From 51977e25f77faae6949c7eb51c86f0319b82a77d Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Tue, 12 Mar 2019 19:22:20 -0700 Subject: [PATCH] linux-user/aarch64: Use qemu_guest_getrandom for PAUTH keys MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Use a better interface for random numbers than rand() * 3. Reviewed-by: Laurent Vivier Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Richard Henderson --- linux-user/aarch64/cpu_loop.c | 29 ++++++----------------------- linux-user/aarch64/target_syscall.h | 2 -- linux-user/syscall.c | 31 ++++++++++++++++++++++++++----- 3 files changed, 32 insertions(+), 30 deletions(-) diff --git a/linux-user/aarch64/cpu_loop.c b/linux-user/aarch64/cpu_loop.c index d75fd9d3e2..cedad39ca0 100644 --- a/linux-user/aarch64/cpu_loop.c +++ b/linux-user/aarch64/cpu_loop.c @@ -20,6 +20,7 @@ #include "qemu/osdep.h" #include "qemu.h" #include "cpu_loop-common.h" +#include "qemu/guest-random.h" #define get_user_code_u32(x, gaddr, env) \ ({ abi_long __r = get_user_u32((x), (gaddr)); \ @@ -147,24 +148,6 @@ void cpu_loop(CPUARMState *env) } } -static uint64_t arm_rand64(void) -{ - int shift = 64 - clz64(RAND_MAX); - int i, n = 64 / shift + (64 % shift != 0); - uint64_t ret = 0; - - for (i = 0; i < n; i++) { - ret = (ret << shift) | rand(); - } - return ret; -} - -void arm_init_pauth_key(ARMPACKey *key) -{ - key->lo = arm_rand64(); - key->hi = arm_rand64(); -} - void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs) { ARMCPU *cpu = arm_env_get_cpu(env); @@ -192,11 +175,11 @@ void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs) #endif if (cpu_isar_feature(aa64_pauth, cpu)) { - arm_init_pauth_key(&env->apia_key); - arm_init_pauth_key(&env->apib_key); - arm_init_pauth_key(&env->apda_key); - arm_init_pauth_key(&env->apdb_key); - arm_init_pauth_key(&env->apga_key); + qemu_guest_getrandom_nofail(&env->apia_key, sizeof(ARMPACKey)); + qemu_guest_getrandom_nofail(&env->apib_key, sizeof(ARMPACKey)); + qemu_guest_getrandom_nofail(&env->apda_key, sizeof(ARMPACKey)); + qemu_guest_getrandom_nofail(&env->apdb_key, sizeof(ARMPACKey)); + qemu_guest_getrandom_nofail(&env->apga_key, sizeof(ARMPACKey)); } ts->stack_base = info->start_stack; diff --git a/linux-user/aarch64/target_syscall.h b/linux-user/aarch64/target_syscall.h index b595e5da82..995e475c73 100644 --- a/linux-user/aarch64/target_syscall.h +++ b/linux-user/aarch64/target_syscall.h @@ -29,6 +29,4 @@ struct target_pt_regs { # define TARGET_PR_PAC_APDBKEY (1 << 3) # define TARGET_PR_PAC_APGAKEY (1 << 4) -void arm_init_pauth_key(ARMPACKey *key); - #endif /* AARCH64_TARGET_SYSCALL_H */ diff --git a/linux-user/syscall.c b/linux-user/syscall.c index f3ea9cac21..72e43b517a 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -108,6 +108,7 @@ #include "qemu.h" #include "qemu/guest-random.h" +#include "qapi/error.h" #include "fd-trans.h" #ifndef CLONE_IO @@ -9765,25 +9766,45 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1, int all = (TARGET_PR_PAC_APIAKEY | TARGET_PR_PAC_APIBKEY | TARGET_PR_PAC_APDAKEY | TARGET_PR_PAC_APDBKEY | TARGET_PR_PAC_APGAKEY); + int ret = 0; + Error *err = NULL; + if (arg2 == 0) { arg2 = all; } else if (arg2 & ~all) { return -TARGET_EINVAL; } if (arg2 & TARGET_PR_PAC_APIAKEY) { - arm_init_pauth_key(&env->apia_key); + ret |= qemu_guest_getrandom(&env->apia_key, + sizeof(ARMPACKey), &err); } if (arg2 & TARGET_PR_PAC_APIBKEY) { - arm_init_pauth_key(&env->apib_key); + ret |= qemu_guest_getrandom(&env->apib_key, + sizeof(ARMPACKey), &err); } if (arg2 & TARGET_PR_PAC_APDAKEY) { - arm_init_pauth_key(&env->apda_key); + ret |= qemu_guest_getrandom(&env->apda_key, + sizeof(ARMPACKey), &err); } if (arg2 & TARGET_PR_PAC_APDBKEY) { - arm_init_pauth_key(&env->apdb_key); + ret |= qemu_guest_getrandom(&env->apdb_key, + sizeof(ARMPACKey), &err); } if (arg2 & TARGET_PR_PAC_APGAKEY) { - arm_init_pauth_key(&env->apga_key); + ret |= qemu_guest_getrandom(&env->apga_key, + sizeof(ARMPACKey), &err); + } + if (ret != 0) { + /* + * Some unknown failure in the crypto. The best + * we can do is log it and fail the syscall. + * The real syscall cannot fail this way. + */ + qemu_log_mask(LOG_UNIMP, + "PR_PAC_RESET_KEYS: Crypto failure: %s", + error_get_pretty(err)); + error_free(err); + return -TARGET_EIO; } return 0; } -- 2.11.0