1 files changed, 39 insertions, 19 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 12afc5a..f82386b 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 */