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![Waiman Long](/assets/img/avatar_default.png)
As said by Linus: A symmetric naming is only helpful if it implies symmetries in use. Otherwise it's actively misleading. In "kzalloc()", the z is meaningful and an important part of what the caller wants. In "kzfree()", the z is actively detrimental, because maybe in the future we really _might_ want to use that "memfill(0xdeadbeef)" or something. The "zero" part of the interface isn't even _relevant_. The main reason that kzfree() exists is to clear sensitive information that should not be leaked to other future users of the same memory objects. Rename kzfree() to kfree_sensitive() to follow the example of the recently added kvfree_sensitive() and make the intention of the API more explicit. In addition, memzero_explicit() is used to clear the memory to make sure that it won't get optimized away by the compiler. The renaming is done by using the command sequence: git grep -w --name-only kzfree |\ xargs sed -i 's/kzfree/kfree_sensitive/' followed by some editing of the kfree_sensitive() kerneldoc and adding a kzfree backward compatibility macro in slab.h. [akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h] [akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more] Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Joe Perches <joe@perches.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Rientjes <rientjes@google.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: "Jason A . Donenfeld" <Jason@zx2c4.com> Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
340 lines
7.7 KiB
C
340 lines
7.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Cryptographic API.
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*
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* Deflate algorithm (RFC 1951), implemented here primarily for use
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* by IPCOMP (RFC 3173 & RFC 2394).
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*
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* Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
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*
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* FIXME: deflate transforms will require up to a total of about 436k of kernel
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* memory on i386 (390k for compression, the rest for decompression), as the
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* current zlib kernel code uses a worst case pre-allocation system by default.
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* This needs to be fixed so that the amount of memory required is properly
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* related to the winbits and memlevel parameters.
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*
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* The default winbits of 11 should suit most packets, and it may be something
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* to configure on a per-tfm basis in the future.
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*
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* Currently, compression history is not maintained between tfm calls, as
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* it is not needed for IPCOMP and keeps the code simpler. It can be
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* implemented if someone wants it.
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/crypto.h>
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#include <linux/zlib.h>
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#include <linux/vmalloc.h>
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#include <linux/interrupt.h>
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#include <linux/mm.h>
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#include <linux/net.h>
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#include <crypto/internal/scompress.h>
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#define DEFLATE_DEF_LEVEL Z_DEFAULT_COMPRESSION
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#define DEFLATE_DEF_WINBITS 11
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#define DEFLATE_DEF_MEMLEVEL MAX_MEM_LEVEL
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struct deflate_ctx {
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struct z_stream_s comp_stream;
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struct z_stream_s decomp_stream;
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};
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static int deflate_comp_init(struct deflate_ctx *ctx, int format)
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{
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int ret = 0;
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struct z_stream_s *stream = &ctx->comp_stream;
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stream->workspace = vzalloc(zlib_deflate_workspacesize(
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MAX_WBITS, MAX_MEM_LEVEL));
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if (!stream->workspace) {
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ret = -ENOMEM;
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goto out;
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}
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if (format)
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ret = zlib_deflateInit(stream, 3);
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else
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ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED,
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-DEFLATE_DEF_WINBITS,
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DEFLATE_DEF_MEMLEVEL,
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Z_DEFAULT_STRATEGY);
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if (ret != Z_OK) {
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ret = -EINVAL;
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goto out_free;
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}
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out:
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return ret;
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out_free:
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vfree(stream->workspace);
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goto out;
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}
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static int deflate_decomp_init(struct deflate_ctx *ctx, int format)
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{
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int ret = 0;
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struct z_stream_s *stream = &ctx->decomp_stream;
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stream->workspace = vzalloc(zlib_inflate_workspacesize());
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if (!stream->workspace) {
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ret = -ENOMEM;
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goto out;
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}
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if (format)
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ret = zlib_inflateInit(stream);
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else
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ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS);
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if (ret != Z_OK) {
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ret = -EINVAL;
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goto out_free;
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}
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out:
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return ret;
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out_free:
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vfree(stream->workspace);
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goto out;
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}
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static void deflate_comp_exit(struct deflate_ctx *ctx)
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{
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zlib_deflateEnd(&ctx->comp_stream);
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vfree(ctx->comp_stream.workspace);
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}
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static void deflate_decomp_exit(struct deflate_ctx *ctx)
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{
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zlib_inflateEnd(&ctx->decomp_stream);
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vfree(ctx->decomp_stream.workspace);
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}
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static int __deflate_init(void *ctx, int format)
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{
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int ret;
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ret = deflate_comp_init(ctx, format);
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if (ret)
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goto out;
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ret = deflate_decomp_init(ctx, format);
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if (ret)
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deflate_comp_exit(ctx);
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out:
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return ret;
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}
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static void *gen_deflate_alloc_ctx(struct crypto_scomp *tfm, int format)
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{
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struct deflate_ctx *ctx;
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int ret;
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ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
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if (!ctx)
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return ERR_PTR(-ENOMEM);
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ret = __deflate_init(ctx, format);
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if (ret) {
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kfree(ctx);
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return ERR_PTR(ret);
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}
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return ctx;
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}
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static void *deflate_alloc_ctx(struct crypto_scomp *tfm)
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{
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return gen_deflate_alloc_ctx(tfm, 0);
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}
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static void *zlib_deflate_alloc_ctx(struct crypto_scomp *tfm)
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{
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return gen_deflate_alloc_ctx(tfm, 1);
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}
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static int deflate_init(struct crypto_tfm *tfm)
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{
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struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
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return __deflate_init(ctx, 0);
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}
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static void __deflate_exit(void *ctx)
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{
