From d3ced2a59a543b3c3fc7dee2e64ee360e9a698cd Mon Sep 17 00:00:00 2001 From: Shu-Chun Weng Date: Wed, 26 Jan 2022 13:25:58 -0800 Subject: [PATCH] linux-user: rt_sigprocmask, check read perms first Linux kernel does it this way (checks read permission before validating `how`) and the latest version of ABSL's `AddressIsReadable()` depends on this behavior. c.f. https://github.com/torvalds/linux/blob/9539ba4308ad5bdca6cb41c7b73cbb9f796dcdd7/kernel/signal.c#L3147 Reviewed-by: Patrick Venture Signed-off-by: Shu-Chun Weng Reviewed-by: Laurent Vivier Signed-off-by: Patrick Venture Message-Id: <20220126212559.1936290-2-venture@google.com> Signed-off-by: Laurent Vivier --- linux-user/syscall.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 2ca0f086db..9f8b497fa3 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -9478,6 +9478,13 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1, } if (arg2) { + p = lock_user(VERIFY_READ, arg2, sizeof(target_sigset_t), 1); + if (!p) { + return -TARGET_EFAULT; + } + target_to_host_sigset(&set, p); + unlock_user(p, arg2, 0); + set_ptr = &set; switch(how) { case TARGET_SIG_BLOCK: how = SIG_BLOCK; @@ -9491,11 +9498,6 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1, default: return -TARGET_EINVAL; } - if (!(p = lock_user(VERIFY_READ, arg2, sizeof(target_sigset_t), 1))) - return -TARGET_EFAULT; - target_to_host_sigset(&set, p); - unlock_user(p, arg2, 0); - set_ptr = &set; } else { how = 0; set_ptr = NULL;