From 320ef1bef081b626c2e230740d85e72313fbefca Mon Sep 17 00:00:00 2001
From: Kyle Evans <kevans@FreeBSD.org>
Date: Thu, 1 Oct 2020 19:56:38 +0000
Subject: [PATCH] auxv: partially revert r366207, cast buflen to unsigned int
 as needed

The warning generated pre-r366207 is actually a sign comparison warning:

error: comparison of integers of different signs: 'unsigned long' and 'int'
                        if (strlcpy(buf, execpath, buflen) >= buflen)

Revert parts that affected other lines and just cast this to unsigned int.

The buflen < 0 -> EINVAL has been kept despite no longer serving any
purposes w.r.t. sign-extension because I do believe it's the right thing to
do: "The provided buffer was not the right size for the requested item."

The original warning is confirmed to still be gone with an:
env WARNS=6 make WITHOUT_TESTS=yes.

Reviewed by:	asomers, kib
X-MFC-With:	r366207
Differential Revision:	https://reviews.freebsd.org/D26631
---
 lib/libc/gen/auxv.c | 32 +++++++++++++++-----------------
 1 file changed, 15 insertions(+), 17 deletions(-)

diff --git a/lib/libc/gen/auxv.c b/lib/libc/gen/auxv.c
index 98f2cf4d0ca2..1dbb8ff3c317 100644
--- a/lib/libc/gen/auxv.c
+++ b/lib/libc/gen/auxv.c
@@ -67,8 +67,7 @@ __init_elf_aux_vector(void)
 }
 
 static pthread_once_t aux_once = PTHREAD_ONCE_INIT;
-static int pagesize, osreldate, ncpus, bsdflags;
-static size_t canary_len, pagesizes_len;
+static int pagesize, osreldate, canary_len, ncpus, pagesizes_len, bsdflags;
 static int hwcap_present, hwcap2_present;
 static char *canary, *pagesizes, *execpath;
 static void *ps_strings, *timekeep;
@@ -246,7 +245,6 @@ int
 _elf_aux_info(int aux, void *buf, int buflen)
 {
 	int res;
-	size_t buflen_;
 
 	__init_elf_aux_vector();
 	if (__elf_aux_vector == NULL)
@@ -255,12 +253,11 @@ _elf_aux_info(int aux, void *buf, int buflen)
 
 	if (buflen < 0)
 		return (EINVAL);
-	buflen_ = (size_t)buflen;
 
 	switch (aux) {
 	case AT_CANARY:
-		if (canary != NULL && canary_len >= buflen_) {
-			memcpy(buf, canary, buflen_);
+		if (canary != NULL && canary_len >= buflen) {
+			memcpy(buf, canary, buflen);
 			memset(canary, 0, canary_len);
 			canary = NULL;
 			res = 0;
@@ -273,35 +270,36 @@ _elf_aux_info(int aux, void *buf, int buflen)
 		else if (buf == NULL)
 			res = EINVAL;
 		else {
-			if (strlcpy(buf, execpath, buflen_) >= buflen_)
+			if (strlcpy(buf, execpath, buflen) >=
+			    (unsigned int)buflen)
 				res = EINVAL;
 			else
 				res = 0;
 		}
 		break;
 	case AT_HWCAP:
-		if (hwcap_present && buflen_ == sizeof(u_long)) {
+		if (hwcap_present && buflen == sizeof(u_long)) {
 			*(u_long *)buf = hwcap;
 			res = 0;
 		} else
 			res = ENOENT;
 		break;
 	case AT_HWCAP2:
-		if (hwcap2_present && buflen_ == sizeof(u_long)) {
+		if (hwcap2_present && buflen == sizeof(u_long)) {
 			*(u_long *)buf = hwcap2;
 			res = 0;
 		} else
 			res = ENOENT;
 		break;
 	case AT_PAGESIZES:
-		if (pagesizes != NULL && pagesizes_len >= buflen_) {
-			memcpy(buf, pagesizes, buflen_);
+		if (pagesizes != NULL && pagesizes_len >= buflen) {
+			memcpy(buf, pagesizes, buflen);
 			res = 0;
 		} else
 			res = ENOENT;
 		break;
 	case AT_PAGESZ:
-		if (buflen_ == sizeof(int)) {
+		if (buflen == sizeof(int)) {
 			if (pagesize != 0) {
 				*(int *)buf = pagesize;
 				res = 0;
@@ -311,7 +309,7 @@ _elf_aux_info(int aux, void *buf, int buflen)
 			res = EINVAL;
 		break;
 	case AT_OSRELDATE:
-		if (buflen_ == sizeof(int)) {
+		if (buflen == sizeof(int)) {
 			if (osreldate != 0) {
 				*(int *)buf = osreldate;
 				res = 0;
@@ -321,7 +319,7 @@ _elf_aux_info(int aux, void *buf, int buflen)
 			res = EINVAL;
 		break;
 	case AT_NCPUS:
-		if (buflen_ == sizeof(int)) {
+		if (buflen == sizeof(int)) {
 			if (ncpus != 0) {
 				*(int *)buf = ncpus;
 				res = 0;
@@ -331,7 +329,7 @@ _elf_aux_info(int aux, void *buf, int buflen)
 			res = EINVAL;
 		break;
 	case AT_TIMEKEEP:
-		if (buflen_ == sizeof(void *)) {
+		if (buflen == sizeof(void *)) {
 			if (timekeep != NULL) {
 				*(void **)buf = timekeep;
 				res = 0;
@@ -341,14 +339,14 @@ _elf_aux_info(int aux, void *buf, int buflen)
 			res = EINVAL;
 		break;
 	case AT_BSDFLAGS:
-		if (buflen_ == sizeof(int)) {
+		if (buflen == sizeof(int)) {
 			*(int *)buf = bsdflags;
 			res = 0;
 		} else
 			res = EINVAL;
 		break;
 	case AT_PS_STRINGS:
-		if (buflen_ == sizeof(void *)) {
+		if (buflen == sizeof(void *)) {
 			if (ps_strings != NULL) {
 				*(void **)buf = ps_strings;
 				res = 0;