Fix bug in generic strstr with large needles (#1631719)

glibc-rh1631719.patch

@@ -0,0 +1,108 @@
+commit 0ef2f4400c06927af34c515555f68840a70ba409
+Author: Wilco Dijkstra <wdijkstr@arm.com>
+Date:   Wed Sep 19 16:50:18 2018 +0100
+
+    Fix strstr bug with huge needles (bug 23637)
+    
+    The generic strstr in GLIBC 2.28 fails to match huge needles.  The optimized
+    AVAILABLE macro reads ahead a large fixed amount to reduce the overhead of
+    repeatedly checking for the end of the string.  However if the needle length
+    is larger than this, two_way_long_needle may confuse this as meaning the end
+    of the string and return NULL.  This is fixed by adding the needle length to
+    the amount to read ahead.
+    
+            [BZ #23637]
+            * string/test-strstr.c (pr23637): New function.
+            (test_main): Add tests with longer needles.
+            * string/strcasestr.c (AVAILABLE): Fix readahead distance.
+            * string/strstr.c (AVAILABLE): Likewise.
+    
+        (cherry picked from commit 83a552b0bb9fc2a5e80a0ab3723c0a80ce1db9f2)
+
+diff --git a/string/strcasestr.c b/string/strcasestr.c
+index 5909fe3cdba88e47..421764bd1b0ff22e 100644
+--- a/string/strcasestr.c
++++ b/string/strcasestr.c
+@@ -37,8 +37,9 @@
+ /* Two-Way algorithm.  */
+ #define RETURN_TYPE char *
+ #define AVAILABLE(h, h_l, j, n_l)			\
+-  (((j) + (n_l) <= (h_l)) || ((h_l) += __strnlen ((void*)((h) + (h_l)), 512), \
+-			      (j) + (n_l) <= (h_l)))
++  (((j) + (n_l) <= (h_l)) \
++   || ((h_l) += __strnlen ((void*)((h) + (h_l)), (n_l) + 512), \
++       (j) + (n_l) <= (h_l)))
+ #define CHECK_EOL (1)
+ #define RET0_IF_0(a) if (!a) goto ret0
+ #define CANON_ELEMENT(c) TOLOWER (c)
+diff --git a/string/strstr.c b/string/strstr.c
+index 265e9f310ce507ce..79ebcc75329d0b17 100644
+--- a/string/strstr.c
++++ b/string/strstr.c
+@@ -33,8 +33,9 @@
+ 
+ #define RETURN_TYPE char *
+ #define AVAILABLE(h, h_l, j, n_l)			\
+-  (((j) + (n_l) <= (h_l)) || ((h_l) += __strnlen ((void*)((h) + (h_l)), 512), \
+-			      (j) + (n_l) <= (h_l)))
++  (((j) + (n_l) <= (h_l)) \
++   || ((h_l) += __strnlen ((void*)((h) + (h_l)), (n_l) + 512), \
++       (j) + (n_l) <= (h_l)))
+ #define CHECK_EOL (1)
+ #define RET0_IF_0(a) if (!a) goto ret0
+ #define FASTSEARCH(S,C,N) (void*) strchr ((void*)(S), (C))
+diff --git a/string/test-strstr.c b/string/test-strstr.c
+index 8d99716ff39cc2c2..5861b01b73e4c315 100644
+--- a/string/test-strstr.c
++++ b/string/test-strstr.c
+@@ -151,6 +151,32 @@ check2 (void)
+     }
+ }
+ 
++#define N 1024
++
++static void
++pr23637 (void)
++{
++  char *h = (char*) buf1;
++  char *n = (char*) buf2;
++
++  for (int i = 0; i < N; i++)
++    {
++      n[i] = 'x';
++      h[i] = ' ';
++      h[i + N] = 'x';
++    }
++
++  n[N] = '\0';
++  h[N * 2] = '\0';
++
++  /* Ensure we don't match at the first 'x'.  */
++  h[0] = 'x';
++
++  char *exp_result = stupid_strstr (h, n);
++  FOR_EACH_IMPL (impl, 0)
++    check_result (impl, h, n, exp_result);
++}
++
+ static int
+ test_main (void)
+ {
+@@ -158,6 +184,7 @@ test_main (void)
+ 
+   check1 ();
+   check2 ();
++  pr23637 ();
+ 
+   printf ("%23s", "");
+   FOR_EACH_IMPL (impl, 0)
+@@ -202,6 +229,9 @@ test_main (void)
+ 	do_test (15, 9, hlen, klen, 1);
+ 	do_test (15, 15, hlen, klen, 0);
+ 	do_test (15, 15, hlen, klen, 1);
++
++	do_test (15, 15, hlen + klen * 4, klen * 4, 0);
++	do_test (15, 15, hlen + klen * 4, klen * 4, 1);
+       }
+ 
+   do_test (0, 0, page_size - 1, 16, 0);

glibc.spec

@@ -1,6 +1,6 @@
 %define glibcsrcdir glibc-2.28
 %define glibcversion 2.28
-%define glibcrelease 13%{?dist}
+%define glibcrelease 14%{?dist}
 # Pre-release tarballs are pulled in from git using a command that is
 # effectively:
 #
@@ -170,6 +170,7 @@ Patch34: glibc-1622674-2.patch
 Patch35: glibc-rh1631338-1.patch
 Patch36: glibc-rh1631338-2.patch
 Patch37: glibc-rh1623519.patch
+Patch38: glibc-rh1631719.patch
 
 ##############################################################################
 # Continued list of core "glibc" package information:
@@ -1911,6 +1912,9 @@ fi
 %files -f compat-libpthread-nonshared.filelist -n compat-libpthread-nonshared
 
 %changelog
+* Wed Sep 26 2018 Florian Weimer <fweimer@redhat.com> - 2.28-14
+- Fix bug in generic strstr with large needles (#1631719)
+
 * Wed Sep 26 2018 Florian Weimer <fweimer@redhat.com> - 2.28-13
 - stdlib/tst-setcontext9 test suite failure (#1623519)