Patchwork [PULL,09/17] acl: acl_add can't insert before last list element, fix

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Submitter Michael Tokarev
Date June 22, 2013, 9:24 a.m.
Message ID <1371893076-9643-10-git-send-email-mjt@msgid.tls.msk.ru>
Download mbox | patch
Permalink /patch/253404/
State New
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Comments

Michael Tokarev - June 22, 2013, 9:24 a.m.
From: Markus Armbruster <armbru@redhat.com>

Watch this:

    $ upstream-qemu -nodefaults -S -vnc :0,acl,sasl -monitor stdio
    QEMU 1.5.50 monitor - type 'help' for more information
    (qemu) acl_add vnc.username drei allow
    acl: added rule at position 1
    (qemu) acl_show vnc.username
    policy: deny
    1: allow drei
    (qemu) acl_add vnc.username zwei allow 1
    acl: added rule at position 2
    (qemu) acl_show vnc.username
    policy: deny
    1: allow drei
    2: allow zwei
    (qemu) acl_add vnc.username eins allow 1
    acl: added rule at position 1
    (qemu) acl_show vnc.username
    policy: deny
    1: allow eins
    2: allow drei
    3: allow zwei

The second acl_add inserts at position 2 instead of 1.

Root cause is an off-by-one in qemu_acl_insert(): when index ==
acl->nentries, it appends instead of inserting before the last list
element.

Cc: qemu-stable@nongnu.org
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
---
 util/acl.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Patch

diff --git a/util/acl.c b/util/acl.c
index a7f33ff..938b7ae 100644
--- a/util/acl.c
+++ b/util/acl.c
@@ -138,9 +138,9 @@  int qemu_acl_insert(qemu_acl *acl,
 
     if (index <= 0)
         return -1;
-    if (index >= acl->nentries)
+    if (index > acl->nentries) {
         return qemu_acl_append(acl, deny, match);
-
+    }
 
     entry = g_malloc(sizeof(*entry));
     entry->match = g_strdup(match);