From: Roberto Sassu roberto.sassu@huawei.com
commit 8e0ab8e26b72a80e991c66a8abc16e6c856abe3d upstream.
Fix two problems found in the strrchr() implementation for s390 architectures: evaluate empty strings (return the string address instead of NULL, if '\0' is passed as second argument); evaluate the first character of non-empty strings (the current implementation stops at the second).
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Reported-by: Heiko Carstens hca@linux.ibm.com (incorrect behavior with empty strings) Signed-off-by: Roberto Sassu roberto.sassu@huawei.com Link: https://lore.kernel.org/r/20211005120836.60630-1-roberto.sassu@huawei.com Signed-off-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Vasily Gorbik gor@linux.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/s390/lib/string.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-)
--- a/arch/s390/lib/string.c +++ b/arch/s390/lib/string.c @@ -259,14 +259,13 @@ EXPORT_SYMBOL(strcmp); #ifdef __HAVE_ARCH_STRRCHR char *strrchr(const char *s, int c) { - size_t len = __strend(s) - s; + ssize_t len = __strend(s) - s;
- if (len) - do { - if (s[len] == (char) c) - return (char *) s + len; - } while (--len > 0); - return NULL; + do { + if (s[len] == (char)c) + return (char *)s + len; + } while (--len >= 0); + return NULL; } EXPORT_SYMBOL(strrchr); #endif