After starting LoL with wine and pushing Play, a Windows opens where you can Login. After putting the Login credentials, League of Legends client throws "There is a problem with the certificate of this site. Do you want to continue anyway"? This is displayed several times in a sequence. Adding certificate to IE within wine does not resolve this. Last comment in this bugreport (https://bugs.winehq.org/show_bug.cgi?id=35264) states that wine uses Systems certificate store, thus a bug should be filed here.
emerge --info Portage 2.3.3 (python 2.7.12-final-0, default/linux/amd64/13.0/desktop/plasma, gcc-4.9.4, glibc-2.23-r3, 4.10.9-gentoo x86_64) ================================================================= System uname: Linux-4.10.9-gentoo-x86_64-Intel-R-_Core-TM-2_Duo_CPU_E8500_@_3.16GHz-with-gentoo-2.3 KiB Swap: 9767516 total, 9767516 free Timestamp of repository gentoo: Wed, 19 Apr 2017 18:00:01 +0000 sh bash 4.3_p48-r1 ld GNU ld (Gentoo 2.26.1 p1.0) 2.26.1 app-shells/bash: 4.3_p48-r1::gentoo dev-lang/perl: 5.22.3_rc4::gentoo dev-lang/python: 2.7.12::gentoo, 3.4.5::gentoo dev-util/cmake: 3.7.2::gentoo dev-util/pkgconfig: 0.28-r2::gentoo sys-apps/baselayout: 2.3::gentoo sys-apps/openrc: 0.23.2::gentoo sys-apps/sandbox: 2.10-r3::gentoo sys-devel/autoconf: 2.13::gentoo, 2.69::gentoo sys-devel/automake: 1.11.6-r1::gentoo, 1.12.6::gentoo, 1.15::gentoo sys-devel/binutils: 2.26.1::gentoo sys-devel/gcc: 4.9.4::gentoo sys-devel/gcc-config: 1.7.3::gentoo sys-devel/libtool: 2.4.6-r3::gentoo sys-devel/make: 4.2.1::gentoo sys-kernel/linux-headers: 4.4::gentoo (virtual/os-headers) sys-libs/glibc: 2.23-r3::gentoo Repositories: gentoo location: /usr/portage sync-type: rsync sync-uri: rsync://rsync.gentoo.org/gentoo-portage priority: -1000 x-portage location: /usr/local/portage masters: gentoo priority: 0 ACCEPT_KEYWORDS="amd64" ACCEPT_LICENSE="* -@EULA" CBUILD="x86_64-pc-linux-gnu" CFLAGS="-march=native -O2 -pipe" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/lib64/libreoffice/program/sofficerc /usr/share/config /usr/share/gnupg/qualified.txt" CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/dconf /etc/env.d /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo" CXXFLAGS="-march=native -O2 -pipe" DISTDIR="/usr/portage/distfiles" FCFLAGS="-O2 -pipe" FEATURES="assume-digests binpkg-logs buildpkg candy config-protect-if-modified distlocks ebuild-locks fixlafiles merge-sync news parallel-fetch preserve-libs protect-owned sandbox sfperms strict unknown-features-warn unmerge-logs unmerge-orphans userfetch userpriv usersandbox usersync xattr" FFLAGS="-O2 -pipe" GENTOO_MIRRORS="http://distfiles.gentoo.org" LANG="de_CH.UTF-8" LC_ALL="de_CH.UTF-8" LDFLAGS="-Wl,-O1 -Wl,--as-needed" MAKEOPTS="-j5" PKGDIR="/usr/portage/packages" PORTAGE_CONFIGROOT="/" PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --omit-dir-times --compress --force --whole-file --delete --stats --human-readable --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages --exclude=/.git" PORTAGE_TMPDIR="/var/tmp" USE="X a52 aac acl acpi alsa amd64 berkdb bluetooth branding bzip2 cairo cdda cdr cli consolekit cracklib crypt cups cxx d3d9 dbus declarative dri dri3 dts dvd dvdr emboss encode exif fam ffmpeg firefox flac fortran frei0r gdbm gif glamor gnutls gpm gtk iconv icu ipv6 jpeg kde kipi kwallet lcms ldap libnotify llvm lm_sensors mad mmx mmxext mng modules mp3 mp4 mpeg multilib ncurses nls nptl ocr ogg openal opencl opengl openmax openmp osmesa pam pango pcre pdf phonon plasma png policykit ppds pulseaudio qml qt3support qt4 qt5 readline realtime s3tc scanner sdl seccomp semantic-desktop session spell spice sse sse2 sse3 ssh ssl ssse3 staging startup-notification svg tcpd theora tiff truetype udev udisks unicode upower usb uxa vaapi vdpau vhost-net vorbis vpx webrtc-aec widgets wxwidgets x264 xattr xcb xcomposite xinerama xml xscreensaver xv xvid zlib" ABI_X86="64 32" ALSA_CARDS="hda-intel" APACHE2_MODULES="authn_core authz_core socache_shmcb unixd actions alias auth_basic authn_alias authn_anon authn_dbm authn_default authn_file authz_dbm authz_default authz_groupfile authz_host authz_owner authz_user autoindex cache cgi cgid dav dav_fs dav_lock deflate dir disk_cache env expires ext_filter file_cache filter headers include info log_config logio mem_cache mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias" CALLIGRA_FEATURES="kexi words flow plan sheets stage tables krita karbon braindump author" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" CPU_FLAGS_X86="mmx mmxext smp sse sse2 sse3 sse4_1 ssse3" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock isync itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf skytraq superstar2 timing tsip tripmate tnt ublox ubx" INPUT_DEVICES="evdev" KERNEL="linux" L10N="de el en fr it tr" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" LINGUAS="de de_DE el en fr fr_FR it tr" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php5-6" PYTHON_SINGLE_TARGET="python3_4" PYTHON_TARGETS="python2_7 python3_4" RUBY_TARGETS="ruby21 ruby22" SANE_BACKENDS="pixma" USERLAND="GNU" VIDEO_CARDS="amdgpu radeon radeonsi intel i965" XFCE_PLUGINS="clock power multiload-nandhp trash" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq steal rawnat logmark ipmark dhcpmac delude chaos account" Unset: CC, CPPFLAGS, CTARGET, CXX, EMERGE_DEFAULT_OPTS, INSTALL_MASK, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS, USE_PYTHON
What version of app-misc/ca-certificates do you have installed? The upstream bug you referenced indicates this is not a wine bug, but a distro certificate bug. Passing it along to base system, who maintains the package of CA certificates.
app-misc/ca-certificates Latest version available: 20161102.3.27.2-r2 Latest version installed: 20161102.3.27.2-r2 Size of files: 7'516 KiB Homepage: http://packages.debian.org/sid/ca-certificates Description: Common CA Certificates PEM files License: MPL-1.1
New LoL client does not suffer from this, so I guess this is solved.