Commit f75f6668 authored Sep 08, 2025 by Dan Moulding Committed by Herbert Xu Sep 20, 2025

crypto: comp - Use same definition of context alloc and free ops



In commit 42d9f6c7 ("crypto: acomp - Move scomp stream allocation
code into acomp"), the crypto_acomp_streams struct was made to rely on
having the alloc_ctx and free_ctx operations defined in the same order
as the scomp_alg struct. But in that same commit, the alloc_ctx and
free_ctx members of scomp_alg may be randomized by structure layout
randomization, since they are contained in a pure ops structure
(containing only function pointers). If the pointers within scomp_alg
are randomized, but those in crypto_acomp_streams are not, then
the order may no longer match. This fixes the problem by removing the
union from scomp_alg so that both crypto_acomp_streams and scomp_alg
will share the same definition of alloc_ctx and free_ctx, ensuring
they will always have the same layout.

Signed-off-by: Dan Moulding <dan@danm.net>
Suggested-by: Herbert Xu <herbert@gondor.apana.org.au>
Fixes: 42d9f6c7 ("crypto: acomp - Move scomp stream allocation code into acomp")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

parent 381e8ee3

crypto/842.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -54,8 +54,10 @@ static int crypto842_sdecompress(struct crypto_scomp *tfm,
		}

		static struct scomp_alg scomp = {
		.streams = {
		.alloc_ctx = crypto842_alloc_ctx,
		.free_ctx = crypto842_free_ctx,
		},
		.compress = crypto842_scompress,
		.decompress = crypto842_sdecompress,
		.base = {

crypto/lz4.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -68,8 +68,10 @@ static int lz4_sdecompress(struct crypto_scomp tfm, const u8 src,
		}

		static struct scomp_alg scomp = {
		.streams = {
		.alloc_ctx = lz4_alloc_ctx,
		.free_ctx = lz4_free_ctx,
		},
		.compress = lz4_scompress,
		.decompress = lz4_sdecompress,
		.base = {

crypto/lz4hc.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -66,8 +66,10 @@ static int lz4hc_sdecompress(struct crypto_scomp tfm, const u8 src,
		}

		static struct scomp_alg scomp = {
		.streams = {
		.alloc_ctx = lz4hc_alloc_ctx,
		.free_ctx = lz4hc_free_ctx,
		},
		.compress = lz4hc_scompress,
		.decompress = lz4hc_sdecompress,
		.base = {

crypto/lzo-rle.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -70,8 +70,10 @@ static int lzorle_sdecompress(struct crypto_scomp tfm, const u8 src,
		}

		static struct scomp_alg scomp = {
		.streams = {
		.alloc_ctx = lzorle_alloc_ctx,
		.free_ctx = lzorle_free_ctx,
		},
		.compress = lzorle_scompress,
		.decompress = lzorle_sdecompress,
		.base = {

crypto/lzo.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -70,8 +70,10 @@ static int lzo_sdecompress(struct crypto_scomp tfm, const u8 src,
		}

		static struct scomp_alg scomp = {
		.streams = {
		.alloc_ctx = lzo_alloc_ctx,
		.free_ctx = lzo_free_ctx,
		},
		.compress = lzo_scompress,
		.decompress = lzo_sdecompress,
		.base = {