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authorMatthew Garrett <mjg59@google.com>2018-06-08 14:57:42 -0700
committerMimi Zohar <zohar@linux.vnet.ibm.com>2018-07-18 07:27:22 -0400
commite2861fa71641c6414831d628a1f4f793b6562580 (patch)
treee832d4eac8fb33e2838a76cc9457bd3c2d6a2065 /include/linux/crypto.h
parentac2409a521f7ec5978fd582567398d19f4a2fdbd (diff)
evm: Don't deadlock if a crypto algorithm is unavailable
When EVM attempts to appraise a file signed with a crypto algorithm the kernel doesn't have support for, it will cause the kernel to trigger a module load. If the EVM policy includes appraisal of kernel modules this will in turn call back into EVM - since EVM is holding a lock until the crypto initialisation is complete, this triggers a deadlock. Add a CRYPTO_NOLOAD flag and skip module loading if it's set, and add that flag in the EVM case in order to fail gracefully with an error message instead of deadlocking. Signed-off-by: Matthew Garrett <mjg59@google.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Diffstat (limited to 'include/linux/crypto.h')
-rw-r--r--include/linux/crypto.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index 6eb06101089f..e8839d3a7559 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -113,6 +113,11 @@
#define CRYPTO_ALG_OPTIONAL_KEY 0x00004000
/*
+ * Don't trigger module loading
+ */
+#define CRYPTO_NOLOAD 0x00008000
+
+/*
* Transform masks and values (for crt_flags).
*/
#define CRYPTO_TFM_NEED_KEY 0x00000001