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Fix race between rmmod and cat /proc/kallsyms

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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>
This commit is contained in:
Alexey Dobriyan
2007-05-08 00:28:39 -07:00
committed by Linus Torvalds
parent ae84e32470
commit ea07890a68
3 changed files with 29 additions and 34 deletions
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12
kernel/module.c
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@@ -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)