From: Sami Kerola <kerolasa@iki.fi>
Date: Mon, 10 Dec 2018 21:41:19 +0000 (+0000)
Subject: hexdump: fix potential null pointer dereference warnings
X-Git-Tag: v2.34-rc1~185^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=577bb86f5b0662ac81699580b55b5a4b11611f01;p=thirdparty%2Futil-linux.git

hexdump: fix potential null pointer dereference warnings

First three fixes on lines 133, 151, and 280 are cosmetic.  Because there
was unobvious null check compiler thought variable might be null, and warned
when after pointer adjustment it was followed without null check.  Perhaps
this will not happen sometime in future when compiler is made more smart,
meanwhile lets give better hints to avoid false positive.

The last change addresses issue that is possible, at least in theory.

text-utils/hexdump-parse.c:465:12: warning: potential null pointer
dereference [-Wnull-dereference]

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
---

diff --git a/text-utils/hexdump-parse.c b/text-utils/hexdump-parse.c
index 2b2735bf73..0b460a70d0 100644
--- a/text-utils/hexdump-parse.c
+++ b/text-utils/hexdump-parse.c
@@ -128,8 +128,8 @@ void add_fmt(const char *fmt, struct hexdump *hex)
 		/* If leading digit, repetition count. */
 		if (isdigit(*p)) {
 			savep = p;
-			while (isdigit(*p) && ++p)
-				;
+			while (isdigit(*p))
+				p++;
 			if (!isspace(*p) && *p != '/')
 				badfmt(fmt);
 			/* may overwrite either white space or slash */
@@ -146,8 +146,8 @@ void add_fmt(const char *fmt, struct hexdump *hex)
 		/* byte count */
 		if (isdigit(*p)) {
 			savep = p;
-			while (isdigit(*p) && ++p)
-				;
+			while (isdigit(*p))
+				p++;
 			if (!isspace(*p))
 				badfmt(fmt);
 			tfu->bcnt = atoi(savep);
@@ -261,7 +261,7 @@ void rewrite_rules(struct hexdump_fs *fs, struct hexdump *hex)
 			if (fu->bcnt) {
 				sokay = USEBCNT;
 				/* skip to conversion character */
-				while (++p1 && strchr(spec, *p1))
+				for (p1++; strchr(spec, *p1); p1++)
 					;
 			} else {
 				/* skip any special chars, field width */
@@ -462,6 +462,8 @@ isint:				cs[3] = '\0';
 				fu->reps += (hex->blocksize - fs->bcnt) / fu->bcnt;
 		if (fu->reps > 1 && !list_empty(&fu->prlist)) {
 			pr = list_last_entry(&fu->prlist, struct hexdump_pr, prlist);
+			if (!pr)
+				continue;
 			for (p1 = pr->fmt, p2 = NULL; *p1; ++p1)
 				p2 = isspace(*p1) ? p1 : NULL;
 			if (p2)