From 5da4e529a22ad8e3b1148fa35325d7e5e9f5fcff Mon Sep 17 00:00:00 2001
From: Pierre Pronchery <khorben@defora.org>
Date: Sun, 28 Jan 2018 19:54:38 +0100
Subject: [PATCH] Take better care of permissions when copying

This is now better enforced for files, fifos and directories.
---
 src/cp.c | 39 +++++++++++++++++++++++----------------
 1 file changed, 23 insertions(+), 16 deletions(-)

diff --git a/src/cp.c b/src/cp.c
index f056e52..d93fc26 100644
--- a/src/cp.c
+++ b/src/cp.c
@@ -92,10 +92,11 @@ static int _cp_confirm(char const * message)
 
 /* _cp_single
  * XXX TOCTOU all over the place (*stat) but seem impossible to avoid */
-static int _cp_single_dir(Prefs * prefs, char const * src, char const * dst);
-static int _cp_single_fifo(char const * dst);
+static int _cp_single_dir(Prefs * prefs, char const * src, char const * dst,
+		mode_t mode);
+static int _cp_single_fifo(char const * dst, mode_t mode);
 static int _cp_single_symlink(char const * src, char const * dst);
-static int _cp_single_regular(char const * src, char const * dst);
+static int _cp_single_regular(char const * src, char const * dst, mode_t mode);
 static int _cp_single_p(char const * dst, struct stat * st);
 
 static int _cp_single(Prefs * prefs, char const * src, char const * dst)
@@ -125,13 +126,13 @@ static int _cp_single(Prefs * prefs, char const * src, char const * dst)
 			return _cp_error(dst, 1);
 	}
 	if(S_ISDIR(st.st_mode))
-		ret = _cp_single_dir(prefs, src, dst);
+		ret = _cp_single_dir(prefs, src, dst, st.st_mode & 0777);
 	else if(S_ISFIFO(st.st_mode))
-		ret = _cp_single_fifo(dst);
+		ret = _cp_single_fifo(dst, st.st_mode & 0666);
 	else if(S_ISLNK(st.st_mode))
 		ret = _cp_single_symlink(src, dst);
 	else
-		ret = _cp_single_regular(src, dst);
+		ret = _cp_single_regular(src, dst, st.st_mode & 0777);
 	if(ret != 0)
 		return ret;
 	if(*prefs & CP_PREFS_p) /* XXX TOCTOU */
@@ -140,18 +141,20 @@ static int _cp_single(Prefs * prefs, char const * src, char const * dst)
 }
 
 /* single_dir */
-static int _cp_single_recurse(Prefs * prefs, char const * src,
-		char const * dst);
+static int _cp_single_recurse(Prefs * prefs, char const * src, char const * dst,
+		mode_t mode);
 
-static int _cp_single_dir(Prefs * prefs, char const * src, char const * dst)
+static int _cp_single_dir(Prefs * prefs, char const * src, char const * dst,
+		mode_t mode)
 {
 	if(*prefs & CP_PREFS_R)
-		return _cp_single_recurse(prefs, src, dst);
+		return _cp_single_recurse(prefs, src, dst, mode);
 	fprintf(stderr, "%s%s%s", "cp: ", src, ": Omitting directory\n");
 	return 0;
 }
 
-static int _cp_single_recurse(Prefs * prefs, char const * src, char const * dst)
+static int _cp_single_recurse(Prefs * prefs, char const * src, char const * dst,
+		mode_t mode)
 {
 	int ret = 0;
 	Prefs prefs2 = *prefs;
@@ -163,7 +166,7 @@ static int _cp_single_recurse(Prefs * prefs, char const * src, char const * dst)
 	char * sdst = NULL;
 	char * p;
 
-	if(mkdir(dst, 0777) != 0 && errno != EEXIST)
+	if(mkdir(dst, mode) != 0 && errno != EEXIST)
 		return _cp_error(dst, 1);
 	srclen = strlen(src);
 	dstlen = strlen(dst);
@@ -198,9 +201,9 @@ static int _cp_single_recurse(Prefs * prefs, char const * src, char const * dst)
 	return ret;
 }
 
-static int _cp_single_fifo(char const * dst)
+static int _cp_single_fifo(char const * dst, mode_t mode)
 {
-	if(mkfifo(dst, 0666) != 0)
+	if(mkfifo(dst, mode) != 0)
 		return _cp_error(dst, 1);
 	return 0;
 }
@@ -218,19 +221,23 @@ static int _cp_single_symlink(char const * src, char const * dst)
 	return 0;
 }
 
-static int _cp_single_regular(char const * src, char const * dst)
+static int _cp_single_regular(char const * src, char const * dst, mode_t mode)
 {
 	int ret = 0;
 	FILE * fsrc;
+	int fd;
 	FILE * fdst;
 	char buf[BUFSIZ];
 	size_t size;
 
 	if((fsrc = fopen(src, "r")) == NULL)
 		return _cp_error(src, 1);
-	if((fdst = fopen(dst, "w")) == NULL)
+	if((fd = open(dst, O_WRONLY | O_CREAT | O_TRUNC, mode)) < 0
+			|| (fdst = fdopen(fd, "w")) == NULL)
 	{
 		ret = _cp_error(dst, 1);
+		if(fd >= 0)
+			close(fd);
 		fclose(fsrc);
 		return ret;
 	}