[libvirt] [PATCH] virConfSaveValue: protect against a NULL pointer reference

Wim Ten Have posted 1 patch 125 weeks ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/libvirt tags/patchew/20170327202043.18950-2-wim.ten.have@oracle.com
src/util/virconf.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

[libvirt] [PATCH] virConfSaveValue: protect against a NULL pointer reference

Posted by Wim Ten Have 125 weeks ago
From: Wim ten Have <wim.ten.have@oracle.com>

Fix xlconfigtest runs build for --enable-test-oom on
        Xen XL-2-XML Parse  channel-pty

Program received signal SIGSEGV, Segmentation fault.

    #0  0x00007ffff3c2b373 in __strchr_sse2 () from /lib64/libc.so.6
==> #1  0x00007ffff7875701 in virConfSaveValue (buf=buf@entry=0x7fffffffd8a0, val=val@entry=0x674750) at util/virconf.c:290
    #2  0x00007ffff7875668 in virConfSaveValue (buf=buf@entry=0x7fffffffd8a0, val=<optimized out>) at util/virconf.c:306
    #3  0x00007ffff78757ef in virConfSaveEntry (buf=buf@entry=0x7fffffffd8a0, cur=cur@entry=0x674780) at util/virconf.c:338
    #4  0x00007ffff78783eb in virConfWriteMem (memory=0x665570 "", len=len@entry=0x7fffffffd910, conf=conf@entry=0x65b940)
        at util/virconf.c:1543
    #5  0x000000000040eccb in testCompareParseXML (replaceVars=<optimized out>, xml=<optimized out>,
        xlcfg=0x662c00 "/home/wtenhave/WORK/libvirt/OOMtesting/libvirt-devel/tests/xlconfigdata/test-channel-pty.cfg")
        at xlconfigtest.c:108
    #6  testCompareHelper (data=<optimized out>) at xlconfigtest.c:205
    #7  0x0000000000410b3a in virTestRun (title=title@entry=0x432cc0 "Xen XL-2-XML Parse  channel-pty",
        body=body@entry=0x40e9b0 <testCompareHelper>, data=data@entry=0x7fffffffd9f0) at testutils.c:247
    #8  0x000000000040f322 in mymain () at xlconfigtest.c:278
    #9  0x0000000000411410 in virTestMain (argc=1, argv=0x7fffffffdba8, func=0x40f660 <mymain>) at testutils.c:992
    #10 0x00007ffff3bc0401 in __libc_start_main () from /lib64/libc.so.6
    #11 0x000000000040e86a in _start ()

    (gdb) frame 1
    #1  0x00007ffff7875701 in virConfSaveValue (buf=buf@entry=0x7fffffffd8a0, val=val@entry=0x674750) at util/virconf.c:290
    290                 if (strchr(val->str, '\n') != NULL) {
    (gdb) print *val
    $1 = {type = VIR_CONF_STRING, next = 0x0, l = 0, str = 0x0, list = 0x0}

Signed-off-by: Wim ten Have <wim.ten.have@oracle.com>
---
 src/util/virconf.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/util/virconf.c b/src/util/virconf.c
index a85a307..9840ca6 100644
--- a/src/util/virconf.c
+++ b/src/util/virconf.c
@@ -287,14 +287,16 @@ virConfSaveValue(virBufferPtr buf, virConfValuePtr val)
             virBufferAsprintf(buf, "%llu", val->l);
             break;
         case VIR_CONF_STRING:
-            if (strchr(val->str, '\n') != NULL) {
-                virBufferAsprintf(buf, "\"\"\"%s\"\"\"", val->str);
-            } else if (strchr(val->str, '"') == NULL) {
-                virBufferAsprintf(buf, "\"%s\"", val->str);
-            } else if (strchr(val->str, '\'') == NULL) {
-                virBufferAsprintf(buf, "'%s'", val->str);
-            } else {
-                virBufferAsprintf(buf, "\"\"\"%s\"\"\"", val->str);
+            if (val->str) {
+                if (strchr(val->str, '\n') != NULL) {
+                    virBufferAsprintf(buf, "\"\"\"%s\"\"\"", val->str);
+                } else if (strchr(val->str, '"') == NULL) {
+                    virBufferAsprintf(buf, "\"%s\"", val->str);
+                } else if (strchr(val->str, '\'') == NULL) {
+                    virBufferAsprintf(buf, "'%s'", val->str);
+                } else {
+                    virBufferAsprintf(buf, "\"\"\"%s\"\"\"", val->str);
+                }
             }
             break;
         case VIR_CONF_LIST: {
-- 
2.9.3

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Re: [libvirt] [PATCH] virConfSaveValue: protect against a NULL pointer reference

Posted by Jim Fehlig 123 weeks ago
Wim Ten Have wrote:
> From: Wim ten Have <wim.ten.have@oracle.com>

Sorry for the delay. I've not had time to work on upstream libvirt activities
recently...

