The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=b1e2f063ae912dc5b7a7f6638ccb3aff14f299cf
commit b1e2f063ae912dc5b7a7f6638ccb3aff14f299cf Author: Konstantin Belousov <[email protected]> AuthorDate: 2021-09-27 16:57:25 +0000 Commit: Konstantin Belousov <[email protected]> CommitDate: 2021-09-27 17:12:46 +0000 amd64 sendsig: fix context corruption Drop fpstate only after copying out xfpustate from the thread usermode save area. Otherwise a context switch between get_fpcontext(), which now returns the pointer directly into user save area, and copyout, would cause reinit of the save area, loosing user registers. Reported, reviewed, and tested by: markj Sponsored by: The FreeBSD Foundation MFC after: 3 days Differential revision: https://reviews.freebsd.org/D32159 --- sys/amd64/amd64/exec_machdep.c | 2 +- sys/amd64/ia32/ia32_signal.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/sys/amd64/amd64/exec_machdep.c b/sys/amd64/amd64/exec_machdep.c index d605f080871a..b93fe7c4b3c7 100644 --- a/sys/amd64/amd64/exec_machdep.c +++ b/sys/amd64/amd64/exec_machdep.c @@ -143,7 +143,6 @@ sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) bcopy(regs, &sf.sf_uc.uc_mcontext.mc_rdi, sizeof(*regs)); sf.sf_uc.uc_mcontext.mc_len = sizeof(sf.sf_uc.uc_mcontext); /* magic */ get_fpcontext(td, &sf.sf_uc.uc_mcontext, &xfpusave, &xfpusave_len); - fpstate_drop(td); update_pcb_bases(pcb); sf.sf_uc.uc_mcontext.mc_fsbase = pcb->pcb_fsbase; sf.sf_uc.uc_mcontext.mc_gsbase = pcb->pcb_gsbase; @@ -203,6 +202,7 @@ sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) sigexit(td, SIGILL); } + fpstate_drop(td); regs->tf_rsp = (long)sfp; regs->tf_rip = p->p_sysent->sv_sigcode_base; regs->tf_rflags &= ~(PSL_T | PSL_D); diff --git a/sys/amd64/ia32/ia32_signal.c b/sys/amd64/ia32/ia32_signal.c index ab7100f5b9fb..6c879eccfc77 100644 --- a/sys/amd64/ia32/ia32_signal.c +++ b/sys/amd64/ia32/ia32_signal.c @@ -607,7 +607,6 @@ ia32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) sf.sf_uc.uc_mcontext.mc_gs = regs->tf_gs; sf.sf_uc.uc_mcontext.mc_len = sizeof(sf.sf_uc.uc_mcontext); /* magic */ ia32_get_fpcontext(td, &sf.sf_uc.uc_mcontext, &xfpusave, &xfpusave_len); - fpstate_drop(td); sf.sf_uc.uc_mcontext.mc_fsbase = td->td_pcb->pcb_fsbase; sf.sf_uc.uc_mcontext.mc_gsbase = td->td_pcb->pcb_gsbase; @@ -661,6 +660,7 @@ ia32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) sigexit(td, SIGILL); } + fpstate_drop(td); regs->tf_rsp = (uintptr_t)sfp; regs->tf_rip = p->p_sysent->sv_sigcode_base; regs->tf_rflags &= ~(PSL_T | PSL_D); _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/dev-commits-src-all To unsubscribe, send any mail to "[email protected]"
