From: Laurent Vivier <laurent@vivier.eu>
To: Stephen Long <steplong@quicinc.com>, qemu-devel@nongnu.org
Cc: riku.voipio@iki.fi, "Alex Bennée" <alex.bennee@linaro.org>,
apazos@quicinc.com
Subject: Re: [PATCH v2] Fix stack smashing when handling PR_GET_PDEATHSIG
Date: Thu, 7 May 2020 21:58:48 +0200 [thread overview]
Message-ID: <51c6917f-40f0-bf5d-19ff-f8fe5e079491@vivier.eu> (raw)
In-Reply-To: <20200507130302.3684-1-steplong@quicinc.com>
Le 07/05/2020 à 15:03, Stephen Long a écrit :
> The bug was triggered by the following code on aarch64-linux-user:
>
> #include <signal.h>
> #include <sys/prctl.h>
>
> int main(void)
> {
> int PDeathSig = 0;
> if (prctl(PR_GET_PDEATHSIG, &PDeathSig) == 0 && PDeathSig == SIGKILL)
> prctl(PR_GET_PDEATHSIG, 0);
> return (PDeathSig == SIGKILL);
> }
>
> Signed-off-by: Stephen Long <steplong@quicinc.com>
> Signed-off-by: Ana Pazos <apazos@quicinc.com>
> ---
>
> I fixed the incorrect subject line. PR_GETDEATHSIG should be PR_GET_PDEATHSIG.
> Is there a test folder where I can include the code that triggered the bug?
Perhaps Alex Bennée knows?
> Also, I thought "int" can be 2 bytes on some machines.
According to my K&R, 4th edition, it could be on 16bit systems, like
PDP-11, but we don't support them ;)
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
>
> linux-user/syscall.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 05f03919ff..91f91147ba 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -10256,7 +10256,7 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
> int deathsig;
> ret = get_errno(prctl(arg1, &deathsig, arg3, arg4, arg5));
> if (!is_error(ret) && arg2
> - && put_user_ual(deathsig, arg2)) {
> + && put_user_s32(deathsig, arg2)) {
> return -TARGET_EFAULT;
> }
> return ret;
>
next prev parent reply other threads:[~2020-05-07 19:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-07 13:03 [PATCH v2] Fix stack smashing when handling PR_GET_PDEATHSIG Stephen Long
2020-05-07 19:58 ` Laurent Vivier [this message]
2020-09-26 1:56 ` Re: [PATCH] " Stephen Long
2020-09-26 10:24 ` Laurent Vivier
2020-09-26 10:20 ` [PATCH v2] " Laurent Vivier
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