sysctl: fix bug 3894 _for real_.

1 files changed, 18 insertions, 7 deletions

diff --git a/procps/sysctl.c b/procps/sysctl.c
index 90e47ea9a..0876a73de 100644
--- a/procps/sysctl.c
+++ b/procps/sysctl.c
@@ -234,19 +234,30 @@ static int sysctl_display_all(const char *path)
 
 static void sysctl_dots_to_slashes(char *name)
 {
-        char *cptr = name;
+        char *cptr, *last_good;
+        char *end = name + strlen(name) - 1;
 
         /* Example from bug 3894:
          * net.ipv4.conf.eth0.100.mc_forwarding ->
-         * net/ipv4/conf/eth0.100/mc_forwarding */
-        while (*cptr != '\0') {
+         * net/ipv4/conf/eth0.100/mc_forwarding. NB:
+         * net/ipv4/conf/eth0/mc_forwarding *also exists*,
+         * therefore we must start from the end, and if
+         * we replaced even one . -> /, start over again,
+         * but never replace dots before the position
+         * where replacement occurred. */
+        last_good = name - 1;
+ again:
+        cptr = end;
+        while (cptr > last_good) {
                 if (*cptr == '.') {
                         *cptr = '\0';
-                        if (access(name, F_OK) == 0)
+                        if (access(name, F_OK) == 0) {
                                 *cptr = '/';
-                        else
-                                *cptr = '.';
+                                last_good = cptr;
+                                goto again;
+                        }
+                        *cptr = '.';
                 }
-                cptr++;
+                cptr--;
         }
 } /* end sysctl_dots_to_slashes() */