1 files changed, 39 insertions, 19 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 12afc5a3ddd3..f82386bd9ee9 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -880,11 +880,23 @@ static int try_to_force_load(struct module *mod, const char *reason)
 }
 
 #ifdef CONFIG_MODVERSIONS
+/* If the arch applies (non-zero) relocations to kernel kcrctab, unapply it. */
+static unsigned long maybe_relocated(unsigned long crc,
+                                     const struct module *crc_owner)
+{
+#ifdef ARCH_RELOCATES_KCRCTAB
+        if (crc_owner == NULL)
+                return crc - (unsigned long)reloc_start;
+#endif
+        return crc;
+}
+
 static int check_version(Elf_Shdr *sechdrs,
                          unsigned int versindex,
                          const char *symname,
                          struct module *mod, 
-                         const unsigned long *crc)
+                         const unsigned long *crc,
+                         const struct module *crc_owner)
 {
         unsigned int i, num_versions;
         struct modversion_info *versions;
@@ -905,10 +917,10 @@ static int check_version(Elf_Shdr *sechdrs,
                 if (strcmp(versions[i].name, symname) != 0)
                         continue;
 
-                if (versions[i].crc == *crc)
+                if (versions[i].crc == maybe_relocated(*crc, crc_owner))
                         return 1;
                 DEBUGP("Found checksum %lX vs module %lX\n",
-                       *crc, versions[i].crc);
+                       maybe_relocated(*crc, crc_owner), versions[i].crc);
                 goto bad_version;
         }
 
@@ -931,7 +943,8 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs,
         if (!find_symbol(MODULE_SYMBOL_PREFIX "module_layout", NULL,
                          &crc, true, false))
                 BUG();
-        return check_version(sechdrs, versindex, "module_layout", mod, crc);
+        return check_version(sechdrs, versindex, "module_layout", mod, crc,
+                             NULL);
 }
 
 /* First part is kernel version, which we ignore if module has crcs. */
@@ -949,7 +962,8 @@ static inline int check_version(Elf_Shdr *sechdrs,
                                 unsigned int versindex,
                                 const char *symname,
                                 struct module *mod, 
-                                const unsigned long *crc)
+                                const unsigned long *crc,
+                                const struct module *crc_owner)
 {
         return 1;
 }
@@ -984,8 +998,8 @@ static const struct kernel_symbol *resolve_symbol(Elf_Shdr *sechdrs,
         /* use_module can fail due to OOM,
            or module initialization or unloading */
         if (sym) {
-                if (!check_version(sechdrs, versindex, name, mod, crc) ||
-                    !use_module(mod, owner))
+                if (!check_version(sechdrs, versindex, name, mod, crc, owner)
+                    || !use_module(mod, owner))
                         sym = NULL;
         }
         return sym;
@@ -996,6 +1010,12 @@ static const struct kernel_symbol *resolve_symbol(Elf_Shdr *sechdrs,
  * J. Corbet <corbet@lwn.net>
  */
 #if defined(CONFIG_KALLSYMS) && defined(CONFIG_SYSFS)
+
+static inline bool sect_empty(const Elf_Shdr *sect)
+{
+        return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0;
+}
+
 struct module_sect_attr
 {
         struct module_attribute mattr;
@@ -1037,8 +1057,7 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect,
 
         /* Count loaded sections and allocate structures */
         for (i = 0; i < nsect; i++)
-                if (sechdrs[i].sh_flags & SHF_ALLOC
-                    && sechdrs[i].sh_size)
+                if (!sect_empty(&sechdrs[i]))
                         nloaded++;
         size[0] = ALIGN(sizeof(*sect_attrs)
                         + nloaded * sizeof(sect_attrs->attrs[0]),
@@ -1056,9 +1075,7 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect,
         sattr = &sect_attrs->attrs[0];
         gattr = &sect_attrs->grp.attrs[0];
         for (i = 0; i < nsect; i++) {
-                if (! (sechdrs[i].sh_flags & SHF_ALLOC))
-                        continue;
-                if (!sechdrs[i].sh_size)
+                if (sect_empty(&sechdrs[i]))
                         continue;
                 sattr->address = sechdrs[i].sh_addr;
                 sattr->name = kstrdup(secstrings + sechdrs[i].sh_name,
@@ -1142,7 +1159,7 @@ static void add_notes_attrs(struct module *mod, unsigned int nsect,
         /* Count notes sections and allocate structures.  */
         notes = 0;
         for (i = 0; i < nsect; i++)
-                if ((sechdrs[i].sh_flags & SHF_ALLOC) &&
+                if (!sect_empty(&sechdrs[i]) &&
                     (sechdrs[i].sh_type == SHT_NOTE))
                         ++notes;
 
@@ -1158,7 +1175,7 @@ static void add_notes_attrs(struct module *mod, unsigned int nsect,
         notes_attrs->notes = notes;
         nattr = &notes_attrs->attrs[0];
         for (loaded = i = 0; i < nsect; ++i) {
-                if (!(sechdrs[i].sh_flags & SHF_ALLOC))
+                if (sect_empty(&sechdrs[i]))
                         continue;
                 if (sechdrs[i].sh_type == SHT_NOTE) {
                         nattr->attr.name = mod->sect_attrs->attrs[loaded].name;
@@ -1896,9 +1913,7 @@ static void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr,
         unsigned int i;
 
         /* only scan the sections containing data */
-        kmemleak_scan_area(mod->module_core, (unsigned long)mod -
-                           (unsigned long)mod->module_core,
-                           sizeof(struct module), GFP_KERNEL);
+        kmemleak_scan_area(mod, sizeof(struct module), GFP_KERNEL);
 
         for (i = 1; i < hdr->e_shnum; i++) {
                 if (!(sechdrs[i].sh_flags & SHF_ALLOC))
@@ -1907,8 +1922,7 @@ static void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr,
                     && strncmp(secstrings + sechdrs[i].sh_name, ".bss", 4) != 0)
                         continue;
 
-                kmemleak_scan_area(mod->module_core, sechdrs[i].sh_addr -
-                                   (unsigned long)mod->module_core,
+                kmemleak_scan_area((void *)sechdrs[i].sh_addr,
                                    sechdrs[i].sh_size, GFP_KERNEL);
         }
 }
@@ -2236,6 +2250,12 @@ static noinline struct module *load_module(void __user *umod,
                                          "_ftrace_events",
                                          sizeof(*mod->trace_events),
                                          &mod->num_trace_events);
+        /*
+         * This section contains pointers to allocated objects in the trace
+         * code and not scanning it leads to false positives.
+         */
+        kmemleak_scan_area(mod->trace_events, sizeof(*mod->trace_events) *
+                           mod->num_trace_events, GFP_KERNEL);
 #endif
 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
         /* sechdrs[0].sh_size is always zero */