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| author | Marko Mäkelä <marko.makela@mariadb.com> | 2020-09-03 09:05:56 +0300 |
|---|---|---|
| committer | Marko Mäkelä <marko.makela@mariadb.com> | 2020-09-03 09:05:56 +0300 |
| commit | 94a520ddbe39ae97de1135d98699cf2674e6b77e (patch) | |
| tree | 051dc62fd84edc150754dd826830d467b45074d8 /sql/debug_sync.cc | |
| parent | a256070e7d94fdd1d63a4823c638ff5c76ca9c73 (diff) | |
| download | mariadb-git-94a520ddbe39ae97de1135d98699cf2674e6b77e.tar.gz | |
MDEV-22387: Do not pass null pointer to some memcpy()
Passing a null pointer to a nonnull argument is not only undefined
behaviour, but it also grants the compiler the permission to optimize
away further checks whether the pointer is null. GCC -O2 at least
starting with version 8 may do that, potentially causing SIGSEGV.
These problems were caught in a WITH_UBSAN=ON build with the
Bug#7024 test in main.view.
Diffstat (limited to 'sql/debug_sync.cc')
| -rw-r--r-- | sql/debug_sync.cc | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/sql/debug_sync.cc b/sql/debug_sync.cc index 591ce5800a8..79f3a241907 100644 --- a/sql/debug_sync.cc +++ b/sql/debug_sync.cc @@ -1,4 +1,5 @@ /* Copyright (c) 2009, 2013, Oracle and/or its affiliates. + Copyright (c) 2013, 2020, MariaDB This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -319,7 +320,8 @@ static char *debug_sync_bmove_len(char *to, char *to_end, DBUG_ASSERT(to_end); DBUG_ASSERT(!length || from); set_if_smaller(length, (size_t) (to_end - to)); - memcpy(to, from, length); + if (length) + memcpy(to, from, length); return (to + length); } |