From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Thu, 7 Jul 2016 18:23:24 +0200 Subject: [PATCH] util: fix off-by-one array access MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Thanks to ASAN, I found this off-by-one memory access in the unix2dos code: /util/unix2dos: ================================================================= ==23589==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60200000dd2f at pc 0x00000040428e bp 0x7ffd6fc31b90 sp 0x7ffd6fc31b80 READ of size 1 at 0x60200000dd2f thread T0 #0 0x40428d in spice_convert_newlines /home/elmarco/src/spice/spice-gtk/src/spice-util.c:355 #1 0x40443a in spice_unix2dos /home/elmarco/src/spice/spice-gtk/src/spice-util.c:382 #2 0x401eae in test_unix2dos /home/elmarco/src/spice/spice-gtk/tests/util.c:69 #3 0x7fb8bcd81983 (/lib64/libglib-2.0.so.0+0x6e983) #4 0x7fb8bcd81b4e (/lib64/libglib-2.0.so.0+0x6eb4e) #5 0x7fb8bcd81d5d in g_test_run_suite (/lib64/libglib-2.0.so.0+0x6ed5d) #6 0x7fb8bcd81d80 in g_test_run (/lib64/libglib-2.0.so.0+0x6ed80) #7 0x402cce in main /home/elmarco/src/spice/spice-gtk/tests/util.c:207 #8 0x7fb8bc755730 in __libc_start_main (/lib64/libc.so.6+0x20730) #9 0x401818 in _start (/home/elmarco/src/spice/spice-gtk/tests/util+0x401818) 0x60200000dd2f is located 1 bytes to the left of 4-byte region [0x60200000dd30,0x60200000dd34) allocated by thread T0 here: #0 0x7fb8c10421d0 in realloc (/lib64/libasan.so.3+0xc71d0) #1 0x7fb8bcd61f1f in g_realloc (/lib64/libglib-2.0.so.0+0x4ef1f) SUMMARY: AddressSanitizer: heap-buffer-overflow /home/elmarco/src/spice/spice-gtk/src/spice-util.c:355 in spice_convert_newlines Signed-off-by: Marc-André Lureau --- src/spice-util.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/spice-util.c b/src/spice-util.c index 7788921..bca3abc 100644 --- a/src/spice-util.c +++ b/src/spice-util.c @@ -352,7 +352,7 @@ static gchar* spice_convert_newlines(const gchar *str, gssize len, if (nl) { /* let's not double \r if it's already in the line */ if (to == NEWLINE_TYPE_CR_LF && - output->str[output->len - 1] != '\r') + (output->len == 0 || output->str[output->len - 1] != '\r')) g_string_append_c(output, '\r'); g_string_append_c(output, '\n');