diff options
| author | Arnd Bergmann <arnd@arndb.de> | 2024-05-28 14:58:03 +0000 |
|---|---|---|
| committer | Miguel Ojeda <ojeda@kernel.org> | 2024-07-08 23:44:01 +0200 |
| commit | 1f9a8286bc0c3df7d789ea625d9d9db3d7779f2d (patch) | |
| tree | 9abdf014774dd6862a8899462cf0ca472ed59863 /lib | |
| parent | 1b580e7b9ba2e5939c4b94da2cb4888605b39955 (diff) | |
uaccess: always export _copy_[from|to]_user with CONFIG_RUST
Rust code needs to be able to access _copy_from_user and _copy_to_user
so that it can skip the check_copy_size check in cases where the length
is known at compile-time, mirroring the logic for when C code will skip
check_copy_size. To do this, we ensure that exported versions of these
methods are available when CONFIG_RUST is enabled.
Alice has verified that this patch passes the CONFIG_TEST_USER_COPY test
on x86 using the Android cuttlefish emulator.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lore.kernel.org/r/20240528-alice-mm-v7-2-78222c31b8f4@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/usercopy.c | 30 |
1 files changed, 4 insertions, 26 deletions
diff --git a/lib/usercopy.c b/lib/usercopy.c index 499a7a7d54db..7b17b83c8042 100644 --- a/lib/usercopy.c +++ b/lib/usercopy.c @@ -12,40 +12,18 @@ /* out-of-line parts */ -#ifndef INLINE_COPY_FROM_USER +#if !defined(INLINE_COPY_FROM_USER) || defined(CONFIG_RUST) unsigned long _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))) { - /* - * 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); - return res; + return _inline_copy_from_user(to, from, n); } EXPORT_SYMBOL(_copy_from_user); #endif -#ifndef INLINE_COPY_TO_USER +#if !defined(INLINE_COPY_TO_USER) || defined(CONFIG_RUST) unsigned long _copy_to_user(void __user *to, const void *from, unsigned long n) { - might_fault(); - if (should_fail_usercopy()) - return n; - if (likely(access_ok(to, n))) { - instrument_copy_to_user(to, from, n); - n = raw_copy_to_user(to, from, n); - } - return n; + return _inline_copy_to_user(to, from, n); } EXPORT_SYMBOL(_copy_to_user); #endif |