Remove libcap support

This is simply a false sense of security, and is worse than just using
setuid. CAP_SYS_ADMIN is an extremely serious capability that is
effectively as powerful as root.

It also required users to be in the input group, which allows any
process to keylog the entire system.
This commit is contained in:
Scott Anderson 2020-04-28 20:44:05 +12:00 committed by Simon Ser
parent 98d949718c
commit 906c0766df
8 changed files with 1 additions and 45 deletions

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@ -2,7 +2,6 @@ image: alpine/edge
packages: packages:
- eudev-dev - eudev-dev
- ffmpeg-dev - ffmpeg-dev
- libcap-dev
- libinput-dev - libinput-dev
- libxkbcommon-dev - libxkbcommon-dev
- mesa-dev - mesa-dev

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@ -2,7 +2,6 @@ image: archlinux
packages: packages:
- clang - clang
- ffmpeg - ffmpeg
- libcap
- libinput - libinput
- libxkbcommon - libxkbcommon
- mesa - mesa

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@ -23,5 +23,5 @@ sources:
tasks: tasks:
- wlroots: | - wlroots: |
cd wlroots cd wlroots
meson build -Dauto_features=enabled -Dlogind=disabled -Dlibcap=disabled meson build -Dauto_features=enabled -Dlogind=disabled
ninja -C build ninja -C build

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@ -55,7 +55,6 @@ Install dependencies:
* pixman * pixman
* systemd (optional, for logind support) * systemd (optional, for logind support)
* elogind (optional, for logind support on systems without systemd) * elogind (optional, for logind support on systems without systemd)
* libcap (optional, for capability support)
If you choose to enable X11 support: If you choose to enable X11 support:

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@ -24,23 +24,6 @@
enum { DRM_MAJOR = 226 }; enum { DRM_MAJOR = 226 };
#if WLR_HAS_LIBCAP
#include <sys/capability.h>
static bool have_permissions(void) {
cap_t cap = cap_get_proc();
cap_flag_value_t val;
if (!cap || cap_get_flag(cap, CAP_SYS_ADMIN, CAP_PERMITTED, &val) || val != CAP_SET) {
wlr_log(WLR_ERROR, "Do not have CAP_SYS_ADMIN; cannot become DRM master");
cap_free(cap);
return false;
}
cap_free(cap);
return true;
}
#else
static bool have_permissions(void) { static bool have_permissions(void) {
#ifdef __linux__ #ifdef __linux__
if (geteuid() != 0) { if (geteuid() != 0) {
@ -50,7 +33,6 @@ static bool have_permissions(void) {
#endif #endif
return true; return true;
} }
#endif
static void send_msg(int sock, int fd, void *buf, size_t buf_len) { static void send_msg(int sock, int fd, void *buf, size_t buf_len) {
char control[CMSG_SPACE(sizeof(fd))] = {0}; char control[CMSG_SPACE(sizeof(fd))] = {0};

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@ -62,23 +62,3 @@ if logind_found
wlr_files += files('logind.c') wlr_files += files('logind.c')
wlr_deps += logind wlr_deps += logind
endif endif
# libcap
msg = []
if get_option('libcap').enabled()
msg += 'Install "libcap" or pass "-Dlibcap=disabled".'
endif
if not get_option('libcap').disabled()
msg += 'Required for POSIX capability support (Not needed if using logind).'
endif
libcap = dependency('libcap',
required: get_option('libcap'),
not_found_message: '\n'.join(msg),
)
if libcap.found()
conf_data.set10('WLR_HAS_LIBCAP', true)
wlr_deps += libcap
endif

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@ -80,7 +80,6 @@ else
endif endif
conf_data = configuration_data() conf_data = configuration_data()
conf_data.set10('WLR_HAS_LIBCAP', false)
conf_data.set10('WLR_HAS_SYSTEMD', false) conf_data.set10('WLR_HAS_SYSTEMD', false)
conf_data.set10('WLR_HAS_ELOGIND', false) conf_data.set10('WLR_HAS_ELOGIND', false)
conf_data.set10('WLR_HAS_X11_BACKEND', false) conf_data.set10('WLR_HAS_X11_BACKEND', false)
@ -170,7 +169,6 @@ wlroots = declare_dependency(
meson.override_dependency('wlroots', wlroots) meson.override_dependency('wlroots', wlroots)
summary({ summary({
'libcap': conf_data.get('WLR_HAS_LIBCAP', 0),
'systemd': conf_data.get('WLR_HAS_SYSTEMD', 0), 'systemd': conf_data.get('WLR_HAS_SYSTEMD', 0),
'elogind': conf_data.get('WLR_HAS_ELOGIND', 0), 'elogind': conf_data.get('WLR_HAS_ELOGIND', 0),
'xwayland': conf_data.get('WLR_HAS_XWAYLAND', 0), 'xwayland': conf_data.get('WLR_HAS_XWAYLAND', 0),

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@ -1,4 +1,3 @@
option('libcap', type: 'feature', value: 'auto', description: 'Enable support for rootless session via capabilities (cap_sys_admin)')
option('logind', type: 'feature', value: 'auto', description: 'Enable support for rootless session via logind') option('logind', type: 'feature', value: 'auto', description: 'Enable support for rootless session via logind')
option('logind-provider', type: 'combo', choices: ['auto', 'systemd', 'elogind'], value: 'auto', description: 'Provider of logind support library') option('logind-provider', type: 'combo', choices: ['auto', 'systemd', 'elogind'], value: 'auto', description: 'Provider of logind support library')
option('xcb-errors', type: 'feature', value: 'auto', description: 'Use xcb-errors util library') option('xcb-errors', type: 'feature', value: 'auto', description: 'Use xcb-errors util library')