From: Szabolcs Nagy Date: Fri, 3 Apr 2020 09:35:41 +0000 (+0000) Subject: aarch64, libgcc: Fix unwinding from pac-ret to normal frames [PR94514] X-Git-Tag: misc/first-auto-changelog-9~34 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=6173489dbfe5828b2c4082d7a450a766779f87c7;p=thirdparty%2Fgcc.git aarch64, libgcc: Fix unwinding from pac-ret to normal frames [PR94514] With -mbranch-protection=pac-ret the debug info toggles the signedness state of the return address so the unwinder knows when the return address needs pointer authentication. The unwind context flags were not updated according to the dwarf frame info. This causes unwinding across frames that were built without pac-ret to incorrectly authenticate the return address wich corrupts the return address on a system where PAuth is enabled. Note: This even affects systems where all code use pac-ret because unwinding across a signal frame the return address is not signed. gcc/testsuite/ChangeLog: Backport from mainline. 2020-04-23 Szabolcs Nagy PR target/94514 * g++.target/aarch64/pr94514.C: Require lp64. * gcc.target/aarch64/pr94514.c: Likewise. Backport from mainline. 2020-04-21 Szabolcs Nagy PR target/94514 * g++.target/aarch64/pr94514.C: New test. * gcc.target/aarch64/pr94514.c: New test. libgcc/ChangeLog: Backport from mainline. 2020-04-21 Szabolcs Nagy PR target/94514 * config/aarch64/aarch64-unwind.h (aarch64_frob_update_context): Update context->flags accroding to the frame state. --- diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index a3dd9c9d090e..847b998e8dab 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,19 @@ +2020-05-14 Szabolcs Nagy + + Backport from mainline. + 2020-04-23 Szabolcs Nagy + + PR target/94514 + * g++.target/aarch64/pr94514.C: Require lp64. + * gcc.target/aarch64/pr94514.c: Likewise. + + Backport from mainline. + 2020-04-21 Szabolcs Nagy + + PR target/94514 + * g++.target/aarch64/pr94514.C: New test. + * gcc.target/aarch64/pr94514.c: New test. + 2020-05-13 Mark Eggleston Backported from master diff --git a/gcc/testsuite/g++.target/aarch64/pr94514.C b/gcc/testsuite/g++.target/aarch64/pr94514.C new file mode 100644 index 000000000000..ae925cafeb61 --- /dev/null +++ b/gcc/testsuite/g++.target/aarch64/pr94514.C @@ -0,0 +1,27 @@ +/* PR target/94514. Unwind across mixed pac-ret and non-pac-ret frames. */ +/* { dg-do run } */ +/* { dg-require-effective-target lp64 } */ + +__attribute__((noinline, target("branch-protection=pac-ret"))) +static void do_throw (void) +{ + throw 42; + __builtin_abort (); +} + +__attribute__((noinline, target("branch-protection=none"))) +static void no_pac_ret (void) +{ + do_throw (); + __builtin_abort (); +} + +int main () +{ + try { + no_pac_ret (); + } catch (...) { + return 0; + } + __builtin_abort (); +} diff --git a/gcc/testsuite/gcc.target/aarch64/pr94514.c b/gcc/testsuite/gcc.target/aarch64/pr94514.c new file mode 100644 index 000000000000..cbc940421d24 --- /dev/null +++ b/gcc/testsuite/gcc.target/aarch64/pr94514.c @@ -0,0 +1,77 @@ +/* PR target/94514. Unwind across mixed pac-ret and non-pac-ret frames. */ +/* { dg-do run } */ +/* { dg-require-effective-target lp64 } */ +/* { dg-options "-fexceptions -O2" } */ + +#include +#include +#include + +#define die() \ + do { \ + printf ("%s:%d: reached unexpectedly.\n", __FILE__, __LINE__); \ + fflush (stdout); \ + abort (); \ + } while (0) + +static struct _Unwind_Exception exc; + +static _Unwind_Reason_Code +force_unwind_stop (int version, _Unwind_Action actions, + _Unwind_Exception_Class exc_class, + struct _Unwind_Exception *exc_obj, + struct _Unwind_Context *context, + void *stop_parameter) +{ + printf ("%s: CFA: %p PC: %p actions: %d\n", + __func__, + (void *)_Unwind_GetCFA (context), + (void *)_Unwind_GetIP (context), + (int)actions); + if (actions & _UA_END_OF_STACK) + die (); + return _URC_NO_REASON; +} + +static void force_unwind (void) +{ +#ifndef __USING_SJLJ_EXCEPTIONS__ + _Unwind_ForcedUnwind (&exc, force_unwind_stop, 0); +#else + _Unwind_SjLj_ForcedUnwind (&exc, force_unwind_stop, 0); +#endif +} + +__attribute__((noinline, target("branch-protection=pac-ret"))) +static void f2_pac_ret (void) +{ + force_unwind (); + die (); +} + +__attribute__((noinline, target("branch-protection=none"))) +static void f1_no_pac_ret (void) +{ + f2_pac_ret (); + die (); +} + +__attribute__((noinline, target("branch-protection=pac-ret"))) +static void f0_pac_ret (void) +{ + f1_no_pac_ret (); + die (); +} + +static void cleanup_handler (void *p) +{ + printf ("%s: Success.\n", __func__); + exit (0); +} + +int main () +{ + char dummy __attribute__((cleanup (cleanup_handler))); + f0_pac_ret (); + die (); +} diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog index 74d3b8599c4e..5554dca9c605 100644 --- a/libgcc/ChangeLog +++ b/libgcc/ChangeLog @@ -1,3 +1,12 @@ +2020-05-14 Szabolcs Nagy + + Backport from mainline. + 2020-04-21 Szabolcs Nagy + + PR target/94514 + * config/aarch64/aarch64-unwind.h (aarch64_frob_update_context): + Update context->flags accroding to the frame state. + 2020-04-22 Andre Vieira Backport from mainline. diff --git a/libgcc/config/aarch64/aarch64-unwind.h b/libgcc/config/aarch64/aarch64-unwind.h index 223ac9157f1e..c936befaeae4 100644 --- a/libgcc/config/aarch64/aarch64-unwind.h +++ b/libgcc/config/aarch64/aarch64-unwind.h @@ -80,6 +80,8 @@ aarch64_frob_update_context (struct _Unwind_Context *context, if (fs->regs.reg[DWARF_REGNUM_AARCH64_RA_STATE].loc.offset & 0x1) /* The flag is used for re-authenticating EH handler's address. */ context->flags |= RA_A_SIGNED_BIT; + else + context->flags &= ~RA_A_SIGNED_BIT; return; }