Date: Mon, 7 May 2018 21:32:08 +0000 (UTC) From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r333337 - head/sys/amd64/amd64 Message-ID: <201805072132.w47LW8RE034907@repo.freebsd.org>
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Author: mjg Date: Mon May 7 21:32:08 2018 New Revision: 333337 URL: https://svnweb.freebsd.org/changeset/base/333337 Log: amd64: stop asserting params != NULL in the syscall path The parameter is effectively controllable by userspace. It does not matter what it is set to as it is being passed to copyin - worst case the operation will just fail. While here stop computing it unless it is going to be used. Noted by: dillon@backplane.com Modified: head/sys/amd64/amd64/trap.c Modified: head/sys/amd64/amd64/trap.c ============================================================================== --- head/sys/amd64/amd64/trap.c Mon May 7 21:26:05 2018 (r333336) +++ head/sys/amd64/amd64/trap.c Mon May 7 21:32:08 2018 (r333337) @@ -886,7 +886,6 @@ cpu_fetch_syscall_args(struct thread *td) reg = 0; regcnt = 6; - params = (caddr_t)frame->tf_rsp + sizeof(register_t); sa->code = frame->tf_rax; if (sa->code == SYS_syscall || sa->code == SYS___syscall) { @@ -910,7 +909,7 @@ cpu_fetch_syscall_args(struct thread *td) argp += reg; memcpy(sa->args, argp, sizeof(sa->args[0]) * 6); if (sa->narg > regcnt) { - KASSERT(params != NULL, ("copyin args with no params!")); + params = (caddr_t)frame->tf_rsp + sizeof(register_t); error = copyin(params, &sa->args[regcnt], (sa->narg - regcnt) * sizeof(sa->args[0])); }
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