[PATCH v1 0/2] Fixes for issues discovered with -fsanitize=address

[PATCH v1 0/2] Fixes for issues discovered with -fsanitize=address

[Todd]

I built a copy of notmuch with gcc 4.8's new -fsanitize=address
feature and ran the test bench. It pointed out these two issues.


Todd (2):
  lib: Fix potential invalid read past an empty string
  lib: Fix use after free

 lib/thread.cc | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

--
1.9.1

[PATCH v1 1/2] lib: Fix potential invalid read past an empty string

[Todd]

==22884== ERROR: AddressSanitizer: heap-buffer-overflow on address 0x601600008291 at pc 0x7ff6295680e5 bp 0x7fff4ab9aa40 sp 0x7fff4ab9aa08
READ of size 1 at 0x601600008291 thread T0
    #0 0x7ff6295680e4 in __interceptor_strcmp ??:?
    #1 0x44763b in _thread_add_message /home/todd/.apps/notmuch/lib/thread.cc:255
    #2 0x4459e8 in notmuch_threads_get /home/todd/.apps/notmuch/lib/query.cc:496
    #3 0x41e2a7 in do_search_threads /home/todd/.apps/notmuch/notmuch-search.c:131
    #4 0x40a408 in main /home/todd/.apps/notmuch/notmuch.c:345
    #5 0x7ff627cb9ec4 in __libc_start_main /build/buildd/eglibc-2.19/csu/libc-start.c:287
    #6 0x40abf3 in _start ??:?
0x601600008291 is located 0 bytes to the right of 97-byte region [0x601600008230,0x601600008291)
allocated by thread T0 here:
    #0 0x7ff62956e41a in malloc ??:?
    #1 0x7ff628b8ab5d in talloc_strdup ??:?
---
 lib/thread.cc | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/thread.cc b/lib/thread.cc
index 4542505..4c49f98 100644
--- a/lib/thread.cc
+++ b/lib/thread.cc
@@ -251,8 +251,8 @@ _thread_add_message (notmuch_thread_t *thread,
 		 term != NULL;
 		 term = term->next)
 	    {
-		/* We ignore initial 'K'. */
-		if (strcmp(tag, (term->string + 1)) == 0) {
+		/* Check for an empty string, and then ignore initial 'K'. */
+		if (*(term->string) && strcmp(tag, (term->string + 1)) == 0) {
 		    message_excluded = TRUE;
 		    break;
 		}
-- 
1.9.1

[PATCH v1 2/2] lib: Fix use after free

[Todd]

_thread_set_subject_from_message sometimes replaces the subject, making the
cur_subject point to free'd memory

==6550== ERROR: AddressSanitizer: heap-use-after-free on address 0x601a0000bec0 at pc 0x4464a4 bp 0x7fffa40be910 sp 0x7fffa40be908
READ of size 1 at 0x601a0000bec0 thread T0
    #0 0x4464a3 in _thread_add_matched_message /home/todd/.apps/notmuch/lib/thread.cc:369
    #1 0x443c2c in notmuch_threads_get /home/todd/.apps/notmuch/lib/query.cc:496
    #2 0x41d947 in do_search_threads /home/todd/.apps/notmuch/notmuch-search.c:131
    #3 0x40a3fe in main /home/todd/.apps/notmuch/notmuch.c:345
    #4 0x7f4e535b4ec4 in __libc_start_main /build/buildd/eglibc-2.19/csu/libc-start.c:287
    #5 0x40abe6 in _start ??:?
0x601a0000bec0 is located 96 bytes inside of 134-byte region [0x601a0000be60,0x601a0000bee6)
freed by thread T0 here:
    #0 0x7f4e54e6933a in __interceptor_free ??:?
    #1 0x7f4e54482fab in _talloc_free ??:?
previously allocated by thread T0 here:
    #0 0x7f4e54e6941a in malloc ??:?
    #1 0x7f4e54485b5d in talloc_strdup ??:?
---
 lib/thread.cc | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/lib/thread.cc b/lib/thread.cc
index 4c49f98..9847cf8 100644
--- a/lib/thread.cc
+++ b/lib/thread.cc
@@ -353,10 +353,8 @@ _thread_add_matched_message (notmuch_thread_t *thread,
 {
     time_t date;
     notmuch_message_t *hashed_message;
-    const char *cur_subject;
 
     date = notmuch_message_get_date (message);
-    cur_subject = notmuch_thread_get_subject(thread);
 
     if (date < thread->oldest || ! thread->matched_messages) {
 	thread->oldest = date;
@@ -366,6 +364,7 @@ _thread_add_matched_message (notmuch_thread_t *thread,
 
     if (date > thread->newest || ! thread->matched_messages) {
 	thread->newest = date;
+	const char *cur_subject = notmuch_thread_get_subject(thread);
 	if (sort != NOTMUCH_SORT_OLDEST_FIRST || EMPTY_STRING(cur_subject))
 	    _thread_set_subject_from_message (thread, message);
     }
-- 
1.9.1

Re: [PATCH v1 0/2] Fixes for issues discovered with -fsanitize=address

[David Bremner]

Todd <todd@electricoding.com> writes:

> I built a copy of notmuch with gcc 4.8's new -fsanitize=address
> feature and ran the test bench. It pointed out these two issues.

Series pushed. Thanks!

d