diff options
| author | Andi Kleen <ak@linux.intel.com> | 2018-02-23 11:41:54 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-02-25 11:03:52 +0100 |
| commit | 6cd5513c813eb57eba081563beb817abd9923a3a (patch) | |
| tree | a028dee1c51a669866fea28cc5d327a045b77a14 /scripts | |
| parent | d5030418b0c82956921545121b4f08df0f9ece70 (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>
[jwang: port to 4.4]
Signed-off-by: Jack Wang <jinpu.wang@profitbricks.com>
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 48958d3cec9e..bd5151915e5a 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -2129,6 +2129,14 @@ 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"; @@ -2473,6 +2481,7 @@ 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); |