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Date:      Mon, 31 Jan 2022 14:56:37 GMT
From:      Mark Johnston <markj@FreeBSD.org>
To:        src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org
Subject:   git: d247611467e0 - stable/13 - exec: Introduce the PROC_PS_STRINGS() macro
Message-ID:  <202201311456.20VEubZE082238@gitrepo.freebsd.org>

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The branch stable/13 has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=d247611467e079f34a1a3f762e2a18c00a3f2bdd

commit d247611467e079f34a1a3f762e2a18c00a3f2bdd
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2022-01-17 16:42:28 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2022-01-31 14:46:57 +0000

    exec: Introduce the PROC_PS_STRINGS() macro
    
    Rather than fetching the ps_strings address directly from a process'
    sysentvec, use this macro.  With stack address randomization the
    ps_strings address is no longer fixed.
    
    Reviewed by:    kib
    Sponsored by:   The FreeBSD Foundation
    
    (cherry picked from commit 706f4a81a81250a326ea25914e7effe1768f1a37)
---
 sys/amd64/ia32/ia32_signal.c          |  2 +-
 sys/amd64/ia32/ia32_syscall.c         |  2 +-
 sys/amd64/linux/linux_sysvec.c        |  2 +-
 sys/arm/arm/exec_machdep.c            |  8 +++++++-
 sys/arm64/arm64/freebsd32_machdep.c   | 10 ++++++++--
 sys/arm64/linux/linux_sysvec.c        |  2 +-
 sys/compat/freebsd32/freebsd32_misc.c |  2 +-
 sys/i386/i386/exec_machdep.c          |  4 ++--
 sys/i386/linux/linux_sysvec.c         |  4 ++--
 sys/kern/imgact_elf.c                 |  4 ++--
 sys/kern/kern_exec.c                  | 18 ++++++++----------
 sys/kern/kern_proc.c                  | 20 ++++++++++----------
 sys/riscv/riscv/exec_machdep.c        |  7 ++++++-
 sys/sys/exec.h                        |  1 +
 14 files changed, 51 insertions(+), 35 deletions(-)

diff --git a/sys/amd64/ia32/ia32_signal.c b/sys/amd64/ia32/ia32_signal.c
index 1349954f40a7..2d807c09a187 100644
--- a/sys/amd64/ia32/ia32_signal.c
+++ b/sys/amd64/ia32/ia32_signal.c
@@ -422,7 +422,7 @@ ia32_osendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 	}
 
 	regs->tf_rsp = (uintptr_t)fp;
-	regs->tf_rip = p->p_sysent->sv_psstrings -
+	regs->tf_rip = PROC_PS_STRINGS(p) -
 	    (_binary_elf_vdso32_so_1_end - _binary_elf_vdso32_so_1_start) +
 	    VDSO_IA32_OSIGCODE_OFFSET;
 	regs->tf_rflags &= ~(PSL_T | PSL_D);
diff --git a/sys/amd64/ia32/ia32_syscall.c b/sys/amd64/ia32/ia32_syscall.c
index 495d6dc84887..0104a5f91c99 100644
--- a/sys/amd64/ia32/ia32_syscall.c
+++ b/sys/amd64/ia32/ia32_syscall.c
@@ -266,7 +266,7 @@ setup_lcall_gate(void)
 	bzero(&uap, sizeof(uap));
 	uap.start = 0;
 	uap.num = 1;
-	lcall_addr = curproc->p_sysent->sv_psstrings -
+	lcall_addr = PROC_PS_STRINGS(curproc) -
 	    (_binary_elf_vdso32_so_1_end - _binary_elf_vdso32_so_1_start) +
 	    VDSO_LCALL_TRAMP_OFFSET;
 	bzero(&desc, sizeof(desc));
diff --git a/sys/amd64/linux/linux_sysvec.c b/sys/amd64/linux/linux_sysvec.c
index 03e17d851a8d..093360537574 100644
--- a/sys/amd64/linux/linux_sysvec.c
+++ b/sys/amd64/linux/linux_sysvec.c
@@ -328,7 +328,7 @@ linux_copyout_strings(struct image_params *imgp, uintptr_t *stack_base)
 	struct proc *p;
 