> 
> Fix xlconfigtest runs build for --enable-test-oom on
>         Xen XL-2-XML Parse  channel-pty
> 
> Program received signal SIGSEGV, Segmentation fault.
> 
>     #0  0x00007ffff3c2b373 in __strchr_sse2 () from /lib64/libc.so.6
> ==> #1  0x00007ffff7875701 in virConfSaveValue (buf=buf@entry=0x7fffffffd8a0, val=val@entry=0x674750) at util/virconf.c:290
>     #2  0x00007ffff7875668 in virConfSaveValue (buf=buf@entry=0x7fffffffd8a0, val=<optimized out>) at util/virconf.c:306
>     #3  0x00007ffff78757ef in virConfSaveEntry (buf=buf@entry=0x7fffffffd8a0, cur=cur@entry=0x674780) at util/virconf.c:338
>     #4  0x00007ffff78783eb in virConfWriteMem (memory=0x665570 "", len=len@entry=0x7fffffffd910, conf=conf@entry=0x65b940)
>         at util/virconf.c:1543
>     #5  0x000000000040eccb in testCompareParseXML (replaceVars=<optimized out>, xml=<optimized out>,
>         xlcfg=0x662c00 "/home/wtenhave/WORK/libvirt/OOMtesting/libvirt-devel/tests/xlconfigdata/test-channel-pty.cfg")
>         at xlconfigtest.c:108
>     #6  testCompareHelper (data=<optimized out>) at xlconfigtest.c:205
>     #7  0x0000000000410b3a in virTestRun (title=title@entry=0x432cc0 "Xen XL-2-XML Parse  channel-pty",
>         body=body@entry=0x40e9b0 <testCompareHelper>, data=data@entry=0x7fffffffd9f0) at testutils.c:247
>     #8  0x000000000040f322 in mymain () at xlconfigtest.c:278
>     #9  0x0000000000411410 in virTestMain (argc=1, argv=0x7fffffffdba8, func=0x40f660 <mymain>) at testutils.c:992
>     #10 0x00007ffff3bc0401 in __libc_start_main () from /lib64/libc.so.6
>     #11 0x000000000040e86a in _start ()
> 
>     (gdb) frame 1
>     #1  0x00007ffff7875701 in virConfSaveValue (buf=buf@entry=0x7fffffffd8a0, val=val@entry=0x674750) at util/virconf.c:290
>     290                 if (strchr(val->str, '\n') != NULL) {
>     (gdb) print *val
>     $1 = {type = VIR_CONF_STRING, next = 0x0, l = 0, str = 0x0, list = 0x0}
> 
> Signed-off-by: Wim ten Have <wim.ten.have@oracle.com>
> ---
>  src/util/virconf.c | 18 ++++++++++--------
>  1 file changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/src/util/virconf.c b/src/util/virconf.c
> index a85a307..9840ca6 100644
> --- a/src/util/virconf.c
> +++ b/src/util/virconf.c
> @@ -287,14 +287,16 @@ virConfSaveValue(virBufferPtr buf, virConfValuePtr val)
>              virBufferAsprintf(buf, "%llu", val->l);
>              break;
>          case VIR_CONF_STRING:
> -            if (strchr(val->str, '\n') != NULL) {
> -                virBufferAsprintf(buf, "\"\"\"%s\"\"\"", val->str);
> -            } else if (strchr(val->str, '"') == NULL) {
> -                virBufferAsprintf(buf, "\"%s\"", val->str);
> -            } else if (strchr(val->str, '\'') == NULL) {
> -                virBufferAsprintf(buf, "'%s'", val->str);
> -            } else {
> -                virBufferAsprintf(buf, "\"\"\"%s\"\"\"", val->str);
> +            if (val->str) {
> +                if (strchr(val->str, '\n') != NULL) {
> +                    virBufferAsprintf(buf, "\"\"\"%s\"\"\"", val->str);
> +                } else if (strchr(val->str, '"') == NULL) {
> +                    virBufferAsprintf(buf, "\"%s\"", val->str);
> +                } else if (strchr(val->str, '\'') == NULL) {
> +                    virBufferAsprintf(buf, "'%s'", val->str);
> +                } else {
> +                    virBufferAsprintf(buf, "\"\"\"%s\"\"\"", val->str);
> +                }

Odd that we've not stumbled across this earlier. But ACK to making this code a
bit more resilient. Patch has been pushed now.

BTW, I noticed a few more OOM test failures in the channel formating code. Patch
sent. Can you help review it?

https://www.redhat.com/archives/libvir-list/2017-April/msg00740.html

Regards,
Jim

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Re: [libvirt] [PATCH] virConfSaveValue: protect against a NULL pointer reference

Posted by Wim ten Have 123 weeks ago
On Thu, 13 Apr 2017 11:12:36 -0600
Jim Fehlig <jfehlig@suse.com> wrote:

> Wim Ten Have wrote:
> > From: Wim ten Have <wim.ten.have@oracle.com>  
> 
> Sorry for the delay. I've not had time to work on upstream libvirt activities
> recently...

  Understood.  There is one more PATCH out per me.  Let me send a reminder under
  its specific cover letter.

> > Fix xlconfigtest runs build for --enable-test-oom on
> >         Xen XL-2-XML Parse  channel-pty
> > 
> > Program received signal SIGSEGV, Segmentation fault.
> > 	..
> 
> Odd that we've not stumbled across this earlier. But ACK to making this code a
> bit more resilient. Patch has been pushed now.
> 
> BTW, I noticed a few more OOM test failures in the channel formating code. Patch
> sent. Can you help review it?

  Sure, i actually had that one in my list to come along soon.
 
> https://www.redhat.com/archives/libvir-list/2017-April/msg00740.html

  This marks correct fix!  Pls go forward.

Regards,
- Wim.

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