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

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This commit is contained in:
Florian Weimer 2018-09-26 22:08:37 +02:00
parent b972da9df0
commit 39e9c94a8d
2 changed files with 113 additions and 1 deletions
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108
glibc-rh1631719.patch Normal file
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@ -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);

6
glibc.spec
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@ -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)