prlimit: don't share pointer for old and new in prlimit(2)

This patch makes the code more robust. We should not share the same
pointer for old and new arguments for prlimit(2) syscall.

Reported-by: Bernhard Voelker <mail@bernhard-voelker.de>
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/sys-utils/prlimit.c b/sys-utils/prlimit.c
index a99cc1e314010ac4a7f2af4676cb28c3c13f2676..bcbfb5a8f7ea2f054cdc56f958e9c4b3e1dfd38b 100644 (file)
--- a/sys-utils/prlimit.c
+++ b/sys-utils/prlimit.c
@@ -328,7 +328,7 @@ static void do_prlimit(struct list_head *lims)
        struct list_head *p, *pnext;
 
        list_for_each_safe(p, pnext, lims) {
-               struct rlimit *new = NULL;
+               struct rlimit *new = NULL, *old = NULL;
                struct prlimit *lim = list_entry(p, struct prlimit, lims);
 
                if (lim->modify) {
@@ -341,7 +341,8 @@ static void do_prlimit(struct list_head *lims)
                                errx(EXIT_FAILURE, _("the soft limit %s cannot exceed the hard limit"),
                                                lim->desc->name);
                        new = &lim->rlim;
-               }
+               } else
+                       old = &lim->rlim;
 
                if (verbose && new) {
                        printf(_("New %s limit: "), lim->desc->name);
@@ -356,7 +357,7 @@ static void do_prlimit(struct list_head *lims)
                                printf(":%ju>\n", new->rlim_max);
                }
 
-               if (prlimit(pid, lim->desc->resource, new, &lim->rlim) == -1)
+               if (prlimit(pid, lim->desc->resource, new, old) == -1)
                        err(EXIT_FAILURE, lim->modify ?
                                _("failed to set the %s resource limit") :
                                _("failed to get the %s resource limit"),