X-Git-Url: http://git.onelab.eu/?p=procprotect.git;a=blobdiff_plain;f=procprotect.c;h=cc5c11793a9bc61ae0f5f57d0c88cec6d8e81e7e;hp=56910b3271669037bbd446ed6797ec773d8accab;hb=c40c7bb97725cfe49729055d5d40901c0d2cda96;hpb=d53194f4cadff25c88ba781da36daeec563226a0

diff --git a/procprotect.c b/procprotect.c
index 56910b3..cc5c117 100644
--- a/procprotect.c
+++ b/procprotect.c
@@ -2,6 +2,7 @@
 #include <linux/moduleparam.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
+#include <linux/version.h>
 #include <linux/fs_struct.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
@@ -154,19 +155,47 @@ static int lookup_slow_entry(struct kretprobe_instance *ri, struct pt_regs *regs
 /* The entry hook ensures that the return hook is only called for
    accesses to /proc */
 
+static int print_once = 0;
+
 static int lookup_slow_ret(struct kretprobe_instance *ri, struct pt_regs *regs)
 {
-    struct procprotect_ctx *ctx = (struct procprotect_ctx *) ri->data;
-    int ret = regs->ax;
+    struct procprotect_ctx *ctx;
+    int ret;
+
+    if (!ri) {printk(KERN_CRIT "ri is 0x0");/* Race condition?*/ return 0;}
+    ctx = (struct procprotect_ctx *) ri->data;
+
+    if (!regs) {
+        if (!print_once++) {
+            printk(KERN_CRIT "Regs is 0x0");
+        }
+        return 0;
+    }
+
+    ret = regs->ax;
 
     if (ret==0) {
-        /* The kernel is going to honor the request. Here's where we step in */
-        /*struct qstr *q = ctx->q;
-        if (!strncmp(q->name,"sysrq-trigger",13)) {
-            printk(KERN_CRIT "lookup_slow sysrqtrigger");
-        }*/
         struct path *p = ctx->path;
+        if (!p) {
+            if (!print_once++) {
+                printk(KERN_CRIT "P is 0x0");
+            }
+            return 0;
+        }
+        if (!p->dentry) {
+            if (!print_once++) {
+                printk(KERN_CRIT "P->dentry is 0x0");
+            }
+            return 0;
+        }
+
         struct inode *inode = p->dentry->d_inode;
+        if (!inode) {
+            if (!print_once++) {
+                printk(KERN_CRIT "inode is 0x0");
+            }
+            return 0;
+        }
         if (!run_acl(inode->i_ino)) {
             regs->ax = -EPERM;
         }
@@ -288,11 +317,12 @@ int procfile_write(struct file *file, const char *buffer, unsigned long count, v
 
 static int __init procprotect_init(void)
 {
-    printk("Procprotect: starting procprotect version %s with ACLs at path %s.\n",
-            VERSION_STR, aclpath);
     int ret;
     int i;
 
+    printk("Procprotect: starting procprotect version %s with ACLs at path %s.\n",
+            VERSION_STR, aclpath);
+
     for(i=0;i<HASH_SIZE;i++) {
         INIT_HLIST_HEAD(&procprotect_hash[i]);
     }