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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Matteo Croce <mcroce@linux.microsoft.com>,
        Kees Cook <keescook@chromium.org>
Subject: [PATCH 5.4 256/270] pstore: Fix linking when crypto API disabled
Date:   Mon, 17 Aug 2020 17:17:37 +0200
Message-Id: <20200817143808.572108530@linuxfoundation.org>
In-Reply-To: <20200817143755.807583758@linuxfoundation.org>
References: <20200817143755.807583758@linuxfoundation.org>
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From: Matteo Croce <mcroce@linux.microsoft.com>

commit fd49e03280e596e54edb93a91bc96170f8e97e4a upstream.

When building a kernel with CONFIG_PSTORE=y and CONFIG_CRYPTO not set,
a build error happens:

    ld: fs/pstore/platform.o: in function `pstore_dump':
    platform.c:(.text+0x3f9): undefined reference to `crypto_comp_compress'
    ld: fs/pstore/platform.o: in function `pstore_get_backend_records':
    platform.c:(.text+0x784): undefined reference to `crypto_comp_decompress'

This because some pstore code uses crypto_comp_(de)compress regardless
of the CONFIG_CRYPTO status. Fix it by wrapping the (de)compress usage
by IS_ENABLED(CONFIG_PSTORE_COMPRESS)

Signed-off-by: Matteo Croce <mcroce@linux.microsoft.com>
Link: https://lore.kernel.org/lkml/20200706234045.9516-1-mcroce@linux.microsoft.com
Fixes: cb3bee0369bc ("pstore: Use crypto compress API")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/pstore/platform.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -275,6 +275,9 @@ static int pstore_compress(const void *i
 {
 	int ret;
 
+	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESSION))
+		return -EINVAL;
+
 	ret = crypto_comp_compress(tfm, in, inlen, out, &outlen);
 	if (ret) {
 		pr_err("crypto_comp_compress failed, ret = %d!\n", ret);
@@ -661,7 +664,7 @@ static void decompress_record(struct pst
 	int unzipped_len;
 	char *unzipped, *workspace;
 
-	if (!record->compressed)
+	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESSION) || !record->compressed)
 		return;
 
 	/* Only PSTORE_TYPE_DMESG support compression. */