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authorLennart Poettering <lennart@poettering.net>2012-05-29 23:33:38 +0200
committerLennart Poettering <lennart@poettering.net>2012-05-29 23:35:17 +0200
commit939b8f14dcd9312140d001b55b4e7a87173682ef (patch)
treebd67229d635bdff07e0a6b8e3da90d82eb00bd70 /src/shared
parent9246319f1fd9625a4a43883ae660ecd5ae41423a (diff)
capabilities: when dropping capabilities system-wide also drop them from usermode helpers
This hooks things up with /proc/sys/kernel/usermodehelper/bset and /proc/sys/kernel/usermodehelper/inheritable.
Diffstat (limited to 'src/shared')
-rw-r--r--src/shared/capability.c51
-rw-r--r--src/shared/capability.h3
2 files changed, 53 insertions, 1 deletions
diff --git a/src/shared/capability.c b/src/shared/capability.c
index 08b7a209da..9b743e86d0 100644
--- a/src/shared/capability.c
+++ b/src/shared/capability.c
@@ -171,3 +171,54 @@ finish:
return r;
}
+
+static int drop_from_file(const char *fn, uint64_t drop) {
+ int r, k;
+ uint32_t hi, lo;
+ uint64_t current, after;
+ char *p;
+
+ r = read_one_line_file(fn, &p);
+ if (r < 0)
+ return r;
+
+ assert_cc(sizeof(hi) == sizeof(unsigned));
+ assert_cc(sizeof(lo) == sizeof(unsigned));
+
+ k = sscanf(p, "%u %u", &lo, &hi);
+ free(p);
+
+ if (k != 2)
+ return -EIO;
+
+ current = (uint64_t) lo | ((uint64_t) hi << 32ULL);
+ after = current & ~drop;
+
+ if (current == after)
+ return 0;
+
+ lo = (unsigned) (after & 0xFFFFFFFFULL);
+ hi = (unsigned) ((after >> 32ULL) & 0xFFFFFFFFULL);
+
+ if (asprintf(&p, "%u %u", lo, hi) < 0)
+ return -ENOMEM;
+
+ r = write_one_line_file(fn, p);
+ free(p);
+
+ return r;
+}
+
+int capability_bounding_set_drop_usermode(uint64_t drop) {
+ int r;
+
+ r = drop_from_file("/proc/sys/kernel/usermodehelper/inheritable", drop);
+ if (r < 0)
+ return r;
+
+ r = drop_from_file("/proc/sys/kernel/usermodehelper/bset", drop);
+ if (r < 0)
+ return r;
+
+ return r;
+}
diff --git a/src/shared/capability.h b/src/shared/capability.h
index 0cc5dd08aa..6cb31bb510 100644
--- a/src/shared/capability.h
+++ b/src/shared/capability.h
@@ -27,6 +27,7 @@
unsigned long cap_last_cap(void);
int have_effective_cap(int value);
-int capability_bounding_set_drop(uint64_t caps, bool right_now);
+int capability_bounding_set_drop(uint64_t drop, bool right_now);
+int capability_bounding_set_drop_usermode(uint64_t drop);
#endif