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deflate_comp_exit(ctx);
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deflate_decomp_exit(ctx);
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}
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static void deflate_free_ctx(struct crypto_scomp *tfm, void *ctx)
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{
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__deflate_exit(ctx);
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kfree_sensitive(ctx);
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}
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static void deflate_exit(struct crypto_tfm *tfm)
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{
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struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
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__deflate_exit(ctx);
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}
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static int __deflate_compress(const u8 *src, unsigned int slen,
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u8 *dst, unsigned int *dlen, void *ctx)
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{
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int ret = 0;
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struct deflate_ctx *dctx = ctx;
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struct z_stream_s *stream = &dctx->comp_stream;
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ret = zlib_deflateReset(stream);
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if (ret != Z_OK) {
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ret = -EINVAL;
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goto out;
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}
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stream->next_in = (u8 *)src;
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stream->avail_in = slen;
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stream->next_out = (u8 *)dst;
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stream->avail_out = *dlen;
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ret = zlib_deflate(stream, Z_FINISH);
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if (ret != Z_STREAM_END) {
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ret = -EINVAL;
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goto out;
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}
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ret = 0;
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*dlen = stream->total_out;
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out:
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return ret;
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}
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static int deflate_compress(struct crypto_tfm *tfm, const u8 *src,
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unsigned int slen, u8 *dst, unsigned int *dlen)
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{
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struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);
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return __deflate_compress(src, slen, dst, dlen, dctx);
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}
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static int deflate_scompress(struct crypto_scomp *tfm, const u8 *src,
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unsigned int slen, u8 *dst, unsigned int *dlen,
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void *ctx)
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{
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return __deflate_compress(src, slen, dst, dlen, ctx);
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}
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static int __deflate_decompress(const u8 *src, unsigned int slen,
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u8 *dst, unsigned int *dlen, void *ctx)
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{
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int ret = 0;
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struct deflate_ctx *dctx = ctx;
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struct z_stream_s *stream = &dctx->decomp_stream;
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ret = zlib_inflateReset(stream);
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if (ret != Z_OK) {
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ret = -EINVAL;
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goto out;
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}
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stream->next_in = (u8 *)src;
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stream->avail_in = slen;
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stream->next_out = (u8 *)dst;
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stream->avail_out = *dlen;
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ret = zlib_inflate(stream, Z_SYNC_FLUSH);
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/*
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* Work around a bug in zlib, which sometimes wants to taste an extra
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* byte when being used in the (undocumented) raw deflate mode.
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* (From USAGI).
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*/
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if (ret == Z_OK && !stream->avail_in && stream->avail_out) {
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u8 zerostuff = 0;
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stream->next_in = &zerostuff;
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stream->avail_in = 1;
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ret = zlib_inflate(stream, Z_FINISH);
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}
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if (ret != Z_STREAM_END) {
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ret = -EINVAL;
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goto out;
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}
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ret = 0;
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*dlen = stream->total_out;
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out:
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return ret;
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}
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static int deflate_decompress(struct crypto_tfm *tfm, const u8 *src,
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unsigned int slen, u8 *dst, unsigned int *dlen)
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{
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struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);
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return __deflate_decompress(src, slen, dst, dlen, dctx);
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}
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static int deflate_sdecompress(struct crypto_scomp *tfm, const u8 *src,
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unsigned int slen, u8 *dst, unsigned int *dlen,
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void *ctx)
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{
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return __deflate_decompress(src, slen, dst, dlen, ctx);
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}
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static struct crypto_alg alg = {
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.cra_name = "deflate",
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.cra_driver_name = "deflate-generic",
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.cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
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.cra_ctxsize = sizeof(struct deflate_ctx),
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.cra_module = THIS_MODULE,
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.cra_init = deflate_init,
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.cra_exit = deflate_exit,
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.cra_u = { .compress = {
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.coa_compress = deflate_compress,
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.coa_decompress = deflate_decompress } }
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};
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static struct scomp_alg scomp[] = { {
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.alloc_ctx = deflate_alloc_ctx,
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.free_ctx = deflate_free_ctx,
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.compress = deflate_scompress,
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.decompress = deflate_sdecompress,
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.base = {
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.cra_name = "deflate",
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.cra_driver_name = "deflate-scomp",
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.cra_module = THIS_MODULE,
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}
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}, {
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.alloc_ctx = zlib_deflate_alloc_ctx,
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.free_ctx = deflate_free_ctx,
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.compress = deflate_scompress,
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.decompress = deflate_sdecompress,
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.base = {
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.cra_name = "zlib-deflate",
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.cra_driver_name = "zlib-deflate-scomp",
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.cra_module = THIS_MODULE,
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}
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} };
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static int __init deflate_mod_init(void)
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{
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int ret;
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ret = crypto_register_alg(&alg);
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if (ret)
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return ret;
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ret = crypto_register_scomps(scomp, ARRAY_SIZE(scomp));
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if (ret) {
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crypto_unregister_alg(&alg);
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return ret;
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}
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return ret;
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}
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static void __exit deflate_mod_fini(void)
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{
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crypto_unregister_alg(&alg);
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crypto_unregister_scomps(scomp, ARRAY_SIZE(scomp));
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}
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subsys_initcall(deflate_mod_init);
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module_exit(deflate_mod_fini);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP");
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MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
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MODULE_ALIAS_CRYPTO("deflate");
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