SymbX/systemd
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

bus: drop creds->capability_size

Browse Source 
The number of available caps can be read from
/proc/sys/kernel/cap_last_cap during runtime. Our helper cap_last_cap()
does that, so there's no reason to remember the size of any capability
cache. We can just pre-allocate arrays with a suitable size for all
available caps and reject any higher caps.

The kernel capability API uses u32 as base so make sure we do the same.
Note that this is specified by POSIX, so it's unlikely to change.
This commit is contained in:
David Herrmann
2014-12-30 08:42:53 +01:00
parent 180a60bc87
commit 34a5d5e526
4 changed files with 25 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/libsystemd/sd-bus/bus-control.c
+6 -2
View File
@@ -33,6 +33,7 @@
#include "bus-control.h"
#include "bus-bloom.h"
#include "bus-util.h"
#include "capability.h"
#include "cgroup-util.h"
_public_ int sd_bus_get_unique_name(sd_bus *bus, const char **unique) {
@@ -520,8 +521,11 @@ static int bus_populate_creds_from_items(
SD_BUS_CREDS_INHERITABLE_CAPS | SD_BUS_CREDS_BOUNDING_CAPS) & mask;
if (m) {
c->capability_size = item->size - offsetof(struct kdbus_item, caps.caps);
c->capability = memdup(item->caps.caps, c->capability_size);
if (item->caps.last_cap != cap_last_cap() ||
item->size - offsetof(struct kdbus_item, caps.caps) < DIV_ROUND_UP(item->caps.last_cap, 32U) * 4 * 4)
return -EBADMSG;
c->capability = memdup(item->caps.caps, item->size - offsetof(struct kdbus_item, caps.caps));
if (!c->capability)
return -ENOMEM;
src/libsystemd/sd-bus/bus-creds.c
+12 -9
View File
@@ -22,6 +22,7 @@
#include <stdlib.h>
#include "util.h"
#include "capability.h"
#include "cgroup-util.h"
#include "fileio.h"
#include "audit.h"
@@ -588,10 +589,11 @@ static int has_cap(sd_bus_creds *c, unsigned offset, int capability) {
size_t sz;
assert(c);
assert(capability >= 0);
assert(c->capability);
sz = c->capability_size / 4;
if ((size_t) capability >= sz*8)
sz = DIV_ROUND_UP(cap_last_cap(), 32U) * 4;
if ((unsigned)capability > cap_last_cap())
return 0;
return !!(c->capability[offset * sz + (capability / 8)] & (1 << (capability % 8)));
@@ -638,12 +640,13 @@ _public_ int sd_bus_creds_has_bounding_cap(sd_bus_creds *c, int capability) {
}
static int parse_caps(sd_bus_creds *c, unsigned offset, const char *p) {
size_t sz;
size_t sz, max;
unsigned i;
assert(c);
assert(p);
max = DIV_ROUND_UP(cap_last_cap(), 32U) * 4;
p += strspn(p, WHITESPACE);
sz = strlen(p);
@@ -651,12 +654,13 @@ static int parse_caps(sd_bus_creds *c, unsigned offset, const char *p) {
return -EINVAL;
sz /= 2;
if (sz > max)
return -EINVAL;
if (!c->capability) {
c->capability = new0(uint8_t, sz * 4);
c->capability = new0(uint8_t, max * 4);
if (!c->capability)
return -ENOMEM;
c->capability_size = sz * 4;
}
for (i = 0; i < sz; i ++) {
@@ -668,7 +672,7 @@ static int parse_caps(sd_bus_creds *c, unsigned offset, const char *p) {
if (x < 0 || y < 0)
return -EINVAL;
c->capability[offset * sz + (sz - i - 1)] = (uint8_t) x << 4 | (uint8_t) y;
c->capability[offset * max + (sz - i - 1)] = (uint8_t) x << 4 | (uint8_t) y;
}
return 0;
@@ -1073,11 +1077,10 @@ int bus_creds_extend_by_pid(sd_bus_creds *c, uint64_t mask, sd_bus_creds **ret)
}
if (c->mask & mask & (SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS)) {
n->capability = memdup(c->capability, c->capability_size);
n->capability = memdup(c->capability, DIV_ROUND_UP(cap_last_cap(), 32U) * 4 * 4);
if (!n->capability)
return -ENOMEM;
n->capability_size = c->capability_size;
n->mask |= c->mask & mask & (SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS);
}
src/libsystemd/sd-bus/bus-creds.h
-1
View File
@@ -61,7 +61,6 @@ struct sd_bus_creds {
char *slice;
uint8_t *capability;
size_t capability_size;
uint32_t audit_session_id;
uid_t audit_login_uid;
src/libsystemd/sd-bus/bus-kernel.c
+7 -1
View File
@@ -32,6 +32,7 @@
#include "util.h"
#include "strv.h"
#include "memfd-util.h"
#include "capability.h"
#include "cgroup-util.h"
#include "fileio.h"
@@ -673,8 +674,13 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) {
break;
case KDBUS_ITEM_CAPS:
if (d->caps.last_cap != cap_last_cap() ||
d->size - offsetof(struct kdbus_item, caps.caps) < DIV_ROUND_UP(d->caps.last_cap, 32U) * 4 * 4) {
r = -EBADMSG;
goto fail;
}
m->creds.capability = (uint8_t *) d->caps.caps;
m->creds.capability_size = d->size - offsetof(struct kdbus_item, caps.caps);
m->creds.mask |= (SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS) & bus->creds_mask;
break;