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From def2d2aebad1a6d1b149780181943e0cafa63bdc Mon Sep 17 00:00:00 2001
From: Mathieu Parent <Mathieu.PARENT@nantesmetropole.fr>
Date: Tue, 8 Mar 2016 16:56:50 +0100
Subject: [PATCH 1/3] createOutputFile: rename already existing file

See https://bugs.debian.org/734688

Closes #23

Upstream-commit: fc1c3eff61edf8e9f0a4bfa980f3a6030a6b271f
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
 logrotate.c            | 20 ++++++++++++++++++--
 test/test              | 26 ++++++++++++++++++++++++++
 test/test-config.72.in |  7 +++++++
 3 files changed, 51 insertions(+), 2 deletions(-)
 create mode 100644 test/test-config.72.in

diff --git a/logrotate.c b/logrotate.c
index f13d140..976210e 100644
--- a/logrotate.c
+++ b/logrotate.c
@@ -395,8 +395,24 @@ static int runScript(struct logInfo *log, char *logfn, char *script)
 int createOutputFile(char *fileName, int flags, struct stat *sb, acl_type acl, int force_mode)
 {
     int fd;
-	struct stat sb_create;
-	int acl_set = 0;
+    struct stat sb_create;
+    int acl_set = 0;
+
+    if (stat(fileName, &sb_create) == 0) {
+	/* the destination file already exists, while it should not */
+	struct tm now = *localtime(&nowSecs);
+	size_t fileName_size = strlen(fileName);
+	char* backupName = alloca(fileName_size + sizeof("-YYYYMMDDHH.backup"));
+	strncpy(backupName, fileName, fileName_size);
+	size_t date_size=strftime(backupName+fileName_size, 12, "-%Y%m%d%H", &now);
+	strncpy(backupName+fileName_size+date_size, ".backup\0", 8);
+	message(MESS_ERROR, "destination %s already exists, renaming to %s\n", fileName, backupName);
+	if (rename(fileName, backupName) != 0) {
+	    message(MESS_ERROR, "error renaming already existing output file %s to %s: %s\n",
+		    fileName, backupName, strerror(errno));
+	    return -1;
+	}
+    }
 
 	fd = open(fileName, (flags | O_EXCL | O_NOFOLLOW),
 		(S_IRUSR | S_IWUSR) & sb->st_mode);
diff --git a/test/test b/test/test
index bcdfe05..b47ac6a 100755
--- a/test/test
+++ b/test/test
@@ -1586,6 +1586,32 @@ EOF
 rm -rf testdir adir
 rm -rf testdir bdir
 
+cleanup 72
+
+# ------------------------------- Test 72 ------------------------------------
+preptest test.log 72 2
+
+$RLR test-config.72 --force
+
+checkoutput <<EOF
+test.log 0
+test.log.1 0 zero
+test.log.2.gz 1 first
+EOF
+
+echo 'unexpected' > test.log.1.gz
+
+$RLR test-config.72 --force
+dt="$(date +%Y%m%d%H)"
+
+checkoutput <<EOF
+test.log 0
+test.log.1 0
+test.log.1.gz-$dt.backup 0 unexpected
+test.log.2.gz 1 zero
+test.log.3.gz 1 first
+EOF
+
 cleanup 73
 
 # ------------------------------- Test 73 ------------------------------------
diff --git a/test/test-config.72.in b/test/test-config.72.in
new file mode 100644
index 0000000..9fe50a2
--- /dev/null
+++ b/test/test-config.72.in
@@ -0,0 +1,7 @@
+&DIR&/test.log {
+    daily
+    rotate 3
+    compress
+    delaycompress
+    create
+}
-- 
2.17.2


From 1fa3ff8477d3766f0cc39631ace8c63ee99a1974 Mon Sep 17 00:00:00 2001
From: Kamil Dudka <kdudka@redhat.com>
Date: Mon, 17 Oct 2016 17:59:31 +0200
Subject: [PATCH 2/3] createOutputFile: eliminate stat/open TOCTOU race

