Module symbols have a limited length, but currently the build system
allows the build finishing even if the driver code contains a too long
symbol name, which eventually overflows the modversion_info[] item.
The compiler may catch at compiling *.mod.c like
CC xxx.mod.o
xxx.mod.c:18:16: warning: initializer-string for array of chars is too long
but it's merely a warning.
This patch adds the check of the symbol length in modpost and stops
the build properly.
As of now, MODULE_NAME_LEN is copied in modpost.c. At best, this
should be read directly from kernel headers. But including
linux/module.h is too troublesome for now, so just paper over it.
Signed-off-by: Takashi Iwai <[email protected]>
---
scripts/mod/modpost.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 12d3db3bd46b..25bda9d2868c 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -2133,6 +2133,9 @@ static void add_staging_flag(struct buffer *b, const char *name)
buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
}
+/* FIXME: better to be included from kernel header */
+#define MODULE_NAME_LEN (64 - sizeof(unsigned long))
+
/**
* Record CRCs for unresolved symbols
**/
@@ -2177,6 +2180,12 @@ static int add_versions(struct buffer *b, struct module *mod)
s->name, mod->name);
continue;
}
+ if (strlen(s->name) >= MODULE_NAME_LEN) {
+ merror("too long symbol \"%s\" [%s.ko]\n",
+ s->name, mod->name);
+ err = 1;
+ break;
+ }
buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n",
s->crc, s->name);
}
--
2.5.0
Takashi Iwai <[email protected]> writes:
> Module symbols have a limited length, but currently the build system
> allows the build finishing even if the driver code contains a too long
> symbol name, which eventually overflows the modversion_info[] item.
> The compiler may catch at compiling *.mod.c like
> CC xxx.mod.o
> xxx.mod.c:18:16: warning: initializer-string for array of chars is too long
> but it's merely a warning.
>
> This patch adds the check of the symbol length in modpost and stops
> the build properly.
>
> As of now, MODULE_NAME_LEN is copied in modpost.c. At best, this
> should be read directly from kernel headers. But including
> linux/module.h is too troublesome for now, so just paper over it.
>
> Signed-off-by: Takashi Iwai <[email protected]>
> ---
> scripts/mod/modpost.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> index 12d3db3bd46b..25bda9d2868c 100644
> --- a/scripts/mod/modpost.c
> +++ b/scripts/mod/modpost.c
> @@ -2133,6 +2133,9 @@ static void add_staging_flag(struct buffer *b, const char *name)
> buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
> }
>
> +/* FIXME: better to be included from kernel header */
> +#define MODULE_NAME_LEN (64 - sizeof(unsigned long))
This isn't quite right, since modpost handles cross-compilation.
#define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
Should work...
Thanks!
Rusty.
> +
> /**
> * Record CRCs for unresolved symbols
> **/
> @@ -2177,6 +2180,12 @@ static int add_versions(struct buffer *b, struct module *mod)
> s->name, mod->name);
> continue;
> }
> + if (strlen(s->name) >= MODULE_NAME_LEN) {
> + merror("too long symbol \"%s\" [%s.ko]\n",
> + s->name, mod->name);
> + err = 1;
> + break;
> + }
> buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n",
> s->crc, s->name);
> }
> --
> 2.5.0
On Thu, 06 Aug 2015 23:09:12 +0200,
Rusty Russell wrote:
>
> Takashi Iwai <[email protected]> writes:
> > Module symbols have a limited length, but currently the build system
> > allows the build finishing even if the driver code contains a too long
> > symbol name, which eventually overflows the modversion_info[] item.
> > The compiler may catch at compiling *.mod.c like
> > CC xxx.mod.o
> > xxx.mod.c:18:16: warning: initializer-string for array of chars is too long
> > but it's merely a warning.
> >
> > This patch adds the check of the symbol length in modpost and stops
> > the build properly.
> >
> > As of now, MODULE_NAME_LEN is copied in modpost.c. At best, this
> > should be read directly from kernel headers. But including
> > linux/module.h is too troublesome for now, so just paper over it.
> >
> > Signed-off-by: Takashi Iwai <[email protected]>
> > ---
> > scripts/mod/modpost.c | 9 +++++++++
> > 1 file changed, 9 insertions(+)
> >
> > diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> > index 12d3db3bd46b..25bda9d2868c 100644
> > --- a/scripts/mod/modpost.c
> > +++ b/scripts/mod/modpost.c
> > @@ -2133,6 +2133,9 @@ static void add_staging_flag(struct buffer *b, const char *name)
> > buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
> > }
> >
> > +/* FIXME: better to be included from kernel header */
> > +#define MODULE_NAME_LEN (64 - sizeof(unsigned long))
>
> This isn't quite right, since modpost handles cross-compilation.
>
> #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
>
> Should work...
Alright, I'll resubmit with this fix.
Thanks!
Takashi