[v4,12/12] aarch64: add NEWS entry about branch protection support

Message ID ea2b1175cf6d13b3cd62a30f08ed971f40f689c6.1591899092.git.szabolcs.nagy@arm.com
State Superseded
Headers show
  • aarch64: branch protection support
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Commit Message

Szabolcs Nagy June 12, 2020, 1:29 p.m.
This is a new security feature that relies on architecture
extensions and needs glibc to be built with a gcc configured
with branch protection.
 NEWS | 12 ++++++++++++
 1 file changed, 12 insertions(+)



diff --git a/NEWS b/NEWS
index a660fc59a8..7d0ca3f520 100644
--- a/NEWS
+++ b/NEWS
@@ -31,6 +31,18 @@  Major new features:
   pthread_attr_getsigmask_np have been added.  They allow applications
   to specify the signal mask of a thread created with pthread_create.
+* AArch64 now supports standard branch protection security hardening
+  in glibc when it is built with a GCC that is configured with
+  --enable-standard-branch-protection. This includes branch target
+  identification (BTI) and pointer authentication for return addresses
+  (PAC-RET). They require armv8.5-a and armv8.3-a architecture
+  extensions respectively for the protection to be effective,
+  otherwise the used instructions are nops. User code can use PAC-RET
+  without libc support, but BTI requires a libc that is built with BTI
+  support, otherwise runtime objects linked into user code will not be
+  BTI compatible. It is recommended to use GCC 10 or newer when
+  building glibc with branch protection.
 Deprecated and removed features, and other changes affecting compatibility:
 * The deprecated <sys/sysctl.h> header and the sysctl function have been