crypto: acomp - Fix CFI failure due to type punning

commit 962ddc5a7a4b04c007bba0f3e7298cda13c62efd upstream.

To avoid a crash when control flow integrity is enabled, make the
workspace ("stream") free function use a consistent type, and call it
through a function pointer that has that same type.

Fixes: 42d9f6c77479 ("crypto: acomp - Move scomp stream allocation code into acomp")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
[Giovanni: Backport to 6.16.y. Removed logic in crypto/zstd.c as commit
f5ad93ffb541 ("crypto: zstd - convert to acomp") is not going to be
backported to stable.]
Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/crypto/deflate.c b/crypto/deflate.c
index fe8e4ad0fee1060c29f30f1b4aff9a48c483fcc0..21404515dc77ec208021d82dc20ae3517e0fbbad 100644 (file)
--- a/crypto/deflate.c
+++ b/crypto/deflate.c
@@ -48,9 +48,14 @@ static void *deflate_alloc_stream(void)
        return ctx;
 }
 
+static void deflate_free_stream(void *ctx)
+{
+       kvfree(ctx);
+}
+
 static struct crypto_acomp_streams deflate_streams = {
        .alloc_ctx = deflate_alloc_stream,
-       .cfree_ctx = kvfree,
+       .free_ctx = deflate_free_stream,
 };
 
 static int deflate_compress_one(struct acomp_req *req,

diff --git a/include/crypto/internal/acompress.h b/include/crypto/internal/acompress.h
index ffffd88bbbad3316e7e34fe6735d4b16def2cc71..2d97440028ffd7bf3ae1c2c69ebb955c523838bb 100644 (file)
--- a/include/crypto/internal/acompress.h
+++ b/include/crypto/internal/acompress.h
@@ -63,10 +63,7 @@ struct crypto_acomp_stream {
 struct crypto_acomp_streams {
        /* These must come first because of struct scomp_alg. */
        void *(*alloc_ctx)(void);
-       union {
-               void (*free_ctx)(void *);
-               void (*cfree_ctx)(const void *);
-       };
+       void (*free_ctx)(void *);
 
        struct crypto_acomp_stream __percpu *streams;
        struct work_struct stream_work;