[Xen-changelog] fix mapping bugs in map_domain_va in xc_ptrace.c

[BitKeeper Bot <riel@xxxxxxxxxxx>]

ChangeSet 1.1332, 2005/03/20 15:07:47+00:00, iap10@xxxxxxxxxxxxxxxxxxxx

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



 xc_ptrace.c |   24 ++++++++++++++++--------
 1 files changed, 16 insertions(+), 8 deletions(-)


diff -Nru a/tools/libxc/xc_ptrace.c b/tools/libxc/xc_ptrace.c
--- a/tools/libxc/xc_ptrace.c   2005-03-21 11:03:13 -05:00
+++ b/tools/libxc/xc_ptrace.c   2005-03-21 11:03:13 -05:00
@@ -123,7 +123,7 @@
 /* --------------------- */
 
 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 @@
     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 @@
     }
     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 @@
     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:


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