();
+ user_read_access_end();
return -EFAULT;
}
EXPORT_SYMBOL(check_zeroed_user);
