Messages in this thread Patch in this message | | | Date | Wed, 5 Jul 2006 12:34:24 -0700 | From | Andrew Morton <> | Subject | Re: NULL terminate over-long /proc/kallsyms symbols |
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Andreas Gruenbacher <agruen@suse.de> wrote: > > Got a customer bug report (https://bugzilla.novell.com/190296) > about kernel symbols longer than 127 characters which end up in > a string buffer that is not NULL terminated, leading to garbage > in /proc/kallsyms. Using strlcpy prevents this from happening, > even though such symbols still won't come out right. > > A better fix would be to not use a fixed-size buffer, but it's > probably not worth the trouble. (Modversion'ed symbols even have > a length limit of 60.) > > (This patch has been ested on a 2.6.16 kernel.) > > Signed-off-by: Andreas Gruenbacher <agruen@suse.de> > > Index: linux-2.6.17/kernel/module.c > =================================================================== > --- linux-2.6.17.orig/kernel/module.c > +++ linux-2.6.17/kernel/module.c > @@ -1935,7 +1935,7 @@ struct module *module_get_kallsym(unsign > if (symnum < mod->num_symtab) { > *value = mod->symtab[symnum].st_value; > *type = mod->symtab[symnum].st_info; > - strncpy(namebuf, > + strlcpy(namebuf, > mod->strtab + mod->symtab[symnum].st_name, > 127); > mutex_unlock(&module_mutex);
Yeah, that assume-the-caller-gave-us-a-128-byte-buffer is a bit rude. How about this?
include/linux/module.h | 6 ++---- kernel/kallsyms.c | 4 ++-- kernel/module.c | 11 ++++------- 3 files changed, 8 insertions(+), 13 deletions(-)
diff -puN kernel/module.c~null-terminate-over-long-proc-kallsyms-symbols kernel/module.c --- a/kernel/module.c~null-terminate-over-long-proc-kallsyms-symbols +++ a/kernel/module.c @@ -2019,10 +2019,8 @@ const char *module_address_lookup(unsign return NULL; } -struct module *module_get_kallsym(unsigned int symnum, - unsigned long *value, - char *type, - char namebuf[128]) +struct module *module_get_kallsym(unsigned int symnum, unsigned long *value, + char *type, char *name, size_t namelen) { struct module *mod; @@ -2031,9 +2029,8 @@ struct module *module_get_kallsym(unsign if (symnum < mod->num_symtab) { *value = mod->symtab[symnum].st_value; *type = mod->symtab[symnum].st_info; - strncpy(namebuf, - mod->strtab + mod->symtab[symnum].st_name, - 127); + strlcpy(name, mod->strtab + mod->symtab[symnum].st_name, + namelen); mutex_unlock(&module_mutex); return mod; } diff -puN include/linux/module.h~null-terminate-over-long-proc-kallsyms-symbols include/linux/module.h --- a/include/linux/module.h~null-terminate-over-long-proc-kallsyms-symbols +++ a/include/linux/module.h @@ -362,10 +362,8 @@ int is_module_address(unsigned long addr /* Returns module and fills in value, defined and namebuf, or NULL if symnum out of range. */ -struct module *module_get_kallsym(unsigned int symnum, - unsigned long *value, - char *type, - char namebuf[128]); +struct module *module_get_kallsym(unsigned int symnum, unsigned long *value, + char *type, char *name, size_t namelen); /* Look for this name: can be of form module:name. */ unsigned long module_kallsyms_lookup_name(const char *name); diff -puN kernel/kallsyms.c~null-terminate-over-long-proc-kallsyms-symbols kernel/kallsyms.c --- a/kernel/kallsyms.c~null-terminate-over-long-proc-kallsyms-symbols +++ a/kernel/kallsyms.c @@ -275,8 +275,8 @@ static void upcase_if_global(struct kall 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); + &iter->value, &iter->type, + iter->name, sizeof(iter->name)); if (iter->owner == NULL) return 0; _ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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