 	p = imgp->proc;
-	arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
+	arginfo = (struct ps_strings *)PROC_PS_STRINGS(p);
 	destp = (uintptr_t)arginfo;
 
 	if (imgp->execpath != NULL && imgp->auxargs != NULL) {
diff --git a/sys/arm/arm/exec_machdep.c b/sys/arm/arm/exec_machdep.c
index 3b952463b1ad..865fc4d86288 100644
--- a/sys/arm/arm/exec_machdep.c
+++ b/sys/arm/arm/exec_machdep.c
@@ -43,6 +43,7 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#include <sys/exec.h>
 #include <sys/imgact.h>
 #include <sys/kdb.h>
 #include <sys/kernel.h>
@@ -63,6 +64,11 @@ __FBSDID("$FreeBSD$");
 #include <machine/vfp.h>
 #include <machine/vmparam.h>
 
+#include <vm/vm.h>
+#include <vm/vm_param.h>
+#include <vm/pmap.h>
+#include <vm/vm_map.h>
+
 /*
  * Clear registers on exec
  */
@@ -340,7 +346,7 @@ sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 	if (sysent->sv_sigcode_base != 0)
 		tf->tf_usr_lr = (register_t)sysent->sv_sigcode_base;
 	else
-		tf->tf_usr_lr = (register_t)(sysent->sv_psstrings -
+		tf->tf_usr_lr = (register_t)(PROC_PS_STRINGS(p) -
 		    *(sysent->sv_szsigcode));
 	/* Set the mode to enter in the signal handler */
 #if __ARM_ARCH >= 7
diff --git a/sys/arm64/arm64/freebsd32_machdep.c b/sys/arm64/arm64/freebsd32_machdep.c
index b1e070feb4f6..f87e4342cfbd 100644
--- a/sys/arm64/arm64/freebsd32_machdep.c
+++ b/sys/arm64/arm64/freebsd32_machdep.c
@@ -27,7 +27,8 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/exec.h>
 #include <sys/proc.h>
 #include <sys/lock.h>
 #include <sys/mutex.h>
@@ -42,6 +43,11 @@ __FBSDID("$FreeBSD$");
 #include <compat/freebsd32/freebsd32_proto.h>
 #include <compat/freebsd32/freebsd32_signal.h>
 
+#include <vm/vm.h>
+#include <vm/vm_param.h>
+#include <vm/pmap.h>
+#include <vm/vm_map.h>
+
 extern void freebsd32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask);
 
 /*
@@ -394,7 +400,7 @@ freebsd32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 	if (sysent->sv_sigcode_base != 0)
 		tf->tf_x[14] = (register_t)sysent->sv_sigcode_base;
 	else
-		tf->tf_x[14] = (register_t)(sysent->sv_psstrings -
+		tf->tf_x[14] = (register_t)(PROC_PS_STRINGS(p) -
 		    *(sysent->sv_szsigcode));
 	/* Set the mode to enter in the signal handler */
 	if ((register_t)catcher & 1)
diff --git a/sys/arm64/linux/linux_sysvec.c b/sys/arm64/linux/linux_sysvec.c
index 50bd53d4b08c..0a56cdc4f299 100644
--- a/sys/arm64/linux/linux_sysvec.c
+++ b/sys/arm64/linux/linux_sysvec.c
@@ -232,7 +232,7 @@ linux_copyout_strings(struct image_params *imgp, uintptr_t *stack_base)
 	int argc, envc, error;
 
 	p = imgp->proc;
-	arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
+	arginfo = (struct ps_strings *)PROC_PS_STRINGS(p);
 	destp = (uintptr_t)arginfo;
 
