Author: jhb Date: Fri Jan 17 19:13:49 2020 New Revision: 356840 URL: https://svnweb.freebsd.org/changeset/base/356840
Log: Check for invalid sstatus values in set_mcontext(). Previously, this check was only in sys_sigreturn() which meant that user applications could write invalid values to the register via setcontext() or swapcontext(). Reviewed by: mhorne Sponsored by: DARPA Differential Revision: https://reviews.freebsd.org/D23219 Modified: head/sys/riscv/riscv/machdep.c Modified: head/sys/riscv/riscv/machdep.c ============================================================================== --- head/sys/riscv/riscv/machdep.c Fri Jan 17 19:01:59 2020 (r356839) +++ head/sys/riscv/riscv/machdep.c Fri Jan 17 19:13:49 2020 (r356840) @@ -367,6 +367,14 @@ set_mcontext(struct thread *td, mcontext_t *mcp) tf = td->td_frame; + /* + * Make sure the processor mode has not been tampered with and + * interrupts have not been disabled. + * Supervisor interrupts in user mode are always enabled. + */ + if ((mcp->mc_gpregs.gp_sstatus & SSTATUS_SPP) != 0) + return (EINVAL); + memcpy(tf->tf_t, mcp->mc_gpregs.gp_t, sizeof(tf->tf_t)); memcpy(tf->tf_s, mcp->mc_gpregs.gp_s, sizeof(tf->tf_s)); memcpy(tf->tf_a, mcp->mc_gpregs.gp_a, sizeof(tf->tf_a)); @@ -523,21 +531,11 @@ struct sigreturn_args { int sys_sigreturn(struct thread *td, struct sigreturn_args *uap) { - uint64_t sstatus; ucontext_t uc; int error; if (copyin(uap->sigcntxp, &uc, sizeof(uc))) return (EFAULT); - - /* - * Make sure the processor mode has not been tampered with and - * interrupts have not been disabled. - * Supervisor interrupts in user mode are always enabled. - */ - sstatus = uc.uc_mcontext.mc_gpregs.gp_sstatus; - if ((sstatus & SSTATUS_SPP) != 0) - return (EINVAL); error = set_mcontext(td, &uc.uc_mcontext); if (error != 0) _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
