453431a549
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>
61 lines
1.2 KiB
Plaintext
61 lines
1.2 KiB
Plaintext
// SPDX-License-Identifier: GPL-2.0-only
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/// NULL check before some freeing functions is not needed.
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///
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/// Based on checkpatch warning
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/// "kfree(NULL) is safe this check is probably not required"
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/// and kfreeaddr.cocci by Julia Lawall.
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///
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// Copyright: (C) 2014 Fabian Frederick.
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// Comments: -
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// Options: --no-includes --include-headers
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virtual patch
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virtual org
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virtual report
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virtual context
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@r2 depends on patch@
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expression E;
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@@
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- if (E != NULL)
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(
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kfree(E);
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kfree_sensitive(E);
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debugfs_remove(E);
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debugfs_remove_recursive(E);
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usb_free_urb(E);
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kmem_cache_destroy(E);
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mempool_destroy(E);
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dma_pool_destroy(E);
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)
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@r depends on context || report || org @
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expression E;
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position p;
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@@
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* if (E != NULL)
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* \(kfree@p\|kfree_sensitive@p\|debugfs_remove@p\|debugfs_remove_recursive@p\|
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* usb_free_urb@p\|kmem_cache_destroy@p\|mempool_destroy@p\|
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* dma_pool_destroy@p\)(E);
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@script:python depends on org@
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p << r.p;
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@@
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cocci.print_main("NULL check before that freeing function is not needed", p)
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@script:python depends on report@
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p << r.p;
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@@
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msg = "WARNING: NULL check before some freeing functions is not needed."
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coccilib.report.print_report(p[0], msg)
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