 	if (imgp->execpath != NULL && imgp->auxargs != NULL) {
diff --git a/sys/compat/freebsd32/freebsd32_misc.c b/sys/compat/freebsd32/freebsd32_misc.c
index 2360d28c15d0..3b62cf582866 100644
--- a/sys/compat/freebsd32/freebsd32_misc.c
+++ b/sys/compat/freebsd32/freebsd32_misc.c
@@ -3357,7 +3357,7 @@ freebsd32_copyout_strings(struct image_params *imgp, uintptr_t *stack_base)
 
 	sysent = imgp->sysent;
 
-	arginfo = (struct freebsd32_ps_strings *)sysent->sv_psstrings;
+	arginfo = (struct freebsd32_ps_strings *)PROC_PS_STRINGS(imgp->proc);
 	imgp->ps_strings = arginfo;
 	destp =	(uintptr_t)arginfo;
 
diff --git a/sys/i386/i386/exec_machdep.c b/sys/i386/i386/exec_machdep.c
index 13628aba7ab1..1f0a9a47a198 100644
--- a/sys/i386/i386/exec_machdep.c
+++ b/sys/i386/i386/exec_machdep.c
@@ -238,7 +238,7 @@ osendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 		    szosigcode;
 	} else {
 		/* a.out sysentvec does not use shared page */
-		regs->tf_eip = p->p_sysent->sv_psstrings - szosigcode;
+		regs->tf_eip = PROC_PS_STRINGS(p) - szosigcode;
 	}
 	regs->tf_eflags &= ~(PSL_T | PSL_D);
 	regs->tf_cs = _ucodesel;
@@ -523,7 +523,7 @@ sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 	regs->tf_esp = (int)sfp;
 	regs->tf_eip = p->p_sysent->sv_sigcode_base;
 	if (regs->tf_eip == 0)
-		regs->tf_eip = p->p_sysent->sv_psstrings - szsigcode;
+		regs->tf_eip = PROC_PS_STRINGS(p) - szsigcode;
 	regs->tf_eflags &= ~(PSL_T | PSL_D);
 	regs->tf_cs = _ucodesel;
 	regs->tf_ds = _udatasel;
diff --git a/sys/i386/linux/linux_sysvec.c b/sys/i386/linux/linux_sysvec.c
index 20108f37584f..1478ff0bf163 100644
--- a/sys/i386/linux/linux_sysvec.c
+++ b/sys/i386/linux/linux_sysvec.c
@@ -198,7 +198,7 @@ linux_copyout_auxargs(struct image_params *imgp, uintptr_t base)
 
 	p = imgp->proc;
 	issetugid = imgp->proc->p_flag & P_SUGID ? 1 : 0;
-	arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
+	arginfo = (struct ps_strings *)PROC_PS_STRINGS(p);
 	uplatform = (Elf32_Addr *)((caddr_t)arginfo - linux_szplatform);
 	args = (Elf32_Auxargs *)imgp->auxargs;
 	argarray = pos = malloc(LINUX_AT_COUNT * sizeof(*pos), M_TEMP,
@@ -278,7 +278,7 @@ linux_copyout_strings(struct image_params *imgp, uintptr_t *stack_base)
 	struct proc *p;
 
 	p = imgp->proc;
-	arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
+	arginfo = (struct ps_strings *)PROC_PS_STRINGS(p);
 	destp = (uintptr_t)arginfo;
 
