From 7d328b544621d4b1bec936dec612947ad8bfb65a Mon Sep 17 00:00:00 2001 From: =?utf8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= Date: Sun, 1 Feb 2015 15:26:46 -0500 Subject: [PATCH 1/1] shared/capability: go frugal on space for caps --- src/shared/capability.c | 5 +++-- src/shared/util.h | 12 +++++++++++- 2 files changed, 14 insertions(+), 3 deletions(-) diff --git a/src/shared/capability.c b/src/shared/capability.c index dcf7ce1a6..3f2f27e23 100644 --- a/src/shared/capability.c +++ b/src/shared/capability.c @@ -269,11 +269,12 @@ int drop_privileges(uid_t uid, gid_t gid, uint64_t keep_capabilities) { return log_oom(); if (keep_capabilities) { - cap_value_t bits[sizeof(keep_capabilities)*8]; + cap_value_t bits[log2u64(keep_capabilities)]; - for (i = 0; i < sizeof(keep_capabilities)*8; i++) + for (i = 0; i < ELEMENTSOF(bits); i++) if (keep_capabilities & (1ULL << i)) bits[j++] = i; + assert((keep_capabilities & (~1ULL << i)) == 0); if (cap_set_flag(d, CAP_EFFECTIVE, j, bits, CAP_SET) < 0 || cap_set_flag(d, CAP_PERMITTED, j, bits, CAP_SET) < 0) { diff --git a/src/shared/util.h b/src/shared/util.h index 531242213..410ce65f1 100644 --- a/src/shared/util.h +++ b/src/shared/util.h @@ -860,7 +860,7 @@ static inline unsigned u32ctz(uint32_t n) { #endif } -static inline int log2i(int x) { +static inline unsigned log2i(int x) { assert(x > 0); return __SIZEOF_INT__ * 8 - __builtin_clz(x) - 1; @@ -872,6 +872,16 @@ static inline unsigned log2u(unsigned x) { return sizeof(unsigned) * 8 - __builtin_clz(x) - 1; } +static inline unsigned log2u64(uint64_t x) { + assert(x > 0); + +#if __SIZEOF_LONG_LONG__ == 8 + return 64 - __builtin_clzll(x) - 1; +#else +#error "Wut?" +#endif +} + static inline unsigned log2u_round_up(unsigned x) { assert(x > 0); -- 2.30.2