modpost: lto: strip .lto from module names

With LTO, everything is compiled into LLVM bitcode, so we have to link
each module into native code before modpost. Kbuild uses the .lto.o
suffix for these files, which also ends up in module information. This
change strips the unnecessary .lto suffix from the module name.

Suggested-by: Bill Wendling <morbo@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-11-samitolvanen@google.com

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index d6c8165..be06421 100644 (file)
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -17,7 +17,6 @@
 #include <ctype.h>
 #include <string.h>
 #include <limits.h>
-#include <stdbool.h>
 #include <errno.h>
 #include "modpost.h"
 #include "../../include/linux/license.h"
@@ -84,14 +83,6 @@ modpost_log(enum loglevel loglevel, const char *fmt, ...)
                error_occurred = true;
 }
 
-static inline bool strends(const char *str, const char *postfix)
-{
-       if (strlen(str) < strlen(postfix))
-               return false;
-
-       return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
-}
-
 void *do_nofail(void *ptr, const char *expr)
 {
        if (!ptr)
@@ -1988,6 +1979,10 @@ static char *remove_dot(char *s)
                size_t m = strspn(s + n + 1, "0123456789");
                if (m && (s[n + m] == '.' || s[n + m] == 0))
                        s[n] = 0;
+
+               /* strip trailing .lto */
+               if (strends(s, ".lto"))
+                       s[strlen(s) - 4] = '\0';
        }
        return s;
 }
@@ -2011,6 +2006,9 @@ static void read_symbols(const char *modname)
                /* strip trailing .o */
                tmp = NOFAIL(strdup(modname));
                tmp[strlen(tmp) - 2] = '\0';
+               /* strip trailing .lto */
+               if (strends(tmp, ".lto"))
+                       tmp[strlen(tmp) - 4] = '\0';
                mod = new_module(tmp);
                free(tmp);
        }

diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index e6f46ee..1f76eea 100644 (file)
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -2,6 +2,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
+#include <stdbool.h>
 #include <string.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -180,6 +181,14 @@ static inline unsigned int get_secindex(const struct elf_info *info,
        return info->symtab_shndx_start[sym - info->symtab_start];
 }
 
+static inline bool strends(const char *str, const char *postfix)
+{
+       if (strlen(str) < strlen(postfix))
+               return false;
+
+       return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
+}
+
 /* file2alias.c */
 extern unsigned int cross_build;
 void handle_moddevtable(struct module *mod, struct elf_info *info,

diff --git a/scripts/mod/sumversion.c b/scripts/mod/sumversion.c
index d587f40..760e6ba 100644 (file)
--- a/scripts/mod/sumversion.c
+++ b/scripts/mod/sumversion.c
@@ -391,10 +391,14 @@ void get_src_version(const char *modname, char sum[], unsigned sumlen)
        struct md4_ctx md;
        char *fname;
        char filelist[PATH_MAX + 1];
+       int postfix_len = 1;
+
+       if (strends(modname, ".lto.o"))
+               postfix_len = 5;
 
        /* objects for a module are listed in the first line of *.mod file. */
        snprintf(filelist, sizeof(filelist), "%.*smod",
-                (int)strlen(modname) - 1, modname);
+                (int)strlen(modname) - postfix_len, modname);
 
        buf = read_text_file(filelist);