Another memory overrun in http-push.c
From: Eygene Ryabinkin <hidden>
Date: 2016-06-15 22:42:57
Me again ;)) Spotted another memory overrun in the http-push.c. In principle, it is the read-only overrun, but it provokes the coredump on my system. The problem is that strlcpy(dst, src, size) returns the length of the 'src' and demands it to be NULL-terminated (see 'man strlcpy' and http://www.gratisoft.us/todd/papers/strlcpy.html). It is not the case for the xml_cdata and possibly other places. So I've just replaced strlcpy with memcpy + zero termination all over the http-push.c. The patch is below.
--- http-push.c.orig Thu Mar 1 18:48:19 2007
+++ http-push.c Thu Mar 1 18:55:24 2007@@ -1271,7 +1271,9 @@ struct xml_ctx *ctx = (struct xml_ctx *)userData; free(ctx->cdata); ctx->cdata = xmalloc(len + 1); - strlcpy(ctx->cdata, s, len + 1); + /* NB: 's' is not null-terminated, can not use strlcpy here */ + memcpy(ctx->cdata, s, len); + ctx->cdata[len] = '\0'; } static struct remote_lock *lock_remote(const char *path, long timeout)
@@ -1473,7 +1475,8 @@ return; path += 8; obj_hex = xmalloc(strlen(path)); - strlcpy(obj_hex, path, 3); + /* NB: path is not null-terminated, can not use strlcpy here */ + memcpy(obj_hex, path, 2); strcpy(obj_hex + 2, path + 3); one_remote_object(obj_hex); free(obj_hex);
@@ -2170,7 +2173,8 @@ /* If it's a symref, set the refname; otherwise try for a sha1 */ if (!strncmp((char *)buffer.buffer, "ref: ", 5)) { *symref = xmalloc(buffer.posn - 5); - strlcpy(*symref, (char *)buffer.buffer + 5, buffer.posn - 5); + memcpy(*symref, (char *)buffer.buffer + 5, buffer.posn - 6); + (*symref)[buffer.posn - 6] = '\0'; } else { get_sha1_hex(buffer.buffer, sha1); }
memcpy(obj_hex, path, 2) is not followed by zero-termination since it will be done by the strcpy that is following. This cured my git-http-push and let it do all PROPFINDS on the rather large repository (175 Mb). Now I have only one SEGV that is happening inside the libcurl both in http-push.c and http-fetch.c. Already talking to CURL people and trying to write the clear testcase for the problem. -- Eygene