aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorFlorian Weimer <fweimer@redhat.com>2019-05-21 10:19:46 +0200
committerFlorian Weimer <fweimer@redhat.com>2019-05-21 12:04:55 +0200
commitc9c15ac3162d10a999bf71418fd710bf5676175e (patch)
tree2264f9e56c7bad8288111a10ac2ff1aad8a317b3
parent7e740ab2e7be7d83b75513aa406e0b10875f7f9c (diff)
downloadglibc-c9c15ac3162d10a999bf71418fd710bf5676175e.tar.gz
glibc-c9c15ac3162d10a999bf71418fd710bf5676175e.tar.xz
glibc-c9c15ac3162d10a999bf71418fd710bf5676175e.zip
wcsmbs: Fix data race in __wcsmbs_clone_conv [BZ #24584]
This also adds an overflow check and documents the synchronization requirement in <gconv.h>.
-rw-r--r--ChangeLog9
-rw-r--r--iconv/gconv.h2
-rw-r--r--wcsmbs/wcsmbsload.c22
3 files changed, 29 insertions, 4 deletions
diff --git a/ChangeLog b/ChangeLog
index 1dcb620e9a8..35e6f7c3223 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,14 @@
2019-05-21 Florian Weimer <fweimer@redhat.com>
+ [BZ #24584]
+ * wcsmbs/wcsmbsload.c (__wcsmbs_clone_conv): Acquire __gconv_lock
+ before updating __counter field and release it afterwards. Add
+ overflow check.
+ * iconv/gconv.h (struct __gconv_step): Mention synchronization
+ requirement for __counter member.
+
+2019-05-21 Florian Weimer <fweimer@redhat.com>
+
[BZ #24583]
* wcsmbs/wcsmbsload.h (__wcsmbs_close_conv): Declare.
* wcsmbs/wcsmbsload.c (__wcsmbs_close_conv): Define.
diff --git a/iconv/gconv.h b/iconv/gconv.h
index 5ad26c06ace..7ce79bcbf68 100644
--- a/iconv/gconv.h
+++ b/iconv/gconv.h
@@ -86,6 +86,8 @@ struct __gconv_step
struct __gconv_loaded_object *__shlib_handle;
const char *__modname;
+ /* For internal use by glibc. (Accesses to this member must occur
+ when the internal __gconv_lock mutex is acquired). */
int __counter;
char *__from_name;
diff --git a/wcsmbs/wcsmbsload.c b/wcsmbs/wcsmbsload.c
index 10e1a4f4f53..840d4abc440 100644
--- a/wcsmbs/wcsmbsload.c
+++ b/wcsmbs/wcsmbsload.c
@@ -20,6 +20,7 @@
#include <langinfo.h>
#include <limits.h>
#include <stdlib.h>
+#include <stdio.h>
#include <string.h>
#include <locale/localeinfo.h>
@@ -223,12 +224,25 @@ __wcsmbs_clone_conv (struct gconv_fcts *copy)
/* Copy the data. */
*copy = *orig;
- /* Now increment the usage counters.
- Note: This assumes copy->*_nsteps == 1. */
+ /* Now increment the usage counters. Note: This assumes
+ copy->*_nsteps == 1. The current locale holds a reference, so it
+ is still there after acquiring the lock. */
+
+ __libc_lock_lock (__gconv_lock);
+
+ bool overflow = false;
if (copy->towc->__shlib_handle != NULL)
- ++copy->towc->__counter;
+ overflow |= __builtin_add_overflow (copy->towc->__counter, 1,
+ &copy->towc->__counter);
if (copy->tomb->__shlib_handle != NULL)
- ++copy->tomb->__counter;
+ overflow |= __builtin_add_overflow (copy->tomb->__counter, 1,
+ &copy->tomb->__counter);
+
+ __libc_lock_unlock (__gconv_lock);
+
+ if (overflow)
+ __libc_fatal ("\
+Fatal glibc error: gconv module reference counter overflow\n");
}