+2016-08-15 Andreas Schwab <schwab@suse.de>
+
+ [BZ #20435]
+ * sysdeps/unix/sysv/linux/arm/setcontext.S (__startcontext): Mark
+ as .cantunwind.
+
2016-08-17 Florian Weimer <fweimer@redhat.com>
[BZ #20452]
Please send GNU C library bug reports via <http://sourceware.org/bugzilla/>
using `glibc' in the "product" field.
+\f
+Version 2.24.1
+
+Security related changes:
+
+* On ARM EABI (32-bit), generating a backtrace for execution contexts which
+ have been created with makecontext could fail to terminate due to a
+ missing .cantunwind annotation. This has been observed to lead to a hang
+ (denial of service) in some Go applications compiled with gccgo. Reported
+ by Andreas Schwab. (CVE-2016-6323)
+
\f
Version 2.24
/* Called when a makecontext() context returns. Start the
context in R4 or fall through to exit(). */
+ /* Unwind descriptors are looked up based on PC - 2, so we have to
+ make sure to mark the instruction preceding the __startcontext
+ label as .cantunwind. */
+ .fnstart
+ .cantunwind
+ nop
ENTRY(__startcontext)
movs r0, r4
bne PLTJMP(__setcontext)
@ New context was 0 - exit
b PLTJMP(HIDDEN_JUMPTARGET(exit))
+ .fnend
END(__startcontext)
#ifdef PIC