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| author | Ben Hutchings <ben@decadent.org.uk> | 2016-04-28 09:24:01 +0930 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-08-20 18:11:04 +0200 |
| commit | c528032b3adf734fba3247517641ee173b26d950 (patch) | |
| tree | 65672c1b15487bb3719c1b5d70e145b3eb419e51 | |
| parent | dbf8fc37852729c8e1022548e2a98944aec4214f (diff) | |
| download | lwn-c528032b3adf734fba3247517641ee173b26d950.tar.gz lwn-c528032b3adf734fba3247517641ee173b26d950.zip | |
module: Invalidate signatures on force-loaded modules
commit bca014caaa6130e57f69b5bf527967aa8ee70fdd upstream.
Signing a module should only make it trusted by the specific kernel it
was built for, not anything else. Loading a signed module meant for a
kernel with a different ABI could have interesting effects.
Therefore, treat all signatures as invalid when a module is
force-loaded.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/module.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/kernel/module.c b/kernel/module.c index 5f71aa63ed2a..6458a2f17d58 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2687,13 +2687,18 @@ static inline void kmemleak_load_module(const struct module *mod, #endif #ifdef CONFIG_MODULE_SIG -static int module_sig_check(struct load_info *info) +static int module_sig_check(struct load_info *info, int flags) { int err = -ENOKEY; const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1; const void *mod = info->hdr; - if (info->len > markerlen && + /* + * Require flags == 0, as a module with version information + * removed is no longer the module that was signed + */ + if (flags == 0 && + info->len > markerlen && memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) { /* We truncate the module to discard the signature */ info->len -= markerlen; @@ -2712,7 +2717,7 @@ static int module_sig_check(struct load_info *info) return err; } #else /* !CONFIG_MODULE_SIG */ -static int module_sig_check(struct load_info *info) +static int module_sig_check(struct load_info *info, int flags) { return 0; } @@ -3498,7 +3503,7 @@ static int load_module(struct load_info *info, const char __user *uargs, long err; char *after_dashes; - err = module_sig_check(info); + err = module_sig_check(info, flags); if (err) goto free_copy; |