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authorAlexander Potapenko <glider@google.com>2022-09-15 17:03:59 +0200
committerAndrew Morton <akpm@linux-foundation.org>2022-10-03 14:03:22 -0700
commit2de6f3bf75058e35eff04e6fab7ca41533bdb027 (patch)
tree32c37c85f7da0f58c1103b0e8ca10c15d9004fae /lib/string.c
parent8ed691b02ade8f755f34aa1fa8beff8ce4f81f6d (diff)
kmsan: disable strscpy() optimization under KMSAN
Disable the efficient 8-byte reading under KMSAN to avoid false positives. Link: https://lkml.kernel.org/r/20220915150417.722975-26-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Eric Biggers <ebiggers@kernel.org> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Ilya Leoshkevich <iii@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'lib/string.c')
-rw-r--r--lib/string.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/lib/string.c b/lib/string.c
index 6f334420f687..3371d26a0e39 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -197,6 +197,14 @@ ssize_t strscpy(char *dest, const char *src, size_t count)
max = 0;
#endif
+ /*
+ * read_word_at_a_time() below may read uninitialized bytes after the
+ * trailing zero and use them in comparisons. Disable this optimization
+ * under KMSAN to prevent false positive reports.
+ */
+ if (IS_ENABLED(CONFIG_KMSAN))
+ max = 0;
+
while (max >= sizeof(unsigned long)) {
unsigned long c, data;