database: run triggers with r*id = e*idHEADv2.14.0+adelie1current

The 'apk' utility is intended to run as root, however it is not
strictly necessary depending on the tasks it needs to execute.

If invoked as euid 0 but ruid something else, the mismatch is
detected by the (shell) interpreter, which sets euid to ruid,
which can cause a trigger expecting privileges to fail silently.

Fixes: horizon#379

1 files changed, 13 insertions, 0 deletions

diff --git a/src/database.c b/src/database.c
index 9864543..b916d59 100644
--- a/src/database.c
+++ b/src/database.c
@@ -1949,6 +1949,19 @@ int apk_db_run_script(struct apk_database *db, char *fn, char **argv)
 			exit(127);
 		}
 
+		if (getuid() != geteuid())
+		{
+			if (setgid(getegid()) != 0) {
+				apk_error("%s: setgid: %s", basename(fn), strerror(errno));
+				exit(127);
+			}
+
+			if (setuid(geteuid()) != 0) {
+				apk_error("%s: setuid: %s", basename(fn), strerror(errno));
+				exit(127);
+			}
+		}
+
 		execve(fn, argv, environment);
 		exit(127); /* should not get here */
 	}