Re: [Xen-devel] [PATCH v2] tools/xl: refuse to set number of vcpus to 0 via xl vcpu-set

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Wed, Sep 05, 2018 at 11:19:09AM +0100, Wei Liu wrote:
> On Mon, Sep 03, 2018 at 02:59:42PM +0200, Juergen Gross wrote:
> > Trying to set the number of vcpus of a domain to 0 isn't refused.
> > We should not allow that.
> > 
> > Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> > ---
> >  tools/libxl/libxl_domain.c | 6 ++++++
> >  tools/xl/xl_vcpu.c         | 5 +++--
> >  2 files changed, 9 insertions(+), 2 deletions(-)
> > 
> > diff --git a/tools/libxl/libxl_domain.c b/tools/libxl/libxl_domain.c
> > index 533bcdf240..3377bba994 100644
> > --- a/tools/libxl/libxl_domain.c
> > +++ b/tools/libxl/libxl_domain.c
> > @@ -1369,6 +1369,12 @@ int libxl_set_vcpuonline(libxl_ctx *ctx, uint32_t 
> > domid, libxl_bitmap *cpumap)
> >      }
> >  
> >      maxcpus = libxl_bitmap_count_set(cpumap);
> > +    if (maxcpus == 0)
> > +    {
> > +        LOGED(ERROR, domid, "Requested 0 VCPUs!");
> > +        rc = ERROR_FAIL;
> > +        goto out;
> > +    }
> >      if (maxcpus > info.vcpu_max_id + 1)
> >      {
> >          LOGED(ERROR, domid, "Requested %d VCPUs, however maxcpus is %d!",
> > diff --git a/tools/xl/xl_vcpu.c b/tools/xl/xl_vcpu.c
> > index aef486864c..3057c22aae 100644
> > --- a/tools/xl/xl_vcpu.c
> > +++ b/tools/xl/xl_vcpu.c
> > @@ -331,13 +331,14 @@ int main_vcpupin(int argc, char **argv)
> >  static int vcpuset(uint32_t domid, const char* nr_vcpus, int check_host)
> >  {
> >      char *endptr;
> > -    unsigned int max_vcpus, i;
> > +    unsigned int i;
> > +    unsigned long max_vcpus;
> >      libxl_bitmap cpumap;
> >      int rc;
> >  
> >      libxl_bitmap_init(&cpumap);
> >      max_vcpus = strtoul(nr_vcpus, &endptr, 10);
> > -    if (nr_vcpus == endptr) {
> > +    if (nr_vcpus == endptr || max_vcpus > INT_MAX) {
> 
> e -I/build/tools/xl/../../tools/include -D__XEN_TOOLS__ 
> -I/build/tools/xl/../../tools/include -Wshadow -include 
> /build/tools/xl/../../tools/config.h   -c -o xl_cdrom.o xl_cdrom.c
> xl_vcpu.c: In function 'vcpuset':
> xl_vcpu.c:341:43: error: 'INT_MAX' undeclared (first use in this function)
>      if (nr_vcpus == endptr || max_vcpus > INT_MAX) {
>                                            ^~~~~~~
> xl_vcpu.c:341:43: note: each undeclared identifier is reported only once for 
> each function it appears in
> xl_vcpu.c:361:29: error: format '%d' expects argument of type 'int', but 
> argument 4 has type 'long unsigned int' [-Werror=format=]
>              fprintf(stderr, "You are overcommmitting! You have %d physical" \
>                              ^
> xl_vcpu.c:379:74: error: format '%d' expects argument of type 'int', but 
> argument 4 has type 'long unsigned int' [-Werror=format=]
>          fprintf(stderr, "libxl_set_vcpuonline failed domid=%u max_vcpus=%d," 
> \
> 
> 
> Missing a header?
> 

Add limits.h and use %ld to print max_vcpus.

---8<---
From 2c0b1824b1cb33a2610f3f55299247f9e0464466 Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@xxxxxxxx>
Date: Mon, 3 Sep 2018 14:59:42 +0200
Subject: [PATCH] tools/xl: refuse to set number of vcpus to 0 via xl vcpu-set

Trying to set the number of vcpus of a domain to 0 isn't refused.
We should not allow that.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 tools/libxl/libxl_domain.c |  6 ++++++
 tools/xl/xl_vcpu.c         | 10 ++++++----
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/tools/libxl/libxl_domain.c b/tools/libxl/libxl_domain.c
index 533bcdf240..3377bba994 100644
--- a/tools/libxl/libxl_domain.c
+++ b/tools/libxl/libxl_domain.c
@@ -1369,6 +1369,12 @@ int libxl_set_vcpuonline(libxl_ctx *ctx, uint32_t domid, 
libxl_bitmap *cpumap)
     }
 
     maxcpus = libxl_bitmap_count_set(cpumap);
+    if (maxcpus == 0)
+    {
+        LOGED(ERROR, domid, "Requested 0 VCPUs!");
+        rc = ERROR_FAIL;
+        goto out;
+    }
     if (maxcpus > info.vcpu_max_id + 1)
     {
         LOGED(ERROR, domid, "Requested %d VCPUs, however maxcpus is %d!",
diff --git a/tools/xl/xl_vcpu.c b/tools/xl/xl_vcpu.c
index aef486864c..71d3a5c96d 100644
--- a/tools/xl/xl_vcpu.c
+++ b/tools/xl/xl_vcpu.c
@@ -13,6 +13,7 @@
  */
 
 #include <stdlib.h>
+#include <limits.h>
 
 #include <libxl.h>
 #include <libxl_utils.h>
@@ -331,13 +332,14 @@ int main_vcpupin(int argc, char **argv)
 static int vcpuset(uint32_t domid, const char* nr_vcpus, int check_host)
 {
     char *endptr;
-    unsigned int max_vcpus, i;
+    unsigned int i;
+    unsigned long max_vcpus;
     libxl_bitmap cpumap;
     int rc;
 
     libxl_bitmap_init(&cpumap);
     max_vcpus = strtoul(nr_vcpus, &endptr, 10);
-    if (nr_vcpus == endptr) {
+    if (nr_vcpus == endptr || max_vcpus > INT_MAX) {
         fprintf(stderr, "Error: Invalid argument.\n");
         return 1;
     }
@@ -358,7 +360,7 @@ static int vcpuset(uint32_t domid, const char* nr_vcpus, 
int check_host)
 
         if (max_vcpus > online_vcpus && max_vcpus > host_cpu) {
             fprintf(stderr, "You are overcommmitting! You have %d physical" \
-                    " CPUs and want %d vCPUs! Aborting, use --ignore-host to" \
+                    " CPUs and want %ld vCPUs! Aborting, use --ignore-host to" 
\
                     " continue\n", host_cpu, max_vcpus);
             return 1;
         }
@@ -375,7 +377,7 @@ static int vcpuset(uint32_t domid, const char* nr_vcpus, 
int check_host)
     if (rc == ERROR_DOMAIN_NOTFOUND)
         fprintf(stderr, "Domain %u does not exist.\n", domid);
     else if (rc)
-        fprintf(stderr, "libxl_set_vcpuonline failed domid=%u max_vcpus=%d," \
+        fprintf(stderr, "libxl_set_vcpuonline failed domid=%u max_vcpus=%ld," \
                 " rc: %d\n", domid, max_vcpus, rc);
 
     libxl_bitmap_dispose(&cpumap);
-- 
2.11.0


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel