The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=cef05c5a62ba63eda222eed083972bfaa1449ac2
commit cef05c5a62ba63eda222eed083972bfaa1449ac2 Author: Konstantin Belousov <[email protected]> AuthorDate: 2026-07-30 03:57:34 +0000 Commit: Konstantin Belousov <[email protected]> CommitDate: 2026-07-30 17:08:24 +0000 amd64: do not allow to set reserved bits in MXCSR for ptrace(PT_SETFPREGS) Also do not mask bits in the mxcsr_mask. It is ignored by FRSTOR/XRSTOR. Reported by: markj Reviewed by: jhb, markj Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D58548 --- sys/amd64/amd64/exec_machdep.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/sys/amd64/amd64/exec_machdep.c b/sys/amd64/amd64/exec_machdep.c index f81fc5f94406..d5d3342b7dff 100644 --- a/sys/amd64/amd64/exec_machdep.c +++ b/sys/amd64/amd64/exec_machdep.c @@ -573,13 +573,16 @@ fill_fpregs_xmm(struct savefpu *sv_xmm, struct fpreg *fpregs) } /* internalize from fpregs into sv_xmm */ -static void +static int set_fpregs_xmm(struct fpreg *fpregs, struct savefpu *sv_xmm) { struct envxmm *penv_xmm = &sv_xmm->sv_env; struct envxmm *penv_fpreg = (struct envxmm *)&fpregs->fpr_env; int i; + if ((penv_fpreg->en_mxcsr & ~cpu_mxcsr_mask) != 0) + return (EINVAL); + /* fpregs -> pcb */ /* FPU control/status */ penv_xmm->en_cw = penv_fpreg->en_cw; @@ -589,7 +592,7 @@ set_fpregs_xmm(struct fpreg *fpregs, struct savefpu *sv_xmm) penv_xmm->en_rip = penv_fpreg->en_rip; penv_xmm->en_rdp = penv_fpreg->en_rdp; penv_xmm->en_mxcsr = penv_fpreg->en_mxcsr; - penv_xmm->en_mxcsr_mask = penv_fpreg->en_mxcsr_mask & cpu_mxcsr_mask; + penv_xmm->en_mxcsr_mask = penv_fpreg->en_mxcsr_mask; /* FPU registers */ for (i = 0; i < 8; ++i) @@ -598,6 +601,8 @@ set_fpregs_xmm(struct fpreg *fpregs, struct savefpu *sv_xmm) /* SSE registers */ for (i = 0; i < 16; ++i) bcopy(fpregs->fpr_xacc[i], sv_xmm->sv_xmm[i].xmm_bytes, 16); + + return (0); } /* externalize from td->pcb */ @@ -617,12 +622,14 @@ fill_fpregs(struct thread *td, struct fpreg *fpregs) int set_fpregs(struct thread *td, struct fpreg *fpregs) { + int error; critical_enter(); - set_fpregs_xmm(fpregs, get_pcb_user_save_td(td)); - fpuuserinited(td); + error = set_fpregs_xmm(fpregs, get_pcb_user_save_td(td)); + if (error == 0) + fpuuserinited(td); critical_exit(); - return (0); + return (error); } /*
