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authorAndi Kleen <ak@linux.intel.com>2018-01-25 15:50:28 -0800
committerThomas Gleixner <tglx@linutronix.de>2018-01-26 15:03:56 +0100
commitcaf7501a1b4ec964190f31f9c3f163de252273b8 (patch)
treef626e796eb8f30eca268595ca07dc90e00b06ec3 /scripts
parentc940a3fb1e2e9b7d03228ab28f375fb5a47ff699 (diff)
module/retpoline: Warn about missing retpoline in module
There's a risk that a kernel which has full retpoline mitigations becomes vulnerable when a module gets loaded that hasn't been compiled with the right compiler or the right option. To enable detection of that mismatch at module load time, add a module info string "retpoline" at build time when the module was compiled with retpoline support. This only covers compiled C source, but assembler source or prebuilt object files are not checked. If a retpoline enabled kernel detects a non retpoline protected module at load time, print a warning and report it in the sysfs vulnerability file. [ tglx: Massaged changelog ] Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: David Woodhouse <dwmw2@infradead.org> Cc: gregkh@linuxfoundation.org Cc: torvalds@linux-foundation.org Cc: jeyu@kernel.org Cc: arjan@linux.intel.com Link: https://lkml.kernel.org/r/20180125235028.31211-1-andi@firstfloor.org
Diffstat (limited to 'scripts')
-rw-r--r--scripts/mod/modpost.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 98314b400a95..54deaa1066cf 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -2165,6 +2165,14 @@ static void add_intree_flag(struct buffer *b, int is_intree)
buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
}
+/* Cannot check for assembler */
+static void add_retpoline(struct buffer *b)
+{
+ buf_printf(b, "\n#ifdef RETPOLINE\n");
+ buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
+ buf_printf(b, "#endif\n");
+}
+
static void add_staging_flag(struct buffer *b, const char *name)
{
static const char *staging_dir = "drivers/staging";
@@ -2506,6 +2514,7 @@ int main(int argc, char **argv)
err |= check_modname_len(mod);
add_header(&buf, mod);
add_intree_flag(&buf, !external_module);
+ add_retpoline(&buf);
add_staging_flag(&buf, mod->name);
err |= add_versions(&buf, mod);
add_depends(&buf, mod, modules);