2 files changed, 57 insertions, 13 deletions

diff --git a/include/linux/module.h b/include/linux/module.h
index 1d3ccb173fd6..aca980365956 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -315,7 +315,7 @@ struct module
          */
         Elf_Sym *symtab, *core_symtab;
         unsigned int num_symtab, core_num_syms;
-        char *strtab;
+        char *strtab, *core_strtab;
 
         /* Section attributes */
         struct module_sect_attrs *sect_attrs;
diff --git a/kernel/module.c b/kernel/module.c
index 97f4d5e15535..39827c3d9484 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1886,12 +1886,17 @@ static bool is_core_symbol(const Elf_Sym *src, const Elf_Shdr *sechdrs,
 static unsigned long layout_symtab(struct module *mod,
                                    Elf_Shdr *sechdrs,
                                    unsigned int symindex,
+                                   unsigned int strindex,
                                    const Elf_Ehdr *hdr,
-                                   const char *secstrings)
+                                   const char *secstrings,
+                                   unsigned long *pstroffs,
+                                   unsigned long *strmap)
 {
         unsigned long symoffs;
         Elf_Shdr *symsect = sechdrs + symindex;
+        Elf_Shdr *strsect = sechdrs + strindex;
         const Elf_Sym *src;
+        const char *strtab;
         unsigned int i, nsrc, ndst;
 
         /* Put symbol section at end of init part of module. */
@@ -1902,14 +1907,31 @@ static unsigned long layout_symtab(struct module *mod,
 
         src = (void *)hdr + symsect->sh_offset;
         nsrc = symsect->sh_size / sizeof(*src);
+        strtab = (void *)hdr + strsect->sh_offset;
         for (ndst = i = 1; i < nsrc; ++i, ++src)
-                if (is_core_symbol(src, sechdrs, hdr->e_shnum))
+                if (is_core_symbol(src, sechdrs, hdr->e_shnum)) {
+                        unsigned int j = src->st_name;
+
+                        while(!__test_and_set_bit(j, strmap) && strtab[j])
+                                ++j;
                         ++ndst;
+                }
 
         /* Append room for core symbols at end of core part. */
         symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1);
         mod->core_size = symoffs + ndst * sizeof(Elf_Sym);
 
+        /* Put string table section at end of init part of module. */
+        strsect->sh_flags |= SHF_ALLOC;
+        strsect->sh_entsize = get_offset(mod, &mod->init_size, strsect,
+                                         strindex) | INIT_OFFSET_MASK;
+        DEBUGP("\t%s\n", secstrings + strsect->sh_name);
+
+        /* Append room for core symbols' strings at end of core part. */
+        *pstroffs = mod->core_size;
+        __set_bit(0, strmap);
+        mod->core_size += bitmap_weight(strmap, strsect->sh_size);
+
         return symoffs;
 }
 
@@ -1919,11 +1941,14 @@ static void add_kallsyms(struct module *mod,
                          unsigned int symindex,
                          unsigned int strindex,
                          unsigned long symoffs,
-                         const char *secstrings)
+                         unsigned long stroffs,
+                         const char *secstrings,
+                         unsigned long *strmap)
 {
         unsigned int i, ndst;
         const Elf_Sym *src;
         Elf_Sym *dst;
+        char *s;
 
