bitkeeper revision 1.1236.1.96 (423d91c3JzdYyXv2iF0lgox0Q4n2tA)

fix mapping bugs in map_domain_va in xc_ptrace.c
map pages RO
Signed-off-by: Kip Macy <kmacy@fsmware.com>
Signed-off-by: ian@xensource.com

diff --git a/tools/libxc/xc_ptrace.c b/tools/libxc/xc_ptrace.c
index 0df422cd2cdef9348121813f75994dc234a2ac92..cac95cb7c41cbd122179b9e8c5b4028b540e87ff 100644 (file)
--- a/tools/libxc/xc_ptrace.c
+++ b/tools/libxc/xc_ptrace.c
@@ -123,7 +123,7 @@ static full_execution_context_t ctxt;
 /* --------------------- */
 
 static void *
-map_domain_va(unsigned long domid, void * guest_va)
+map_domain_va(unsigned long domid, void * guest_va, int perm)
 {
     unsigned long pde, page;
     unsigned long va = (unsigned long)guest_va;
@@ -134,6 +134,8 @@ map_domain_va(unsigned long domid, void * guest_va)
     static unsigned long *pde_virt;
     static unsigned long page_phys;
     static unsigned long *page_virt;
+    
+    static int prev_perm;
     if (!regs_valid) 
     {
        int retval = xc_domain_getfullinfo(xc_handle, domid, 0, NULL, &ctxt);
@@ -166,17 +168,19 @@ map_domain_va(unsigned long domid, void * guest_va)
     }
     if ((page = pde_virt[vtopti(va)]) == 0)
        goto error_out;
-    if (page != page_phys) 
+    if (page != page_phys || perm != prev_perm) 
     {
        page_phys = page;
        if (page_virt)
            munmap(page_virt, PAGE_SIZE);
        if ((page_virt = xc_map_foreign_range(xc_handle, domid, PAGE_SIZE,
-                                            PROT_READ|PROT_WRITE,
+                                            perm,
                                              page_phys >> PAGE_SHIFT)) == NULL) {
            printf("cr3 %lx pde %lx page %lx pti %lx\n", cr3, pde, page, vtopti(va));
+           page_phys = 0;
            goto error_out;
        }
+       prev_perm = perm;
     }  
     return (void *)(((unsigned long)page_virt) | (va & BSD_PAGE_MASK));
 
@@ -247,17 +251,21 @@ xc_ptrace(enum __ptrace_request request, pid_t pid, void *addr, void *data)
     switch (request) { 
     case PTRACE_PEEKTEXT:
     case PTRACE_PEEKDATA:
+       if ((guest_va = (unsigned long *)map_domain_va(pid, addr, PROT_READ)) == NULL) {
+           status = EFAULT;
+           goto done;
+       }
+
+       retval = *guest_va;
+       break;
     case PTRACE_POKETEXT:
     case PTRACE_POKEDATA:
-       if ((guest_va = (unsigned long *)map_domain_va(pid, addr)) == NULL) {
+       if ((guest_va = (unsigned long *)map_domain_va(pid, addr, PROT_READ|PROT_WRITE)) == NULL) {
            status = EFAULT;
            goto done;
        }
 
-       if (request == PTRACE_PEEKTEXT || request == PTRACE_PEEKDATA)
-           retval = *guest_va;
-       else
-           *guest_va = (unsigned long)data;
+       *guest_va = (unsigned long)data;
        break;
     case PTRACE_GETREGS:
     case PTRACE_GETFPREGS: