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authorAlexey Dobriyan <adobriyan@sw.ru>2007-05-08 00:28:39 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-08 11:15:08 -0700
commitea07890a680273b25127129fb555aac0d9324bea (patch)
treeb0742aa5dd90792dc10be3563c1181582d0f5d9e
parentae84e324709d6320ed8c1fd7b1736fcbaf26df95 (diff)
Fix race between rmmod and cat /proc/kallsyms
module_get_kallsym() leaks "struct module *" outside of module_mutex which is no-no, because module can dissapear right after mutex unlock. Copy all needed information from inside module_mutex into caller-supplied space. [bunk@stusta.de: is_exported() can now become static] Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/module.h21
-rw-r--r--kernel/kallsyms.c30
-rw-r--r--kernel/module.c12
3 files changed, 29 insertions, 34 deletions
diff --git a/include/linux/module.h b/include/linux/module.h
index 79993021662..58d5a10cdf0 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -370,16 +370,14 @@ struct module *module_text_address(unsigned long addr);
struct module *__module_text_address(unsigned long addr);
int is_module_address(unsigned long addr);
-/* Returns module and fills in value, defined and namebuf, or NULL if
+/* Returns 0 and fills in value, defined and namebuf, or -ERANGE if
symnum out of range. */
-struct module *module_get_kallsym(unsigned int symnum, unsigned long *value,
- char *type, char *name);
+int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
+ char *name, char *module_name, int *exported);
/* Look for this name: can be of form module:name. */
unsigned long module_kallsyms_lookup_name(const char *name);
-int is_exported(const char *name, const struct module *mod);
-
extern void __module_put_and_exit(struct module *mod, long code)
__attribute__((noreturn));
#define module_put_and_exit(code) __module_put_and_exit(THIS_MODULE, code);
@@ -527,11 +525,11 @@ static inline const char *module_address_lookup(unsigned long addr,
return NULL;
}
-static inline struct module *module_get_kallsym(unsigned int symnum,
- unsigned long *value,
- char *type, char *name)
+static inline int module_get_kallsym(unsigned int symnum, unsigned long *value,
+ char *type, char *name,
+ char *module_name, int *exported)
{
- return NULL;
+ return -ERANGE;
}
static inline unsigned long module_kallsyms_lookup_name(const char *name)
@@ -539,11 +537,6 @@ static inline unsigned long module_kallsyms_lookup_name(const char *name)
return 0;
}
-static inline int is_exported(const char *name, const struct module *mod)
-{
- return 0;
-}
-
static inline int register_module_notifier(struct notifier_block * nb)
{
/* no events will happen anyway, so this can always succeed */
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index d086c91d44e..f1ea6f66ac6 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -301,25 +301,20 @@ void __print_symbol(const char *fmt, unsigned long address)
struct kallsym_iter
{
loff_t pos;
- struct module *owner;
unsigned long value;
unsigned int nameoff; /* If iterating in core kernel symbols */
char type;
char name[KSYM_NAME_LEN+1];
+ char module_name[MODULE_NAME_LEN + 1];
+ int exported;
};
static int get_ksymbol_mod(struct kallsym_iter *iter)
{
- iter->owner = module_get_kallsym(iter->pos - kallsyms_num_syms,
- &iter->value, &iter->type,
- iter->name);
- if (iter->owner == NULL)
+ if (module_get_kallsym(iter->pos - kallsyms_num_syms, &iter->value,
+ &iter->type, iter->name, iter->module_name,
+ &iter->exported) < 0)
return 0;
-
- /* Label it "global" if it is exported, "local" if not exported. */
- iter->type = is_exported(iter->name, iter->owner)
- ? toupper(iter->type) : tolower(iter->type);
-
return 1;
}
@@ -328,7 +323,7 @@ static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
{
unsigned off = iter->nameoff;
- iter->owner = NULL;
+ iter->module_name[0] = '\0';
iter->value = kallsyms_addresses[iter->pos];
iter->type = kallsyms_get_symbol_type(off);
@@ -392,12 +387,17 @@ static int s_show(struct seq_file *m, void *p)
if (!iter->name[0])
return 0;
- if (iter->owner)
+ if (iter->module_name[0]) {
+ char type;
+
+ /* Label it "global" if it is exported,
+ * "local" if not exported. */
+ type = iter->exported ? toupper(iter->type) :
+ tolower(iter->type);
seq_printf(m, "%0*lx %c %s\t[%s]\n",
(int)(2*sizeof(void*)),
- iter->value, iter->type, iter->name,
- module_name(iter->owner));
- else
+ iter->value, type, iter->name, iter->module_name);
+ } else
seq_printf(m, "%0*lx %c %s\n",
(int)(2*sizeof(void*)),
iter->value, iter->type, iter->name);
diff --git a/kernel/module.c b/kernel/module.c
index 43a529a1fa4..5ee65994a3b 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1472,7 +1472,7 @@ static void setup_modinfo(struct module *mod, Elf_Shdr *sechdrs,
}
#ifdef CONFIG_KALLSYMS
-int is_exported(const char *name, const struct module *mod)
+static int is_exported(const char *name, const struct module *mod)
{
if (!mod && lookup_symbol(name, __start___ksymtab, __stop___ksymtab))
return 1;
@@ -2124,8 +2124,8 @@ const char *module_address_lookup(unsigned long addr,
return NULL;
}
-struct module *module_get_kallsym(unsigned int symnum, unsigned long *value,
- char *type, char *name)
+int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
+ char *name, char *module_name, int *exported)
{
struct module *mod;
@@ -2136,13 +2136,15 @@ struct module *module_get_kallsym(unsigned int symnum, unsigned long *value,
*type = mod->symtab[symnum].st_info;
strlcpy(name, mod->strtab + mod->symtab[symnum].st_name,
KSYM_NAME_LEN + 1);
+ strlcpy(module_name, mod->name, MODULE_NAME_LEN + 1);
+ *exported = is_exported(name, mod);
mutex_unlock(&module_mutex);
- return mod;
+ return 0;
}
symnum -= mod->num_symtab;
}
mutex_unlock(&module_mutex);
- return NULL;
+ return -ERANGE;
}
static unsigned long mod_find_symname(struct module *mod, const char *name)