59 lines
1.8 KiB
Diff
59 lines
1.8 KiB
Diff
From: Ben Hutchings <ben@decadent.org.uk>
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Date: Sun, 17 Apr 2016 22:59:03 +0100
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Subject: module: Invalidate signatures on force-loaded modules
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Forwarded: http://mid.gmane.org/20160423184501.GM3348@decadent.org.uk
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Signing a module should only make it trusted by the specific kernel it
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was built for, not anything else. Loading a signed module meant for a
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kernel with a different ABI could have interesting effects.
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Therefore, treat all signatures as invalid when a module is
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force-loaded.
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Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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Cc: stable@vger.kernel.org
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---
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kernel/module.c | 13 +++++++++----
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1 file changed, 9 insertions(+), 4 deletions(-)
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--- a/kernel/module.c
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+++ b/kernel/module.c
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@@ -2597,13 +2597,18 @@ static inline void kmemleak_load_module(
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#endif
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#ifdef CONFIG_MODULE_SIG
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-static int module_sig_check(struct load_info *info)
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+static int module_sig_check(struct load_info *info, int flags)
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{
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int err = -ENOKEY;
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const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
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const void *mod = info->hdr;
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- if (info->len > markerlen &&
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+ /*
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+ * Require flags == 0, as a module with version information
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+ * removed is no longer the module that was signed
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+ */
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+ if (flags == 0 &&
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+ info->len > markerlen &&
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memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {
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/* We truncate the module to discard the signature */
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info->len -= markerlen;
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@@ -2622,7 +2627,7 @@ static int module_sig_check(struct load_
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return err;
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}
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#else /* !CONFIG_MODULE_SIG */
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-static int module_sig_check(struct load_info *info)
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+static int module_sig_check(struct load_info *info, int flags)
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{
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return 0;
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}
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@@ -3429,7 +3434,7 @@ static int load_module(struct load_info
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long err;
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char *after_dashes;
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- err = module_sig_check(info);
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+ err = module_sig_check(info, flags);
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if (err)
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goto free_copy;
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