From cdeb90515b67fcb70c230ebdf02bb7acca329afe Mon Sep 17 00:00:00 2001
From: Benno Schulenberg <bensberg@justemail.net>
Date: Tue, 9 Feb 2016 20:53:11 +0000
Subject: [PATCH] Checking the result of a stat() to avoid referencing
unitialized data. The original patch was by Kamil Dudka.
git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@5621 35c25a1d-7b9e-4130-9fde-d3aeb78583b8
---
ChangeLog | 5 +++++
src/files.c | 34 ++++++++++++++++++++--------------
2 files changed, 25 insertions(+), 14 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 4c017e58..a6963108 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2016-02-09 Benno Schulenberg <bensberg@justemail.net>
+ * src/files.c (stat_with_alloc, open_buffer, write_file): Check the
+ result of a stat() to avoid referencing unitialized data. Original
+ patch was by Kamil Dudka.
+
2016-02-07 Benno Schulenberg <bensberg@justemail.net>
* src/files.c (update_poshistory): Don't put files in the history list
when they have the default cursor position (line 1, column 1).
diff --git a/src/files.c b/src/files.c
index ae4f2be1..52ec6349 100644
--- a/src/files.c
+++ b/src/files.c
@@ -383,6 +383,20 @@ int do_lockfile(const char *filename)
return retval;
}
+
+/* Perform a stat call on the given filename, allocating a stat struct
+ * if necessary. On success, *pstat points to the stat's result. On
+ * failure, *pstat is freed and made NULL. */
+void stat_with_alloc(const char *filename, struct stat **pstat)
+{
+ if (*pstat == NULL)
+ *pstat = (struct stat *)nmalloc(sizeof(struct stat));
+
+ if (stat(filename, *pstat) != 0) {
+ free(*pstat);
+ *pstat = NULL;
+ }
+}
#endif /* !NANO_TINY */
/* If it's not "", filename is a file to open. We make a new buffer, if
@@ -466,11 +480,8 @@ bool open_buffer(const char *filename, bool undoable)
if (rc > 0) {
read_file(f, rc, filename, undoable, new_buffer);
#ifndef NANO_TINY
- if (openfile->current_stat == NULL) {
- openfile->current_stat =
- (struct stat *)nmalloc(sizeof(struct stat));
- stat(filename, openfile->current_stat);
- }
+ if (openfile->current_stat == NULL)
+ stat_with_alloc(filename, &openfile->current_stat);
#endif
}
@@ -1801,10 +1812,8 @@ bool write_file(const char *name, FILE *f_open, bool tmp, append_type
* specified it interactively), stat and save the value now,
* or else we will chase null pointers when we do modtime checks,
* preserve file times, and so on, during backup. */
- if (openfile->current_stat == NULL && !tmp && realexists) {
- openfile->current_stat = (struct stat *)nmalloc(sizeof(struct stat));
- stat(realname, openfile->current_stat);
- }
+ if (openfile->current_stat == NULL && !tmp && realexists)
+ stat_with_alloc(realname, &openfile->current_stat);
/* We backup only if the backup toggle is set, the file isn't
* temporary, and the file already exists. Furthermore, if we
@@ -2181,12 +2190,9 @@ bool write_file(const char *name, FILE *f_open, bool tmp, append_type
}
#ifndef NANO_TINY
- /* Update current_stat to reference the file as it is now. */
- if (openfile->current_stat == NULL)
- openfile->current_stat =
- (struct stat *)nmalloc(sizeof(struct stat));
if (!openfile->mark_set)
- stat(realname, openfile->current_stat);
+ /* Get or update the stat info to reflect the current state. */
+ stat_with_alloc(realname, &openfile->current_stat);
#endif
statusbar(P_("Wrote %lu line", "Wrote %lu lines",
--
GitLab