[Xen-devel] [PATCH v2 39/52] xen: check parameter validity when parsing command line

[Juergen Gross <jgross@xxxxxxxx>]

Where possible check validity of parameters in _cmdline_parse() and
issue a warning message in case of an error detected.

Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
V2:
- replaced literal 8 by BITS_PER_BYTE (Wei Liu)
- added test for empty string to parse_bool()
---
 xen/common/kernel.c | 47 ++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 36 insertions(+), 11 deletions(-)

diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index ce7cb8adb5..756380be5b 100644
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -23,9 +23,11 @@ enum system_state system_state = SYS_STATE_early_boot;
 xen_commandline_t saved_cmdline;
 static const char __initconst opt_builtin_cmdline[] = CONFIG_CMDLINE;
 
-static void __init assign_integer_param(
+static int __init assign_integer_param(
     const struct kernel_param *param, uint64_t val)
 {
+    unsigned int bits = param->len * BITS_PER_BYTE;
+
     switch ( param->len )
     {
     case sizeof(uint8_t):
@@ -43,14 +45,17 @@ static void __init assign_integer_param(
     default:
         BUG();
     }
+
+    return ( (val & (~0ULL << bits)) && ~(val | (~0ULL >> (65 - bits))) ) ?
+           -EOVERFLOW : 0;
 }
 
 static void __init _cmdline_parse(const char *cmdline)
 {
     char opt[128], *optval, *optkey, *q;
-    const char *p = cmdline;
+    const char *p = cmdline, *s;
     const struct kernel_param *param;
-    int bool_assert;
+    int bool_assert, rc = 0;
 
     for ( ; ; )
     {
@@ -97,8 +102,9 @@ static void __init _cmdline_parse(const char *cmdline)
                      !strncmp(param->name, opt, q + 1 - opt) )
                 {
                     optval[-1] = '=';
-                    ((void (*)(const char *))param->var)(q);
+                    rc = ((int (*)(const char *))param->var)(q);
                     optval[-1] = '\0';
+                    break;
                 }
                 continue;
             }
@@ -106,24 +112,34 @@ static void __init _cmdline_parse(const char *cmdline)
             switch ( param->type )
             {
             case OPT_STR:
+                rc = 0;
                 strlcpy(param->var, optval, param->len);
                 break;
             case OPT_UINT:
-                assign_integer_param(
+                rc = assign_integer_param(
                     param,
-                    simple_strtoll(optval, NULL, 0));
+                    simple_strtoll(optval, &s, 0));
+                if ( *s )
+                    rc = -EINVAL;
                 break;
             case OPT_BOOL:
-                if ( !parse_bool(optval) )
+                rc = parse_bool(optval);
+                if ( rc == -1 )
+                    break;
+                if ( !rc )
                     bool_assert = !bool_assert;
+                rc = 0;
                 assign_integer_param(param, bool_assert);
                 break;
             case OPT_SIZE:
-                assign_integer_param(
+                rc = assign_integer_param(
                     param,
-                    parse_size_and_unit(optval, NULL));
+                    parse_size_and_unit(optval, &s));
+                if ( *s )
+                    rc = -EINVAL;
                 break;
             case OPT_CUSTOM:
+                rc = -EINVAL;
                 if ( !bool_assert )
                 {
                     if ( *optval )
@@ -131,13 +147,21 @@ static void __init _cmdline_parse(const char *cmdline)
                     safe_strcpy(opt, "no");
                     optval = opt;
                 }
-                ((void (*)(const char *))param->var)(optval);
+                rc = ((int (*)(const char *))param->var)(optval);
                 break;
             default:
                 BUG();
                 break;
             }
+
+            break;
         }
+
+        if ( rc )
+            printk("parameter \"%s\" has invalid value \"%s\"!\n", optkey,
+                   optval);
+        if ( param >= __setup_end )
+            printk("parameter \"%s\" unknown!\n", optkey);
     }
 }
 
@@ -176,7 +200,8 @@ int __init parse_bool(const char *s)
          !strcmp("on", s) ||
          !strcmp("true", s) ||
          !strcmp("enable", s) ||
-         !strcmp("1", s) )
+         !strcmp("1", s) ||
+         !*s )
         return 1;
 
     return -1;
-- 
2.12.3


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