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| author | Lennart Poettering <lennart@poettering.net> | 2018-10-10 11:07:54 +0200 |
|---|---|---|
| committer | Lennart Poettering <lennart@poettering.net> | 2018-10-10 11:11:48 +0200 |
| commit | 5f00c5684f96c93a22840f7241ee444b9a632b1e (patch) | |
| tree | 47891f18b69aa3943668e2aeede589165f793cf2 | |
| parent | ca92fe36e07d0d495baef1f860d66925bc0dc165 (diff) | |
| download | systemd-5f00c5684f96c93a22840f7241ee444b9a632b1e.tar.gz | |
capability: introduce CAP_TO_MASK_CORRECTED() macro replacing CAP_TO_MASK()
linux/capability.h's CAP_TO_MASK potentially shifts a signed int "1"
(i.e. 32bit wide) left by 31 which means it becomes negative. That's
just weird, and ubsan complains about it. Let's introduce our own macro
CAP_TO_MASK_CORRECTED which doesn't fall into this trap, and make use of
it.
Fixes: #10347
| -rw-r--r-- | src/basic/capability-util.h | 4 | ||||
| -rw-r--r-- | src/libsystemd/sd-bus/bus-creds.c | 2 |
2 files changed, 5 insertions, 1 deletions
diff --git a/src/basic/capability-util.h b/src/basic/capability-util.h index 4a4a86093a..59591d4b52 100644 --- a/src/basic/capability-util.h +++ b/src/basic/capability-util.h @@ -39,3 +39,7 @@ static inline bool cap_test_all(uint64_t caps) { } bool ambient_capabilities_supported(void); + +/* Identical to linux/capability.h's CAP_TO_MASK(), but uses an unsigned 1U instead of a signed 1 for shifting left, in + * order to avoid complaints about shifting a signed int left by 31 bits, which would make it negative. */ +#define CAP_TO_MASK_CORRECTED(x) (1U << ((x) & 31U)) diff --git a/src/libsystemd/sd-bus/bus-creds.c b/src/libsystemd/sd-bus/bus-creds.c index 738c922ce0..b454270d3f 100644 --- a/src/libsystemd/sd-bus/bus-creds.c +++ b/src/libsystemd/sd-bus/bus-creds.c @@ -661,7 +661,7 @@ static int has_cap(sd_bus_creds *c, unsigned offset, int capability) { sz = DIV_ROUND_UP(cap_last_cap(), 32U); - return !!(c->capability[offset * sz + CAP_TO_INDEX(capability)] & CAP_TO_MASK(capability)); + return !!(c->capability[offset * sz + CAP_TO_INDEX((uint32_t) capability)] & CAP_TO_MASK_CORRECTED((uint32_t) capability)); } _public_ int sd_bus_creds_has_effective_cap(sd_bus_creds *c, int capability) { |