fix false negatives with periodic needles in strstr, wcsstr, and memmem

in cases where the memorized match range from the right factor
exceeded the length of the left factor, it was wrongly treated as a
mismatch rather than a match.

issue reported by Yves Bastide.

(cherry picked from commit 476cd1d96560aaf7f210319597556e7fbcd60469)

diff --git a/src/string/memmem.c b/src/string/memmem.c
index a5a249f2ca04a350e77d9bc7ff1ca31891b32c1b..3b1ae18316a1d355bc6e2eabb46648060cf7decb 100644 (file)
--- a/src/string/memmem.c
+++ b/src/string/memmem.c
@@ -120,7 +120,7 @@ static char *twoway_memmem(const unsigned char *h, const unsigned char *z, const
                }
                /* Compare left half */
                for (k=ms+1; k>mem && n[k-1] == h[k-1]; k--);
-               if (k == mem) return (char *)h;
+               if (k <= mem) return (char *)h;
                h += p;
                mem = mem0;
        }

diff --git a/src/string/strstr.c b/src/string/strstr.c
index 915c0a22f6c239125bafbec63571519d9ac52bd7..cd0691275b2e4880853837738a1569ad1d06fc80 100644 (file)
--- a/src/string/strstr.c
+++ b/src/string/strstr.c
@@ -130,7 +130,7 @@ static char *twoway_strstr(const unsigned char *h, const unsigned char *n)
                }
                /* Compare left half */
                for (k=ms+1; k>mem && n[k-1] == h[k-1]; k--);
-               if (k == mem) return (char *)h;
+               if (k <= mem) return (char *)h;
                h += p;
                mem = mem0;
        }

diff --git a/src/string/wcsstr.c b/src/string/wcsstr.c
index 3e28e287f25fa7a8f51f3da15f7cf342bd1ab0e4..4caaef3c94bf1a43ec462264fad90ca914c82da0 100644 (file)
--- a/src/string/wcsstr.c
+++ b/src/string/wcsstr.c
@@ -84,7 +84,7 @@ static wchar_t *twoway_wcsstr(const wchar_t *h, const wchar_t *n)
                }
                /* Compare left half */
                for (k=ms+1; k>mem && n[k-1] == h[k-1]; k--);
-               if (k == mem) return (wchar_t *)h;
+               if (k <= mem) return (wchar_t *)h;
                h += p;
                mem = mem0;
        }