[Xen-devel] [PATCH v3 09/52] xen/arch/x86/hvm/viridian.c: let custom parameter parsing routines return errno

[Juergen Gross <jgross@xxxxxxxx>]

Modify the custom parameter parsing routines in:

xen/arch/x86/hvm/viridian.c

to indicate whether the parameter value was parsed successfully.

Fix an error in the parsing function: up to now it would overwrite the
stack in case more than 3 values are specified.

Cc: Paul Durrant <paul.durrant@xxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
V3:
- dont modify option value in parsing function
- fix error in parsing routine
---
 xen/arch/x86/hvm/viridian.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/xen/arch/x86/hvm/viridian.c b/xen/arch/x86/hvm/viridian.c
index aa9b87c0ab..2edf9d0b23 100644
--- a/xen/arch/x86/hvm/viridian.c
+++ b/xen/arch/x86/hvm/viridian.c
@@ -1083,7 +1083,7 @@ static int viridian_load_vcpu_ctxt(struct domain *d, 
hvm_domain_context_t *h)
 HVM_REGISTER_SAVE_RESTORE(VIRIDIAN_VCPU, viridian_save_vcpu_ctxt,
                           viridian_load_vcpu_ctxt, 1, HVMSR_PER_VCPU);
 
-static void __init parse_viridian_version(char *arg)
+static int __init parse_viridian_version(const char *arg)
 {
     const char *t;
     unsigned int n[3];
@@ -1093,17 +1093,24 @@ static void __init parse_viridian_version(char *arg)
     n[1] = viridian_minor;
     n[2] = viridian_build;
 
-    while ( (t = strsep(&arg, ",")) != NULL )
-    {
+    do {
         const char *e;
 
-        if ( *t == '\0' )
-            continue;
+        t = strchr(arg, ',');
+        if ( !t )
+            t = strchr(arg, '\0');
+
+        if ( *arg && *arg != ',' && i < 3 )
+        {
+            n[i] = simple_strtoul(arg, &e, 0);
+            if ( e != t )
+                goto fail;
+        }
+
+        i++;
+        arg = t + 1;
+    } while ( *t );
 
-        n[i++] = simple_strtoul(t, &e, 0);
-        if ( *e != '\0' )
-            goto fail;
-    }
     if ( i != 3 )
         goto fail;
 
@@ -1118,10 +1125,11 @@ static void __init parse_viridian_version(char *arg)
 
     printk("viridian-version = %#x,%#x,%#x\n",
            viridian_major, viridian_minor, viridian_build);
-    return;
+    return 0;
 
  fail:
     printk(XENLOG_WARNING "Invalid viridian-version, using default\n");
+    return -EINVAL;
 }
 custom_param("viridian-version", parse_viridian_version);
 
-- 
2.12.3


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