git: e96ecc712e85 - stable/15 - bin/sh: Fix history long line truncation/corruption

The branch stable/15 has been updated by jilles:

URL: https://cgit.FreeBSD.org/src/commit/?id=e96ecc712e85af65a728f70a84ca46df7c8a5d67

commit e96ecc712e85af65a728f70a84ca46df7c8a5d67
Author:     Kristofer Peterson <[email protected]>
AuthorDate: 2026-02-16 15:53:47 +0000
Commit:     Jilles Tjoelker <[email protected]>
CommitDate: 2026-08-03 21:37:37 +0000

    bin/sh: Fix history long line truncation/corruption
    
    When reading from standard input with editline history enabled, increase
    buffer size to accomodate long lines so that history is recorded
    correctly. Cleanup el_gets() handling avoiding potentially dangerous
    retention of pointers to editline buffers across calls.  Ensure struct
    parsefile objects are properly zero initialised when created. Remove
    push argument from setinputstring() and simplify logic as it was always
    called with a value of one and as was written was potentially dangerous
    if ever called with a value of zero.
    
    This commit does not fix long lines when history is enabled but editing
    is not (e.g. if there is no terminal).
    
    MFC after:      3 weeks
    Pull Request:   https://github.com/freebsd/freebsd-src/pull/2028
    Signed-off-by: Kristofer Peterson <[email protected]>
    (cherry picked from commit 95e4fce8f0c4fc6bf828288b1d63faf0f1300198)
---
 bin/sh/eval.c   |   2 +-
 bin/sh/input.c  | 146 ++++++++++++++++++++++++++++----------------------------
 bin/sh/input.h  |   2 +-
 bin/sh/parser.c |   4 +-
 4 files changed, 76 insertions(+), 78 deletions(-)

diff --git a/bin/sh/eval.c b/bin/sh/eval.c
index fdc7a2560694..466193e20bb2 100644
--- a/bin/sh/eval.c
+++ b/bin/sh/eval.c
@@ -151,7 +151,7 @@ evalstring(const char *s, int flags)
 	flags &= ~EV_EXIT;
 	any = 0;
 	setstackmark(&smark);
-	setinputstring(s, 1);
+	setinputstring(s);
 	while ((n = parsecmd(0)) != NEOF) {
 		if (n != NULL && !nflag) {
 			if (flags_exit && preadateof())
diff --git a/bin/sh/input.c b/bin/sh/input.c
index 26f233ebf7b6..64bbae04149b 100644
--- a/bin/sh/input.c
+++ b/bin/sh/input.c
@@ -79,6 +79,7 @@ struct parsefile {
 	int lleft;		/* number of lines left in this buffer */
 	const char *nextc;	/* next char in buffer */
 	char *buf;		/* input buffer */
+	size_t bufsize;		/* input buffer size */
 	struct strpush *strpush; /* for pushing strings at this level */
 	struct strpush basestrpush; /* so pushing one is fast */
 };
@@ -91,7 +92,8 @@ const char *parsenextc;		/* copy of parsefile->nextc */
 static char basebuf[BUFSIZ + 1];/* buffer for top level input file */
 static struct parsefile basepf = {	/* top level input file */
 	.nextc = basebuf,
-	.buf = basebuf
+	.buf = basebuf,
+	.bufsize = sizeof(basebuf),
 };
 static struct parsefile *parsefile = &basepf;	/* current input file */
 int whichprompt;		/* 1 == PS1, 2 == PS2 */
@@ -125,52 +127,61 @@ static int
 preadfd(void)
 {
 	int nr;
-	parsenextc = parsefile->buf;
 