 	/* Install LINUX_PLATFORM. */
diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c
index 721c24af7fe6..4bba6b21153b 100644
--- a/sys/kern/imgact_elf.c
+++ b/sys/kern/imgact_elf.c
@@ -2662,9 +2662,9 @@ __elfN(note_procstat_psstrings)(void *arg, struct sbuf *sb, size_t *sizep)
 		KASSERT(*sizep == size, ("invalid size"));
 		structsize = sizeof(ps_strings);
 #if defined(COMPAT_FREEBSD32) && __ELF_WORD_SIZE == 32
-		ps_strings = PTROUT(p->p_sysent->sv_psstrings);
+		ps_strings = PTROUT(PROC_PS_STRINGS(p));
 #else
-		ps_strings = p->p_sysent->sv_psstrings;
+		ps_strings = PROC_PS_STRINGS(p);
 #endif
 		sbuf_bcat(sb, &structsize, sizeof(structsize));
 		sbuf_bcat(sb, &ps_strings, sizeof(ps_strings));
diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
index 97857c82f7a7..301490b9ad28 100644
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -160,19 +160,18 @@ static int
 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS)
 {
 	struct proc *p;
-	int error;
+	vm_offset_t ps_strings;
 
 	p = curproc;
 #ifdef SCTL_MASK32
 	if (req->flags & SCTL_MASK32) {
 		unsigned int val;
-		val = (unsigned int)p->p_sysent->sv_psstrings;
-		error = SYSCTL_OUT(req, &val, sizeof(val));
-	} else
+		val = (unsigned int)PROC_PS_STRINGS(p);
+		return (SYSCTL_OUT(req, &val, sizeof(val)));
+	}
 #endif
-		error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings,
-		   sizeof(p->p_sysent->sv_psstrings));
-	return error;
+	ps_strings = PROC_PS_STRINGS(p);
+	return (SYSCTL_OUT(req, &ps_strings, sizeof(ps_strings)));
 }
 
 static int
@@ -1669,9 +1668,8 @@ exec_copyout_strings(struct image_params *imgp, uintptr_t *stack_base)
 	p = imgp->proc;
 	sysent = p->p_sysent;
 
-	arginfo = (struct ps_strings *)sysent->sv_psstrings;
-	destp =	(uintptr_t)arginfo;
-	imgp->ps_strings = arginfo;
+	destp =	PROC_PS_STRINGS(p);
+	arginfo = imgp->ps_strings = (void *)destp;
 
 	/*
 	 * Install sigcode.
diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c
index dc3068c29514..063fe2eb1fe2 100644
--- a/sys/kern/kern_proc.c
+++ b/sys/kern/kern_proc.c
@@ -1838,8 +1838,8 @@ get_proc_vector32(struct thread *td, struct proc *p, char ***proc_vectorp,
 	int i, error;
 
