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authorAndrey Ryabinin <a.ryabinin@samsung.com>2015-02-13 14:39:45 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-13 21:21:41 -0800
commitdf4c0e36f1b1782b0611a77c52cc240e5c4752dd (patch)
tree1cdb9be1182864d4604200bf58f044673fa85843
parent0316bec22ec95ea2faca6406437b0b5950553b7c (diff)
downloadlinux-df4c0e36f1b1782b0611a77c52cc240e5c4752dd.tar.bz2
fs: dcache: manually unpoison dname after allocation to shut up kasan's reports
We need to manually unpoison rounded up allocation size for dname to avoid kasan's reports in dentry_string_cmp(). When CONFIG_DCACHE_WORD_ACCESS=y dentry_string_cmp may access few bytes beyound requested in kmalloc() size. dentry_string_cmp() relates on that fact that dentry allocated using kmalloc and kmalloc internally round up allocation size. So this is not a bug, but this makes kasan to complain about such accesses. To avoid such reports we mark rounded up allocation size in shadow as accessible. Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrey Konovalov <adech.fo@gmail.com> Cc: Yuri Gribov <tetra2005@gmail.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/dcache.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index d04be762b216..7d34f04ec7aa 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -38,6 +38,8 @@
#include <linux/prefetch.h>
#include <linux/ratelimit.h>
#include <linux/list_lru.h>
+#include <linux/kasan.h>
+
#include "internal.h"
#include "mount.h"
@@ -1429,6 +1431,9 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
}
atomic_set(&p->u.count, 1);
dname = p->name;
+ if (IS_ENABLED(CONFIG_DCACHE_WORD_ACCESS))
+ kasan_unpoison_shadow(dname,
+ round_up(name->len + 1, sizeof(unsigned long)));
} else {
dname = dentry->d_iname;
}