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Subject[PATCH] module: fix signature check failures when using in-kernel decompression
The new flag MODULE_INIT_COMPRESSED_FILE unintentionally trips check in
module_sig_check(). The check was supposed to catch case when version
info or magic was removed from a signed module, making signature
invalid, but it was coded too broadly and was catching this new flag as
well.

Change the check to only test the 2 particular flags affecting signature
validity.

Fixes: b1ae6dc41eaa ("module: add in-kernel support for decompressing")
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
kernel/module.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 201398d58079..24dab046e16c 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2883,12 +2883,13 @@ static int module_sig_check(struct load_info *info, int flags)
const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
const char *reason;
const void *mod = info->hdr;
-
+ bool mangled_module = flags & (MODULE_INIT_IGNORE_MODVERSIONS |
+ MODULE_INIT_IGNORE_VERMAGIC);
/*
- * Require flags == 0, as a module with version information
- * removed is no longer the module that was signed
+ * Do not allow mangled modules as a module with version information
+ * removed is no longer the module that was signed.
*/
- if (flags == 0 &&
+ if (!mangled_module &&
info->len > markerlen &&
memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {
/* We truncate the module to discard the signature */
--
2.34.1.703.g22d0c6ccf7-goog

--
Dmitry

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