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| author | Marko Mäkelä <marko.makela@mariadb.com> | 2020-09-03 08:41:47 +0300 |
|---|---|---|
| committer | Marko Mäkelä <marko.makela@mariadb.com> | 2020-09-03 08:41:47 +0300 |
| commit | a256070e7d94fdd1d63a4823c638ff5c76ca9c73 (patch) | |
| tree | adb07b5d0224c94ed91a9048d0b450f80e996c66 | |
| parent | cd36bc01a5f1c1cd126cdd0668c6049cc78be40a (diff) | |
| download | mariadb-git-a256070e7d94fdd1d63a4823c638ff5c76ca9c73.tar.gz | |
MDEV-7110 follow-up fix: Do not pass NULL as nonnull parameter
Passing a null pointer to the "%s" argument of a printf-like
function is undefined behaviour. In the GNU libc implementation
of the printf() family of functions, it happens to work.
GCC 10.2.0 would diagnose this with -Wformat-overflow -Og.
In -fsanitize=undefined (WITH_UBSAN=ON) builds, a runtime error
would be generated. In some other builds, GCC 8 or later might infer
that the parameter is nonnull and optimize away further checks whether
the parameter is null, leading to SIGSEGV.
| -rw-r--r-- | sql/mysqld.cc | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/sql/mysqld.cc b/sql/mysqld.cc index 6a5162e2f03..8d00b5af948 100644 --- a/sql/mysqld.cc +++ b/sql/mysqld.cc @@ -3974,7 +3974,8 @@ rpl_make_log_name(const char *opt, const char *ext) { DBUG_ENTER("rpl_make_log_name"); - DBUG_PRINT("enter", ("opt: %s, def: %s, ext: %s", opt, def, ext)); + DBUG_PRINT("enter", ("opt: %s, def: %s, ext: %s", opt ? opt : "(null)", + def, ext)); char buff[FN_REFLEN]; const char *base= opt ? opt : def; unsigned int options= |