diff options
| author |   Catalin Marinas <catalin.marinas@arm.com> | 2019-07-23 19:58:39 +0200 |
|---|---|---|
| committer |   Will Deacon <will@kernel.org> | 2019-08-06 18:08:45 +0100 |
| commit | 63f0c60379650d82250f22e4cf4137ef3dc4f43d (patch) | |
| tree | af76cdc5d0eeca023d86c43664d073af25d63546 /kernel/sys.c | |
| parent | arm64: untag user pointers in access_ok and __uaccess_mask_ptr (diff) | |
| download | linux-dev-63f0c60379650d82250f22e4cf4137ef3dc4f43d.tar.xz linux-dev-63f0c60379650d82250f22e4cf4137ef3dc4f43d.zip | |
arm64: Introduce prctl() options to control the tagged user addresses ABI
It is not desirable to relax the ABI to allow tagged user addresses into
the kernel indiscriminately. This patch introduces a prctl() interface
for enabling or disabling the tagged ABI with a global sysctl control
for preventing applications from enabling the relaxed ABI (meant for
testing user-space prctl() return error checking without reconfiguring
the kernel). The ABI properties are inherited by threads of the same
application and fork()'ed children but cleared on execve(). A Kconfig
option allows the overall disabling of the relaxed ABI.
The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
MTE-specific settings like imprecise vs precise exceptions.
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'kernel/sys.c')
| -rw-r--r-- | kernel/sys.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/kernel/sys.c b/kernel/sys.c index 2969304c29fe..c6c4d5358bd3 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -124,6 +124,12 @@ #ifndef PAC_RESET_KEYS # define PAC_RESET_KEYS(a, b) (-EINVAL) #endif +#ifndef SET_TAGGED_ADDR_CTRL +# define SET_TAGGED_ADDR_CTRL(a) (-EINVAL) +#endif +#ifndef GET_TAGGED_ADDR_CTRL +# define GET_TAGGED_ADDR_CTRL() (-EINVAL) +#endif /* * this is where the system-wide overflow UID and GID are defined, for @@ -2492,6 +2498,12 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, return -EINVAL; error = PAC_RESET_KEYS(me, arg2); break; + case PR_SET_TAGGED_ADDR_CTRL: + error = SET_TAGGED_ADDR_CTRL(arg2); + break; + case PR_GET_TAGGED_ADDR_CTRL: + error = GET_TAGGED_ADDR_CTRL(); + break; default: error = -EINVAL; break; |