diff options
Diffstat (limited to 'include/linux/uaccess.h')
| -rw-r--r-- | include/linux/uaccess.h | 28 |
1 files changed, 22 insertions, 6 deletions
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index d8e4105a2f21..43844510d5d0 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -33,6 +33,14 @@ }) #endif +#ifdef masked_user_access_begin + #define can_do_masked_user_access() 1 +#else + #define can_do_masked_user_access() 0 + #define masked_user_access_begin(src) NULL + #define mask_user_address(src) (src) +#endif + /* * Architectures should provide two primitives (raw_copy_{to,from}_user()) * and get rid of their private instances of copy_{to,from}_user() and @@ -152,19 +160,27 @@ _inline_copy_from_user(void *to, const void __user *from, unsigned long n) { unsigned long res = n; might_fault(); - if (!should_fail_usercopy() && likely(access_ok(from, n))) { + if (should_fail_usercopy()) + goto fail; + if (can_do_masked_user_access()) + from = mask_user_address(from); + else { + if (!access_ok(from, n)) + goto fail; /* * Ensure that bad access_ok() speculation will not * lead to nasty side effects *after* the copy is * finished: */ barrier_nospec(); - instrument_copy_from_user_before(to, from, n); - res = raw_copy_from_user(to, from, n); - instrument_copy_from_user_after(to, from, n, res); } - if (unlikely(res)) - memset(to + (n - res), 0, res); + instrument_copy_from_user_before(to, from, n); + res = raw_copy_from_user(to, from, n); + instrument_copy_from_user_after(to, from, n, res); + if (likely(!res)) + return 0; +fail: + memset(to + (n - res), 0, res); return res; } extern __must_check unsigned long |