 	error = 0;
-	if (proc_readmem(td, p, (vm_offset_t)p->p_sysent->sv_psstrings, &pss,
-	    sizeof(pss)) != sizeof(pss))
+	if (proc_readmem(td, p, PROC_PS_STRINGS(p), &pss, sizeof(pss)) !=
+	    sizeof(pss))
 		return (ENOMEM);
 	switch (type) {
 	case PROC_ARG:
@@ -1914,8 +1914,8 @@ get_proc_vector(struct thread *td, struct proc *p, char ***proc_vectorp,
 	if (SV_PROC_FLAG(p, SV_ILP32) != 0)
 		return (get_proc_vector32(td, p, proc_vectorp, vsizep, type));
 #endif
-	if (proc_readmem(td, p, (vm_offset_t)p->p_sysent->sv_psstrings, &pss,
-	    sizeof(pss)) != sizeof(pss))
+	if (proc_readmem(td, p, PROC_PS_STRINGS(p), &pss, sizeof(pss)) !=
+	    sizeof(pss))
 		return (ENOMEM);
 	switch (type) {
 	case PROC_ARG:
@@ -2981,13 +2981,13 @@ sysctl_kern_proc_ps_strings(SYSCTL_HANDLER_ARGS)
 		 * process.
 		 */
 		ps_strings32 = SV_PROC_FLAG(p, SV_ILP32) != 0 ?
-		    PTROUT(p->p_sysent->sv_psstrings) : 0;
+		    PTROUT(PROC_PS_STRINGS(p)) : 0;
 		PROC_UNLOCK(p);
 		error = SYSCTL_OUT(req, &ps_strings32, sizeof(ps_strings32));
 		return (error);
 	}
 #endif
-	ps_strings = p->p_sysent->sv_psstrings;
+	ps_strings = PROC_PS_STRINGS(p);
 	PROC_UNLOCK(p);
 	error = SYSCTL_OUT(req, &ps_strings, sizeof(ps_strings));
 	return (error);
@@ -3104,9 +3104,9 @@ sysctl_kern_proc_sigtramp(SYSCTL_HANDLER_ARGS)
 				    *sv->sv_szsigcode :
 				    (uintptr_t)sv->sv_szsigcode);
 			} else {
-				kst32.ksigtramp_start = sv->sv_psstrings -
+				kst32.ksigtramp_start = PROC_PS_STRINGS(p) -
 				    *sv->sv_szsigcode;
-				kst32.ksigtramp_end = sv->sv_psstrings;
+				kst32.ksigtramp_end = PROC_PS_STRINGS(p);
 			}
 		}
 		PROC_UNLOCK(p);
@@ -3121,9 +3121,9 @@ sysctl_kern_proc_sigtramp(SYSCTL_HANDLER_ARGS)
 		    ((sv->sv_flags & SV_DSO_SIG) == 0 ? *sv->sv_szsigcode :
 		    (uintptr_t)sv->sv_szsigcode);
 	} else {
-		kst.ksigtramp_start = (char *)sv->sv_psstrings -
+		kst.ksigtramp_start = (char *)PROC_PS_STRINGS(p) -
 		    *sv->sv_szsigcode;
-		kst.ksigtramp_end = (char *)sv->sv_psstrings;
+		kst.ksigtramp_end = (char *)PROC_PS_STRINGS(p);
 	}
 	PROC_UNLOCK(p);
 	error = SYSCTL_OUT(req, &kst, sizeof(kst));
diff --git a/sys/riscv/riscv/exec_machdep.c b/sys/riscv/riscv/exec_machdep.c
index e06cc97eca9a..e71279e039d2 100644
--- a/sys/riscv/riscv/exec_machdep.c
+++ b/sys/riscv/riscv/exec_machdep.c
@@ -65,6 +65,11 @@ __FBSDID("$FreeBSD$");
 #include <machine/sbi.h>
 #include <machine/trap.h>
 
+#include <vm/vm.h>
+#include <vm/vm_param.h>
+#include <vm/pmap.h>
+#include <vm/vm_map.h>
+
 #ifdef FPE
 #include <machine/fpe.h>
 #endif
@@ -409,7 +414,7 @@ sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 	if (sysent->sv_sigcode_base != 0)
 		tf->tf_ra = (register_t)sysent->sv_sigcode_base;
 	else
-		tf->tf_ra = (register_t)(sysent->sv_psstrings -
+		tf->tf_ra = (register_t)(PROC_PS_STRINGS(p) -
 		    *(sysent->sv_szsigcode));
 
 	CTR3(KTR_SIG, "sendsig: return td=%p pc=%#x sp=%#x", td, tf->tf_sepc,
diff --git a/sys/sys/exec.h b/sys/sys/exec.h
index c7b3aa8b9550..ccd7eb0ecd7d 100644
--- a/sys/sys/exec.h
+++ b/sys/sys/exec.h
@@ -77,6 +77,7 @@ struct execsw {
  * Prefer the kern.ps_strings or kern.proc.ps_strings sysctls to this constant.
  */
 #define	PS_STRINGS	(USRSTACK - sizeof(struct ps_strings))
+#define	PROC_PS_STRINGS(p)	((p)->p_sysent->sv_psstrings)
 
 int exec_map_first_page(struct image_params *);        
 void exec_unmap_first_page(struct image_params *);       



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