Using setegid() directly makes the code easier to read.
Some of these calls will be removed in a later diff.
- todd
Index: crontab.c
===================================================================
RCS file: /cvs/src/usr.sbin/cron/crontab.c,v
retrieving revision 1.78
diff -u -p -u -r1.78 crontab.c
--- crontab.c 31 Oct 2015 12:13:01 -0000 1.78
+++ crontab.c 2 Nov 2015 18:31:52 -0000
@@ -30,7 +30,8 @@ enum opt_t { opt_unknown, opt_list, opt_
static char *getoptargs = "u:ler";
static pid_t Pid;
-static gid_t save_egid;
+static gid_t crontab_gid;
+static gid_t user_gid;
static char User[MAX_UNAME], RealUser[MAX_UNAME];
static char Filename[MAX_FNAME], TempFilename[MAX_FNAME];
static FILE *NewCrontab;
@@ -47,17 +48,6 @@ static void list_cmd(void),
die(int);
static int replace_cmd(void);
-static int swap_gids(void)
-{
- save_egid = getegid();
- return (setegid(getgid()));
-}
-
-static int swap_gids_back(void)
-{
- return (setegid(save_egid));
-}
-
static void
usage(const char *msg)
{
@@ -78,6 +68,8 @@ main(int argc, char *argv[])
int exitstatus;
Pid = getpid();
+ user_gid = getgid();
+ crontab_gid = getegid();
ProgramName = argv[0];
if (pledge("stdio rpath wpath cpath fattr getpw unix flock id proc
exec",
@@ -208,16 +200,16 @@ parse_args(int argc, char *argv[])
* the race.
*/
- if (swap_gids() < 0) {
- perror("swapping gids");
+ if (setegid(user_gid) < 0) {
+ perror("setegid(user_gid)");
exit(EXIT_FAILURE);
}
if (!(NewCrontab = fopen(Filename, "r"))) {
perror(Filename);
exit(EXIT_FAILURE);
}
- if (swap_gids_back() < 0) {
- perror("swapping gids back");
+ if (setegid(crontab_gid) < 0) {
+ perror("setegid(crontab_gid)");
exit(EXIT_FAILURE);
}
}
@@ -322,13 +314,13 @@ edit_cmd(void)
fprintf(stderr, "path too long\n");
goto fatal;
}
- if (swap_gids() < 0) {
- perror("swapping gids");
+ if (setegid(user_gid) < 0) {
+ perror("setegid(user_gid)");
exit(EXIT_FAILURE);
}
t = mkstemp(Filename);
- if (swap_gids_back() < 0) {
- perror("swapping gids back");
+ if (setegid(crontab_gid) < 0) {
+ perror("setegid(crontab_gid)");
exit(EXIT_FAILURE);
}
if (t == -1) {
@@ -355,13 +347,13 @@ edit_cmd(void)
fprintf(stderr, "%s: error while writing new crontab to %s\n",
ProgramName, Filename);
fatal:
- if (swap_gids() < 0) {
- perror("swapping gids");
+ if (setegid(user_gid) < 0) {
+ perror("setegid(user_gid)");
exit(EXIT_FAILURE);
}
unlink(Filename);
- if (swap_gids_back() < 0) {
- perror("swapping gids back");
+ if (setegid(crontab_gid) < 0) {
+ perror("setegid(crontab_gid)");
exit(EXIT_FAILURE);
}
exit(EXIT_FAILURE);
@@ -384,8 +376,8 @@ edit_cmd(void)
goto fatal;
}
if (timespeccmp(&ts[1], &statbuf.st_mtim, ==)) {
- if (swap_gids() < 0) {
- perror("swapping gids");
+ if (setegid(user_gid) < 0) {
+ perror("setegid(user_gid)");
exit(EXIT_FAILURE);
}
if (lstat(Filename, &xstatbuf) == 0 &&
@@ -393,8 +385,8 @@ edit_cmd(void)
fprintf(stderr, "%s: crontab temp file moved, editor "
"may create backup files improperly\n", ProgramName);
}
- if (swap_gids_back() < 0) {
- perror("swapping gids back");
+ if (setegid(crontab_gid) < 0) {
+ perror("setegid(crontab_gid)");
exit(EXIT_FAILURE);
}
fprintf(stderr, "%s: no changes made to crontab\n",
@@ -437,13 +429,13 @@ edit_cmd(void)
goto fatal;
}
remove:
- if (swap_gids() < 0) {
- perror("swapping gids");
+ if (setegid(user_gid) < 0) {
+ perror("setegid(user_gid)");
exit(EXIT_FAILURE);
}
unlink(Filename);
- if (swap_gids_back() < 0) {
- perror("swapping gids back");
+ if (setegid(crontab_gid) < 0) {
+ perror("setegid(crontab_gid)");
exit(EXIT_FAILURE);
}
done:
