| Message ID | 20230718125847.3869700-2-ardb@kernel.org (mailing list archive) |
|---|---|
| State | RFC |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | crypto: consolidate and clean up compression APIs | expand |
On Tue, Jul 18, 2023 at 02:58:27PM +0200, Ard Biesheuvel wrote: > This reverts commit a368f43d6e3a001e684e9191a27df384fbff12f5. > > "zlib-deflate" was introduced 6 years ago, but it does not have any > users. So let's remove the generic implementation and the test vectors, > but retain the "zlib-deflate" entry in the testmgr code to avoid > introducing warning messages on systems that implement zlib-deflate in > hardware. > > Note that RFC 1950 which forms the basis of this algorithm dates back to > 1996, and predates RFC 1951, on which the existing IPcomp is based and > which we have supported in the kernel since 2003. So it seems rather > unlikely that we will ever grow the need to support zlib-deflate. > > Signed-off-by: Ard Biesheuvel <ardb@kernel.org> > --- > crypto/deflate.c | 61 +++++----------- > crypto/testmgr.c | 8 +-- > crypto/testmgr.h | 75 -------------------- > 3 files changed, 18 insertions(+), 126 deletions(-) So if this is really unused, it's probably fair to remove it on that basis. However, it's not correct to claim that DEFLATE is obsoleted by zlib (the data format). zlib is just DEFLATE plus a checksum, as is gzip. Many users of zlib or gzip use an external checksum and therefore would be better served by DEFLATE, avoiding a redundant builtin checksum. Typically, people have chosen zlib or gzip simply because their compression library defaulted to it, they didn't understand the difference, and they overlooked that they're paying the price for a redundant builtin checksum. An example of someone doing it right is EROFS, which is working on adding DEFLATE support (not zlib or gzip!): https://lore.kernel.org/r/20230713001441.30462-1-hsiangkao@linux.alibaba.com Of course, they are using the library API instead of the clumsy crypto API. - Eric
On Tue, Jul 18, 2023 at 03:32:39PM -0700, Eric Biggers wrote: > On Tue, Jul 18, 2023 at 02:58:27PM +0200, Ard Biesheuvel wrote: > > This reverts commit a368f43d6e3a001e684e9191a27df384fbff12f5. > > > > "zlib-deflate" was introduced 6 years ago, but it does not have any > > users. So let's remove the generic implementation and the test vectors, > > but retain the "zlib-deflate" entry in the testmgr code to avoid > > introducing warning messages on systems that implement zlib-deflate in > > hardware. > > > > Note that RFC 1950 which forms the basis of this algorithm dates back to > > 1996, and predates RFC 1951, on which the existing IPcomp is based and > > which we have supported in the kernel since 2003. So it seems rather > > unlikely that we will ever grow the need to support zlib-deflate. > > > > Signed-off-by: Ard Biesheuvel <ardb@kernel.org> > > --- > > crypto/deflate.c | 61 +++++----------- > > crypto/testmgr.c | 8 +-- > > crypto/testmgr.h | 75 -------------------- > > 3 files changed, 18 insertions(+), 126 deletions(-) > > So if this is really unused, it's probably fair to remove it on that basis. > However, it's not correct to claim that DEFLATE is obsoleted by zlib (the data > format). zlib is just DEFLATE plus a checksum, as is gzip. > > Many users of zlib or gzip use an external checksum and therefore would be > better served by DEFLATE, avoiding a redundant builtin checksum. Typically, > people have chosen zlib or gzip simply because their compression library > defaulted to it, they didn't understand the difference, and they overlooked that > they're paying the price for a redundant builtin checksum. > > An example of someone doing it right is EROFS, which is working on adding > DEFLATE support (not zlib or gzip!): > https://lore.kernel.org/r/20230713001441.30462-1-hsiangkao@linux.alibaba.com > > Of course, they are using the library API instead of the clumsy crypto API. > Ah, I misread this patch, sorry. It's actually removing support for zlib (the data format) from the scomp API, leaving just DEFLATE. That's fine too; again, it ultimately just depends on what is actually being used via the scomp API. But similarly you can't really claim that zlib is obsoleted by DEFLATE just because of the RFC dates. As I mentioned, many people do use zlib (the data format), often just because it's the default of zlib (the library) and they didn't know any better. For example, btrfs compression supports zlib. - Eric
On Wed, 19 Jul 2023 at 00:54, Eric Biggers <ebiggers@kernel.org> wrote: > > On Tue, Jul 18, 2023 at 03:32:39PM -0700, Eric Biggers wrote: > > On Tue, Jul 18, 2023 at 02:58:27PM +0200, Ard Biesheuvel wrote: > > > This reverts commit a368f43d6e3a001e684e9191a27df384fbff12f5. > > > > > > "zlib-deflate" was introduced 6 years ago, but it does not have any > > > users. So let's remove the generic implementation and the test vectors, > > > but retain the "zlib-deflate" entry in the testmgr code to avoid > > > introducing warning messages on systems that implement zlib-deflate in > > > hardware. > > > > > > Note that RFC 1950 which forms the basis of this algorithm dates back to > > > 1996, and predates RFC 1951, on which the existing IPcomp is based and > > > which we have supported in the kernel since 2003. So it seems rather > > > unlikely that we will ever grow the need to support zlib-deflate. > > > > > > Signed-off-by: Ard Biesheuvel <ardb@kernel.org> > > > --- > > > crypto/deflate.c | 61 +++++----------- > > > crypto/testmgr.c | 8 +-- > > > crypto/testmgr.h | 75 -------------------- > > > 3 files changed, 18 insertions(+), 126 deletions(-) > > > > So if this is really unused, it's probably fair to remove it on that basis. > > However, it's not correct to claim that DEFLATE is obsoleted by zlib (the data > > format). zlib is just DEFLATE plus a checksum, as is gzip. > > > > Many users of zlib or gzip use an external checksum and therefore would be > > better served by DEFLATE, avoiding a redundant builtin checksum. Typically, > > people have chosen zlib or gzip simply because their compression library > > defaulted to it, they didn't understand the difference, and they overlooked that > > they're paying the price for a redundant builtin checksum. > > > > An example of someone doing it right is EROFS, which is working on adding > > DEFLATE support (not zlib or gzip!): > > https://lore.kernel.org/r/20230713001441.30462-1-hsiangkao@linux.alibaba.com > > > > Of course, they are using the library API instead of the clumsy crypto API. > > > > Ah, I misread this patch, sorry. It's actually removing support for zlib (the > data format) from the scomp API, leaving just DEFLATE. That's fine too; again, > it ultimately just depends on what is actually being used via the scomp API. > But similarly you can't really claim that zlib is obsoleted by DEFLATE just > because of the RFC dates. As I mentioned, many people do use zlib (the data > format), often just because it's the default of zlib (the library) and they > didn't know any better. For example, btrfs compression supports zlib. > I am not suggesting either is obsolete. I am merely pointing out that zlib-deflate is as old as plain deflate, and so we could have implemented both at the same time when IPcomp support was added, but we never bothered.
On Tue, Jul 18, 2023 at 02:58:27PM +0200, Ard Biesheuvel wrote: > This reverts commit a368f43d6e3a001e684e9191a27df384fbff12f5. > > "zlib-deflate" was introduced 6 years ago, but it does not have any > users. So let's remove the generic implementation and the test vectors, > but retain the "zlib-deflate" entry in the testmgr code to avoid > introducing warning messages on systems that implement zlib-deflate in > hardware. > > Note that RFC 1950 which forms the basis of this algorithm dates back to > 1996, and predates RFC 1951, on which the existing IPcomp is based and > which we have supported in the kernel since 2003. So it seems rather > unlikely that we will ever grow the need to support zlib-deflate. > > Signed-off-by: Ard Biesheuvel <ardb@kernel.org> > --- > crypto/deflate.c | 61 +++++----------- > crypto/testmgr.c | 8 +-- > crypto/testmgr.h | 75 -------------------- > 3 files changed, 18 insertions(+), 126 deletions(-) > > diff --git a/crypto/deflate.c b/crypto/deflate.c > index b2a46f6dc961e71d..f4f127078fe2a5aa 100644 > --- a/crypto/deflate.c > +++ b/crypto/deflate.c > @@ -39,24 +39,20 @@ struct deflate_ctx { > struct z_stream_s decomp_stream; > }; > > -static int deflate_comp_init(struct deflate_ctx *ctx, int format) > +static int deflate_comp_init(struct deflate_ctx *ctx) > { > int ret = 0; > struct z_stream_s *stream = &ctx->comp_stream; > > stream->workspace = vzalloc(zlib_deflate_workspacesize( > - MAX_WBITS, MAX_MEM_LEVEL)); > + -DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL)); > if (!stream->workspace) { > ret = -ENOMEM; > goto out; > } > - if (format) > - ret = zlib_deflateInit(stream, 3); > - else > - ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED, > - -DEFLATE_DEF_WINBITS, > - DEFLATE_DEF_MEMLEVEL, > - Z_DEFAULT_STRATEGY); > + ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED, > + -DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL, > + Z_DEFAULT_STRATEGY); nit: The two lines above partially use spaces instead of tabs for indentation. ...
Hi Ard, On Tue, Jul 18, 2023 at 01:58:27PM +0100, Ard Biesheuvel wrote: > This reverts commit a368f43d6e3a001e684e9191a27df384fbff12f5. > > "zlib-deflate" was introduced 6 years ago, but it does not have any > users. So let's remove the generic implementation and the test vectors, > but retain the "zlib-deflate" entry in the testmgr code to avoid > introducing warning messages on systems that implement zlib-deflate in > hardware. > > Note that RFC 1950 which forms the basis of this algorithm dates back to > 1996, and predates RFC 1951, on which the existing IPcomp is based and > which we have supported in the kernel since 2003. So it seems rather > unlikely that we will ever grow the need to support zlib-deflate. > > Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Support for zlib-deflate was added for [1] but that work was not completed. Based on [2], either we leave this SW implementation or we remove the HW implementations in the QAT [3] and in the Hisilicon Zip [4] drivers. [1] https://patchwork.kernel.org/project/linux-btrfs/patch/1467083180-111750-1-git-send-email-weigang.li@intel.com/ [2] https://lore.kernel.org/lkml/ZIw%2Fjtxdg6O1O0j3@gondor.apana.org.au/ [3] https://elixir.bootlin.com/linux/latest/source/drivers/crypto/intel/qat/qat_common/qat_comp_algs.c#L457 [4] https://elixir.bootlin.com/linux/latest/source/drivers/crypto/hisilicon/zip/zip_crypto.c#L754 Regards,
Hello Giovanni, On Thu, 3 Aug 2023 at 11:51, Giovanni Cabiddu <giovanni.cabiddu@intel.com> wrote: > > Hi Ard, > > On Tue, Jul 18, 2023 at 01:58:27PM +0100, Ard Biesheuvel wrote: > > This reverts commit a368f43d6e3a001e684e9191a27df384fbff12f5. > > > > "zlib-deflate" was introduced 6 years ago, but it does not have any > > users. So let's remove the generic implementation and the test vectors, > > but retain the "zlib-deflate" entry in the testmgr code to avoid > > introducing warning messages on systems that implement zlib-deflate in > > hardware. > > > > Note that RFC 1950 which forms the basis of this algorithm dates back to > > 1996, and predates RFC 1951, on which the existing IPcomp is based and > > which we have supported in the kernel since 2003. So it seems rather > > unlikely that we will ever grow the need to support zlib-deflate. > > > > Signed-off-by: Ard Biesheuvel <ardb@kernel.org> > Support for zlib-deflate was added for [1] but that work was not > completed. > Any clue why zlib_deflate was chosen in this case? /me also notes that this is another occurrence of the antipattern where we use an asynchronous API and subsequently sleep on the completion. > Based on [2], either we leave this SW implementation or we remove the HW > implementations in the QAT [3] and in the Hisilicon Zip [4] drivers. > That would work for me as well - dead code is just busywork. > [1] https://patchwork.kernel.org/project/linux-btrfs/patch/1467083180-111750-1-git-send-email-weigang.li@intel.com/ > [2] https://lore.kernel.org/lkml/ZIw%2Fjtxdg6O1O0j3@gondor.apana.org.au/ > [3] https://elixir.bootlin.com/linux/latest/source/drivers/crypto/intel/qat/qat_common/qat_comp_algs.c#L457 > [4] https://elixir.bootlin.com/linux/latest/source/drivers/crypto/hisilicon/zip/zip_crypto.c#L754 > > Regards, > > -- > Giovanni
On Thu, Aug 03, 2023 at 11:59:00AM +0200, Ard Biesheuvel wrote:
> Any clue why zlib_deflate was chosen in this case?
I believe it was done for integrity.
The output of zlib_deflate is raw deflate with an header and a footer
defined in rfc1950. The footer contains a checksum which gets
calculated over the uncompressed data during compression and checked
after decompression.
diff --git a/crypto/deflate.c b/crypto/deflate.c index b2a46f6dc961e71d..f4f127078fe2a5aa 100644 --- a/crypto/deflate.c +++ b/crypto/deflate.c @@ -39,24 +39,20 @@ struct deflate_ctx { struct z_stream_s decomp_stream; }; -static int deflate_comp_init(struct deflate_ctx *ctx, int format) +static int deflate_comp_init(struct deflate_ctx *ctx) { int ret = 0; struct z_stream_s *stream = &ctx->comp_stream; stream->workspace = vzalloc(zlib_deflate_workspacesize( - MAX_WBITS, MAX_MEM_LEVEL)); + -DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL)); if (!stream->workspace) { ret = -ENOMEM; goto out; } - if (format) - ret = zlib_deflateInit(stream, 3); - else - ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED, - -DEFLATE_DEF_WINBITS, - DEFLATE_DEF_MEMLEVEL, - Z_DEFAULT_STRATEGY); + ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED, + -DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL, + Z_DEFAULT_STRATEGY); if (ret != Z_OK) { ret = -EINVAL; goto out_free; @@ -68,7 +64,7 @@ static int deflate_comp_init(struct deflate_ctx *ctx, int format) goto out; } -static int deflate_decomp_init(struct deflate_ctx *ctx, int format) +static int deflate_decomp_init(struct deflate_ctx *ctx) { int ret = 0; struct z_stream_s *stream = &ctx->decomp_stream; @@ -78,10 +74,7 @@ static int deflate_decomp_init(struct deflate_ctx *ctx, int format) ret = -ENOMEM; goto out; } - if (format) - ret = zlib_inflateInit(stream); - else - ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS); + ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS); if (ret != Z_OK) { ret = -EINVAL; goto out_free; @@ -105,21 +98,21 @@ static void deflate_decomp_exit(struct deflate_ctx *ctx) vfree(ctx->decomp_stream.workspace); } -static int __deflate_init(void *ctx, int format) +static int __deflate_init(void *ctx) { int ret; - ret = deflate_comp_init(ctx, format); + ret = deflate_comp_init(ctx); if (ret) goto out; - ret = deflate_decomp_init(ctx, format); + ret = deflate_decomp_init(ctx); if (ret) deflate_comp_exit(ctx); out: return ret; } -static void *gen_deflate_alloc_ctx(struct crypto_scomp *tfm, int format) +static void *deflate_alloc_ctx(struct crypto_scomp *tfm) { struct deflate_ctx *ctx; int ret; @@ -128,7 +121,7 @@ static void *gen_deflate_alloc_ctx(struct crypto_scomp *tfm, int format) if (!ctx) return ERR_PTR(-ENOMEM); - ret = __deflate_init(ctx, format); + ret = __deflate_init(ctx); if (ret) { kfree(ctx); return ERR_PTR(ret); @@ -137,21 +130,11 @@ static void *gen_deflate_alloc_ctx(struct crypto_scomp *tfm, int format) return ctx; } -static void *deflate_alloc_ctx(struct crypto_scomp *tfm) -{ - return gen_deflate_alloc_ctx(tfm, 0); -} - -static void *zlib_deflate_alloc_ctx(struct crypto_scomp *tfm) -{ - return gen_deflate_alloc_ctx(tfm, 1); -} - static int deflate_init(struct crypto_tfm *tfm) { struct deflate_ctx *ctx = crypto_tfm_ctx(tfm); - return __deflate_init(ctx, 0); + return __deflate_init(ctx); } static void __deflate_exit(void *ctx) @@ -286,7 +269,7 @@ static struct crypto_alg alg = { .coa_decompress = deflate_decompress } } }; -static struct scomp_alg scomp[] = { { +static struct scomp_alg scomp = { .alloc_ctx = deflate_alloc_ctx, .free_ctx = deflate_free_ctx, .compress = deflate_scompress, @@ -296,17 +279,7 @@ static struct scomp_alg scomp[] = { { .cra_driver_name = "deflate-scomp", .cra_module = THIS_MODULE, } -}, { - .alloc_ctx = zlib_deflate_alloc_ctx, - .free_ctx = deflate_free_ctx, - .compress = deflate_scompress, - .decompress = deflate_sdecompress, - .base = { - .cra_name = "zlib-deflate", - .cra_driver_name = "zlib-deflate-scomp", - .cra_module = THIS_MODULE, - } -} }; +}; static int __init deflate_mod_init(void) { @@ -316,7 +289,7 @@ static int __init deflate_mod_init(void) if (ret) return ret; - ret = crypto_register_scomps(scomp, ARRAY_SIZE(scomp)); + ret = crypto_register_scomp(&scomp); if (ret) { crypto_unregister_alg(&alg); return ret; @@ -328,7 +301,7 @@ static int __init deflate_mod_init(void) static void __exit deflate_mod_fini(void) { crypto_unregister_alg(&alg); - crypto_unregister_scomps(scomp, ARRAY_SIZE(scomp)); + crypto_unregister_scomp(&scomp); } subsys_initcall(deflate_mod_init); diff --git a/crypto/testmgr.c b/crypto/testmgr.c index 216878c8bc3d62f8..b41a8e8c1d1a1987 100644 --- a/crypto/testmgr.c +++ b/crypto/testmgr.c @@ -5774,14 +5774,8 @@ static const struct alg_test_desc alg_test_descs[] = { } }, { .alg = "zlib-deflate", - .test = alg_test_comp, + .test = alg_test_null, .fips_allowed = 1, - .suite = { - .comp = { - .comp = __VECS(zlib_deflate_comp_tv_template), - .decomp = __VECS(zlib_deflate_decomp_tv_template) - } - } }, { .alg = "zstd", .test = alg_test_comp, diff --git a/crypto/testmgr.h b/crypto/testmgr.h index 5ca7a412508fbfb2..0cd6e0600255aad9 100644 --- a/crypto/testmgr.h +++ b/crypto/testmgr.h @@ -35754,81 +35754,6 @@ static const struct comp_testvec deflate_decomp_tv_template[] = { }, }; -static const struct comp_testvec zlib_deflate_comp_tv_template[] = { - { - .inlen = 70, - .outlen = 44, - .input = "Join us now and share the software " - "Join us now and share the software ", - .output = "\x78\x5e\xf3\xca\xcf\xcc\x53\x28" - "\x2d\x56\xc8\xcb\x2f\x57\x48\xcc" - "\x4b\x51\x28\xce\x48\x2c\x4a\x55" - "\x28\xc9\x48\x55\x28\xce\x4f\x2b" - "\x29\x07\x71\xbc\x08\x2b\x01\x00" - "\x7c\x65\x19\x3d", - }, { - .inlen = 191, - .outlen = 129, - .input = "This document describes a compression method based on the DEFLATE" - "compression algorithm. This document defines the application