From fff112f4c4442af52bec90353e80bc4e801ab79b Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Mon, 15 Jan 2018 16:05:36 +0100 Subject: [PATCH] nptl: Open libgcc.so with RTLD_NOW during pthread_cancel [BZ #22636] Disabling lazy binding reduces stack usage during unwinding. Note that RTLD_NOW only makes a difference if libgcc.so has not already been loaded, so this is only a partial fix. Reviewed-by: Adhemerval Zanella (cherry picked from commit f993b8754080ac7572b692870e926d8b493db16c) --- ChangeLog | 6 ++++++ NEWS | 1 + sysdeps/nptl/unwind-forcedunwind.c | 2 +- 3 files changed, 8 insertions(+), 1 deletion(-) diff --git a/ChangeLog b/ChangeLog index 7f37d678be2..48292d6bf05 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2018-01-10 Florian Weimer + + [BZ #22636] + * sysdeps/nptl/unwind-forcedunwind.c (pthread_cancel_init): Open + libgcc.so with RTLD_NOW, to avoid lazy binding during unwind. + 2018-01-08 Szabolcs Nagy [BZ #22637] diff --git a/NEWS b/NEWS index f2e9b3bf9f9..9a11b86b115 100644 --- a/NEWS +++ b/NEWS @@ -71,6 +71,7 @@ The following bugs are resolved with this release: [21609] x86-64: Align the stack in __tls_get_addr [21624] Unsafe alloca allows local attackers to alias stack and heap (CVE-2017-1000366) [21654] nss: Fix invalid cast in group merging + [22636] PTHREAD_STACK_MIN is too small on x86-64 [22637] nptl: Fix stack guard size accounting [22644] string: memmove-sse2-unaligned on 32bit x86 produces garbage when crossing 2GB threshold (CVE-2017-18269) diff --git a/sysdeps/nptl/unwind-forcedunwind.c b/sysdeps/nptl/unwind-forcedunwind.c index ca757c48ce6..24a1c5b30d3 100644 --- a/sysdeps/nptl/unwind-forcedunwind.c +++ b/sysdeps/nptl/unwind-forcedunwind.c @@ -49,7 +49,7 @@ pthread_cancel_init (void) return; } - handle = __libc_dlopen (LIBGCC_S_SO); + handle = __libc_dlopen_mode (LIBGCC_S_SO, RTLD_NOW | __RTLD_DLOPEN); if (handle == NULL || (resume = __libc_dlsym (handle, "_Unwind_Resume")) == NULL -- 2.47.2