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authorWilco Dijkstra <wdijkstr@arm.com>2018-09-19 16:50:18 +0100
committerWilco Dijkstra <wdijkstr@arm.com>2018-09-19 16:50:18 +0100
commit83a552b0bb9fc2a5e80a0ab3723c0a80ce1db9f2 (patch)
tree4861e51f5b6524e080ca62aefceb6a1d052fc652 /string
parentd734727837b5135c4c4c540d8c53e5a06aa7556a (diff)
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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.
Diffstat (limited to 'string')
-rw-r--r--string/strcasestr.c5
-rw-r--r--string/strstr.c5
-rw-r--r--string/test-strstr.c30
3 files changed, 36 insertions, 4 deletions
diff --git a/string/strcasestr.c b/string/strcasestr.c
index 1f6b7b846f8..8aa76037dcc 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 33acdc5442d..f74d7189ed1 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 8d99716ff39..5861b01b73e 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);