of " - "the DEFLATE algorithm to the IP Payload Compression Protocol.", - .output = "\x78\x5e\x5d\xce\x41\x0a\xc3\x30" - "\x0c\x04\xc0\xaf\xec\x0b\xf2\x87" - "\xd2\xa6\x50\xe8\xc1\x07\x7f\x40" - "\xb1\x95\x5a\x60\x5b\xc6\x56\x0f" - "\xfd\x7d\x93\x1e\x42\xe8\x51\xec" - "\xee\x20\x9f\x64\x20\x6a\x78\x17" - "\xae\x86\xc8\x23\x74\x59\x78\x80" - "\x10\xb4\xb4\xce\x63\x88\x56\x14" - "\xb6\xa4\x11\x0b\x0d\x8e\xd8\x6e" - "\x4b\x8c\xdb\x7c\x7f\x5e\xfc\x7c" - "\xae\x51\x7e\x69\x17\x4b\x65\x02" - "\xfc\x1f\xbc\x4a\xdd\xd8\x7d\x48" - "\xad\x65\x09\x64\x3b\xac\xeb\xd9" - "\xc2\x01\xc0\xf4\x17\x3c\x1c\x1c" - "\x7d\xb2\x52\xc4\xf5\xf4\x8f\xeb" - "\x6a\x1a\x34\x4f\x5f\x2e\x32\x45" - "\x4e", - }, -}; - -static const struct comp_testvec zlib_deflate_decomp_tv_template[] = { - { - .inlen = 128, - .outlen = 191, - .input = "\x78\x9c\x5d\x8d\x31\x0e\xc2\x30" - "\x10\x04\xbf\xb2\x2f\xc8\x1f\x10" - "\x04\x09\x89\xc2\x85\x3f\x70\xb1" - "\x2f\xf8\x24\xdb\x67\xd9\x47\xc1" - "\xef\x49\x68\x12\x51\xae\x76\x67" - "\xd6\x27\x19\x88\x1a\xde\x85\xab" - "\x21\xf2\x08\x5d\x16\x1e\x20\x04" - "\x2d\xad\xf3\x18\xa2\x15\x85\x2d" - "\x69\xc4\x42\x83\x23\xb6\x6c\x89" - "\x71\x9b\xef\xcf\x8b\x9f\xcf\x33" - "\xca\x2f\xed\x62\xa9\x4c\x80\xff" - "\x13\xaf\x52\x37\xed\x0e\x52\x6b" - "\x59\x02\xd9\x4e\xe8\x7a\x76\x1d" - "\x02\x98\xfe\x8a\x87\x83\xa3\x4f" - "\x56\x8a\xb8\x9e\x8e\x5c\x57\xd3" - "\xa0\x79\xfa\x02\x2e\x32\x45\x4e", - .output = "This document describes a compression method based on the DEFLATE" - "compression algorithm. This document defines the application of " - "the DEFLATE algorithm to the IP Payload Compression Protocol.", - }, { - .inlen = 44, - .outlen = 70, - .input = "\x78\x9c\xf3\xca\xcf\xcc\x53\x28" - "\x2d\x56\xc8\xcb\x2f\x57\x48\xcc" - "\x4b\x51\x28\xce\x48\x2c\x4a\x55" - "\x28\xc9\x48\x55\x28\xce\x4f\x2b" - "\x29\x07\x71\xbc\x08\x2b\x01\x00" - "\x7c\x65\x19\x3d", - .output = "Join us now and share the software " - "Join us now and share the software ", - }, -}; - /* * LZO test vectors (null-terminated strings). */
This reverts commit a368f43d6e3a001e684e9191a27df384fbff12f5. "zlib-deflate" was introduced 6 years ago, but it does not have any users. So let's remove the generic implementation and the test vectors, but retain the "zlib-deflate" entry in the testmgr code to avoid introducing warning messages on systems that implement zlib-deflate in hardware. Note that RFC 1950 which forms the basis of this algorithm dates back to 1996, and predates RFC 1951, on which the existing IPcomp is based and which we have supported in the kernel since 2003. So it seems rather unlikely that we will ever grow the need to support zlib-deflate. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> --- crypto/deflate.c | 61 +++++----------- crypto/testmgr.c | 8 +-- crypto/testmgr.h | 75 -------------------- 3 files changed, 18 insertions(+), 126 deletions(-)