53de3b080d
This patch avoids a kernel panic due to accessing an error pointer set by
crypto_alloc_shash(). It occurs especially when there are many files that
require an unsupported algorithm, as it would increase the likelihood of
the following race condition:
Task A: *tfm = crypto_alloc_shash() <= error pointer
Task B: if (*tfm == NULL) <= *tfm is not NULL, use it
Task B: rc = crypto_shash_init(desc) <= panic
Task A: *tfm = NULL
This patch uses the IS_ERR_OR_NULL macro to determine whether or not a new
crypto context must be created.
Cc: stable@vger.kernel.org
Fixes:
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|---|---|---|
| .. | ||
| evm.h | ||
| evm_crypto.c | ||
| evm_main.c | ||
| evm_posix_acl.c | ||
| evm_secfs.c | ||
| Kconfig | ||
| Makefile | ||