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authorLennart Poettering <lennart@poettering.net>2010-03-31 16:25:33 +0200
committerLennart Poettering <lennart@poettering.net>2010-03-31 16:25:33 +0200
commit693ced48727b3e40defd95147148a361acd7dcce (patch)
tree31441eec117bf46a48aa04dbcfe615e8636ad0d0
parent5021be21bfc2a3a23a09d60d98e2dcdd1cf504fe (diff)
execute: try to suppress PR_SET_SECUREBITS if unnecessary
-rw-r--r--execute.c23
1 files changed, 16 insertions, 7 deletions
diff --git a/execute.c b/execute.c
index bdb0f92179..85d9873918 100644
--- a/execute.c
+++ b/execute.c
@@ -461,9 +461,13 @@ static int enforce_user(const ExecContext *context, uid_t uid) {
/* First step: If we need to keep capabilities but
* drop privileges we need to make sure we keep our
* caps, whiel we drop priviliges. */
- if (uid != 0)
- if (prctl(PR_SET_SECUREBITS, context->secure_bits|SECURE_KEEP_CAPS) < 0)
- return -errno;
+ if (uid != 0) {
+ int sb = context->secure_bits|SECURE_KEEP_CAPS;
+
+ if (prctl(PR_GET_SECUREBITS) != sb)
+ if (prctl(PR_SET_SECUREBITS, sb) < 0)
+ return -errno;
+ }
/* Second step: set the capabilites. This will reduce
* the capabilities to the minimum we need. */
@@ -671,10 +675,15 @@ int exec_spawn(const ExecCommand *command,
goto fail;
}
- if (prctl(PR_SET_SECUREBITS, context->secure_bits) < 0) {
- r = EXIT_SECUREBITS;
- goto fail;
- }
+ /* PR_GET_SECUREBITS is not priviliged, while
+ * PR_SET_SECUREBITS is. So to suppress
+ * potential EPERMs we'll try not to call
+ * PR_SET_SECUREBITS unless necessary. */
+ if (prctl(PR_GET_SECUREBITS) != context->secure_bits)
+ if (prctl(PR_SET_SECUREBITS, context->secure_bits) < 0) {
+ r = EXIT_SECUREBITS;
+ goto fail;
+ }
if (context->capabilities)
if (cap_set_proc(context->capabilities) < 0) {