From 057255fbbf2ecb1c46e025b04087fa9340d9880d Mon Sep 17 00:00:00 2001 From: Tom Gundersen Date: Wed, 4 Feb 2015 09:23:24 +0100 Subject: [PATCH] shared/capability: don't be too frugal on space for caps We were dropping the most significant bit. Add an assert to make sure it does not happen again. Fixes a bug introduced in 7d328b544621d4b1bec936dec612947ad8bfb65a. --- src/shared/capability.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/src/shared/capability.c b/src/shared/capability.c index 3f2f27e23fe..57f392a4da8 100644 --- a/src/shared/capability.c +++ b/src/shared/capability.c @@ -269,12 +269,16 @@ int drop_privileges(uid_t uid, gid_t gid, uint64_t keep_capabilities) { return log_oom(); if (keep_capabilities) { - cap_value_t bits[log2u64(keep_capabilities)]; + cap_value_t bits[u64log2(keep_capabilities) + 1]; for (i = 0; i < ELEMENTSOF(bits); i++) if (keep_capabilities & (1ULL << i)) bits[j++] = i; + + /* don't keep too many bits */ assert((keep_capabilities & (~1ULL << i)) == 0); + /* don't throw away too many bits */ + assert(((keep_capabilities >> i) & (~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) {