Upstream-commit: aff4a30807218a52b6b5f200c5aa0eea335547ba
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
 logrotate.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/logrotate.c b/logrotate.c
index 976210e..fdc81ac 100644
--- a/logrotate.c
+++ b/logrotate.c
@@ -394,11 +394,18 @@ static int runScript(struct logInfo *log, char *logfn, char *script)
 
 int createOutputFile(char *fileName, int flags, struct stat *sb, acl_type acl, int force_mode)
 {
-    int fd;
+    int fd = -1;
     struct stat sb_create;
     int acl_set = 0;
+    int i;
+
+    for (i = 0; i < 2; ++i) {
+	fd = open(fileName, (flags | O_EXCL | O_NOFOLLOW),
+		(S_IRUSR | S_IWUSR) & sb->st_mode);
+
+	if ((fd >= 0) || (errno != EEXIST))
+	    break;
 
-    if (stat(fileName, &sb_create) == 0) {
 	/* the destination file already exists, while it should not */
 	struct tm now = *localtime(&nowSecs);
 	size_t fileName_size = strlen(fileName);
@@ -412,11 +419,9 @@ int createOutputFile(char *fileName, int flags, struct stat *sb, acl_type acl, i
 		    fileName, backupName, strerror(errno));
 	    return -1;
 	}
+	/* existing file renamed, try it once again */
     }
 
-	fd = open(fileName, (flags | O_EXCL | O_NOFOLLOW),
-		(S_IRUSR | S_IWUSR) & sb->st_mode);
-
     if (fd < 0) {
 	message(MESS_ERROR, "error creating output file %s: %s\n",
 		fileName, strerror(errno));
-- 
2.20.1


From 86d67f5769575104add7846b822069008c912b3c Mon Sep 17 00:00:00 2001
From: Kamil Dudka <kdudka@redhat.com>
Date: Mon, 17 Oct 2016 18:13:32 +0200
Subject: [PATCH 3/3] createOutputFile: improve code readability

Upstream-commit: 5ecd908033a481c1e127ba583697d6662ffea4a3
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
 logrotate.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/logrotate.c b/logrotate.c
index fdc81ac..5b0df30 100644
--- a/logrotate.c
+++ b/logrotate.c
@@ -409,14 +409,24 @@ int createOutputFile(char *fileName, int flags, struct stat *sb, acl_type acl, i
 	/* the destination file already exists, while it should not */
 	struct tm now = *localtime(&nowSecs);
 	size_t fileName_size = strlen(fileName);
-	char* backupName = alloca(fileName_size + sizeof("-YYYYMMDDHH.backup"));
-	strncpy(backupName, fileName, fileName_size);
-	size_t date_size=strftime(backupName+fileName_size, 12, "-%Y%m%d%H", &now);
-	strncpy(backupName+fileName_size+date_size, ".backup\0", 8);
-	message(MESS_ERROR, "destination %s already exists, renaming to %s\n", fileName, backupName);
+	size_t buf_size = fileName_size + sizeof("-YYYYMMDDHH.backup");
+	char *backupName = alloca(buf_size);
+	char *ptr = backupName;
+
+	/* construct backupName starting with fileName */
+	strcpy(ptr, fileName);
+	ptr += fileName_size;
+	buf_size -= fileName_size;
+
+	/* append the -YYYYMMDDHH time stamp and the .backup suffix */
+	ptr += strftime(ptr, buf_size, "-%Y%m%d%H", &now);
+	strcpy(ptr, ".backup");
+
+	message(MESS_ERROR, "destination %s already exists, renaming to %s\n",
+		fileName, backupName);
 	if (rename(fileName, backupName) != 0) {
-	    message(MESS_ERROR, "error renaming already existing output file %s to %s: %s\n",
-		    fileName, backupName, strerror(errno));
+	    message(MESS_ERROR, "error renaming already existing output file"
+		    " %s to %s: %s\n", fileName, backupName, strerror(errno));
 	    return -1;
 	}
 	/* existing file renamed, try it once again */
-- 
2.20.1