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authorDavid Herrmann <dh.herrmann@gmail.com>2014-12-30 09:09:41 +0100
committerDavid Herrmann <dh.herrmann@gmail.com>2014-12-30 09:09:41 +0100
commit7d9fcc2bf6869993e5f38d5eb183fb59e8a52816 (patch)
treec891ab50009613299173845bcce0cea428bc08f3
parent34a5d5e52661212c7a145cbab45e70a6df7ba284 (diff)
bus: fix capabilities on big-endian
The kernel provides capabilities as a u32 array, sd-bus uses an u8 array. This works fine on little-endian as both are encoded the same way. However, this fails on big-endian if we do not perform sufficient byte-swapping on each u32 entry. This patch makes sd-bus use u32, too. We avoid changing any kernel provided data so we can keep pointing into kdbus pool buffers which contain u32 arrays.
-rw-r--r--src/libsystemd/sd-bus/bus-creds.c31
-rw-r--r--src/libsystemd/sd-bus/bus-creds.h2
-rw-r--r--src/libsystemd/sd-bus/bus-kernel.c2
3 files changed, 20 insertions, 15 deletions
diff --git a/src/libsystemd/sd-bus/bus-creds.c b/src/libsystemd/sd-bus/bus-creds.c
index 55d6fb6b43..54e76ab6c4 100644
--- a/src/libsystemd/sd-bus/bus-creds.c
+++ b/src/libsystemd/sd-bus/bus-creds.c
@@ -20,6 +20,7 @@
***/
#include <stdlib.h>
+#include <linux/capability.h>
#include "util.h"
#include "capability.h"
@@ -592,11 +593,11 @@ static int has_cap(sd_bus_creds *c, unsigned offset, int capability) {
assert(capability >= 0);
assert(c->capability);
- sz = DIV_ROUND_UP(cap_last_cap(), 32U) * 4;
+ sz = DIV_ROUND_UP(cap_last_cap(), 32U);
if ((unsigned)capability > cap_last_cap())
return 0;
- return !!(c->capability[offset * sz + (capability / 8)] & (1 << (capability % 8)));
+ return !!(c->capability[offset * sz + CAP_TO_INDEX(capability)] & CAP_TO_MASK(capability));
}
_public_ int sd_bus_creds_has_effective_cap(sd_bus_creds *c, int capability) {
@@ -641,38 +642,42 @@ _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, max;
- unsigned i;
+ unsigned i, j;
assert(c);
assert(p);
- max = DIV_ROUND_UP(cap_last_cap(), 32U) * 4;
+ max = DIV_ROUND_UP(cap_last_cap(), 32U);
p += strspn(p, WHITESPACE);
sz = strlen(p);
- if (sz % 2 != 0)
+ if (sz % 8 != 0)
return -EINVAL;
- sz /= 2;
+ sz /= 8;
if (sz > max)
return -EINVAL;
if (!c->capability) {
- c->capability = new0(uint8_t, max * 4);
+ c->capability = new0(uint32_t, max * 4);
if (!c->capability)
return -ENOMEM;
}
for (i = 0; i < sz; i ++) {
- int x, y;
+ uint32_t v = 0;
- x = unhexchar(p[i*2]);
- y = unhexchar(p[i*2+1]);
+ for (j = 0; j < 8; ++j) {
+ int t;
- if (x < 0 || y < 0)
- return -EINVAL;
+ t = unhexchar(*p++);
+ if (t < 0)
+ return -EINVAL;
- c->capability[offset * max + (sz - i - 1)] = (uint8_t) x << 4 | (uint8_t) y;
+ v = (v << 4) | t;
+ }
+
+ c->capability[offset * max + (sz - i - 1)] = v;
}
return 0;
diff --git a/src/libsystemd/sd-bus/bus-creds.h b/src/libsystemd/sd-bus/bus-creds.h
index 2480a4a0b1..3b337efa32 100644
--- a/src/libsystemd/sd-bus/bus-creds.h
+++ b/src/libsystemd/sd-bus/bus-creds.h
@@ -60,7 +60,7 @@ struct sd_bus_creds {
char *user_unit;
char *slice;
- uint8_t *capability;
+ uint32_t *capability;
uint32_t audit_session_id;
uid_t audit_login_uid;
diff --git a/src/libsystemd/sd-bus/bus-kernel.c b/src/libsystemd/sd-bus/bus-kernel.c
index eeb4a518d1..6ee3f92832 100644
--- a/src/libsystemd/sd-bus/bus-kernel.c
+++ b/src/libsystemd/sd-bus/bus-kernel.c
@@ -680,7 +680,7 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) {
goto fail;
}
- m->creds.capability = (uint8_t *) d->caps.caps;
+ m->creds.capability = d->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;