diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2019-08-29 10:24:45 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-09-21 07:15:44 +0200 |
| commit | 771c5c0955f14fc9bdf9f27ad4a25f8632f4a54e (patch) | |
| tree | 301a4517ffcb4cae33731135b3ce7fe2b883186b /arch/x86/include | |
| parent | 053a30de97e4972366e19e77d16da22e76fbacf6 (diff) | |
x86/uaccess: Don't leak the AC flags into __get_user() argument evaluation
[ Upstream commit 9b8bd476e78e89c9ea26c3b435ad0201c3d7dbf5 ]
Identical to __put_user(); the __get_user() argument evalution will too
leak UBSAN crud into the __uaccess_begin() / __uaccess_end() region.
While uncommon this was observed to happen for:
drivers/xen/gntdev.c: if (__get_user(old_status, batch->status[i]))
where UBSAN added array bound checking.
This complements commit:
6ae865615fc4 ("x86/uaccess: Dont leak the AC flag into __put_user() argument evaluation")
Tested-by Sedat Dilek <sedat.dilek@gmail.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: broonie@kernel.org
Cc: sfr@canb.auug.org.au
Cc: akpm@linux-foundation.org
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: mhocko@suse.cz
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20190829082445.GM2369@hirez.programming.kicks-ass.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/uaccess.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 4111edb3188e..971830341061 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -451,8 +451,10 @@ do { \ ({ \ int __gu_err; \ __inttype(*(ptr)) __gu_val; \ + __typeof__(ptr) __gu_ptr = (ptr); \ + __typeof__(size) __gu_size = (size); \ __uaccess_begin_nospec(); \ - __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \ + __get_user_size(__gu_val, __gu_ptr, __gu_size, __gu_err, -EFAULT); \ __uaccess_end(); \ (x) = (__force __typeof__(*(ptr)))__gu_val; \ __builtin_expect(__gu_err, 0); \ |