diff options
| author | Andi Kleen <ak@linux.intel.com> | 2018-01-25 15:50:28 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-02-13 12:35:58 +0100 |
| commit | a1745ad92f50e95b6c2d101cd9b77253969ddccc (patch) | |
| tree | 12c037a145c0703d8f1d45e9157f5137c37f09d1 /scripts | |
| parent | ec86a1dad0c00757ceb49e86b4c10dd7fbc380cb (diff) | |
module/retpoline: Warn about missing retpoline in module
(cherry picked from commit caf7501a1b4ec964190f31f9c3f163de252273b8)
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
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'scripts')
| -rw-r--r-- | scripts/mod/modpost.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 845eb9b800f3..238db4ffd30c 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -2130,6 +2130,14 @@ 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"; @@ -2474,6 +2482,7 @@ int main(int argc, char **argv) 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); |