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Re: [PATCH v2] linux-user: Correct host errno for IP[V6]_RECVERR socket
From: |
Laurent Vivier |
Subject: |
Re: [PATCH v2] linux-user: Correct host errno for IP[V6]_RECVERR socket options |
Date: |
Mon, 13 Sep 2021 21:17:43 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 |
Le 11/09/2021 à 19:08, Philippe Mathieu-Daudé a écrit :
> Host errno must be converted to target errno in IP_RECVERR
> and IPV6_RECVERR socket options.
>
> Fixes: ee1ac3a1822 ("linux-user: Add sockopts for IPv6")
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/602
> Reported-by: Conrad Meyer <cem@FreeBSD.org>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
> v2: Corrected patch description
> ---
> linux-user/syscall.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index ccd3892b2df..edc9d6b5ba2 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -1967,7 +1967,8 @@ static inline abi_long host_to_target_cmsg(struct
> target_msghdr *target_msgh,
> tgt_len != sizeof(struct errhdr_t)) {
> goto unimplemented;
> }
> - __put_user(errh->ee.ee_errno, &target_errh->ee.ee_errno);
> + __put_user(get_errno(errh->ee.ee_errno),
> + &target_errh->ee.ee_errno);
> __put_user(errh->ee.ee_origin, &target_errh->ee.ee_origin);
> __put_user(errh->ee.ee_type, &target_errh->ee.ee_type);
> __put_user(errh->ee.ee_code, &target_errh->ee.ee_code);
> @@ -2011,7 +2012,8 @@ static inline abi_long host_to_target_cmsg(struct
> target_msghdr *target_msgh,
> tgt_len != sizeof(struct errhdr6_t)) {
> goto unimplemented;
> }
> - __put_user(errh->ee.ee_errno, &target_errh->ee.ee_errno);
> + __put_user(get_errno(errh->ee.ee_errno),
> + &target_errh->ee.ee_errno);
> __put_user(errh->ee.ee_origin, &target_errh->ee.ee_origin);
> __put_user(errh->ee.ee_type, &target_errh->ee.ee_type);
> __put_user(errh->ee.ee_code, &target_errh->ee.ee_code);
>
I don't think it's the correct use of get_errno() here.
get_errno() is:
static inline abi_long get_errno(abi_long ret)
{
if (ret == -1)
return -host_to_target_errno(errno);
else
return ret;
}
and ee_errno is:
struct sock_extended_err {
__u32 ee_errno;
__u8 ee_origin;
__u8 ee_type;
__u8 ee_code;
__u8 ee_pad;
__u32 ee_info;
union {
__u32 ee_data;
struct sock_ee_data_rfc4884 ee_rfc4884;
};
};
https://man7.org/linux/man-pages/man7/ip.7.html
ee_errno contains the errno number of the queued error.
so ee_errno is never negative.
You should use "host_to_target_errno(errh->ee.ee_errno)"
Thanks,
Laurent