I have not tested this, but it's "obviously correct", and it
should fix a minor error reported by the Stanford checker in khttpd;
see http://marc.theaimsgroup.com/?l=linux-kernel&m=99601418013486
It was posted to the khttpd mailing list a week or so ago.
Comments welcome.
- Dan
--- linux-2.4.19-pre9/net/khttpd/security.c.orig Tue Aug 6 16:13:21 2002
+++ linux/net/khttpd/security.c Tue Aug 6 16:33:08 2002
@@ -83,22 +83,21 @@
*/
struct file *OpenFileForSecurity(char *Filename)
{
- struct file *filp;
+ struct file *filp = NULL;
struct DynamicString *List;
umode_t permission;
-
-
EnterFunction("OpenFileForSecurity");
if (Filename==NULL)
- return NULL;
+ goto out_error;
- if (strlen(Filename)>=256 ) return NULL; /* Sanity check */
+ if (strlen(Filename)>=256 )
+ goto out_error; /* Sanity check */
/* Rule no. 1 -- No "?" characters */
#ifndef BENCHMARK
if (strchr(Filename,'?')!=NULL)
- return NULL;
+ goto out_error;
/* Intermediate step: decode all %hex sequences */
@@ -106,9 +105,8 @@
/* Rule no. 2 -- Must start with a "/" */
-
if (Filename[0]!='/')
- return NULL;
+ goto out_error;
#endif
/* Rule no. 3 -- Does the file exist ? */
@@ -116,55 +114,44 @@
filp = filp_open(Filename, O_RDONLY, 0);
if (IS_ERR(filp))
- return NULL;
+ goto out_error;
#ifndef BENCHMARK
permission = filp->f_dentry->d_inode->i_mode;
/* Rule no. 4 : must have enough permissions */
-
if ((permission & sysctl_khttpd_permreq)==0)
- {
- if (filp!=NULL)
- fput(filp);
- filp=NULL;
- return NULL;
- }
-
+ goto out_error_put;
+
/* Rule no. 5 : cannot have "forbidden" permission */
-
if ((permission & sysctl_khttpd_permforbid)!=0)
- {
- if (filp!=NULL)
- fput(filp);
- filp=NULL;
- return NULL;
- }
+ goto out_error_put;
/* Rule no. 6 : No string in DynamicList can be a
substring of the filename */
-
List = DynamicList;
-
while (List!=NULL)
{
if (strstr(Filename,List->value)!=NULL)
- {
- if (filp!=NULL)
- fput(filp);
- filp=NULL;
- return NULL;
- }
+ goto out_error_put;
+
List = List->Next;
}
#endif
LeaveFunction("OpenFileForSecurity - success");
-
+out:
return filp;
+
+out_error_put:
+ fput(filp);
+out_error:
+ filp=NULL;
+ LeaveFunction("OpenFileForSecurity - fail");
+ goto out;
}
/*
-
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This archive was generated by hypermail 2b29 : Thu Aug 15 2002 - 22:00:32 EST