diff options
| author | Kees Cook <kees@kernel.org> | 2024-06-10 14:02:27 -0700 |
|---|---|---|
| committer | Dave Hansen <dave.hansen@linux.intel.com> | 2024-06-11 16:08:43 -0700 |
| commit | 8c860ed825cb85f6672cd7b10a8f33e3498a7c81 (patch) | |
| tree | 4753db8ce9f1f4d4a13b7bf738b3ff8f40359577 /arch | |
| parent | c625dabbf1c4a8e77e4734014f2fde7aa9071a1f (diff) | |
x86/uaccess: Fix missed zeroing of ia32 u64 get_user() range checking
When reworking the range checking for get_user(), the get_user_8() case
on 32-bit wasn't zeroing the high register. (The jump to bad_get_user_8
was accidentally dropped.) Restore the correct error handling
destination (and rename the jump to using the expected ".L" prefix).
While here, switch to using a named argument ("size") for the call
template ("%c4" to "%c[size]") as already used in the other call
templates in this file.
Found after moving the usercopy selftests to KUnit:
# usercopy_test_invalid: EXPECTATION FAILED at
lib/usercopy_kunit.c:278
Expected val_u64 == 0, but
val_u64 == -60129542144 (0xfffffff200000000)
Closes: https://lore.kernel.org/all/CABVgOSn=tb=Lj9SxHuT4_9MTjjKVxsq-ikdXC4kGHO4CfKVmGQ@mail.gmail.com
Fixes: b19b74bc99b1 ("x86/mm: Rework address range check in get_user() and put_user()")
Reported-by: David Gow <davidgow@google.com>
Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Tested-by: David Gow <davidgow@google.com>
Link: https://lore.kernel.org/all/20240610210213.work.143-kees%40kernel.org
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/uaccess.h | 4 | ||||
| -rw-r--r-- | arch/x86/lib/getuser.S | 6 |
2 files changed, 7 insertions, 3 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 0f9bab92a43d..3a7755c1a441 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -78,10 +78,10 @@ extern int __get_user_bad(void); int __ret_gu; \ register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \ __chk_user_ptr(ptr); \ - asm volatile("call __" #fn "_%c4" \ + asm volatile("call __" #fn "_%c[size]" \ : "=a" (__ret_gu), "=r" (__val_gu), \ ASM_CALL_CONSTRAINT \ - : "0" (ptr), "i" (sizeof(*(ptr)))); \ + : "0" (ptr), [size] "i" (sizeof(*(ptr)))); \ instrument_get_user(__val_gu); \ (x) = (__force __typeof__(*(ptr))) __val_gu; \ __builtin_expect(__ret_gu, 0); \ diff --git a/arch/x86/lib/getuser.S b/arch/x86/lib/getuser.S index 10d5ed8b5990..a1cb3a4e6742 100644 --- a/arch/x86/lib/getuser.S +++ b/arch/x86/lib/getuser.S @@ -44,7 +44,11 @@ or %rdx, %rax .else cmp $TASK_SIZE_MAX-\size+1, %eax +.if \size != 8 jae .Lbad_get_user +.else + jae .Lbad_get_user_8 +.endif sbb %edx, %edx /* array_index_mask_nospec() */ and %edx, %eax .endif @@ -154,7 +158,7 @@ SYM_CODE_END(__get_user_handle_exception) #ifdef CONFIG_X86_32 SYM_CODE_START_LOCAL(__get_user_8_handle_exception) ASM_CLAC -bad_get_user_8: +.Lbad_get_user_8: xor %edx,%edx xor %ecx,%ecx mov $(-EFAULT),%_ASM_AX |