On 02/09/2017 09:21 AM, Marc Hartmayer wrote:
On Thu, Feb 09, 2017 at 03:13 PM +0100, Marc Hartmayer <mhartmay@xxxxxxxxxxxxxxxxxx> wrote:We have to allocate first and if, and only if, it was successful we can set the count. A segfault has occurred in virNetServerServiceNewPostExecRestart() when VIR_ALLOC_N(svc->socks, n) has failed, but svc->nsocsk = n was already set. Thus virObejectUnref(svc) was called and therefore it was possible that virNetServerServiceDispose was called => segmentation fault. For safeness NULL pointer check were added in virNetServerServiceDispose(). Signed-off-by: Marc Hartmayer <mhartmay@xxxxxxxxxxxxxxxxxx> Reviewed-by: Boris Fiuczynski <fiuczy@xxxxxxxxxxxxxxxxxx> Reviewed-by: Bjoern Walk <bwalk@xxxxxxxxxxxxxxxxxx> --- src/rpc/virnetserverservice.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/src/rpc/virnetserverservice.c b/src/rpc/virnetserverservice.c index 1ef0636..006d041 100644 --- a/src/rpc/virnetserverservice.c +++ b/src/rpc/virnetserverservice.c @@ -228,9 +228,9 @@ virNetServerServicePtr virNetServerServiceNewUNIX(const char *path, svc->tls = virObjectRef(tls); #endif - svc->nsocks = 1; - if (VIR_ALLOC_N(svc->socks, svc->nsocks) < 0) + if (VIR_ALLOC_N(svc->socks, 1) < 0) goto error; + svc->nsocks = 1; if (virNetSocketNewListenUNIX(path, mask, @@ -289,9 +289,9 @@ virNetServerServicePtr virNetServerServiceNewFD(int fd, svc->tls = virObjectRef(tls); #endif - svc->nsocks = 1; - if (VIR_ALLOC_N(svc->socks, svc->nsocks) < 0) + if (VIR_ALLOC_N(svc->socks, 1) < 0) goto error; + svc->nsocks = 1; if (virNetSocketNewListenFD(fd, &svc->socks[0]) < 0) @@ -367,9 +367,9 @@ virNetServerServicePtr virNetServerServiceNewPostExecRestart(virJSONValuePtr obj goto error; } - svc->nsocks = n; - if (VIR_ALLOC_N(svc->socks, svc->nsocks) < 0) + if (VIR_ALLOC_N(svc->socks, n) < 0) goto error; + svc->nsocks = n; for (i = 0; i < svc->nsocks; i++) { virJSONValuePtr child = virJSONValueArrayGet(socks, i); @@ -492,9 +492,11 @@ void virNetServerServiceDispose(void *obj) virNetServerServicePtr svc = obj; size_t i; - for (i = 0; i < svc->nsocks; i++) - virObjectUnref(svc->socks[i]); - VIR_FREE(svc->socks); + if (svc->socks) { + for (i = 0; i < svc->nsocks; i++) + virObjectUnref(svc->socks[i]); + VIR_FREE(svc->socks);Should we set svc->nsocks = 0 instead of using a NULL-pointer check (or do both)?
For consistency with other code, we should set svc->nsocks = 0. svc->socks should also be NULL if it's not pointing to anything valid, but as long as it is initialized to NULL (it is) and always freed with VIR_FREE() (it should be), then that will always be the case.
When checking at vir*Free() time, we don't need the "if (svc->socks)", since nsocks == 0 will prevent the for loop from being executed, and VIR_FREE() is a NOP if the pointer is NULL.
I think your patch is fine after removing the "if (svc->socks)" (the original problem was just that nsocks was set before we tried to allocate socks). Unless you see some other issue, I will make that one change and push it (I'll wait for word back from you though).
+ } #if WITH_GNUTLS virObjectUnref(svc->tls); -- 2.5.5-- Beste Grüße / Kind regards Marc Hartmayer IBM Deutschland Research & Development GmbH Vorsitzende des Aufsichtsrats: Martina Koederitz Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen Registergericht: Amtsgericht Stuttgart, HRB 243294 -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
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