         mod->symtab = (void *)sechdrs[symindex].sh_addr;
         mod->num_symtab = sechdrs[symindex].sh_size / sizeof(Elf_Sym);
@@ -1941,16 +1966,25 @@ static void add_kallsyms(struct module *mod,
                 if (!is_core_symbol(src, sechdrs, shnum))
                         continue;
                 dst[ndst] = *src;
+                dst[ndst].st_name = bitmap_weight(strmap, dst[ndst].st_name);
                 ++ndst;
         }
         mod->core_num_syms = ndst;
+
+        mod->core_strtab = s = mod->module_core + stroffs;
+        for (*s = 0, i = 1; i < sechdrs[strindex].sh_size; ++i)
+                if (test_bit(i, strmap))
+                        *++s = mod->strtab[i];
 }
 #else
 static inline unsigned long layout_symtab(struct module *mod,
                                           Elf_Shdr *sechdrs,
                                           unsigned int symindex,
+                                          unsigned int strindex,
                                           const Elf_Hdr *hdr,
-                                          const char *secstrings)
+                                          const char *secstrings,
+                                          unsigned long *pstroffs,
+                                          unsigned long *strmap)
 {
 }
 static inline void add_kallsyms(struct module *mod,
@@ -1959,7 +1993,9 @@ static inline void add_kallsyms(struct module *mod,
                                 unsigned int symindex,
                                 unsigned int strindex,
                                 unsigned long symoffs,
-                                const char *secstrings)
+                                unsigned long stroffs,
+                                const char *secstrings,
+                                const unsigned long *strmap)
 {
 }
 #endif /* CONFIG_KALLSYMS */
@@ -2035,7 +2071,7 @@ static noinline struct module *load_module(void __user *umod,
         long err = 0;
         void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
 #ifdef CONFIG_KALLSYMS
-        unsigned long symoffs;
+        unsigned long symoffs, stroffs, *strmap;
 #endif
         mm_segment_t old_fs;
 
@@ -2118,10 +2154,6 @@ static noinline struct module *load_module(void __user *umod,
         /* Don't keep modinfo and version sections. */
         sechdrs[infoindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
         sechdrs[versindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
-#ifdef CONFIG_KALLSYMS
-        /* Keep string table for decoding later. */
-        sechdrs[strindex].sh_flags |= SHF_ALLOC;
-#endif
 
         /* Check module struct version now, before we try to use module. */
         if (!check_modstruct_version(sechdrs, versindex, mod)) {
@@ -2157,6 +2189,13 @@ static noinline struct module *load_module(void __user *umod,
                 goto free_hdr;
         }
 
+        strmap = kzalloc(BITS_TO_LONGS(sechdrs[strindex].sh_size)
+                         * sizeof(long), GFP_KERNEL);
+        if (!strmap) {
+                err = -ENOMEM;
+                goto free_mod;
+        }
+
         if (find_module(mod->name)) {
                 err = -EEXIST;
                 goto free_mod;
@@ -2186,7 +2225,8 @@ static noinline struct module *load_module(void __user *umod,
            this is done generically; there doesn't appear to be any
            special cases for the architectures. */
         layout_sections(mod, hdr, sechdrs, secstrings);
-        symoffs = layout_symtab(mod, sechdrs, symindex, hdr, secstrings);
+        symoffs = layout_symtab(mod, sechdrs, symindex, strindex, hdr,
+                                secstrings, &stroffs, strmap);
 
         /* Do the allocs. */
         ptr = module_alloc_update_bounds(mod->core_size);
@@ -2392,7 +2432,9 @@ static noinline struct module *load_module(void __user *umod,
                        sechdrs[pcpuindex].sh_size);
 
         add_kallsyms(mod, sechdrs, hdr->e_shnum, symindex, strindex,
-                     symoffs, secstrings);
+                     symoffs, stroffs, secstrings, strmap);
+        kfree(strmap);
+        strmap = NULL;
 
         if (!mod->taints) {
                 struct _ddebug *debug;
@@ -2481,6 +2523,7 @@ static noinline struct module *load_module(void __user *umod,
                 percpu_modfree(percpu);
  free_mod:
         kfree(args);
+        kfree(strmap);
  free_hdr:
         vfree(hdr);
         return ERR_PTR(err);
@@ -2573,6 +2616,7 @@ SYSCALL_DEFINE3(init_module, void __user *, umod,
 #ifdef CONFIG_KALLSYMS
         mod->num_symtab = mod->core_num_syms;
         mod->symtab = mod->core_symtab;
+        mod->strtab = mod->core_strtab;
 #endif
         module_free(mod, mod->module_init);
         mod->module_init = NULL;