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207 lines
6.7 KiB
207 lines
6.7 KiB
Author: Charles Fol <folcharles@gmail.com> |
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Date: Thu Mar 28 12:25:38 2024 -0300 |
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iconv: ISO-2022-CN-EXT: fix out-of-bound writes when writing escape sequence (CVE-2024-2961) |
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ISO-2022-CN-EXT uses escape sequences to indicate character set changes |
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(as specified by RFC 1922). While the SOdesignation has the expected |
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bounds checks, neither SS2designation nor SS3designation have its; |
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allowing a write overflow of 1, 2, or 3 bytes with fixed values: |
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'$+I', '$+J', '$+K', '$+L', '$+M', or '$*H'. |
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Checked on aarch64-linux-gnu. |
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Co-authored-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> |
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Reviewed-by: Carlos O'Donell <carlos@redhat.com> |
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Tested-by: Carlos O'Donell <carlos@redhat.com> |
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Conflicts: |
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iconvdata/Makefile |
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(usual tests conflict) |
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diff --git a/iconvdata/Makefile b/iconvdata/Makefile |
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index d5507a048c6a6508..25bd004e7f92a994 100644 |
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--- a/iconvdata/Makefile |
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+++ b/iconvdata/Makefile |
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@@ -75,7 +75,7 @@ ifeq (yes,$(build-shared)) |
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tests = bug-iconv1 bug-iconv2 tst-loading tst-e2big tst-iconv4 bug-iconv4 \ |
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tst-iconv6 bug-iconv5 bug-iconv6 tst-iconv7 bug-iconv8 bug-iconv9 \ |
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bug-iconv10 bug-iconv11 bug-iconv12 tst-iconv-big5-hkscs-to-2ucs4 \ |
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- bug-iconv13 bug-iconv14 bug-iconv15 |
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+ bug-iconv13 bug-iconv14 bug-iconv15 tst-iconv-iso-2022-cn-ext |
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ifeq ($(have-thread-library),yes) |
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tests += bug-iconv3 |
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endif |
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@@ -330,6 +330,8 @@ $(objpfx)bug-iconv14.out: $(addprefix $(objpfx), $(gconv-modules)) \ |
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$(addprefix $(objpfx),$(modules.so)) |
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$(objpfx)bug-iconv15.out: $(addprefix $(objpfx), $(gconv-modules)) \ |
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$(addprefix $(objpfx),$(modules.so)) |
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+$(objpfx)tst-iconv-iso-2022-cn-ext.out: $(addprefix $(objpfx), $(gconv-modules)) \ |
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+ $(addprefix $(objpfx),$(modules.so)) |
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$(objpfx)iconv-test.out: run-iconv-test.sh \ |
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$(addprefix $(objpfx), $(gconv-modules)) \ |
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diff --git a/iconvdata/iso-2022-cn-ext.c b/iconvdata/iso-2022-cn-ext.c |
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index 2aca91c021f21ba0..c1339fe933d9d1c4 100644 |
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--- a/iconvdata/iso-2022-cn-ext.c |
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+++ b/iconvdata/iso-2022-cn-ext.c |
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@@ -575,6 +575,12 @@ DIAG_IGNORE_Os_NEEDS_COMMENT (5, "-Wmaybe-uninitialized"); |
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{ \ |
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const char *escseq; \ |
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\ |
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+ if (outptr + 4 > outend) \ |
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+ { \ |
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+ result = __GCONV_FULL_OUTPUT; \ |
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+ break; \ |
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+ } \ |
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+ \ |
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assert (used == CNS11643_2_set); /* XXX */ \ |
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escseq = "*H"; \ |
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*outptr++ = ESC; \ |
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@@ -588,6 +594,12 @@ DIAG_IGNORE_Os_NEEDS_COMMENT (5, "-Wmaybe-uninitialized"); |
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{ \ |
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const char *escseq; \ |
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\ |
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+ if (outptr + 4 > outend) \ |
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+ { \ |
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+ result = __GCONV_FULL_OUTPUT; \ |
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+ break; \ |
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+ } \ |
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+ \ |
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assert ((used >> 5) >= 3 && (used >> 5) <= 7); \ |
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escseq = "+I+J+K+L+M" + ((used >> 5) - 3) * 2; \ |
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*outptr++ = ESC; \ |
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diff --git a/iconvdata/tst-iconv-iso-2022-cn-ext.c b/iconvdata/tst-iconv-iso-2022-cn-ext.c |
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new file mode 100644 |
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index 0000000000000000..96a8765fd5369681 |
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--- /dev/null |
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+++ b/iconvdata/tst-iconv-iso-2022-cn-ext.c |
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@@ -0,0 +1,128 @@ |
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+/* Verify ISO-2022-CN-EXT does not write out of the bounds. |
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+ Copyright (C) 2024 Free Software Foundation, Inc. |
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+ This file is part of the GNU C Library. |
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+ |
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+ The GNU C Library is free software; you can redistribute it and/or |
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+ modify it under the terms of the GNU Lesser General Public |
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+ License as published by the Free Software Foundation; either |
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+ version 2.1 of the License, or (at your option) any later version. |
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+ |
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+ The GNU C Library is distributed in the hope that it will be useful, |
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of |
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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+ Lesser General Public License for more details. |
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+ |
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+ You should have received a copy of the GNU Lesser General Public |
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+ License along with the GNU C Library; if not, see |
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+ <https://www.gnu.org/licenses/>. */ |
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+ |
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+#include <stdio.h> |
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+#include <string.h> |
