On Dec 30, 2014, at 11:48 PM, Andrew Pinski wrote:
>> If we have 64-bit kernel and 64-bit application is executed sys_getresuid is
>> used for getresuid syscall, otherwise if 32-bit application is executed --
>> sys_getresuid16 is used. Thus 64-bit application will never call
>> sys_getresuid16 implemenation. Then
>> getresuid16/getresgid16/getgroups16/setgroups16/etc only needs to in 32-bit
>> binary of libsanitizer. Same should apply for x86_64/i*86.
>> 
>> Is that correct?
> 
> Kinda.  It only applies for aarch32 and not for AARCH64:ILP32.
> AARCH64:ILP32 uses the standard system calls here too.


I am attaching an updated patch, bootstrapped trunk on arrch64 with kernels 3.12 and 3.17 (QEMU).

I looked at kernel source. If CONFIG_COMPAT is set then CONFIG_HAVE_UID16 is set.

From include/linux/syscalls.h

523 #ifdef CONFIG_UID16
524 asmlinkage long sys_chown16(const char __user *filename,
525                                 old_uid_t user, old_gid_t group);
526 asmlinkage long sys_lchown16(const char __user *filename,
527                                 old_uid_t user, old_gid_t group);
528 asmlinkage long sys_fchown16(unsigned int fd, old_uid_t user, old_gid_t group);
529 asmlinkage long sys_setregid16(old_gid_t rgid, old_gid_t egid);
530 asmlinkage long sys_setgid16(old_gid_t gid);
531 asmlinkage long sys_setreuid16(old_uid_t ruid, old_uid_t euid);
532 asmlinkage long sys_setuid16(old_uid_t uid);
533 asmlinkage long sys_setresuid16(old_uid_t ruid, old_uid_t euid, old_uid_t suid);
534 asmlinkage long sys_getresuid16(old_uid_t __user *ruid,
535                                 old_uid_t __user *euid, old_uid_t __user *suid);
536 asmlinkage long sys_setresgid16(old_gid_t rgid, old_gid_t egid, old_gid_t sgid);
537 asmlinkage long sys_getresgid16(old_gid_t __user *rgid,
538                                 old_gid_t __user *egid, old_gid_t __user *sgid);
539 asmlinkage long sys_setfsuid16(old_uid_t uid);
540 asmlinkage long sys_setfsgid16(old_gid_t gid);
541 asmlinkage long sys_getgroups16(int gidsetsize, old_gid_t __user *grouplist);
542 asmlinkage long sys_setgroups16(int gidsetsize, old_gid_t __user *grouplist);
543 asmlinkage long sys_getuid16(void);
544 asmlinkage long sys_geteuid16(void);
545 asmlinkage long sys_getgid16(void);
546 asmlinkage long sys_getegid16(void);
547 #endif

Thus I disabled such syscalls in libsanitizer with SANITIZER_WORDSIZE macro and disabled
type checks for __kernel_old_{uid,gid}_t. Did not touch the fragment which sets 
__kernel_old_{uid,gid}_t.

SANITIZER_WORDSIZE is set based on _LP64 macro.

If patch is acceptable I could do more tests after holidays.

Thanks,
david