Merge remote-tracking branch 'riku/linux-user-for-upstream' into staging

linux-user/elfload.c

@@ -332,6 +332,49 @@ enum
     ARM_HWCAP_ARM_VFPv3D16  = 1 << 13,
 };
 
+#define TARGET_HAS_GUEST_VALIDATE_BASE
+/* We want the opportunity to check the suggested base */
+bool guest_validate_base(unsigned long guest_base)
+{
+    unsigned long real_start, test_page_addr;
+
+    /* We need to check that we can force a fault on access to the
+     * commpage at 0xffff0fxx
+     */
+    test_page_addr = guest_base + (0xffff0f00 & qemu_host_page_mask);
+    /* Note it needs to be writeable to let us initialise it */
+    real_start = (unsigned long)
+                 mmap((void *)test_page_addr, qemu_host_page_size,
+                     PROT_READ | PROT_WRITE,
+                     MAP_ANONYMOUS | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+
+    /* If we can't map it then try another address */
+    if (real_start == -1ul) {
+        return 0;
+    }
+
+    if (real_start != test_page_addr) {
+        /* OS didn't put the page where we asked - unmap and reject */
+        munmap((void *)real_start, qemu_host_page_size);
+        return 0;
+    }
+
+    /* Leave the page mapped
+     * Populate it (mmap should have left it all 0'd)
+     */
+
+    /* Kernel helper versions */
+    __put_user(5, (uint32_t *)g2h(0xffff0ffcul));
+
+    /* Now it's populated make it RO */
+    if (mprotect((void *)test_page_addr, qemu_host_page_size, PROT_READ)) {
+        perror("Protecting guest commpage");
+        exit(-1);
+    }
+
+    return 1; /* All good */
+}
+
 #define ELF_HWCAP (ARM_HWCAP_ARM_SWP | ARM_HWCAP_ARM_HALF               \
                    | ARM_HWCAP_ARM_THUMB | ARM_HWCAP_ARM_FAST_MULT      \
                    | ARM_HWCAP_ARM_FPA | ARM_HWCAP_ARM_VFP              \
@@ -1309,6 +1352,14 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
     return sp;
 }
 
+#ifndef TARGET_HAS_GUEST_VALIDATE_BASE
+/* If the guest doesn't have a validation function just agree */
+bool guest_validate_base(unsigned long guest_base)
+{
+    return 1;
+}
+#endif
+
 static void probe_guest_base(const char *image_name,
                              abi_ulong loaddr, abi_ulong hiaddr)
 {
@@ -1345,7 +1396,9 @@ static void probe_guest_base(const char *image_name,
             if (real_start == (unsigned long)-1) {
                 goto exit_perror;
             }
-            if (real_start == host_start) {
+            guest_base = real_start - loaddr;
+            if ((real_start == host_start) &&
+                guest_validate_base(guest_base)) {
                 break;
             }
             /* That address didn't work.  Unmap and try a different one.
@@ -1368,7 +1421,6 @@ static void probe_guest_base(const char *image_name,
         qemu_log("Relocating guest address space from 0x"
                  TARGET_ABI_FMT_lx " to 0x%lx\n",
                  loaddr, real_start);
-        guest_base = real_start - loaddr;
     }
     return;
 

linux-user/qemu.h

@@ -202,6 +202,12 @@ int get_osversion(void);
 void fork_start(void);
 void fork_end(int child);
 
+/* Return true if the proposed guest_base is suitable for the guest.
+ * The guest code may leave a page mapped and populate it if the
+ * address is suitable.
+ */
+bool guest_validate_base(unsigned long guest_base);
+
 #include "qemu-log.h"
 
 /* strace.c */

linux-user/syscall.c

@@ -70,6 +70,9 @@ int __clone2(int (*fn)(void *), void *child_stack_base,
 #ifdef CONFIG_EPOLL
 #include <sys/epoll.h>
 #endif
+#ifdef CONFIG_ATTR
+#include <attr/xattr.h>
+#endif
 
 #define termios host_termios
 #define winsize host_winsize
@@ -796,6 +799,15 @@ abi_long do_brk(abi_ulong new_brk)
                                         MAP_ANON|MAP_PRIVATE, 0, 0));
 
     if (mapped_addr == brk_page) {
+        /* Heap contents are initialized to zero, as for anonymous
+         * mapped pages.  Technically the new pages are already
+         * initialized to zero since they *are* anonymous mapped
+         * pages, however we have to take care with the contents that
+         * come from the remaining part of the previous page: it may
+         * contains garbage data due to a previous heap usage (grown
+         * then shrunken).  */
+        memset(g2h(target_brk), 0, brk_page - target_brk);
+
         target_brk = new_brk;
         brk_page = HOST_PAGE_ALIGN(target_brk);
         DEBUGF_BRK("%#010x (mapped_addr == brk_page)\n", target_brk);
@@ -7632,22 +7644,67 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
 #endif
         break;
 #endif
+#ifdef CONFIG_ATTR
 #ifdef TARGET_NR_setxattr
-    case TARGET_NR_setxattr:
     case TARGET_NR_lsetxattr:
     case TARGET_NR_fsetxattr:
-    case TARGET_NR_getxattr:
     case TARGET_NR_lgetxattr:
     case TARGET_NR_fgetxattr:
     case TARGET_NR_listxattr:
     case TARGET_NR_llistxattr:
     case TARGET_NR_flistxattr:
-    case TARGET_NR_removexattr:
     case TARGET_NR_lremovexattr:
     case TARGET_NR_fremovexattr:
         ret = -TARGET_EOPNOTSUPP;
         break;
+    case TARGET_NR_setxattr:
+        {
+            void *p, *n, *v;
+            p = lock_user_string(arg1);
+            n = lock_user_string(arg2);
+            v = lock_user(VERIFY_READ, arg3, arg4, 1);
+            if (p && n && v) {
+                ret = get_errno(setxattr(p, n, v, arg4, arg5));
+            } else {
+                ret = -TARGET_EFAULT;
+            }
+            unlock_user(p, arg1, 0);
+            unlock_user(n, arg2, 0);
+            unlock_user(v, arg3, 0);
+        }
+        break;
+    case TARGET_NR_getxattr:
+        {
+            void *p, *n, *v;
+            p = lock_user_string(arg1);
+            n = lock_user_string(arg2);
+            v = lock_user(VERIFY_WRITE, arg3, arg4, 0);
+            if (p && n && v) {
+                ret = get_errno(getxattr(p, n, v, arg4));
+            } else {
+                ret = -TARGET_EFAULT;
+            }
+            unlock_user(p, arg1, 0);
+            unlock_user(n, arg2, 0);
+            unlock_user(v, arg3, arg4);
+        }
+        break;
+    case TARGET_NR_removexattr:
+        {
+            void *p, *n;
+            p = lock_user_string(arg1);
+            n = lock_user_string(arg2);
+            if (p && n) {
+                ret = get_errno(removexattr(p, n));
+            } else {
+                ret = -TARGET_EFAULT;
+            }
+            unlock_user(p, arg1, 0);
+            unlock_user(n, arg2, 0);
+        }
+        break;
 #endif
+#endif /* CONFIG_ATTR */
 #ifdef TARGET_NR_set_thread_area
     case TARGET_NR_set_thread_area:
 #if defined(TARGET_MIPS)