[v2] Add getsockopt for settable SOL_IPV6 options

From: Tom Deseyn <tom.deseyn@gmail.com>

Signed-off-by: Tom Deseyn <tom.deseyn@gmail.com>
---
 linux-user/syscall.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

On 13/12/2018 14:37, tom.deseyn@gmail.com wrote:
> From: Tom Deseyn <tom.deseyn@gmail.com>
> 
> Signed-off-by: Tom Deseyn <tom.deseyn@gmail.com>
> ---

Please add here an history of the changes between the version 1 and 2:

v2: ?????

>  linux-user/syscall.c | 38 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 38 insertions(+)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 280137da8c..ad52cfbd54 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -2352,6 +2352,44 @@ static abi_long do_getsockopt(int sockfd, int level, int optname,
>              break;
>          }
>          break;
> +    case SOL_IPV6:
> +        switch (optname) {
> +        case IPV6_MTU_DISCOVER:
> +        case IPV6_MTU:
> +        case IPV6_V6ONLY:
> +        case IPV6_RECVPKTINFO:
> +        case IPV6_UNICAST_HOPS:
> +        case IPV6_MULTICAST_HOPS:
> +        case IPV6_MULTICAST_LOOP:
> +        case IPV6_RECVERR:
> +        case IPV6_RECVHOPLIMIT:
> +        case IPV6_2292HOPLIMIT:
> +        case IPV6_CHECKSUM:
> +            if (get_user_u32(len, optlen))
> +                return -TARGET_EFAULT;
> +            if (len < 0)
> +                return -TARGET_EINVAL;
> +            lv = sizeof(lv);
> +            ret = get_errno(getsockopt(sockfd, level, optname, &val, &lv));
> +            if (ret < 0)
> +                return ret;
> +            if (len < sizeof(int) && len > 0 && val >= 0 && val < 255) {
> +                len = 1;
> +                if (put_user_u32(len, optlen)
> +                    || put_user_u8(val, optval_addr))
> +                    return -TARGET_EFAULT;
> +            } else {
> +                if (len > sizeof(int))
> +                    len = sizeof(int);
> +                if (put_user_u32(len, optlen)
> +                    || put_user_u32(val, optval_addr))
> +                    return -TARGET_EFAULT;
> +            }

This way to compute the size of the result is good for SOL_IP, but not
for SOL_IPV6, in kernel do_ip_getsockopt() we have:

       if (len < sizeof(int) && len > 0 && val >= 0 && val <= 255) {
                unsigned char ucval = (unsigned char)val;
                len = 1;
                if (put_user(len, optlen))
                        return -EFAULT;
                if (copy_to_user(optval, &ucval, 1))
                        return -EFAULT;
        } else {
                len = min_t(unsigned int, sizeof(int), len);
                if (put_user(len, optlen))
                        return -EFAULT;
                if (copy_to_user(optval, &val, len))
                        return -EFAULT;
        }

Whereas in kernel do_ipv6_getsockopt():

        default:
                return -ENOPROTOOPT;
        }
        len = min_t(unsigned int, sizeof(int), len);
        if (put_user(len, optlen))
                return -EFAULT;
        if (copy_to_user(optval, &val, len))
                return -EFAULT;
        return 0;


So in QEMU for SOL_IPV6 to mimic this I think you should use something like:

    len = min(lv, sizeof(val));
    if (put_user_u32(len, optlen) {
         return -TARGET_EFAULT;
    }
    target_addr =  lock_user(VERIFY_WRITE, optval_addr, len, 0);
    tswap32s(&val);
    memcpy(target_addr, &val, len);
    unlock_user(target_addr, optval_addr, len);

Thanks,
Laurent

Patchew URL: https://patchew.org/QEMU/20181213133733.8110-1-tom.deseyn@gmail.com/



Hi,

This series seems to have some coding style problems. See output below for
more information:

Type: series
Message-id: 20181213133733.8110-1-tom.deseyn@gmail.com
Subject: [Qemu-devel] [PATCH v2] Add getsockopt for settable SOL_IPV6 options

=== TEST SCRIPT BEGIN ===
#!/bin/bash

BASE=base
n=1
total=$(git log --oneline $BASE.. | wc -l)
failed=0

git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram

commits="$(git log --format=%H --reverse $BASE..)"
for c in $commits; do
    echo "Checking PATCH $n/$total: $(git log -n 1 --format=%s $c)..."
    if ! git show $c --format=email | ./scripts/checkpatch.pl --mailback -; then
        failed=1
        echo
    fi
    n=$((n+1))
done

exit $failed
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
Switched to a new branch 'test'
c7f204a Add getsockopt for settable SOL_IPV6 options

=== OUTPUT BEGIN ===
Checking PATCH 1/1: Add getsockopt for settable SOL_IPV6 options...
ERROR: braces {} are necessary for all arms of this statement
#30: FILE: linux-user/syscall.c:2368:
+            if (get_user_u32(len, optlen))
[...]

ERROR: braces {} are necessary for all arms of this statement
#32: FILE: linux-user/syscall.c:2370:
+            if (len < 0)
[...]

ERROR: braces {} are necessary for all arms of this statement
#36: FILE: linux-user/syscall.c:2374:
+            if (ret < 0)
[...]

ERROR: braces {} are necessary for all arms of this statement
#44: FILE: linux-user/syscall.c:2382:
+                if (len > sizeof(int))
[...]

total: 4 errors, 0 warnings, 44 lines checked

Your patch has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

=== OUTPUT END ===

Test command exited with code: 1


The full log is available at
http://patchew.org/logs/20181213133733.8110-1-tom.deseyn@gmail.com/testing.checkpatch/?type=message.
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