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capabilities: keep bounding set in non-inverted format.

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Change the capability bounding set parser and logic so that the bounding
set is kept as a positive set internally. This means that the set
reflects those capabilities that we want to keep instead of drop.
This commit is contained in:
Ismo Puustinen
2016-01-12 12:14:50 +02:00
parent f466acdc63
commit a103496ca5
13 changed files with 71 additions and 61 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/basic/capability-util.c
+8 -8
View File
@@ -96,7 +96,7 @@ unsigned long cap_last_cap(void) {
return p;
}
int capability_bounding_set_drop(uint64_t drop, bool right_now) {
int capability_bounding_set_drop(uint64_t keep, bool right_now) {
_cleanup_cap_free_ cap_t after_cap = NULL;
cap_flag_value_t fv;
unsigned long i;
@@ -137,7 +137,7 @@ int capability_bounding_set_drop(uint64_t drop, bool right_now) {
for (i = 0; i <= cap_last_cap(); i++) {
if (drop & ((uint64_t) 1ULL << (uint64_t) i)) {
if (!(keep & (UINT64_C(1) << i))) {
cap_value_t v;
/* Drop it from the bounding set */
@@ -176,7 +176,7 @@ finish:
return r;
}
static int drop_from_file(const char *fn, uint64_t drop) {
static int drop_from_file(const char *fn, uint64_t keep) {
int r, k;
uint32_t hi, lo;
uint64_t current, after;
@@ -196,7 +196,7 @@ static int drop_from_file(const char *fn, uint64_t drop) {
return -EIO;
current = (uint64_t) lo | ((uint64_t) hi << 32ULL);
after = current & ~drop;
after = current & keep;
if (current == after)
return 0;
@@ -213,14 +213,14 @@ static int drop_from_file(const char *fn, uint64_t drop) {
return r;
}
int capability_bounding_set_drop_usermode(uint64_t drop) {
int capability_bounding_set_drop_usermode(uint64_t keep) {
int r;
r = drop_from_file("/proc/sys/kernel/usermodehelper/inheritable", drop);
r = drop_from_file("/proc/sys/kernel/usermodehelper/inheritable", keep);
if (r < 0)
return r;
r = drop_from_file("/proc/sys/kernel/usermodehelper/bset", drop);
r = drop_from_file("/proc/sys/kernel/usermodehelper/bset", keep);
if (r < 0)
return r;
@@ -257,7 +257,7 @@ int drop_privileges(uid_t uid, gid_t gid, uint64_t keep_capabilities) {
return log_error_errno(errno, "Failed to disable keep capabilities flag: %m");
/* Drop all caps from the bounding set, except the ones we want */
r = capability_bounding_set_drop(~keep_capabilities, true);
r = capability_bounding_set_drop(keep_capabilities, true);
if (r < 0)
return log_error_errno(r, "Failed to drop capabilities: %m");
src/basic/capability-util.h
+10 -2
View File
@@ -29,10 +29,12 @@
#include "macro.h"
#include "util.h"
#define CAP_ALL (uint64_t) -1
unsigned long cap_last_cap(void);
int have_effective_cap(int value);
int capability_bounding_set_drop(uint64_t drop, bool right_now);
int capability_bounding_set_drop_usermode(uint64_t drop);
int capability_bounding_set_drop(uint64_t keep, bool right_now);
int capability_bounding_set_drop_usermode(uint64_t keep);
int drop_privileges(uid_t uid, gid_t gid, uint64_t keep_capabilities);
@@ -46,3 +48,9 @@ static inline void cap_free_charpp(char **p) {
cap_free(*p);
}
#define _cleanup_cap_free_charp_ _cleanup_(cap_free_charpp)
static inline bool cap_test_all(uint64_t caps) {
uint64_t m;
m = (UINT64_C(1) << (cap_last_cap() + 1)) - 1;
return (caps & m) == m;
}