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Fix strstr bug with huge needles (bug 23637)

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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.
This commit is contained in:
Wilco Dijkstra
2018-09-19 16:50:18 +01:00
parent d734727837
commit 83a552b0bb
4 changed files with 44 additions and 4 deletions
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5
string/strstr.c
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@ -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))