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[msan] fix iconv interceptor. before the fix the interceptor failed to mark memory as initialized if iconv returned -1. Found in a hard way while fuzzing libxml2 :( 

llvm-svn: 300010
This commit is contained in:
Kostya Serebryany 2017-04-12 00:12:34 +00:00
parent 308624127f
commit 13c8daf57a
2 changed files with 29 additions and 1 deletions
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2
compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
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@ -4637,7 +4637,7 @@ INTERCEPTOR(SIZE_T, iconv, void *cd, char **inbuf, SIZE_T *inbytesleft,
// its metadata. See
// https://github.com/google/sanitizers/issues/321.
SIZE_T res = REAL(iconv)(cd, inbuf, inbytesleft, outbuf, outbytesleft);
if (res != (SIZE_T) - 1 && outbuf && *outbuf > outbuf_orig) {
if (outbuf && *outbuf > outbuf_orig) {
SIZE_T sz = (char *)*outbuf - (char *)outbuf_orig;
COMMON_INTERCEPTOR_WRITE_RANGE(ctx, outbuf_orig, sz);
}

28
compiler-rt/test/sanitizer_common/TestCases/Linux/iconv_test.c Normal file
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@ -0,0 +1,28 @@
// RUN: %clang %s -o %t && %run %t
// Verify that even if iconv returned -1
// we still treat the initialized part of outbuf as properly initialized.
#include <iconv.h>
#include <assert.h>
#include <stdio.h>
int main() {
iconv_t cd = iconv_open("UTF-8", "no");
assert(cd != (iconv_t)-1);
char in[11] = {0x7e, 0x7e, 0x5f, 0x53, 0x55, 0x3e,
0x99, 0x3c, 0x7e, 0x7e, 0x7e};
fprintf(stderr, "cd: %p\n", (void*)cd);
char out[100];
char *inbuf = &in[0];
size_t inbytesleft = 11;
char *outbuf = &out[0];
size_t outbytesleft = 100;
int ret = iconv(cd, &inbuf, &inbytesleft, &outbuf, &outbytesleft);
assert(ret == -1);
assert(outbuf - &out[0] == 10);
for (int i = 0; i < 10; i++) {
if (out[i] == 0x77) return 1;
fprintf(stderr, "OUT%d 0x%x -- OK\n", i, (unsigned char)out[i]);
}
iconv_close(cd);
}