 retry:
 #ifndef NO_HISTORY
 	if (parsefile->fd == 0 && el) {
-		static const char *rl_cp;
-		static int el_len;
-
-		if (rl_cp == NULL) {
-			el_resize(el);
-			rl_cp = el_gets(el, &el_len);
-		}
-		if (rl_cp == NULL)
-			nr = el_len == 0 ? 0 : -1;
-		else {
-			nr = el_len;
-			if (nr > BUFSIZ)
-				nr = BUFSIZ;
-			memcpy(parsefile->buf, rl_cp, nr);
-			if (nr != el_len) {
-				el_len -= nr;
-				rl_cp += nr;
-			} else
-				rl_cp = NULL;
+		const char *line;
+
+		el_resize(el);
+		line = el_gets(el, &nr);
+		if (nr > 0 && parsefile->bufsize < (size_t)nr + 1) {
+			size_t bufsize;
+
+			INTOFF;
+			if (parsefile->buf != basebuf) {
+				ckfree(parsefile->buf);
+				parsefile->buf = NULL;
+				parsefile->bufsize = 0;
+			}
+			bufsize = (size_t)nr + BUFSIZ + 1;
+			bufsize -= bufsize % BUFSIZ;
+			parsefile->buf = ckmalloc(bufsize);
+			parsefile->bufsize = bufsize;
+			INTON;
 		}
+		if (nr > 0 && line != NULL)
+			memcpy(parsefile->buf, line, nr);
+		else
+			nr = nr ? -1 : 0;
 	} else
 #endif
-		nr = read(parsefile->fd, parsefile->buf, BUFSIZ);
-
-	if (nr <= 0) {
-                if (nr < 0) {
-                        if (errno == EINTR)
-                                goto retry;
-                        if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
-                                int flags = fcntl(0, F_GETFL, 0);
-                                if (flags >= 0 && flags & O_NONBLOCK) {
-                                        flags &=~ O_NONBLOCK;
-                                        if (fcntl(0, F_SETFL, flags) >= 0) {
-						out2fmt_flush("sh: turning off NDELAY mode\n");
-                                                goto retry;
-                                        }
-                                }
-                        }
+	nr = read(parsefile->fd, parsefile->buf, parsefile->bufsize - 1);
+
+	if (nr < 0)
+		switch (errno) {
+			int flags;
+
+		case EINTR:
+			goto retry;
+		case EWOULDBLOCK:
+			if (parsefile->fd != 0)
+				break;
+			if ((flags = fcntl(0, F_GETFL, 0)) < 0)
+				break;
+			if (!(flags & O_NONBLOCK))
+				break;
+			if (fcntl(0, F_SETFL, flags & ~O_NONBLOCK) < 0)
+				break;
+			out2fmt_flush("sh: turning off NDELAY mode\n");
+			goto retry;
                 }
-                nr = -1;
-	}
+	else if (nr > 0)
+		parsefile->buf[nr] = '\0';
+	else
+		nr = -1;
+
+	parsenextc = parsefile->buf;
 	return nr;
 }
 
@@ -187,7 +198,8 @@ retry:
 int
 preadbuffer(void)
 {
-	char *p, *q, *r, *end;
+	const char *end;
+	char *q, *r;
 	char savec;
 
 	while (parsefile->strpush) {
@@ -206,31 +218,22 @@ preadbuffer(void)
 		return PEOF;
 
