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CTF containers use the ctf_dtoldid field as a threshold type index which

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indicates the range of type indices which have been committed to the
container by ctf_update(). However, the top bit of the dtd_type field is
not part of the type index; rather, it is a flag used to indicate that the
corresponding CTF container is a parent. This is why the maximum CTF type
index is 2^15 - 1 rather than 2^16 - 1. Therefore, this flag must be masked
off (using the CTF_TYPE_TO_INDEX macro) when comparing a type index with the
ctf_dtoldid field of a container.

This bug was causing libctf to erroneously free committed type definitions
in ctf_discard(). libdtrace holds some references to such types, resulting
in a use-after-free.

MFC after:	2 weeks
Sponsored by:	EMC / Isilon Storage Division
This commit is contained in:
Mark Johnston 2015-03-10 21:08:58 +00:00
parent 2bb7e77385
commit b0ee912984
1 changed files with 2 additions and 2 deletions
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4
cddl/contrib/opensolaris/common/ctf/ctf_create.c
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@ -584,7 +584,7 @@ ctf_discard(ctf_file_t *fp)
for (dtd = ctf_list_prev(&fp->ctf_dtdefs); dtd != NULL; dtd = ntd) {
ntd = ctf_list_prev(dtd);
if (dtd->dtd_type <= fp->ctf_dtoldid)
if (CTF_TYPE_TO_INDEX(dtd->dtd_type) <= fp->ctf_dtoldid)
continue; /* skip types that have been committed */
ctf_dtd_delete(fp, dtd);
@ -1328,7 +1328,7 @@ ctf_add_type(ctf_file_t *dst_fp, ctf_file_t *src_fp, ctf_id_t src_type)
*/
if (dst_type == CTF_ERR && name[0] != '\0') {
for (dtd = ctf_list_prev(&dst_fp->ctf_dtdefs); dtd != NULL &&
dtd->dtd_type > dst_fp->ctf_dtoldid;
CTF_TYPE_TO_INDEX(dtd->dtd_type) > dst_fp->ctf_dtoldid;
dtd = ctf_list_prev(dtd)) {
if (CTF_INFO_KIND(dtd->dtd_data.ctt_info) == kind &&
dtd->dtd_name != NULL &&