Messages in this thread Patch in this message | | | Date | Tue, 30 May 2017 20:30:44 -0700 | From | Jessica Yu <> | Subject | Re: [PATCH] modpost: abort if a module name is too long |
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+++ Wanlong Gao [31/05/17 10:23 +0800]: >Hi Jessica, > >On 2017/5/29 17:10, Jessica Yu wrote: >> +++ Xie XiuQi [20/05/17 15:46 +0800]: >>> From: Wanlong Gao <gaowanlong@huawei.com> >>> >>> Module name has a limited length, but currently the build system >>> allows the build finishing even if the module name is too long. >>> >>> CC /root/kprobe_example/abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz.mod.o >>> /root/kprobe_example/abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz.mod.c:9:2: >>> warning: initializer-string for array of chars is too long [enabled by default] >>> .name = KBUILD_MODNAME, >>> ^ >>> >>> but it's merely a warning. >>> >>> This patch adds the check of the module name length in modpost and stops >>> the build properly. >>> >>> Signed-off-by: Wanlong Gao <gaowanlong@huawei.com> >>> Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com> >>> --- >>> scripts/mod/modpost.c | 11 +++++++++++ >>> 1 file changed, 11 insertions(+) >>> >>> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c >>> index 30d752a..db11c57 100644 >>> --- a/scripts/mod/modpost.c >>> +++ b/scripts/mod/modpost.c >>> @@ -2166,6 +2166,17 @@ static int add_versions(struct buffer *b, struct module *mod) >>> { >>> struct symbol *s, *exp; >>> int err = 0; >>> + const char *mod_name; >>> + >>> + mod_name = strrchr(mod->name, '/'); >>> + if (mod_name == NULL) >>> + mod_name = mod->name; >>> + else >>> + mod_name++; >>> + if (strlen(mod_name) >= MODULE_NAME_LEN) { >>> + merror("module name is too long [%s.ko]\n", mod->name); >>> + return 1; >>> + } >> >> Hi Xie, >> >> This check shouldn't be in add_versions() (which does something else entirely), >> it should probably be put in a separate helper function called from main. But >> I'm not a big fan of the extra string manipulation to do something this simple. >> >> I think this check can be vastly simplified, how about something like the >> following? > >This looks better, would you apply your following patch? > >Reviewed-by: Wanlong Gao <gaowanlong@huawei.com> >Tested-by: Wanlong Gao <gaowanlong@huawei.com>
Sure, thanks for testing. I'll go ahead and format this into a proper patch and resend.
Jessica
>> >> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c >> index 48397fe..bb09fc7 100644 >> --- a/scripts/mod/modpost.c >> +++ b/scripts/mod/modpost.c >> @@ -2139,6 +2139,9 @@ static void add_header(struct buffer *b, struct module *mod) >> "#endif\n"); >> buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n"); >> buf_printf(b, "};\n"); >> + buf_printf(b, "\n"); >> + buf_printf(b, "static void __attribute__((section(\".discard\"), used)) __modname_test(void)\n"); >> + buf_printf(b, "{ BUILD_BUG_ON(sizeof(KBUILD_MODNAME) > MODULE_NAME_LEN); }\n"); >> } >> >> static void add_intree_flag(struct buffer *b, int is_intree) >> >> This simply checks if KBUILD_MODNAME > MODULE_NAME_LEN and breaks the build if >> it does. >> >> Jessica >> >>> for (s = mod->unres; s; s = s->next) { >>> exp = find_symbol(s->name); >>> -- >>> 1.8.3.1 >>> >> >> . >> >
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