 again:
-	if (parselleft <= 0) {
-		if ((parselleft = preadfd()) == -1) {
-			parselleft = parsenleft = EOF_NLEFT;
-			return PEOF;
-		}
+	if (parselleft <= 0 && (parselleft = preadfd()) == -1) {
+		parselleft = parsenleft = EOF_NLEFT;
+		return (PEOF);
 	}
-
-	p = parsefile->buf + (parsenextc - parsefile->buf);
-	end = p + parselleft;
-	*end = '\0';
-	q = strchrnul(p, '\n');
-	if (q != end && *q == '\0') {
+	end = parsenextc + parselleft;
+	q = strchrnul(parsenextc, '\n');
+	if (*q == '\0' && q != end) {
 		/* delete nul characters */
-		for (r = q; q != end; q++) {
+		for (r = q++; q != end; q++)
 			if (*q != '\0')
 				*r++ = *q;
-		}
-		parselleft -= end - r;
-		if (parselleft == 0)
-			goto again;
-		end = p + parselleft;
-		*end = '\0';
-		q = strchrnul(p, '\n');
+		*r = '\0';
+		parselleft = r - parsenextc;
+		goto again;
 	}
-	if (q == end) {
+	if (*q == '\0') {
 		parsenleft = parselleft;
 		parselleft = 0;
 	} else /* *q == '\n' */ {
@@ -305,7 +308,7 @@ pushstring(const char *s, int len, struct alias *ap)
 	INTOFF;
 /*out2fmt_flush("*** calling pushstring: %s, %d\n", s, len);*/
 	if (parsefile->strpush) {
-		sp = ckmalloc(sizeof (struct strpush));
+		sp = ckmalloc(sizeof(struct strpush));
 		sp->prev = parsefile->strpush;
 		parsefile->strpush = sp;
 	} else
@@ -389,15 +392,15 @@ setinputfile(const char *fname, int push, int verify)
 void
 setinputfd(int fd, int push)
 {
-	if (push) {
+	if (push)
 		pushfile();
-		parsefile->buf = ckmalloc(BUFSIZ + 1);
-	}
 	if (parsefile->fd > 0)
 		close(parsefile->fd);
 	parsefile->fd = fd;
-	if (parsefile->buf == NULL)
+	if (parsefile->buf == NULL) {
 		parsefile->buf = ckmalloc(BUFSIZ + 1);
+		parsefile->bufsize = BUFSIZ + 1;
+	}
 	parselleft = parsenleft = 0;
 	plinno = 1;
 }
@@ -408,14 +411,12 @@ setinputfd(int fd, int push)
  */
 
 void
-setinputstring(const char *string, int push)
+setinputstring(const char *string)
 {
 	INTOFF;
-	if (push)
-		pushfile();
+	pushfile();
 	parsenextc = string;
 	parselleft = parsenleft = strlen(string);
-	parsefile->buf = NULL;
 	plinno = 1;
 	INTON;
 }
@@ -432,15 +433,12 @@ pushfile(void)
 {
 	struct parsefile *pf;
 
+	pf = (struct parsefile *)ckmalloc(sizeof(struct parsefile));
+	*pf = (struct parsefile){ .prev = parsefile, .fd = -1 };
 	parsefile->nleft = parsenleft;
 	parsefile->lleft = parselleft;
 	parsefile->nextc = parsenextc;
 	parsefile->linno = plinno;
-	pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
-	pf->prev = parsefile;
-	pf->fd = -1;
-	pf->strpush = NULL;
-	pf->basestrpush.prev = NULL;
 	parsefile = pf;
 }
 
diff --git a/bin/sh/input.h b/bin/sh/input.h
index 8cf4df1e4044..f98b592c4c6b 100644
--- a/bin/sh/input.h
+++ b/bin/sh/input.h
@@ -52,7 +52,7 @@ void pungetc(void);
 void pushstring(const char *, int, struct alias *);
 void setinputfile(const char *, int, int);
 void setinputfd(int, int);
-void setinputstring(const char *, int);
+void setinputstring(const char *);
 void popfile(void);
 struct parsefile *getcurrentfile(void);
 void popfilesupto(struct parsefile *);
diff --git a/bin/sh/parser.c b/bin/sh/parser.c
index 0c1b7a91c257..68d4238c00ad 100644
--- a/bin/sh/parser.c
+++ b/bin/sh/parser.c
@@ -1165,7 +1165,7 @@ parsebackq(char *out, struct nodelist **pbqlist,
 		INTOFF;
 		ostr = ckmalloc(olen);
 		memcpy(ostr, stackblock(), olen);
-		setinputstring(ostr, 1);
+		setinputstring(ostr);
 		INTON;
         }
 	nlpp = pbqlist;
@@ -2244,7 +2244,7 @@ expandstr(const char *ps)
 	if (!setjmp(jmploc.loc)) {
 		handler = &jmploc;
 		parser_temp = NULL;
-		setinputstring(ps, 1);
+		setinputstring(ps);
 		doprompt = 0;
 		readtoken1(pgetc(), DQSYNTAX, NOEOFMARK, 0);
 		if (backquotelist != NULL)