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+ |
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+#include <errno.h> |
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+#include <iconv.h> |
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+#include <sys/mman.h> |
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+ |
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+#include <support/xunistd.h> |
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+#include <support/check.h> |
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+#include <support/support.h> |
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+ |
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+/* The test sets up a two memory page buffer with the second page marked |
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+ PROT_NONE to trigger a fault if the conversion writes beyond the exact |
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+ expected amount. Then we carry out various conversions and precisely |
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+ place the start of the output buffer in order to trigger a SIGSEGV if the |
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+ process writes anywhere between 1 and page sized bytes more (only one |
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+ PROT_NONE page is setup as a canary) than expected. These tests exercise |
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+ all three of the cases in ISO-2022-CN-EXT where the converter must switch |
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+ character sets and may run out of buffer space while doing the |
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+ operation. */ |
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+ |
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+static int |
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+do_test (void) |
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+{ |
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+ iconv_t cd = iconv_open ("ISO-2022-CN-EXT", "UTF-8"); |
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+ TEST_VERIFY_EXIT (cd != (iconv_t) -1); |
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+ |
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+ char *ntf; |
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+ size_t ntfsize; |
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+ char *outbufbase; |
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+ { |
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+ int pgz = getpagesize (); |
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+ TEST_VERIFY_EXIT (pgz > 0); |
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+ ntfsize = 2 * pgz; |
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+ |
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+ ntf = xmmap (NULL, ntfsize, PROT_READ | PROT_WRITE, MAP_PRIVATE |
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+ | MAP_ANONYMOUS, -1); |
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+ xmprotect (ntf + pgz, pgz, PROT_NONE); |
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+ |
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+ outbufbase = ntf + pgz; |
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+ } |
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+ |
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+ /* Check if SOdesignation escape sequence does not trigger an OOB write. */ |
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+ { |
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+ char inbuf[] = "\xe4\xba\xa4\xe6\x8d\xa2"; |
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+ |
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+ for (int i = 0; i < 9; i++) |
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+ { |
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+ char *inp = inbuf; |
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+ size_t inleft = sizeof (inbuf) - 1; |
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+ |
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+ char *outp = outbufbase - i; |
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+ size_t outleft = i; |
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+ |
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+ TEST_VERIFY_EXIT (iconv (cd, &inp, &inleft, &outp, &outleft) |
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+ == (size_t) -1); |
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+ TEST_COMPARE (errno, E2BIG); |
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+ |
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+ TEST_VERIFY_EXIT (iconv (cd, NULL, NULL, NULL, NULL) == 0); |
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+ } |
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+ } |
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+ |
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+ /* Same as before for SS2designation. */ |
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+ { |
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+ char inbuf[] = "㴽 \xe3\xb4\xbd"; |
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+ |
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+ for (int i = 0; i < 14; i++) |
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+ { |
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+ char *inp = inbuf; |
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+ size_t inleft = sizeof (inbuf) - 1; |
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+ |
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+ char *outp = outbufbase - i; |
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+ size_t outleft = i; |
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+ |
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+ TEST_VERIFY_EXIT (iconv (cd, &inp, &inleft, &outp, &outleft) |
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+ == (size_t) -1); |
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+ TEST_COMPARE (errno, E2BIG); |
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+ |
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+ TEST_VERIFY_EXIT (iconv (cd, NULL, NULL, NULL, NULL) == 0); |
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+ } |
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+ } |
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+ |
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+ /* Same as before for SS3designation. */ |
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+ { |
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+ char inbuf[] = "劄 \xe5\x8a\x84"; |
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+ |
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+ for (int i = 0; i < 14; i++) |
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+ { |
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+ char *inp = inbuf; |
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+ size_t inleft = sizeof (inbuf) - 1; |
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+ |
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+ char *outp = outbufbase - i; |
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+ size_t outleft = i; |
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+ |
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+ TEST_VERIFY_EXIT (iconv (cd, &inp, &inleft, &outp, &outleft) |
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+ == (size_t) -1); |
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+ TEST_COMPARE (errno, E2BIG); |
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+ |
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+ TEST_VERIFY_EXIT (iconv (cd, NULL, NULL, NULL, NULL) == 0); |
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+ } |
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+ } |
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+ |
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+ TEST_VERIFY_EXIT (iconv_close (cd) != -1); |
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+ |
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+ xmunmap (ntf, ntfsize); |
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+ |
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+ return 0; |
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+} |
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+ |
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+#include <support/test-driver.c>
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