From e659c96bca2c9dbb800ce7882610fd39172c1cef Mon Sep 17 00:00:00 2001 From: Joe Stringer Date: Mon, 7 Mar 2016 11:31:02 -0800 Subject: [PATCH] nx-match: Fix use-after-free parsing matches. Address pointed by header_ptr might be free'd due to realloc happened in ofpbuf_put_hex(). Reported by valgrind in the test 379: check TCP flags expression in OXM and NXM. Invalid write of size 4 nx_match_from_string_raw (nx-match.c:1510) nx_match_from_string (nx-match.c:1538) ofctl_parse_nxm__ (ovs-ofctl.c:3325) ovs_cmdl_run_command (command-line.c:121) main (ovs-ofctl.c:137) Address 0x7a2cc40 is 0 bytes inside a block of size 64 free'd free (vg_replace_malloc.c:530) ofpbuf_resize__ (ofpbuf.c:246) ofpbuf_put (ofpbuf.c:386) ofpbuf_put_hex (ofpbuf.c:414) nx_match_from_string_raw (nx-match.c:1488) nx_match_from_string (nx-match.c:1538) ofctl_parse_nxm__ (ovs-ofctl.c:3325) Reported-by: William Tu Signed-off-by: Joe Stringer Acked-by: Ben Pfaff --- lib/nx-match.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/lib/nx-match.c b/lib/nx-match.c index 5cad24c08..edac68bcf 100644 --- a/lib/nx-match.c +++ b/lib/nx-match.c @@ -1468,7 +1468,6 @@ nx_match_from_string_raw(const char *s, struct ofpbuf *b) const char *name; uint64_t header; ovs_be64 nw_header; - ovs_be64 *header_ptr; int name_len; size_t n; @@ -1485,7 +1484,7 @@ nx_match_from_string_raw(const char *s, struct ofpbuf *b) s += name_len + 1; - header_ptr = ofpbuf_put_uninit(b, nxm_header_len(header)); + b->header = ofpbuf_put_uninit(b, nxm_header_len(header)); s = ofpbuf_put_hex(b, s, &n); if (n != nxm_field_bytes(header)) { const struct mf_field *field = mf_from_oxm_header(header); @@ -1508,7 +1507,7 @@ nx_match_from_string_raw(const char *s, struct ofpbuf *b) } } nw_header = htonll(header); - memcpy(header_ptr, &nw_header, nxm_header_len(header)); + memcpy(b->header, &nw_header, nxm_header_len(header)); if (nxm_hasmask(header)) { s += strspn(s, " "); -- 2.20.1